Glucosamine is a compound made inside the body from the amino acid glutamine and glucose. It’s used to synthesize glycosaminoglycans, an important component of joint cartilage and the synovial fluid that surrounds it. Glucosamine is also available in supplement form where it’s used as a natural treatment for osteoarthritis, often combined with chondroitin sulfate for additional joint benefits. Supplying the joints with more glucosamine may reduce cartilage damage that can worsen the symptoms of osteoarthritis. Glucosamine also makes up the exoskeleton of arthropods and crustaceans, and glucosamine for supplements can be made from this source. As a joint health supplement, glucosamine seems to have benefits, although studies looking at its effectiveness for osteoarthritis have been mixed.
Glycosaminoglycans are also found in the dermal layer of skin. One of the most important skin glycosaminoglycans is hyaluronic acid. Hyaluronic acid is a powerful, natural humectant that has the capacity to bind and hold onto water. This helps to hydrate skin and make wrinkles less apparent. Glucosamine also blocks the action of tyrosinase, an enzyme involved in the production of melanin, the pigment that gives skin its color. Blocking tyrosinase helps to lighten areas of pigmentation caused by overexposure to ultraviolet light. Because it stimulates the synthesis of hyaluronic acid and blocks melanin production, studies have been carried out looking at its skin anti-aging benefits and its potential for lightening pigmented areas.
Research looking at the skin anti-aging benefits of glucosamine has been encouraging. Several studies show that topical n-acetyl-glucosamine, a more stable form of glucosamine, lightens areas of increased skin pigmentation on the face. In one study, it was more effective than niacinamide for treating areas of increased pigmentation. Another study showed that it lessened the appearance of fine lines and wrinkles in middle-aged women who used it topically. Cell culture studies show that adding glucosamine to skin cells boosts the synthesis of hyaluronic acid, an important regulator of skin hydration. Hyaluronic acid levels decline with age. This partially explains why mature skin is dryer and has a rougher texture than more youthful skin. Hyaluronic acid is also involved in wound healing, and younger skin with more hyaluronic acid heals more rapidly and is less likely to scar. Hyaluronic acid levels in skin decline with age.
Glucosamine also has antioxidant and anti-inflammatory benefits. It helps to counteract the effects of free radicals skin cells produce when they’re exposed to ultraviolet light or pollutants. Many of the effects we see with skin aging like wrinkling and skin laxity are an indirect result of oxidative damage from exposure to ultraviolet light. Free radicals produced by sunlight exposure activate enzymes that break down collagen, a protein in the dermis of the skin that gives skin its support and youthful appearance. Glucosamine may help to counteract some of this damage. Because of its anti-inflammatory properties, research is also looking at glucosamine as a potential treatment for inflammatory bowel diseases like ulcerative colitis and Crohn’s disease.
Glucosamine is already found in some moisturizers, eye creams and skin anti-aging products and appears to be safe when used topically. As an oral supplement, it can theoretically cause elevations in blood sugar, so oral glucosamine supplements may not be suitable for diabetics. In addition, it may increase the risk of bleeding due to its effect on platelets, so people taking blood thinners or supplements that have a blood thinning effect shouldn’t use it orally. It can also interact with other medications. This shouldn’t be an issue when used topically in the amounts found in skin care products.
Although most research looking at glucosamine has centered around glucosamine sulfate and its benefits for joint health, there’s growing evidence that n-acetyl-glucosamine can lighten areas of increased skin pigmentation, make fine lines and wrinkles less apparent and offer some protection against skin damage due to its anti-inflammatory effects. It also appears to be safe when used topically.