Glucosamine and Hyperpigmentation
A study in Japan on 50 women (aged 25-55) showed that glucasamine and niacinamide help tone down age spots. A Harvard dermatologist oversaw another study of 200 subjects (aged 40-60). Half used a sunscreen and a moisturizer with glucasamine and niacinamide and the other half a sunscreen and moisturizer without the actives. It was concluded that the actives resulted in a reduction in hyper-melanized spot size and heterogeneity of melanin distribution.
In a 'split-face' clinical test for Proctor & Gamble, using a topical 2% NAG, it was concluded that it reduced the appearance of facial hyperpigmentation. A second study showed that it worked even better combined with 4% niacinamide.
The P&G study found that the two complexes stimulated the production of hyaluronic acid, a key process in the rehydration of skin, as well as increased collagen expression. This suggests that it could be an anti-ager as well since improved hydration led to a visible reduction in the fine lines and wrinkles of the women who tested the formulation, particularly in the eye area of the face.