N-acetyl glucosamine is a precursor to hyaluronic acid and is found throughout the human tissue. Its effects are significant in hydrating skin as well, as n-acetyl glucosamine has been shown to increase hyaluronic acid production in the skin after regular topical application (Journal of Cosmetic Dermatology, 2006). N-acetyl glucosamine is an ingredient that has been proven to treat hyperpigmentation (Journal of Cosmetic Dermatology, 2006). Its effects to reduce hyper-pigmentation instigates from the inhibition of tyrosinase glycosylation. This reduces the amount of melanin production in melanocytes. It has a very high safety profile.
Glucosamine itself has been reported to decrease melanogenesis, however formulating a topical agent has been difficult due to its instability. More recently, focus has now shifted to the development of n-acetyl glucosamine containing cosmeceuticals given its greater stability, good skin penetration and overall tolerability.
Glucosamine works best in conjunction with niacinamide, which is found in Olay products. According to a 2007 study in the Journal of Cosmetic Dermatology, a double-blind, placebo-controlled, randomized study found that n-acetyl glucosamine and niacinamide used in conjunction on one side of the face are more effective than glucosamine alone in treating signs of hyperpigmentation.
In 2006, the International Consensus on Glucosamine Skin Benefits was held with leading scientists in conjunction with Proctor and Gamble Beauty. The panel determined that N-Acetyl Glucosamine, a more stable form of glucosamine, reduced the amount of melanin in skin cells, meaning there was less excess pigment in the skin to cause age spots. Additionally, the panel concluded that a formulation of N-Acetyl Glucosamin and niacinamide, a Vitamin B derivative, significantly reduced the amount and appearance of hyperpigmentation, age spots and uneven melanin distribution. Proctor & Gamble discovered n-acetyl glucosamine used in 2% concentration in combination with 4 % niacinamide leads to greater clinical effect due to synergistic effect.
In a study conducting by Bissett in 2007 (journal of cosmetic dermatology), 2% n-acetyl glucosamine was found to have a greater de-pigmenting effect after eight weeks of application. Through an 8 weeks study, it was shown that n-acteyl glucosamine (NAG) was effective in improving the overall appearance of facial hyperpigmentation as shown in figure 1:
Other than being an effective compound to improve hyperpigmentation, NAG help in synthesizing Hyaluronic acid, providing hydration and anti-aging benefits to the skin. One study shows that NAG increases the rate that skin fibroblasts make hyaluronic acid and collagen, while simultaneously lowering inflammation in skin. The researchers noted that aging fibroblasts exhibited more youthful behavior under the influence of NAG.
Figure 2 shows that hyaluronic acid (a commonly used hydrating active) exists mainly in the skin and articulation. In fact, hyaluronic acid is a combination of N-acetylglucosamine and glucuronic acid one after another.
Due to its big molecular size, hyaluronic acid is difficult to be absorbed into the body. However, as the size of N-acetylglucosamine, a precursor of hyaluronic acid, is only 1/1000 of hyaluronic acid, it can be absorbed in the body easily and can produce efficient hyaluronic acid there.
In another study it has been found that NAG reduces the amount of free radical damage from UV radiation to fibroblasts, in turn preventing the activation of enzymes that break down skin collagen and accelerate skin aging.
The researchers concluded that NAG-induced changes in the skin fibroblasts properties which maybe important for prevention of the age-dependent changes in its structure and function.