GLUCOSAMINE AND CHONDROITIN AFTER 50: WHAT THE TRIALS MEASURED

Glucosamine and chondroitin are among the most common supplements on the shelf for adults over 50 with sore knees. They have also been studied for decades, in some of the largest supplement trials ever run. The results are mixed, and the way the studies disagree is worth understanding before spending money on a bottle.

The Largest U.S. Trial

The Glucosamine/chondroitin Arthritis Intervention Trial (GAIT), published in the New England Journal of Medicine in 2006, randomized 1,583 people with painful knee osteoarthritis to 1,500 mg of glucosamine a day, 1,200 mg of chondroitin sulfate a day, both together, the anti-inflammatory drug celecoxib, or placebo for 24 weeks. Mean age was 59, and 64% were women.

The primary outcome was a 20% drop in knee pain. Placebo got there for 60.1% of participants. Glucosamine was 3.9 percentage points higher (P=0.30), chondroitin 5.3 points higher (P=0.17), and the combination 6.5 points higher (P=0.09). None of those differences was statistically significant. Celecoxib, the active control, was 10.0 points higher (P=0.008).

In the smaller group with moderate-to-severe pain at the start (354 people), the combination had a higher response rate than placebo, 79.2% versus 54.3% (P=0.002). The authors called that analysis exploratory. Adverse events were mild and spread evenly across the groups.

Pooling the Big Trials

In 2010, Wandel and colleagues published a network meta-analysis in the BMJ. They included only large trials (over 200 patients each): 10 trials and 3,803 patients with knee or hip osteoarthritis. On a 10 cm pain scale, the difference versus placebo was −0.4 cm for glucosamine, −0.3 cm for chondroitin, and −0.5 cm for the combination. The authors had set −0.9 cm in advance as the smallest difference that would matter to a patient, and none of the estimates reached it. Changes in joint space width were minute, with intervals that overlapped zero.

One detail in that paper stands out: trials run independently of industry showed smaller effects than commercially funded trials (P=0.02 for the interaction).

Where the Evidence Points the Other Way

Not every analysis lands in the same place. A 2018 network meta-analysis in JAMA by Gregori and colleagues looked only at trials lasting at least 12 months: 47 trials, 22,037 patients, mostly aged 55 to 70. Glucosamine sulfate was associated with a decrease in pain (standardized mean difference −0.29) and with less joint space narrowing (−0.42). Chondroitin sulfate was also associated with less narrowing (−0.20). The authors still described large uncertainty around every pain estimate versus placebo. Several of the authors work for Rottapharm Biotech, a spin-off of Rottapharm, which ran glucosamine sulfate trials, as disclosed in the paper.

Glucosamine comes in more than one form, and the favorable long-term signals in this review were reported for glucosamine sulfate specifically.

A 2016 trial in the Annals of the Rheumatic Diseases (MOVES) randomized 606 people with knee osteoarthritis and moderate-to-severe pain to chondroitin plus glucosamine hydrochloride or to celecoxib for six months. Pain dropped about 50% in both groups, and the combination met the trial's non-inferiority margin against celecoxib. That trial had no placebo arm, so it cannot say how much of that improvement either treatment caused.

The Newest Summary

A 2026 umbrella review in Frontiers in Nutrition by Li and colleagues pooled 19 earlier systematic reviews of glucosamine for knee osteoarthritis, most of which the authors rated low or critically low quality. Glucosamine produced a small reduction in pain on a visual analog scale (standardized mean difference −0.36), but no significant difference on the WOMAC pain scale and no significant improvement in function. It was associated with slower joint space narrowing (−0.32), mainly from long-duration sulfate trials. The authors reported that every significant effect sat at or below the threshold for a clinically important difference, and that adverse event rates did not differ from placebo.

Added on Top of Exercise

For an active reader, this is the closest comparison. A 2023 meta-analysis by Čeh and Šarabon pooled six randomized trials (297 participants) that added glucosamine, or glucosamine with chondroitin, to an exercise program for knee osteoarthritis. Compared with exercise alone, the supplements did not significantly change knee pain (WOMAC pain SMD −0.18, p=0.23; visual analog pain SMD −0.34, p=0.20) or physical function (SMD −0.13, p=0.76). The authors rated the average trial quality as good.

The Mortality Headlines

You may have seen reports that glucosamine users live longer. A 2020 UK Biobank analysis of 495,077 adults (mean age 56.6) found regular glucosamine use was associated with lower all-cause mortality over a median 8.9 years (hazard ratio 0.85). That is an observational association, not a trial.

In 2022, Suissa and colleagues reviewed 11 such observational studies in Pharmacoepidemiology and Drug Safety. They showed how a type of selection bias, built into cohorts where people were already taking glucosamine before joining, could produce that kind of result. Using the UK Biobank study as their illustration, they showed a true mortality ratio of 1.0 could appear as 0.82. Their conclusion was that these studies cannot support taking glucosamine to prevent death or chronic disease.

What I Could Not Find

I searched PubMed for a randomized trial of glucosamine or chondroitin in masters athletes and found none. The trials above were run in people with diagnosed knee osteoarthritis and joint pain, not in active adults using these supplements to protect healthy joints.

The Bottom Line on the Evidence

• The largest U.S. trial missed its primary pain endpoint for glucosamine, chondroitin, and the combination.
• Pooled analyses find small pain differences that the authors report sit at or below what patients would notice.
• Longer trials of glucosamine sulfate are associated with slower joint space narrowing, with low-quality evidence behind that signal.
• Added to an exercise program, the supplements did not change pain or function in the pooled trials.
• The mortality associations come from observational cohorts, and a published analysis attributes them to selection bias.

Knee osteoarthritis is a medical diagnosis. If you have knee pain or take a blood thinner or other medication, talk with your physician before starting a joint supplement.

Sources

1. Clegg DO, Reda DJ, Harris CL, Klein MA, O'Dell JR, Hooper MM, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med. 2006;354(8):795-808. PMID 16495392
2. Wandel S, Jüni P, Tendal B, Nüesch E, Villiger PM, Welton NJ, et al. Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis. BMJ. 2010;341:c4675. PMID 20847017
3. Gregori D, Giacovelli G, Minto C, Barbetta B, Gualtieri F, Azzolina D, et al. Association of Pharmacological Treatments With Long-term Pain Control in Patients With Knee Osteoarthritis: A Systematic Review and Meta-analysis. JAMA. 2018;320(24):2564-2579. PMID 30575881
4. Hochberg MC, Martel-Pelletier J, Monfort J, Möller I, Castillo JR, Arden N, et al. Combined chondroitin sulfate and glucosamine for painful knee osteoarthritis: a multicentre, randomised, double-blind, non-inferiority trial versus celecoxib. Ann Rheum Dis. 2016;75(1):37-44. PMID 25589511
5. Li Y, Wang R, Xu J, Shen Y, Hu G, Lu S. Glucosamine for knee osteoarthritis: an umbrella review. Front Nutr. 2026;13:1806413. PMID 42643227
6. Čeh T, Šarabon N. Effects of adding glucosamine or glucosamine combined with chondroitin to exercise on pain and physical function in adults with knee osteoarthritis: a systematic review and meta-analysis. Eur J Transl Myol. 2023;33(4):12013. PMID 37997783
7. Li ZH, Gao X, Chung VC, Zhong WF, Fu Q, Lv YB, et al. Associations of regular glucosamine use with all-cause and cause-specific mortality: a large prospective cohort study. Ann Rheum Dis. 2020;79(6):829-836. PMID 32253185
8. Suissa K, Hudson M, Suissa S. Glucosamine and lower mortality and cancer incidence: Selection bias in the observational studies. Pharmacoepidemiol Drug Saf. 2022;31(12):1272-1279. PMID 36029480