Wool & UV Protection

Alongside its other natural performance properties, wool provides excellent protection from the sun’s UV rays. Even when completely untreated, wool absorbs radiation from across the entire UV spectrum.

Depending on the density of the fabric and how it has been treated and/or dyed, woollen apparel usually has an Ultraviolet Protection Factor (UPF) of between 20 and 50. (Compare the average UPF of 10 for a cotton t-shirt.)

It is worth noting that UPF does decrease a lot when any fabric is wet.

Manufacturers of performance garments often use a treatment to enhance the UV protection that already exists in wool. When purchasing woollen clothing, it is always worth verifying whether any UPF rating has been boosted with a treatment, as that may reduce over time. But rest assured, wool does naturally provide a degree of permanent UV protection.

How Wool Protects Against UV Light – the Science

Separate research projects by Hilfiker (1996), Reinert (1997) and Haerri (2000) have shown that wool – Merino fibre in particular – is a far better barrier against UV light than any other fabric.

Wool absorbs radiation throughout the UV spectrum while cotton, nylon, acrylic and silk are very poor absorbers of UV, absorbing only limited wavelengths of the ultraviolet range.

A 2001 study of the UV protection abilities of 236 different fabrics found that more than half of the test fibres fell short of the European standard for UV protection. Merino wool was one of the fabrics that passed all of the tests conducted during the study, while nylon, linen, viscose and cotton all fared extremely poorly.

The bottom line is that Merino wool, among its many other benefits, provides unparalleled protection against UV rays.