Vitamin K as a new ally for hair?

The vitamin K is a vitamin commonly prescribed in medicine as an anticoagulant treatment. However, its incorporation into cosmetic products is increasingly noticeable, particularly in skincare. But one might wonder if it has significant effects on the hair.

It is important to note that to date, no hair care product containing vitamin K has been put on the market. In fact, no study has demonstrated any benefits from the use of vitamin K in hair application. However, it is conceivable to make assumptions about the potential effects it could have on the hair.

Henk H.W. THIJSSEN and his team sought to study the antioxidant effectiveness of the Vitamin K cycle against lipoperoxidation, which is the degradation of lipids by free radicals produced during oxidative stress, in rat liver fragments. They combined Vitamin K epoxide reductase, an enzyme that converts Vitamin K into Vitamin K-hydroquinone, with liver proteins, and then initiated the Vitamin K cycle reaction by incorporating oxidants to induce lipoperoxidation.

The results indicate that the vitamin K cycle inhibits lipid peroxidation. The effect of vitamin K was concentration-dependent, with 90% inhibition at 1 μM. Furthermore, an increase in the levels of vitamin K-hydroquinone leads to a decrease in lipid peroxidation. It is therefore likely to be the antioxidant species of the vitamin K cycle. The breaking of the free radical chain is probably the cause of the antioxidant effect. It can thus be inferred that vitamin K may protect us from photoaging and other effects of oxidative stress.

Lipid oxidation impairs the hair fibre during photo-aggravation of hair ageing. Hair pigments absorb and filter solar radiation to protect hair proteins, such as keratin. However, when the pigments act to protect these proteins, they themselves can be degraded, resulting in greyish to white hair. Thus, vitamin K reduces the effects of oxidative stress on the hair and may limit hair discolouration associated with photoageing by preserving the pigments.

These are merely hypotheses. Furthermore, the cited study does not show any effect of Vitamin K on its own. More experiments on this subject are necessary to clarify these results.