Dglucosamine

D-glucosamine is an amino sugar known chemically as the D-enantiomer of 2-amino-2-deoxy-D-glucose. It serves as a building block for glycosaminoglycans and proteoglycans, components of cartilage and connective tissue. In humans, glucosamine is produced endogenously through the hexosamine biosynthetic pathway from glucose-derived intermediates, and it is also obtained from dietary supplements and certain foods.

Commercially, glucosamine is produced from chitin and marketed mainly as dietary supplements in several salt forms, including glucosamine sulfate and glucosamine hydrochloride. A related compound, N-acetyl-D-glucosamine, is used in other contexts such as nutritional supplements and is a separate molecule in terms of function and regulation. The active ingredient in most over-the-counter products is the D-glucosamine moiety, though the accompanying salt or acetyl group affects formulation and absorption.

D-glucosamine is most widely used as a supplement for osteoarthritis. Clinical evidence shows mixed results; some trials report modest improvements in pain and joint function, particularly in knee osteoarthritis, while others show little or no benefit. It is not widely regarded as disease-modifying therapy, and there is no conclusive evidence that it halts radiographic progression of osteoarthritis. Benefits, when present, are generally small and may vary between individuals.

Safety considerations are important. Glucosamine is usually well tolerated, with common side effects including gastrointestinal upset, heartburn, or diarrhea. Potential interactions with anticoagulants such as warfarin have been reported, and products derived from shellfish may raise concerns for some individuals, though allergen risks are typically low due to processing. Regulatory oversight for dietary supplements varies by country, and product quality can differ; consumers should consult healthcare providers, especially if managing diabetes, taking anticoagulants, pregnant, or breastfeeding.