Merino Wool 2020: The Definitive Guide

Merino Wool 2020: The Definitive Guide

by Kyle Barraclough

This is a long guide packed with more information than any other single wool guide on the internet. Read from the beginning or jump to what interests you by using our easy-to-follow links:

      Merino Wool: A Great Fiber? Or, the GREATEST Fiber?


      From lasting elegance to performance, nothing manifests the perfection of evolution better than wool from Merino sheep. Thanks to innovations in textile technology, these benefits can now be found in lightweight garments with next-to-skin comfort. Hot, heavy & itchy wool is a thing of the past.

      In plain language, this wool guide summarizes scientific studies to answer all the “How’s” & “Why’s” of new wool. Comparisons to common clothing fibers (e.g. cotton, polyester & nylon) are also used to support the science and are included throughout the guide.

      Without exaggeration, Merino...

      • Never smells of body odor
      • Resists wrinkles
      • Can be comfortably worn in summer and winter
      • Is quick-drying
      • Can be machine washed
      • Fights harmful ultraviolet (UV) light
      • Resists staining
      • Is flame resistant

      Microscopic Merino

      The secret to these capabilities is found at the microscopic level. The physical structure and chemical composition of the wool fiber are the foundation of the natural performance characteristics. The image below is referred to many times in this article.

      Merino wool fiber structure is the secret to the unbeatable performance capabilities such as: odor resistance, wrinkle resistance, UV resistance, stain resistance, body temperature or thermoregulation, moisture wicking and many more.


      Many travelers consider wrinkle resistance as their number one criteria for travel clothing. But, it isn’t just about looking good after sitting in a plane for 5-10 hours. A fabric’s resilience is also an indicator of user comfort and longevity.

      Comfort in that the wearer knows they will look much better after that 10-hour flight than if another type of travel clothing were worn. By comparison, cotton and many other fabrics, look like they were pulled out of a pile on the floor after even a short flight.

      Garment longevity and durability are indicated by the bending and recovery of the fibers without stretching from repeated use. Obviously, if the fibers did not recover, the garment’s appearance would be adversely affected. But, beyond appearance there is utility. If the stress causes enough stretching, the garment can literally fail and be rendered unusable.

      Merino vs Manmade vs Synthetic

      Polyester and nylon are common fibers found in technical clothing. While they are very strong, comparable yarns (i.e. same thickness) cannot stretch as far as wool without breaking. To compensate for this, technical apparel brands often add spandex to create an elastic quality. While a combination of synthetic and man-made fibers with spandex can stretch further than wool and provide exceptional durability, they repel moisture instead of absorb which has a negative impact on breathability.

      Merino Advantage

      Merino fiber has natural wrinkle resistance thanks to its alpha helix structure. This structure gives it the elastic properties. The give and take action of hydrogen and covalent disulphide bonds within the helix results in the ability to extend >30% of its length without breaking and then recover. (Wood, e., 2009, tangling with wool, a resource book of information and activities about wool and textiles, agResearch).

      In addition to the alpha helix structure, raw wool is ‘wavy.’ Also called a “crimp,” this pattern creates a spring-like action and adds to the resilience that contributes to the wrinkle-fighting performance. The waves in the diagram are due to the complex internal structure which also creates air spaces resulting in a very soft and ‘springy’ hand feel.

      The Libertad Difference

      Many customers regard Libertad’s wrinkle resistance as the best on the market (Don’t take our word for it, read the reviews!). But, we didn’t invent wool or the button-up collared shirt, so what did we do to maximize this quality that is already naturally present?

      We experimented for 18 months with variations on the only things nature let’s modern technology control:

      1. Yarn diameter. Measured in “microns” (1 micron = .001 inch, or 1/1000 inch).
      2. TPM (Twists per Meter). This is the number of full revolutions in each meter of the yarn.

      For micron, our testing revealed that 18.0 microns was the happy medium between softness and resilience/rigidity. Merino customers know from various brands’ fabric specifications that most Merino activewear is made with yarn between 17.5 and 18.5. Libertad lands right in the middle because 17.5 is so soft that it allows more wrinkling. 18.5 mic performs very well in this category, but it can be a little coarse decreasing the comfort level.

      TPM is where there are endless variations. Some yarns are made up with two smaller yarns. These yarns are given different twist counts before being counter twisted together. Think of a hose, or electrical cord, when it gets twisted and then winds itself together. The big, twisted mess is pretty strong and hard to undo. We do something similar in the yarn manufacturing process, but we control the process to create tension that serves the customer with superior wrinkle resistance and recovery.

      Maintenance While Traveling

      All shirts, regardless of material, wrinkle to some degree. But, the combination of wool’s natural structure and Libertad’s construction, maximize the wrinkle recovery. In other words, after a long day of traveling, many folds in the shirt will relax when hung up overnight allowing for multi-day wear with minimal maintenance.


      For comfort and efficiency, the odor free capability, often incorrectly referred to as antibacterial or antimicrobial, gives Merino a distinct advantage over other types of clothing. It may seem unbelievable that wool is forever odor free when the market is flooded with clothing that claims to be antibacterial or antimicrobial yet begin to collect odor rapidly. But, the secret to Merino’s superiority in this area is again found in the natural structure of the fiber whereas cotton/polyester/nylon/etc. rely on chemical treatments that become less efficacious with each wash.

      What causes body odor?

      Bacteria and microorganisms that are found on the skin. As sweat accumulates, the moisture creates the perfect environment for these molecules to multiply. It is when the bacteria excrete fatty acids as waste that odor builds and becomes detectable to the noses of anyone nearby. There are only two ways to stop this process:

      1. The clothing system must lower the amount of sweat the body produces (BEWARE: On long, hot treks down unexplored paths in foreign destinations, reducing the body-cooling sweat might not be a good idea for the wearers health.)
      2. The clothing system must make the microclimate between the skin and fabric uninhabitable for the bacteria.

      All-Natural Wool vs. Antibacterial Chemical Treatments

      Cotton, polyester, nylon, etc. do not have the natural physical and chemical properties of wool and do not inhibit bacteria growth on their own. Any garment made of these fibers that claims to fight odor uses chemical treatments. And there are two big problems with such chemicals.

      First, there can be environmental issues. There are environmentally neutral treatments, but details on what a brand uses is often not readily available. Any customer concerned about the biological and environmental risks at all stages from fabric production to customer use should direct inquiries to the manufacturer of that garment. (Common chemicals are triclosan, quaternary silanes, polyhexamethylene biguanides, and silver.)

      Second, such treatments lessen with each wash. This is more information that is not promoted by brands, so the customer cannot calculate how long the shirt will be effective. However, it is important to note that the textile and apparel industries consider treatments to be effective for the life of the shirt if it lasts for as few as ten (10) washes. Some treatments may test to have efficacy for up to 25 washes or more. But again, all of them decrease in effectiveness after the first wash until they are completely ineffective.

      Merino to the Rescue

      Exactly how Merino remains odor free is a partial mystery. But, we know that the aforementioned alpha helix and chemical composition of the fiber are involved. The short story is that after water vapor is wicked off the skin and absorbed into the wool, the evaporation of the moisture into the external environment leaves the odorous molecules trapped and neutralized inside the alpha helix. Those bacteria are then washed out in the laundry.

      The unknown aspect is in how the neutralization occurs. It's hypothesized that there may be chemical binding inside the structure (McQueen et all 2007a). As Merino wool’s odor suppression is all-natural and built into the very physical structure, the capability never decreases.

      Odor-Free Travel

      No longer be embarrassed by body odor after a flight. Combined with Merino’s wrinkle resistance, these two capabilities allow for greater efficiency and saved energy. The wearer can truly go all day long without a change of shirt. However, these capabilities do cause some misconceptions about wool clothing systems.

      First, just because it doesn’t stink, doesn’t mean it isn’t dirty. As tempting as it is to avoid the headaches of doing laundry, going too long between washes can cause the garment to look dingy. Additionally, deodorant can build up in the underarm area if it is not cleaned from time to time.

      Second, Merino does not stop perspiration. Sweat is natural and cooling. Preventing the body from maintaining a healthy temperature can negatively affect energy levels and immune function.

      Issues of perspiration and body temperature lead nicely into another area of Merino performance: moisture and the microclimate.


      “Wicking” is the buzzword for any item that pulls moisture off the skin. But, there is a downside to fabric that simply wicks instead of using the moisture to the wearer’s benefit.

      As we already know, the human body excretes moisture (sweat) to reduce skin surface temperature and thereby regulate the core body temperature. If a clothing system does not work symbiotically with the body’s natural cooling system comfort, performance, endurance and immune function can all be negatively impacted. This is where Merino has a significant advantage over other fibers. Wool is naturally hygroscopic which means that its structure has the ability to absorb moisture; transfer the moisture from the inside surface to the outer fabric surface; and then desorb the moisture into the macro-climate.

      In this process, each step has an effect on the body’s surface temperature. First, wool pulls vapor off the surface of the skin and condenses it to liquid inside the structure of the fiber. This vapor transfer has a cooling effect on the skin. Second, the moisture that is stored inside the wool itself acts as a regulating barrier to the variations of humidity in the environment.

      By contrast, other fibers perform what is marketed as “moisture wicking.” They remove the liquid, not vapor, off the skin and then release it into the external environment as vapor. The cooling effect of releasing vapor occurs on the surface of the fabric and not the surface of the skin. Additionally, the fibers do not store much moisture, so there is no regulating barrier created. Therefore, these fibers often keep the skin dry, but the microclimate (i.e. area between skin and garment) temperature is not controlled.

      The bottom line on moisture management vs. moisture wicking is that wool’s multi-function, symbiotic capability is a result of the hygroscopic physical structure. Common moisture wicking fibers like polyester and nylon try to replicate this, but end up only drying quickly which is actually an indicator of their inability to absorb moisture. Fast drying can be attractive in certain applications, but it is a disadvantage in many travel scenarios where there are multiple temperature changes during a single excursion and temperature modulation is needed. The lack of symbiotic function with the body over time increases the possibility of adverse effects on the body’s surface and core temperature.


      Merino is quick-drying, but this is one area where some man-made and synthetic technical textiles may outperform. This may or may not be good news depending on the physiological needs of the wearer in certain environmental conditions.

      Perhaps the best way to compare is by viewing an excellent field test by ( This is a well constructed test as all the garments were comparable in terms of type and weight. Environmental conditions are clearly stated so the test can be replicated and variables accounted for.

      In short, the polyester shirt was faster, but the Merino shirts (100% and blends) all dried in less than an hour. The widest gap between quick-drying polyester and 100% Merino was only 16 minutes.

      The drying speed of polyester is usually due to the inability to absorb moisture. After it wicks moisture off the skin, it releases the sweat into the air. However, as stated in the next section, “Thermoregulation,” Merino absorbs and desorbs moisture which creates and dissipates heat allowing the body’s core temperature to be modulated. Synthetics do not do that and can leave the wearer feeling cold when physical activity ceases and body temperature drops.


      Thermoregulation is the body’s ability to maintain its temperature within a safe range as the external environment changes. Any conditions resulting in the body being too hot or too cold for too long causes discomfort at a minimum and death at a maximum.

      The key players in the body’s thermoregulation process are 1) the skin 2) the brain and 3) the blood vessels. The skin detects environmental changes and communicates them to the brain. The brain then triggers the blood vessels to make the adjustments necessary to keep the body temperature in the ideal range. If the body cannot perform this process, the result is either hypothermia or hyperthermia.

      Clothing Systems and Thermoregulation

      Layering and fabric thickness are common ways clothing systems are used to control body temperature. Simply remove a layer when hot and add a layer when cold. Or, put on heavier/lighter clothing as conditions dictate. The limitation of these methods is that they rely on the wearer to regulate body temperature instead of relying on the body’s physiology.

      Merino Wool and Thermoregulation

      Wool clothing acts symbiotically with the body’s physiology to regulate temperature and relies less on wearer intervention. This is related to the moisture absorption described in the “Moisture Management” section. Essentially, Merino generates and dissipates heat with the absorption and desorption of sweat. In practical terms, Merino clothing warms and cools when the body needs it the most.

      Travel and Rapid Climate Changes

      Travelers need a garment system that is thermoregulating to manage rapid changes of the macro-climate. In the space of a couple of hours an air traveler can be in the humidity of a big city; cold airport air conditioning; a pressurized aircraft at 35,000 feet; a high altitude destination. These types of changes put stress on the body’s core temperature which can affect the energy levels and/or the immune system.

      The Libertad Difference

      Libertad’s innovation in wool was that we introduced to the market the lightest weight, 100% Merino woven fabric. We were the first to achieve 130 grams per square meter (gsm). At this fabric weight we effectively expanded the temperature range in which wool could be comfortably worn. Prior to our fabric, most wearers would agree that woven wool button-up shirts would be too heavy to wear in the heat and humidity. But, by making such a shirt lighter per square meter, we achieved a fabric weight that could comfortably introduce Merino’s thermoregulation to hotter and wetter destinations.


      Prolonged exposure to ultraviolet (UV) radiation can result in uncomfortable sunburns; cause premature aging; and result in skin cancer.

      A fabric, or any substance that has the ability to inhibit UV radiation exposure is rated either by SPF (solar protection factor) or UPF (ultraviolet protection factor). These are measures of the time it takes before damage to the skin begins to occur (usually indicated by redness).

      Merino vs...

      As customers demand more comfort and performance from their clothing, technical apparel manufacturers have responded with chemical treatments; new fabric compositions; and new constructions to compete with the natural advantage Merino has.

      Increasingly, UPF ratings are included in brand marketing material and, sometimes, on the hangtag of the garment. The simple rule of thumb in interpreting this rating is the more radiation that passes through the fabric, the lower the UPF.

      Just like sun creams that have a variable rating between 0-70 UPF (or SPF), textiles are rated on the same scale because not all clothing offers the same protection even though it may seem they do because they cover the body the same way. But, simply covering the skin with clothing does not ensure adequate protection when exposure to sunlight is prolonged.

      Through radiation absorption, Merino protects the wearer across the UV spectrum. By contrast, common apparel fabrics without chemical treatments perform poorly in harmful sections of the spectrum.

      Whether it is wool, cotton, polyester or nylon, some of the factors that influence a garment’s Ultraviolet Protection Factor (UPF) are:

      • Fibre type - The customer must determine if the non-Merino fiber is treated or untreated with UV protection chemicals. Untreated cotton, polyester, nylon, etc. does not offer the same protection as comparable, natural, Merino fabric.
      • Fabric density - Tighter weaves/knits will likely have a higher UPF.
      • Degree of stretch - When stretched, the UPF declines. So, make sure the shirt fits properly and is not in a stretched state when worn.
      • Fabric color - As a rule of thumb, darker colors usually provide greater UPF. However there are mitigating factors such as the amount of dye, the chemical composition of the dye, etc.
      • Moisture level - UPF decreases significantly when the garment is wet.
      • Finishing treatments - These are not to be mistaken with performance chemical treatments. Finishing agents are often used in garments to change the appearance. UV absorbing and/or brightening chemicals may either increase or decrease the UPF rating.
      • Construction - In addition to the weaves and knits mentioned above, fabric weight and design contribute to the UPF rating. Heavier garments usually have higher protection, but any gaps, big or small, will allow radiation to reach the skin.

      NOTE: Even though Merino might have natural UV protection, not all Merino fabrics perform at the same level. Additionally, UV chemical treatments to cotton/poly/nylon/etc. weaken with each washing. UV protection can be increased on all fabrics, including Merino, by using chemical finishes.

      UV Exposure and Travel

      The strength of UV radiation can vary day to day; from season to season; and change according to the geography. Altitude, as well as latitude & longitude, are all critical considerations when devising a clothing system to maximize protection.


      Static electricity in a shirt, hat or other clothing items is annoying and uncomfortable. It can even be dangerous if disrupting electronic equipment (e.g. navigation instruments). In terms of physical safety, the big dangers are in unknown and unstable environments such as where flammable liquids and gases are present.

      Why Does Clothing Generate Static Electricity?

      When two different fabrics brush against each other, a positive charge accumulates on one and a negative on the other. Some fabrics are able to conduct electricity and neutralize the charge, however fabrics that cannot dissipate the charge allow the static to build up and result in an electric shock.

      In addition to friction, other static generating conditions are low environmental humidity and low moisture content in the fabric fibers.

      Merino vs...

      Synthetics such as nylon, polyester and acrylic are particularly susceptible to static electricity build up because they are hydrophobic and do not absorb well. The wicking performance creates low humidity environments where static charges can be generated.

      By contrast, Merino’s wicking process includes storing water vapor inside the fiber structure (i.e. hygroscopic). This reservoir of moisture dissipates the charge creating the anti-static effect. For this reason, wool is used in products designed for sensitive environments (e.g. aircraft carpets, fuel storage, any building with sensitive instruments).


      Flame resistance isn’t often considered when travelers put together their packing list. However, anyone that has ever explored a village and walked through a crowded open air market, knows that safety standards abroad are sometimes nonexistent. Charcoal and fire grills on rickety stands and/or flames shooting out of oil-filled woks are everywhere. Equally a concern, industrial safety standards (e.g. metal, gas, petroleum, etc.) can be unenforced.

      Protection Level Comparison

      All fabrics can burn. However, there are significant differences in the ease/difficulty in catching fire; ignition temperature; rate of burning; and ease/difficulty in putting the fire out. For example, cotton/poly/nylon/rayon all burn at lower temperatures than wool. Polyester and nylon will actually melt on skin before producing a flame.

      As with most of the capabilities described in this guide, any flame resistance claimed by cotton, poly, nylon, rayon garment manufacturers was achieved with chemical additives. On the other hand, wool achieves its considerable resistance naturally and the secret is once again found in the structure and natural chemistry of the fiber. Part of this ability is the high nitrogen level (14%) and moisture level (referred to in sections “Moisture Management” and “Thermoregulation”).

      NOTE: Wool can also be treated with chemicals to enhance flame resistance beyond the natural ability.

      Fiber comparison fast facts:

      • Merino ignites at 570+ degrees Celsius; cotton at 255 C; Nylon & Polyester at 485 C and rayon at 420 C.
      • Wool and cotton generate much lower heat when burning than synthetics.
      • Wool, cotton & rayon do not melt or stick to the skin. Nylon and polyester melt at 160 C and 252 C respectively.
      • If the heat source is removed, ignited wool will go out on its own.
      • Burnt wool will actually form an insulating layer.
      • Wool releases less toxic emissions than the other common clothing fabrics.


      While “stain resistant” is not the same as “stain proof,” all travel clothes can use a little protection when air turbulence splashes coffee or when eating wiggly noodles with chopsticks (just try not to flick the curry onto your shirt!).

      NOTE: Any fabric can stain. Variables include fabric composition; chemical treatments; temperature; duration of contact with substance; method of substance removal; method of washing; etc.

      How can wool be stain resistant if it is hydrophilic and will readily absorb moisture? The answer takes us back to the miraculous alpha helix structure and natural chemical composition. It is true that the inner fiber can absorb between 30-35% of its weight. However, the external layer of the fiber is composed of a wax-like substance that will repel liquid. (Unlike stain-resisting chemical treatments on cotton/poly/nylon/etc., the waxy layer does not easily wash off).

      It must be noted that wool’s ability to repel liquid varies according to fabric construction and the liquid that comes in contact with the surface. For example, lightweight fabric might not be as resistant as a thick wool rug and a wine stain might be worse than an oily curry (i.e. wool tends to perform better against oils than other liquids). Since a stain-resistant rating system is not usually published for apparel fabrics, customers can perform a simple test by placing a few drops of clean water on the garment and measure how long the moisture beads on the surface before being absorbed into the fiber.

      Additionally, the aforementioned static electricity resistance attracts less dust and lint keeping wool clothing a bit cleaner for longer periods.

      Merino Vs….

      This is actually an area where polyester and nylon might perform better than wool. However, the performance would depend on the construction, composition and treatments of the fiber.


      In travel clothing, physical comfort leads to mental comfort when enduring long days on the road. Changing temperatures and altitudes; physical exertion; disruption of the sleep cycle; and many other conditions deplete energy levels and immune systems. This is why travel clothes should be different, or higher functioning, than everyday wear. In the same way as an athlete’s uniform can enhance performance, the right clothing system can protect a traveler.

      Energy Levels

      Central to the physiological benefits of wool clothing are the previously discussed capabilities of thermoregulation and moisture management. Wool aids the body in maintaining core temperature by moving heat and moisture away from the wearer during exertion and insulates the wearer when the body is cooling. Core temperature outside of the optimal range can result in fatigue and decline in immune function.

      Heart Rate

      A study by (Laing et al 2007) showed that a wool t-shirt had positive effects on heart rate compared with a similar polyester t-shirt. Two key findings are:

      1. In hot weather, the wearer of 100% Merino t-shirt showed a lower heart while resting and walking.
      2. In lower temperatures, wearers showed lower heart rate under physical exertion such as running or walking.


      The apparel and textile industries are toxic and wasteful. Whether it is synthetic or natural fibers, there is a lot of blame to go around. Synthetics are made from petrochemicals and heavily pollute water and air. Natural fibers like cotton and wool are responsible for habitat destruction and use excessive amounts of water. That’s just the production side. At the end of the garment life cycle, huge amounts of apparel waste require more energy to dispose of in landfills around the world.
      With these issues in mind, conscientious consumers might well consider buying fewer clothes that last longer. But when it is time to buy, what are the issues surrounding sustainable production that customers can inquire about from their favorite brands?

      Wool Is (can be) Eco-Friendly

      Wool is renewable and biodegradable. On the face of it, that sounds like wool qualifies as environmentally friendly, but being a sustainable fiber actually depends on how it is produced. Mismanagement of land and sheep can result in negatives that outweigh the positives. Conversely, proper management has the potential of making wool the most responsible and ethical fiber in the world.

      Land Management

      It’s a delicate balance between animal and land to operate an industrial sheep farm. Sheep need the land to graze, but can destroy the habitat in so doing if the land is not managed properly. Sheep farmers, in cooperation with local and national governments, seek to graze sheep in a way that keeps the sheep healthy, produces predictable supply while using the land that does not impair its own renewable capability.

      Areas of focus in land management include:

      • Grazing strategies that protect sensitive ecosystems
      • Soil erosion
      • Loss of soil organic matter
      • Toxic/hazardous material use and disposal
      • Fertilizer management
      • Pesticide use
      • Invasive insect, animal and plant species
      • Nutrient deficiencies

      It must be noted that implementing programs to address these issues takes education, time and resources. As a result, development can be slow and/or uneven.

      There are many certifying organizations, but membership is not widespread. Part of the reason for this is that membership might not benefit the sheep farmers as resources and support might be inadequate. Furthermore, textile mills, brands and consumers don’t know who they are and don’t demand the certification from the farmers. If there is no increase in visibility and sales from the certification, there is no financial incentive to pay the membership fee.

      Adding to this dilemma is how the majority of raw wool is purchased by wool mills around the world. Few mills buy wool from a single source. The bales that are shipped from one country to another are usually mixed with wool from multiple farms. They might be further mixed once they arrive at the destination processing facility.

      NOTE: Some fabric is made from single-origin wool, but it is rare. Not quite as rare, but still uncommon, is wool textile from multiple farms from the same geographic area under the same manufacturing standards. That notwithstanding, most fabric is still comprised of wool from multiple farms that may or may not adhere to the same production practices. Under these circumstances, complete traceability isn't possible.

      Conscientious Consumers

      Traceability and supply chain transparency is a constant focus in the wool industry. But, there are significant challenges when there are many different entities across multiple continents involved in the making of just one pair of socks, for example.
      That may sound discouraging at first, but there is good news. There are long-standing, international certifications for the textile industry about which customers can inquire from brands to make sure they are buying a wool garment that meets the current minimum standards.

      Textile Manufacturing Standards & Certifications

      This guide will focus on three certifications that any responsible manufacturer of wool products will have. The first two, Okeo-Tex and Bluesign, can be applied to any textile, not just wool. The non-mulesed certificate is applicable to wool only.

      • Okeo-Tex

      For manufacturing at all levels, from raw materials to the finished fabric, brands should partner with wool mills that continually maintain their qualification for Okeo-Tex Standard 100. This standard is for all textiles and brands should know their manufacturing partners have a current certification.

      From their website, Okeo-Tex defines the standard this way, “The STANDARD 100 by OEKO-TEX® is a worldwide consistent, independent testing and certification system for raw, semi-finished, and finished textile products at all processing levels, as well as accessory materials used…” (

      • Bluesign

      Bluesign is a certification covering each component of the fabric such as dyes and other chemicals. Bluesign defines itself this way, “Each textile product is the result of a comprehensive manufacturing process. Raw materials and many other components are needed for this, such as dyes or chemical auxiliary materials. The bluesign® SYSTEM offers solutions for manufacturers of these components. They can have their production processes and composition of the components tested based on the bluesign® CRITERIA and optimize sustainability. Tested and sustainably produced components are designated as bluesign® APPROVED. Thus, step by step, there are no missing links in sustainable materials and work steps – from the raw material to the finished product.” (

      Brands can verify that their manufacturing partners only use products that qualify. It should be noted that even if some components are Bluesign certified, that doesn’t mean the finished fabric is Bluesign certified.

      Non-Mulesed Wool

      Certified “non-mulesed” is specific to the wool industry and is covered in the “Animal Welfare” section. It is mentioned alongside Okeo-Tex and Bluesign to aid customers in formulating inquiries directed to brands.


      From governments to growers, the wool industry recognizes that improvement is necessary in order to achieve the goal of being the world’s most environmentally sustainable and ethical fiber.

      The International Wool Textile Organization (IWTO) defines proper animal welfare as the sheep having The Five Freedoms:

      1. Freedom from hunger, malnutrition and thirst
      2. Freedom from fear and distress
      3. Freedom from physical and thermal discomfort
      4. Freedom from pain, injury and disease
      5. Freedom to express normal patterns of behavior

      Making improvements in all these areas requires cooperation between government policy makers, various scientific/research institutions, local & federal departments/bureaus and wool growers themselves. In the US, for example, if the federal government decides to protect one species of animal the result can be the reduction of grasslands for commercial sheep to graze. With so many entities involved, it can be difficult to find lasting balance.


      The most controversial issue in sheep welfare is that of mulesing.

      What is mulesing?

      Mulesing is the surgical removal of skin on the buttocks to prevent life-threatening infections caused by flystrike.

      What is flystrike?

      Blowflies are attracted to moist areas on the sheep to lay their eggs. The urine and fecal matter that collects on the wool and skin around the anus is particularly attractive to the flies. The eggs develop into maggots that eat the sheep’s flesh while simultaneously poisoning them with their ammonia secretions. This is a fast acting condition and can result in sheep death as quickly as 3-6 days from the first strike.

      Why is mulesing controversial if it saves the lives of sheep?

      Mulesing is a painful procedure often administered without any anesthesia or other pain reduction medication. The wounds can take several weeks to heal, during which time the sheep are susceptible to infection and flystrike. As such, many regard it as cruel and inhumane. Although it is effective at reducing the incidence of flystrike, it does not eliminate it as blowflies can lay their eggs on other parts of the sheep.

      Additionally, there are alternatives. But, the high costs and effectiveness level of the other methods have not eliminated mulesing as an option for some wool growers.

      What are the alternatives to mulesing?

      • Breeding Strategies

      Wool growers are attempting to breed sheep that do not have wool growing on the skin around the anus. This would eliminate the need for mulesing and, therefore, a long term solution. However, this will take a lot of time and there are millions of sheep that need flystrike prevention and treatment in the interim.

      • Intradermal Technology

      Via needle-less injection, a chemical compound is injected into the skin at the breech of the sheep. The compound breaks down the proteins in the skin leading to a scab that eventually forms a bare area that can be kept clean and dry. One drawback of this approach is that it is only appropriate for older sheep over a certain body weight. Therefore, it is not a solution for lambs.

      • Insecticides

      Certain insecticides have been used as preventative measures with success. However, Blowfly larvae do develop resistance over time. Therefore, this is not a permanent solution.

      • Eliminating the Blowfly

      Analysis of the blowfly genome could reveal opportunities to chemically control their population. Currently, the study continues and a program has not been instituted.

      • Sheep DNA

      Similar to selective breeding, animal scientists are targeting the sheep genome to produce desirable traits to fight flystrike. This effort is relatively new and results are not expected for several years at a minimum.

      • Topical Treatments

      Liquid nitrogen and laser technology seek to create a bare area at the breech. Nitrogen achieves this by damaging skin cells resulting in a scar and reduction in skin wrinkles. Lasers are used to remove hair, but do not appear to be able to prevent wool regrowth when applied at safe levels. Both technologies are continuing development.

      What is the current state of mulesing in the wool industry?

      Mulesing still exists and it is not illegal. However, there is growing pressure on wool producing countries (e.g. Australia, New Zealand) from other countries (e.g. EU), animal rights organizations (e.g. PETA), retailers and consumers that has caused Australia and NZ to significantly increase investment in finding a universally agreed upon alternative. Additionally, new certifying organizations that are gaining international recognition are totally mulesing free.

      How do I buy non-mulesed wool clothing?

      Wool mills have the option of buying non-mulesed wool. This wool comes with a certificate that is available to the brands that purchase wool fabric from the mill. In turn, brands can promote their garments as non-mulesed to their customers. If not readily visible on a website or garment tag, customers can ask brands what kind of wool they used. Any responsible producer will know the answer and will have obtained the non-mulesed certificate from their wool mill.


      Why do all wool clothes have different care instructions?

      Caring for wool garments varies because the processing of raw wool before it gets made into clothing varies greatly from item to item. Basically, clothing made with untreated wool needs more careful handling and is prone to felting and shrinkage. On the other end of the spectrum, much newer Merino wool clothing can be machine washed and, usually, hung to dry.

      Can you machine wash merino wool that says, ‘dry clean only?’

      The safe answer is, ‘no.’ But, there’s good news! Most 100% Merino wool clothing being made today is machine washable. Washability is a relatively recent innovation in textile technology that is partly responsible for the increasing popularity of Merino clothing. But, care instructions vary from item to item, so know what you’re buying.
      If a care label says, ‘dry clean only’ in a world of washable wool, there is probably a very good reason for it. As previously mentioned, wool fibers have microscopic scales that comprise the outer layer. If the garment is made of untreated wool and proper instructions are not followed, the scales can lock together (i.e. felting) resulting in irreversible damage. Wool clothing that cannot be machine washed is usually made of wool with the scales still intact.

      Machine washable wool garments are made of raw wool that has treated the scales so they do not felt after being submerged in water. There are various treatments to make this possible and they can be summarized by two general categories: Descaling and coating.

      1. Descaling. Eliminating/reducing these scales is achieved by applying chemicals, or enzymes, that destroy the scales.
      2. Coating. A less damaging method is to coat the wool with a resin which forms a thin skin over each fiber. This film masks the surface scales, so they can no longer interlock.

      Different manufacturers may use different treatments. Therefore, the conscientious consumer should check with their brand of choice to see if their washable wool was processed according to internationally recognized environmental standards such as Okeo-Tex Standard 100 (see “Okeo-Tex” in the Sustainability & Ethics section for a description of this certification).

      Does Merino Wool Shrink?

      Almost always, yes. The severity of shrinkage depends on how the raw material is treated (see previous section); how it is washed; and how it is dried. Manufacturers don’t often advertise this aspect of their clothing, so an inquiry to the company usually needs to be made. Nevertheless, any responsible brand will have the answer as shrink testing is a standard part of the manufacturing process. (NOTE: Brands know the amount of shrinkage under laboratory conditions. Real world results can vary according to water & air temperature, altitude, etc.).

      Anti-shrink treatments are a part of making machine washable wool. The result of the treatment should be a fiber with increased longevity and durability as well as excellent shape retention. Industry standards for all types of fabrics are < 3% shrinkage after two (2) wash/dry cycles across multiple dimensions of finished garments (see next section “The Libertad Difference” for information on how we exceed industry standards).

      How do you wash Merino wool without shrinking?

      Brands are hesitant to promise “no-shrinking.” It’s almost impossible to achieve and results can vary according to environmental conditions (e.g. temperature, altitude, etc.). However, while not explicitly stated, the instructions on care labels are meant to help clothing maintain shape and reduce shrinkage. So, they should be followed closely.

      Does Merino wool shrink in the dryer?

      Yes, and the amount is unpredictable, so don’t do it unless you want it to shrink.
      A word of caution on intentional shrinking: Wool varies from sheep to sheep, or from one season to the next. Nature is variable. Therefore, two of the same garments from the same brand might shrink differently if not from the same batch (and even sometimes from the same batch!)

      Can you unshrink (i.e. stretch) merino wool?

      This is highly dependent on the clothing item. A knitted sweater or t-shirt might be able to be re-stretched, but a woven button-up Merino shirt cannot. The previously discussed processing methods/treatments have a lot to do with this. But, one factor not mentioned is the knit vs. woven aspect of a garment.

      Sweaters, socks, t-shirts, etc. are all knitted. The pattern that ‘binds’ the yarns together winds and twists building into the garment the ability to stretch like an accordion. Methods of stretching after shrinking (i.e. “unshrink”) vary from manufacturer to manufacturer. But, they all involve re-submerging in water, fabric (or hair) conditioners and manual reshaping.

      Woven items (e.g. plain weave, twill, etc.) usually follow some type of over-under weave that does not have built in stretch. So, when shrinking occurs some amount re-stretching might be achievable at the yarn level, but not much if any.

      The Libertad Difference

      Libertad shirts are intentionally made to shrink less than other 100% Merino shirts. Our standards are higher to make our shirts last longer and impress our customers. Instead of the standard shrink testing after two (2) wash/dry cycles, we make our shirts meet the <3% shrinkage after three (3) wash/dry cycles.

      They can be thrown in a washing machine with standard laundry soap, or in a hotel sink, then hung to dry (a cool, shady spot is recommended). Merino dries quickly on its own, but Libertad is lightweight, so the air dries it even faster. We made it quick and efficient, so our customers can make the most of their travels.

      How do you stop Merino Wool from pilling?

      Pills are the unsightly little balls of fabric on the surface of a garment that appear after some kind of friction with other textiles (usually in the wash).
      Wool is particularly susceptible to pilling because each wool yarn is composed of shorter ‘hairs’ of varying lengths. The short hairs make their way to the surface when agitated and bundle together to make the balls or “pills.”

      The Libertad Difference

      Pilling is not inevitable. During testing, Libertad fabric is subjected to 10,000 rubs. If the fabric pills, it is rejected. If not, it becomes a shirt. Our customers know that no pilling will occur after rubbing on an airplane seat, underneath a sport coat or during washing.


      Merino doesn’t do everything and isn’t for everyone. In this section, we answer the following questions that prospective Merino customers must ask.

      • Why aren’t there any white shirts made out of Merino?
      • Why is Merino wool so expensive?
      • If Merino is so soft, why does it make me itch?
      • I’m allergic to regular wool, will I be allergic to Merino?
      • Why did my Merino shirt get holes in it?
      • Why does my Merino shirt get sopping wet when I sweat?
      • Is Merino wool vegan friendly?

      White Merino Shirts

      The number one request from Merino fans is, “Can you make a white Merino shirt?” Unfortunately, the answer is, “no.”

      Raw wool comes in a range of off-white colors (some are even a little beige). While the fiber takes mid to dark dyes to make luxuriously deep colors, it is totally resistant to light colors; especially white. No matter what is done, whites and pastels will ‘yellow’ sooner than later and sunlight speeds the process. In other words, you can violate every environmental standard on the books by bleaching the heck out of the wool and it still won’t work.

      Merino is Expensive

      There are several reasons why Merino is typically more expensive than other materials. The first reason is consumer demand. Wool’s popularity is rising faster than the supply is growing. Raw wool is bought at auction from the suppliers and it sells out every year. With the expectation that there will be nothing left at the end of the season, wool commands a premium.

      Even Super Soft Merino Makes Some People Itch

      Brands and customers often say Merino is so soft that it doesn’t itch. However, despite having a very soft hand feel, there is an anecdotal estimate that 2-3% of the population find any wool intolerable to wear next to the skin. What causes this discomfort? It’s either a wool allergy or a wool sensitivity.

      People often confuse a wool sensitivity with a wool allergy. Medical professionals indicate that actual wool allergies are very rare with the source being the wool alcohols contained in lanolin. However, it should be noted that recent scientific research questions whether wool allergies are even real and suggest reported skin irritation is caused by outdated processing methods and chemical additives. The studies further hypothesize that modern methods and chemicals would not produce the same skin reactions as in the past. More studies need to be conducted, but the only reality that matters is the comfort of the customer.

      Wool may be soft, but it isn’t as soft as cotton, or as smooth as polyester. The wool fiber has microscopic ‘hairs’ that stick out. You can’t see them or feel them with your fingers, but putting on a shirt does feel different than what many people are used to. For most, this awareness of the difference disappears after wearing for a few minutes and they feel like regular clothes. For a few others, it is a distraction. The latter group could be described as having a wool sensitivity.

      Everyone is different. Some people can wear anything. Yet others can wear wool clothes from one brand, but not other brands. The converse is also true. What is totally comfortable for one is not necessarily for the other.

      NOTE: If concerned about discomfort, layering with a t-shirt will provide comfort while preserving most of the benefits of wearing wool.

      Is Merino Durable?

      Yes and No. Merino and regular wool are very durable and garments can last a long time. But, claims that Merino is stronger than cotton and polyester are only partially true. Considerations of fabric weight (i.e. thickness) and type of strength being measured must be acknowledged.

      First, consider the weight of the fabric. Historically, wool fabric was much thicker and used to make suits, blankets, fireman coats, etc. It was heavy and supremely durable. Lightweight wool (e.g. t-shirts) is relatively new to the market and is not as strong and durable as a suit.

      Second, there is more than one type of fabric, or fiber, strength. A common assertion in the wool industry is that wool is stronger than cotton, polyester, etc. To support this claim, a study is cited that compares the number of times each of those fibers can be bent back and forth before it breaks. For this performance metric, wool is far more durable than the others. However, tensile strength and abrasion resistance are other types of strength for which comparable yarns of cotton and polyester outperform wool.

      As a real world example, lightweight Merino t-shirts used for backpacking are often cited as developing holes after limited use. This happens because the weight of the backpack rubbing the lightweight wool mile after mile exposes a limitation of certain fabric constructions and/or manufacturing processes. Some brands are responding to this weakness by changing the yarn manufacturing and weaving/knitting methods to increase abrasion resistance.

      The Limits of Moisture Wicking and Quick-Drying Merino

      The “Moisture Management” section of this guide details the miraculous process of wicking, thermoregulation and drying involved in Merino’s handling of sweat. Central to this process is the fiber’s ability to absorb 30% of its weight in moisture. That’s impressive and neither cotton nor polyester can do that, but what happens if the wearer keeps sweating after the fibers hit the 30% capacity? The result is a garment that cannot do anything with the excess sweat and the clothing system and skin can become a river of sweat.

      When evaluating the purchase of a Merino garment, consider if activities will involve prolonged exposure to high heat and rain. Normally, wearers are in-and-out of heat and avoid the rain. Nevertheless, use the right tool for the right job.

      Merino Wool is Not Vegan Friendly

      Sheep are sheared to collect the wool. During this process, the sheep are handled by shearers that sometimes treat them roughly. Occasionally, the mechanical shears nick the skin of the sheep causing a small wound. In extreme cases, shearers that are paid by the pound have treated sheep so roughly that the sheep have died in an effort to collect wool more rapidly. This is considered inexcusable, but these errors do occur.


      International Wool Trade Organization

      Australian Wool Innovation Ltd.


      Kyle Barraclough
      Kyle Barraclough


      Founder, Libertad Apparel

      Merino Business Travel Shirt Size Guide