Skin whitening wheat, rye, and barley. It is applied topically in a cream formulation at a 10–20% concentration. Azelaic acid is used to treat acne, but there also is research showing it to be effective for skin discolorations. Other research also indicates azelaic acid may be an option for inhibiting melanin production. Vitamin C and its various forms (ascorbic acid, magnesium ascorbyl phosphate, etc.) are considered an effective antioxidant for the skin and help to lighten skin. One study found it raises glutathione levels in the body. Another study found that brownish guinea pigs given vitamin C, vitamin E and L-cysteine, simultaneously,
Vitamin B12 leading to vitamin B deficiency. Protein-bound vitamin B must be released from the proteins by the action of digestive proteases in both the stomach and small intestine. Gastric acid releases the vitamin from food particles; therefore antacid and acid-blocking medications (especially proton-pump inhibitors) may inhibit absorption of B. B taken in a low-solubility, non-chewable supplement pill form may bypass the mouth and stomach and not mix with gastric acids, but acids are not necessary for the absorption of free B not bound to protein; acid is necessary only to recover naturally-occurring vitamin B from foods. R-protein (also known as haptocorrin