Some other vitamins and vitamin precursors used in cosmetic products are biotin, niacinamide, vitamin D, vitamin B6, beta-carotene, and, in a few products, vitamin K. For all these substances there exists a rationale for their use in cosmetics but there are either no studies or insufficient studies available that prove their efficacy when topically applied.
Systemic use of 2.5 mg biotin per day has shown good effect on brittle nails and has improved hair quality [46-49]. As it has good effect on these keratin structures, it can be assumed that this vitamin could also have interesting effects on the keratinization process in the epidermis.
Beta-carotene is known for its quenching activity on singlet oxygen. It would be an ideal partner for vitamin E and vitamin C to strengthen the antioxidant defense system of the skin. Oral supplementation with beta-carotene over several weeks has shown to reduce the risk of UV-induced skin damage .
Unfortunately for cosmetics, beta-carotene is a strong coloring agent and concentrations of more than 0.05% in a cosmetic product can lead to undesirable coloration of the clothes of its users. Low concentrations of beta-carotene are used in some cosmetics as natural coloring agent for creams.
Roccheggiani showed a depression of sebum production with the tripalmitate ester of vitamin B6 . Vitamin D could be an ideal partner for total sun blockers, as the UV-ray barrier of these products partly prevents the natural formation of vitamin D in the skin. Vitamin D is on the ''list of substances which must not form part of the composition of cosmetic products'' of the European Cosmetic Regulations. It can be used, however, in other countries.
Was this article helpful?