FAST contain Cystine, cysteine and methionine which are sulfur containing amino acids. Over 90% of the dry weight of hair comprises proteins called keratins, which have high disulfide content, from the amino acid cysteine. Methionine is able to strengthen the structure of hair and nails.
A published study, resulting from a dermatology congress in Florence in 2006, found that the amount of hair found to be in the Anagen growth phase was significantly higher in a group of people who had taken methionine as part of an amino acid and vitamin B complex combination treatment than a control group which had taken nothing.
Biotin or vitamin B7 is part of the B-complex vitamins. Biotin is also called Vitamin H, “H” coming from the German word “Haar and Haut” meaning hair and skin. Biotin is often recommended for strengthening hair and nails.
Panthenol is the biological active alcohol analog of pantothenic acid or vitamin B5, a member of the B-complex vitamins. Due to its conversion to pantothenic acid in the skin and hair, its commonly used name is Provitamin B5.
The main function of panthenol in hair care is its long lasting moisturizing effects. Panthenol has strong deposition onto the cuticle and deeply penetrates the cortex of a hair. Since panthenol penetrates into hair and improves its ability to regulate its moisture content, it increases its resistance to damage and brittleness.
Inositol is found in many foods, especially in fruits. It plays an important role in the health of cell membranes. For hair, Inositol is said to promote healthy hair and hair growth, according to some reports, Inositol strengthens the cells of the hair helping it to retain moisture.
Tocopheryl Acetate or Vitamin E is a fat soluble vitamin that is known for its anti-oxidant properties. Tocopheryl acetate does not get oxidized in the skin, where about 5% is converted to free tocopherol and provides beneficial antioxidant effects.