Synopsis

Source of validity: Scientific
Rating (out of 5): 3

Keratin is a fibrous structural protein that is a major component of hair, skin, and nails. In hair care, keratin-based treatments and products are widely used with the aim of repairing, strengthening, or smoothing hair. The scientific basis for using keratin in hair care lies in the fact that chemical processing, heat styling, and environmental stressors can damage the natural keratin in hair, leading to weakened, brittle, or frizzy strands. Topical application of hydrolyzed keratin (broken down into smaller peptides) is believed to temporarily fill in gaps in the hair shaft and improve hair's mechanical properties.

Laboratory studies demonstrate that hydrolyzed keratin can increase hair strength, reduce breakage, and improve the surface smoothness of hair fibers. Some clinical studies and in vitro research suggest that keratin treatments can lead to smoother, shinier, and less frizzy hair, at least temporarily. However, the effects are not permanent, and repeated treatments are necessary. There is also some controversy regarding the safety of salon-based "keratin treatments," as some formulations contain formaldehyde or related compounds that can pose health risks.

In summary, while there is moderate scientific evidence (rated 3 out of 5) supporting the use of keratin for improving the appearance and manageability of hair, the benefits are largely cosmetic and temporary. Consumers should also be aware of potential safety concerns with certain in-salon keratin treatments.

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Products containing keratin

Nature's Sunshine Power Greens