Hair Extension Weft Application: Cotton Thread vs Nylon Thread

If you sew weft hair extensions, the thread you use matters more than most stylists initially realise. Cotton and nylon are the two main options, and while both will hold a weft in place, they perform very differently over time. Here's an honest comparison so you can make the right call for your clients.

Cotton Thread

Cotton is a natural fibre — soft, widely available, and familiar. For weft application, however, it has some significant drawbacks that become apparent over the weeks following application.

• Retains water — cotton absorbs moisture and takes a long time to dry fully after washing. Even when it feels dry, it often isn't.
• Harbours bacteria — retained moisture creates the conditions for bacterial and mould growth against the scalp.
• Stretches and swells — cotton stretches when wet and swells as it absorbs moisture, which can loosen the weft over time.
• Adds bulk and weight — cotton thread is thicker and heavier than nylon, which affects how the weft sits.
• Weaker tensile strength — cotton is more likely to snap or fray under tension, particularly at the knot points.
• Can cause scalp irritation — the texture and moisture retention of cotton can cause itching and discomfort for clients.

Nylon Thread

Nylon is the professional standard for weft application, and once you understand why, it's hard to go back to cotton.

• Strong and durable — nylon has significantly higher tensile strength than cotton and won't snap or fray under normal tension.
• Doesn't retain water — nylon dries quickly and doesn't hold moisture against the scalp.
• UV resistant — nylon holds its colour and integrity even with sun exposure.
• Doesn't stretch — the weft stays exactly where you placed it throughout the wear period.
• No bulk or added weight — nylon thread is fine and lightweight, so it doesn't affect how the weft sits or feels.
• Hygienic — because it doesn't retain moisture, nylon doesn't create the conditions for bacterial growth.

The Verdict

For professional weft application, nylon is the clear choice. The performance difference is significant enough that most experienced extensionists won't use cotton at all. The comfort, hygiene, and durability advantages of nylon directly affect client satisfaction and how long the weft holds between refits.

Hair Made Easi Nylon Weaving Thread

At Hair Made Easi, we stock a professional range of nylon weaving thread in 12 colours — including two training threads for stylists learning the technique. Our Ghost Thread (200 Metres) is a popular choice for stylists who want a virtually invisible result, particularly on lighter hair colours.

Browse our full range of weft hair extension tools — all available with trade pricing for salons and training providers.