“Moisture wicking” describes how a fabric moves liquid sweat away from the skin and spreads it so it can evaporate. No single feature creates it. Fibre, yarn, knit structure and finish all contribute, and the claim means little until you know which of them is doing the work in your fabric.

Fibre and yarn

Many wicking fabrics are made from synthetic fibres such as polyester, sometimes with special yarn shapes or blends designed to move liquid. Cotton absorbs moisture and holds it, which feels different on the skin. Ask the mill for the fibre content of the face and the back of the fabric, the yarn type and whether it is a standard or an engineered yarn.

Knit structure

The knit decides how liquid spreads. Two-layer constructions, open structures and different face and back yarns can pull liquid to the outer surface. Ask for the knit type, the weight and the finished thickness, and compare two or three constructions on skin in a wear trial.

Inherent or finish

Some wicking comes from the fibre and knit, and some from a chemical finish added at the mill. A finish can wear off with washing, so ask the mill directly which one applies. Request test results on washed fabric as well as new fabric. Do not assume the first-wash behaviour is the long-term behaviour.

Tests to request

AATCC lists a family of moisture-management methods, including TM79 for absorbency, TM195 for liquid moisture management, TM197 and TM213 for vertical wicking, TM198 for horizontal wicking and TM199 for drying time. Agree which methods you want and the number of washes before testing, using a named washing procedure such as ISO 6330. Check mass per unit area with ASTM D3776 so you know the tested fabric is the bulk fabric.

Blends and cotton

Blends of cotton and polyester sit between the two. The polyester can help the fabric dry, while the cotton holds moisture, so the real behaviour depends on the blend ratio and the knit. Test the actual blend you plan to buy instead of assuming it behaves like either fibre alone, and ask whether the face and back are different yarns.

Keep the claim modest

Describe what you measured, for example “tested for drying time and wicking after the stated number of washes,” and avoid promises about comfort or odour unless you can support them.