Glucosamine
Glucosamine is a natural compound found in cartilage, the tissue that cushions joints. It helps the body produce chemicals needed to build tendons, ligaments, cartilage, and joint fluid. In supplements, glucosamine is either extracted from shellfish shells or made synthetically in a lab.
Is this used to correct a deficiency or achieve supramaximal levels?
Supramaximal
Is it taken for life span or health span?
Healthspan
Is it targeting a specific disease? Or general health?
Joint health
Any genetic involvement?
Genes involved in cartilage synthesis
Is there a biomarker to track its effects?
Blood plasma and synovial fluid
MOA of supplement
It’s mechanism of action is unknown; however, it has been noted that it stimulates the synthesis of glycosaminoglycans, which form cartilage tissue in the body.
Risk vs reward
+ Treat osteoarthritis
+ May relieve joint pain
+ May reduce all cause mortality
+ May reduce diabetic complications
- May slighly increase CVD risk
- Unclear if increase insulin insensitivity
Evidence for it?
A 2023 systematic review analysed 15 randomised controlled trials to assess glucosamine’s effects on knee osteoarthritis. Most studies showed that glucosamine (typically 1,500 mg/day) reduced joint pain more than placebo, based on pain scales like VAS and WOMAC. It also helped with stiffness and physical function, though the improvements were modest. No serious side effects or drug interactions were reported. Overall, glucosamine appears safe and somewhat effective for long-term relief of knee osteoarthritis symptoms.
A large UK Biobank study followed nearly 500,000 adults over about 9 years to explore the effects of regular glucosamine use on lifespan. Around 19% of participants took glucosamine supplements. These users had a 15% lower risk of dying from any cause compared to non-users. Death rates were also lower for heart disease (18% less), cancer (6% less), lung conditions (27% less), and digestive diseases (26% less). The link was even stronger in current smokers. While this doesn’t prove causation, the findings suggest glucosamine may be linked to better long-term health and lower mortality.
An animal study found that glucosamine, a supplement often used for joint health, may also help extend lifespan. In both worms and mice, it worked by slightly blocking how the body processes sugar, which triggered healthy stress responses in cells—similar to what happens with a low-carb diet. This led to more energy production, better use of nutrients, and longer life. In mice, it also lowered blood sugar and boosted metabolism. These findings suggest glucosamine might support healthy aging by mimicking the effects of eating fewer carbs.
A large UK Biobank study looked at over 21,000 people with type 2 diabetes to see if regular glucosamine use affected their risk of developing diabetes-related complications. About 14.5% of participants reported taking glucosamine, and they were followed for over 12 years. The results showed that those who used glucosamine had a lower risk of developing kidney complications (diabetic nephropathy) and fewer overall microvascular problems. However, glucosamine didn’t significantly reduce the risk of eye (retinopathy) or nerve (neuropathy) damage. These findings suggest glucosamine may help protect kidney health in people with type 2 diabetes.
Evidence against it?
A RCT in 164 adults with moderate-to-severe knee osteoarthritis tested a daily combination of glucosamine sulfate (1,500 mg) and chondroitin sulfate (1,200 mg) for 6 months. Surprisingly, joint pain improved less in the treatment group than in those taking placebo (about 12 mm vs 20 mm reduction on a 100 mm pain scale). Both groups showed similar improvements in function and overall symptoms, with no difference in need for pain medication. The treatment was well tolerated, with no serious side effects linked to the supplements.
This study reviewed existing data on geroprotectors to assess their safety profiles e.g. glucosamine and its associated risks. Previous studies have raised concerns about glucosamine’s potential to increase cardiovascular risk. These studies found that glucosamine may elevate fasting blood glucose levels, accelerate the development of atherosclerosis, reduce insulin sensitivity, and inhibit the production of nitric oxide, a molecule that helps protect blood vessels. Together, these effects suggest that glucosamine use could be linked to a higher risk of cardiovascular disease, especially among patients with osteoarthritis.
This study systematically reviewed clinical trials and prospective studies to evaluate whether glucosamine affects glucose metabolism in humans. Some studies found that glucosamine use, particularly oral supplements, may decrease insulin sensitivity or increase fasting blood glucose, especially in people with pre-existing insulin resistance or impaired glucose tolerance. However, the overall evidence was mixed, and more research is needed to clarify glucosamine’s impact on glucose regulation, particularly in individuals at higher risk for metabolic problems.
Best bioavailable form?
Capsule or powder
Advice on taking it?
Taken with food