Synthetic hair is made by melting plastic polymers into liquid form, forcing the liquid through tiny holes to create thin strands, and then cooling, stretching, and texturing those strands to mimic the look and feel of real hair. The entire process transforms small plastic pellets into fibers that can be styled into wigs, extensions, braids, and hairpieces.
What Synthetic Hair Is Made From
At its core, synthetic hair is plastic. The most common polymers used are polyester, acrylic, polyvinyl chloride (PVC), nylon (polyamide), and modacrylic blends. One of the most recognizable brand names in synthetic hair is Kanekalon, a modacrylic fiber made from a copolymer of acrylonitrile and vinyl chloride. Toyokalon is another well-known branded fiber. Each polymer has slightly different properties: some are softer, some hold heat better, and some are easier to texture into curls.
Manufacturers choose and blend these polymers based on what the final product needs to do. A sleek, straight wig might use a different fiber composition than a tightly coiled braiding hair. Polypropylene is common in extensions, while polyester monofilaments are popular for wigs that need to hold a specific shape.
From Plastic Pellets to Hair Strands
The manufacturing process starts with small resin pellets, roughly the size of a grain of rice. These pellets are mixed with other raw ingredients, including color pigments and chemical additives, then fed into a machine called an extruder. Inside the extruder, the pellets are heated until they melt into a thick liquid. For polypropylene-based hair, the melt temperature typically runs between 380°F and 450°F.
Once molten, the material is pushed through a filtration screen to remove impurities and ensure consistent quality. Then comes the key step: a gear pump forces the liquid polymer at a steady, controlled rate through a spinneret, which is essentially a metal plate with dozens of tiny holes. Each hole produces one continuous filament. A single spinneret might have 48 holes, and multiple spinnerets run simultaneously. The filaments that emerge are typically 0.4 to 0.9 millimeters in diameter, tuned to approximate the thickness of natural hair (a single human hair measures roughly 20 denier).
As the filaments exit the spinneret, they’re still soft and molten. They immediately pass through a quench air duct, positioned just a few centimeters below, where a controlled stream of cool air solidifies them. The newly formed strands are then drawn over a series of rollers called godets, which stretch and align the polymer chains inside the fiber. This stretching step is critical because it gives the filaments their strength and flexibility. Without it, the strands would be brittle and snap easily. Finally, the continuous filaments are wound onto spinning packages, large spools ready for the next stage.
How Color Gets Into the Fiber
Unlike human hair, which can absorb liquid dye, synthetic fibers are essentially solid plastic. Color is added during manufacturing by mixing pigments directly into the molten polymer before it’s pushed through the spinneret. This means the color runs all the way through the strand rather than sitting on the surface. It’s closer to how colored plastic is made than how hair is dyed at a salon.
This is why you can’t dye synthetic hair with traditional hair color. The fiber has no porous structure to absorb it. When people change the color of synthetic hair at home, they’re coating the surface with temporary sprays, pigment waxes, or fabric-based tints that sit on top of the strand and eventually wash or wear off.
Texturing: Straight, Wavy, or Curly
Freshly extruded synthetic filaments come off the spools completely straight. To create waves, curls, or the popular “Yaki” texture that mimics relaxed natural hair, manufacturers use heat-setting processes. The basic principle is the same one behind curling real hair with a hot iron, but done at an industrial scale with permanent results.
The filaments are arranged into their desired shape, often wound around rods or forms, and then exposed to heated air or steam. For polyester fibers, crimping typically happens at temperatures between 265°F and 355°F using hot air, sometimes mixed with steam. Steam-saturated methods work at slightly lower temperatures, starting around 245°F. The treatment lasts anywhere from 10 to 60 minutes depending on the desired curl pattern and the fiber type.
Some methods involve applying a moisture-retaining agent to the fibers before heating, which helps the curl set more deeply and last longer. Others use a two-stage approach: first shaping the hair with dry hot air, then permanently locking the texture with a follow-up steam treatment. Once set and cooled, the texture is essentially permanent. It won’t wash out or relax over time the way a curling iron style would in human hair. After texturing, the fiber bundles are cut to length, bundled, and packaged into the wefts, braids, or wig caps you see on shelves.
Heat Resistance and Flame Retardants
Standard synthetic hair fibers have a relatively low melting point, around 180°F, which means a curling iron or flat iron will damage or melt them. Heat-resistant synthetic fibers are chemically treated during manufacturing to raise that threshold to somewhere between 270°F and 350°F. Modacrylic fibers like Kanekalon generally tolerate temperatures up to about 300°F, while treated polyester blends can handle up to 350°F. For comparison, human hair can withstand styling tools up to about 450°F before sustaining serious damage.
Flame retardancy is another key property built into many synthetic hair fibers. Kanekalon, for instance, is marketed as flame retardant. A 2025 study published in ACS Environment & Health used chemical analysis to investigate what gives these fibers their fire resistance. Researchers detected very high concentrations of chlorine in all Kanekalon samples tested, suggesting that the vinyl chloride component of the polymer itself provides the flame retardant effect. In blended fiber products labeled “Mastermix,” the researchers found significant levels of bromine, pointing to a bromine-based flame retardant compound. Several specific flame retardant chemicals, including organophosphates and brominated compounds, were identified across both synthetic and bio-based hair extension samples.
Environmental Concerns
Because synthetic hair is made from nonrenewable plastic, it doesn’t biodegrade in any practical timeframe. Discarded wigs, braids, and extensions that end up in landfills can take hundreds of years to break down. The fibers can also shed microplastics during use and washing, similar to synthetic clothing.
Recycling synthetic hair is technically possible but rarely done. The complex combination of different polymers, chemical additives, and flame retardants in a single product makes it difficult to process through standard recycling systems. The economics don’t work in most cases either, since separating and reprocessing these mixed-material fibers costs more than manufacturing new ones. Most synthetic hair currently ends up in household waste.