Fake hair is made from either synthetic plastic fibers, chemically processed human hair, animal hair, or (less commonly) plant-based fibers. The vast majority of wigs, extensions, and hairpieces on the market fall into one of the first two categories, and the specific materials determine how the hair looks, feels, responds to heat, and holds up over time.
Synthetic Fibers: The Most Common Material
Most affordable wigs and extensions are made from plastic-based fibers engineered to mimic real hair. The two biggest names in synthetic hair fiber are Kanekalon and Toyokalon, and they’re built from different polymers. Kanekalon, which has been around since the late 1950s, uses a proprietary modacrylic fiber with a semi-hollow, cuticle-mimicking structure designed to replicate the luster and feel of natural hair. Toyokalon uses a modified PVC and acrylic blend with a smooth, solid fiber construction that tends to feel silkier but less textured.
Other synthetic hair products use polypropylene or polyester fibers. Polypropylene is common in lower-cost extensions, while treated polyester shows up in heat-resistant options.
To create these fibers, manufacturers melt plastic pellets and force the molten material through a device called a spinneret, which has dozens of tiny holes. The melted plastic exits as thin filaments (typically around 0.6 mm in diameter), then passes through a cooling duct where air solidifies the strands. The resulting yarn is gathered into bundles, sometimes run through a furnace to relax the fibers, and then cut and styled into the final product.
Standard vs. Heat-Resistant Synthetic Hair
Not all synthetic fibers behave the same way around heat. Standard synthetic wigs will melt or deform if you touch them with a curling iron or flat iron, because their melting point sits around 180°F. Heat-resistant synthetic fibers are chemically treated during manufacturing to raise that threshold significantly, tolerating temperatures between 270°F and 350°F depending on the fiber type. Modacrylic fibers generally handle up to 300°F, while treated polyester blends can reach 350°F. For comparison, real human hair can withstand styling tools up to about 450°F.
If you’re buying a synthetic wig and want to style it with heat tools, check the stated temperature limit before plugging anything in. The packaging or product listing should specify the safe range.
Coatings and Chemical Additives
Synthetic and even human hair extensions often receive a silicone coating during production. This thin layer gives the hair a glossy, healthy-looking shine and creates a slick surface that reduces tangling and friction between strands. It also makes the hair easier to comb and style. Over time and with washing, silicone coatings gradually wear off, which is why some extensions lose their initial smoothness after several weeks of use.
Many synthetic fibers also contain flame-retardant chemicals added during manufacturing. Some of the compounds used in flame retardant treatments, including certain chlorinated and brominated chemicals, are listed under California’s Proposition 65 as potential carcinogens. These substances can be absorbed through the skin, which is one reason some people experience scalp irritation with synthetic hairpieces. Other common irritants in synthetic hair include acrylates (used in bonding agents), disperse dyes, and added fragrances. Fragrance is actually one of the most frequently identified allergens in hair styling products overall.
How Human Hair Extensions Are Processed
Human hair wigs and extensions are labeled “100% human hair,” but the raw material goes through extensive chemical processing before it reaches you. Hair is typically sourced from donors in countries like India, China, and Southeast Asian nations, then sorted by length and quality. From there, it undergoes a multi-step industrial treatment.
First, the hair’s outer cuticle layer is chemically stripped using a solution containing bleach and acid. This step removes the natural scales on each strand, creating a blank canvas. Next, the hair goes through a series of chemical baths: a treatment with iron-based compounds and reducing agents to prepare it for color, a cleaning step using organic acids like citric or oxalic acid to remove residual metals, and finally a bleaching bath using hydrogen peroxide or similar oxidizers to lighten the hair to the desired base shade. The entire process takes several hours.
After bleaching, the hair is dyed to its final color, conditioned, and often coated with silicone. The result is hair that looks uniform and shiny on the shelf but has been fundamentally altered from its original state. This is why even “human hair” extensions can feel different from hair growing out of your head, and why they require specific care to maintain their condition.
Higher-end products labeled “virgin” or “Remy” hair skip some of these steps. Virgin hair has never been chemically treated, while Remy hair keeps the cuticles intact and aligned in one direction to reduce tangling. Both cost significantly more.
Animal Hair in Wigs and Hairpieces
Several animals contribute hair to the wig industry, including yaks, horses, sheep, and goats (mohair comes from Angora goats). Animal hair is rarely used on its own. Instead, it’s typically blended with human hair to add volume or texture at a lower cost. Yak hair in particular is popular because it shares several qualities with human hair: similar sheen, comparable feel, and a range of natural textures from straight to wavy. Like human hair, animal fibers can be chemically treated to change their color and texture.
Plant-Based and Biodegradable Options
A small but growing segment of the market uses plant-derived fibers as an alternative to both plastic and human hair. Pineapple leaf fiber and banana fiber, both repurposed from agricultural waste, are being turned into lightweight, breathable wigs. These fibers are biodegradable, which addresses a real environmental problem: synthetic wigs made from plastic polymers don’t break down in landfills. Plant-based options are still niche and harder to find than conventional synthetic or human hair products, but they’re expanding as demand for sustainable alternatives grows.
How Material Affects Your Choice
The material a wig or extension is made from directly affects its lifespan, styling flexibility, comfort, and price. Synthetic hair holds its style well out of the box and costs less, but standard versions can’t be heat-styled and typically last a few months with regular wear. Heat-resistant synthetic extends that versatility somewhat. Human hair extensions last longer (often a year or more with proper care), can be styled with any heat tool, and generally look more natural, but they cost several times more and require washing and conditioning like your own hair.
If you have sensitive skin or a history of contact dermatitis, the chemical additives in synthetic hair, particularly dyes and flame retardants, are worth considering. Opting for uncoated, fragrance-free options or higher-quality human hair can reduce the risk of scalp irritation.