Vitamins and amino acids

Vitamins and amino acids

The effectiveness of vitamins, amino acids and "pro-vitamins" to shampoo is also largely debatable. Vitamins are substances that are essential for chemical processes that occur within the body, chiefly inside living cells and in the bloodstream. They cannot have the same beneficial effects on dead tissues like grown hair. However, the physical properties of some vitamins (like vitamin E oil or panthenol) would have a temporary cosmetic effect on the hair shaft while not having any bioactivity.

The proteins that make up the strand are chains of amino acids connected in very specific sequences, and are tightly packed in interlocking arrangements. Proteins are unable to penetrate the skin or the hair, and even if they stick to the outside of the hair they will not help strengthen it. Amino acids cannot penetrate cells through the skin, either; they may be able to enter the dead strands, but without the complex protein-building machinery of the living cells they will not actually return damaged hair proteins to their undamaged state.