What Fabrics Does a Period Underwear Manufacturer Use?

Period underwear is usually built from 3–5 textile layers rather than one absorbent fabric. A common construction uses cotton, modal, viscose, or lyocell for the body; polyester or microfiber for moisture transfer and absorption; 5–15% elastane for stretch; and a thin TPU or polyurethane laminate below the absorbent layer to reduce leakage. Body fabrics often sit around 140–220 GSM, while absorbent zones use heavier or multi-layer structures. Manufacturers also measure shrinkage, drying time, liquid spreading, wash resistance, and chemical safety because a fabric that absorbs well can still perform poorly if it stays wet, shrinks unevenly, or allows the waterproof membrane to separate.

A manufacturer normally starts with the body fabric because it controls fit, softness, stretch, and much of the wearer’s thermal comfort. Cotton jersey remains common, often blended with roughly 5–10% elastane so the garment stretches around the waist and legs and returns closer to its original dimensions after wear.

Cotton absorbs moisture readily, but high moisture retention also makes thick cotton structures slower to dry. A manufacturer may therefore use cotton against the body while placing polyester microfiber or another engineered absorbent textile below it. In a 4-layer gusset, every layer can have a separate job instead of asking one fabric to manage skin comfort, fluid storage, and leakage at the same time.

Modal and lyocell are frequently selected when a brand wants a smoother surface than standard cotton jersey. Both are regenerated cellulose fibers, and body fabrics commonly contain about 5–10% elastane to improve recovery. Their soft hand and drape make them suitable for briefs, bikinis, boyshorts, and high-waisted styles where the underwear needs to remain flexible rather than feel like a reusable pad.

The same distinction matters when suppliers describe “bamboo fabric.” In the United States, the Federal Trade Commission states that a textile made from regenerated cellulose sourced from bamboo should normally be identified as rayon or viscose made from bamboo, rather than simply as bamboo. FTC enforcement on misleading bamboo textile claims dates back to 2009, so accurate fiber naming matters in specifications and retail copy.

A supplier specification saying “95% bamboo, 5% spandex” should be checked carefully. If the soft fiber is regenerated cellulose, a more accurate commercial specification may be “95% viscose made from bamboo, 5% elastane.”

Once the body fabric is selected, attention moves to the surface that first receives menstrual fluid. That layer should spread or transfer liquid quickly instead of allowing one wet area to remain against the skin. Polyester knits, fine-gauge synthetic fabrics, and selected cellulosic blends are commonly used because yarn structure and finishing can be adjusted for liquid transport.

Textile moisture management can be measured rather than judged only by touch. AATCC TM195 evaluates properties including absorption rate, one-way liquid transport, and spreading speed, combining several measurements into an overall moisture-management assessment. A manufacturer comparing 3 candidate lining fabrics can therefore measure how each fabric handles liquid instead of choosing the softest sample by hand.

Below the acquisition layer sits the absorbent section. Microfiber polyester is common because very fine fibers create substantial surface area without requiring the thickness of a dense cotton insert. Terry constructions are another option; their loop structure increases available textile surface and can use cotton, viscose, polyester, or blends depending on the required drying time and hand feel.

Higher capacity is not created simply by adding fabric. If a manufacturer adds 2 extra absorbent layers, the gusset may hold more liquid but can also become thicker, warmer, and slower to air-dry. Product development therefore compares fluid capacity with thickness, spreading, compression, and drying performance rather than treating maximum milliliters as the only specification.

A light-flow brief might use 1 main absorbent layer, while moderate or overnight products may use 2 or more absorbent layers or extend the absorbent area farther toward the front and back. Coverage matters because menstrual fluid does not always move vertically; body position during sleep can move liquid toward the rear before the central absorbent area has reached its stated capacity.

A product described as holding 20 mL should not be assumed to provide the same protection as every other 20 mL product. The area covered, intake speed, pressure on the saturated fabric, and position of the waterproof barrier all affect real wear.

Leak prevention normally comes from a polyurethane-based barrier located under the absorbent material. TPU membranes are widely used because they can be thin, flexible, and laminated to a textile backing. Manufacturers need enough resistance to liquid penetration without turning the gusset into a stiff plastic-feeling panel.

The membrane also has to tolerate repeated laundering. A waterproof structure that works when new can become less reliable if heat, detergent, stretching, or repeated bending damages the laminate. A development program may therefore compare samples after 10, 20, or 30 wash cycles and inspect for peeling, cracking, edge separation, puckering, or changes in liquid resistance.

Fabric shrinkage becomes more important when several materials are sewn into one small gusset. If a cotton body fabric loses 5% of its length after washing while the laminated barrier changes very little, the finished panel can wrinkle or curl. Pre-production wash tests help manufacturers adjust patterns and sewing allowances before bulk cutting.

GSM adds another layer of control. Two fabrics can both contain 95% cotton and 5% elastane but behave very differently if one weighs 150 GSM and another weighs 210 GSM. The heavier version may feel more substantial and opaque, while the lighter version can dry faster and reduce total garment weight.

For absorbent materials, GSM must be considered with construction. A 250 GSM looped textile does not necessarily absorb or spread liquid in the same way as a 250 GSM flat knit. Yarn type, loop height, density, finishing, fiber blend, and compression can change the amount of liquid held inside the textile structure.

Manufacturers also use nylon or polyamide when the outer garment needs a smoother, lighter feel. Nylon-elastane blends work well in close-fitting underwear because they offer abrasion resistance and high stretch. A body fabric containing around 15% elastane can provide stronger compression and recovery than a casual cotton jersey containing 5%, although actual stretch also depends on knitting structure.

That fit affects fluid management. If leg openings loosen after repeated washing, liquid can escape around the sides even when the absorbent core itself is not saturated. For this reason, Ljvogues and other period underwear manufacturers need to evaluate fabric recovery, gusset dimensions, elastic tension, and absorbent placement as one garment construction rather than separate material purchases.

Chemical requirements add another specification layer because period underwear remains in close contact with skin. OEKO-TEX STANDARD 100 places underwear in Product Class II for products with direct skin contact, while Product Class I applies stricter requirements to products intended for babies and children up to 36 months. The standard covers textile components from fibers and fabrics through finished articles.

OEKO-TEX documentation also includes requirements covering substance groups such as banned azo colorants, lead, cadmium, and PFAS-related chemicals. A brand should still verify the certificate number, scope, supplier, material description, and validity rather than treating an OEKO-TEX logo as proof that every component in a finished garment has been assessed.

Fiber certification requires the same level of care. A product containing 95% organic cotton is not automatically certified simply because the supplier calls the yarn organic. Certification scope, processing stages, trims, dyes, and chain-of-custody documentation need to match the claim being used on the finished product.

Recycled polyester and recycled nylon can replace part of the virgin synthetic content in body fabrics or absorbent layers, but the change still requires testing. A revised yarn source can alter stretch recovery, dye uptake, pilling, hand feel, and shrinkage even when the nominal composition remains 90% polyester and 10% elastane.

Drying performance deserves equal attention because reusable underwear is repeatedly washed. A thick cotton-rich gusset can stay damp much longer than a lighter microfiber construction. Brands selling 3-pair sets, for example, should consider whether normal air drying allows a wearer to rotate garments comfortably without relying on high-temperature tumble drying that may shorten membrane life.

Sewing construction can also change fabric performance. Needle size, seam allowance, stitch density, elastic tension, and laminate handling all affect the gusset. A technically suitable 4-layer stack can still leak if needle holes are excessive near the waterproof area or if the laminate is distorted during sewing.

Bulk production should therefore follow an approved material specification rather than a generic description such as “cotton period underwear.” A useful specification lists fiber composition, GSM, usable width, stretch percentage, shrinkage tolerance, colorfastness requirements, absorbent construction, membrane type, care conditions, and approved supplier references.

Before approving production, brands can compare several samples under the same conditions: record dry weight, add a controlled liquid volume, observe spreading time, check the outer layer for penetration, then repeat the assessment after washing. Testing 5 garments per size or construction provides more useful production information than relying on a single showroom sample.

A supplier should also state whether the quoted absorbency figure refers to the material alone or the finished garment. Claims such as 15 mL, 20 mL, or 30 mL can use different test procedures, liquid types, loading speeds, and end points. Without a stated method, numbers from two manufacturers are not necessarily comparable.

For most commercial products, no single fiber provides every required property. Cotton and regenerated cellulose can provide comfort; microfiber and technical knits can manage fluid; elastane supplies roughly 5–15% of many stretch blends; and polyurethane-based membranes provide leakage resistance. Material selection works best when each layer is specified according to its actual job and then checked again after repeated washing, stretching, and wear.