Sustainable Sun Protection: The UV-Blocking Benefits of Bast Fibers

The ability of clothing to block ultraviolet (UV) radiation largely depends on the structure and thickness of the fabric, whether woven or knitted. Several key factors influence a garment’s UV protection performance, including fabric density, thickness, weave or knit pattern, and porosity. In general, the tighter and denser the fabric, the fewer gaps there are for harmful UV rays to penetrate, enhancing the overall protective effect (Gies et al., 2013; Gambichler et al., 2002).

However, even fabrics with dense construction and adequate thickness don’t always guarantee full protection—especially under intense solar exposure. UV resistance is also influenced by the type of fiber, the color of the fabric, and any special finishes or surface treatments applied (Sarkar, 2004). In environments with high UV intensity, these additional factors become particularly important.

Bast fibers—such as hemp, flax, jute, and ramie—have a natural edge when it comes to sun protection. Their chemical composition includes lignin and phenolic acids, such as ferulic acid, which are known for their ability to absorb UV rays (Mwaikambo & Ansell, 2002; Bledzki & Gassan, 1999). This gives bast fibers inherent UV-resistant properties that, when combined with the right fabric construction, can result in excellent barrier performance.

While textiles made from bast fibers can significantly reduce UV exposure, true sun safety and comfort depend on the complete garment design and the conditions in which it’s worn — factors like moisture, stretch, and wear can lower protection levels (Wilson et al., 2008).

And remember — clothing helps, but always wear additional sun protection!