Chondroitin

What is chondroitin and what does it do in the body?

According to NCCIH, chondroitin is a component of the cartilage in joints and plays a role in cartilage resisting compression. ^[1] This is “role in the body” information; it does not mean that chondroitin taken by mouth repairs damaged cartilage, and the effect of the supplement is measured in separate studies. In a 2017 survey in the US, chondroitin (with glucosamine or alone) was reported as the most commonly used dietary supplement in people aged 35 and older diagnosed with osteoarthritis. ^[1]

In what forms and from what sources is chondroitin found?

In the US, chondroitin is sold as a dietary supplement in the form of chondroitin sulfate; in some countries, certain chondroitin and glucosamine preparations are prescription drugs. ^[1] This distinction affects how the evidence is interpreted: in the meta-analysis by Honvo and colleagues, when only studies at low risk of bias were examined, a significant difference emerged between pharmaceutical-grade chondroitin from a single source and other preparations. ^[3]

The chondroitin sulfate rows in the Restricted Substances List in Türkiye distinguish two source groups: chondroitin obtained from fermentation of strain U1-41 (ATCC 23502) of the bacterium Escherichia coli O5:K4:H4, and “other sources” (cattle, chicken, chemical synthesis). ^[13]

Does chondroitin help knee pain?

Cochrane review (2015)

The Cochrane review by Singh and colleagues examined 43 randomized studies in adults with osteoarthritis (4,962 participants receiving chondroitin and 4,148 receiving placebo or another control); most studies were in knee osteoarthritis. In the short term (under 6 months), the absolute risk difference for pain was 10% lower (95% CI 6%–15%; NNT 5; 8 studies; low-certainty evidence, high risk of bias; I² 70%). In studies longer than 6 months, the difference was 9% (95% CI 18% lower to 0%; 6 studies; low-certainty evidence). The rate of 20% improvement in WOMAC pain was 53 per 100 people in the chondroitin group and 47 in the placebo group (RR 1.12; 95% CI 1.01–1.24; 2 studies, 1,253 participants; high-certainty evidence). The benefit for pain and the Lequesne index became uncertain when restricted to studies with adequate allocation concealment, studies with large samples (>200), and studies without pharmaceutical company funding. ^[2]

The same Cochrane review analyzed together the comparisons in which chondroitin was used alone or with glucosamine or another supplement: a 10% lower absolute risk difference in pain compared with placebo or active control (95% CI 5%–14%; NNT 4; 17 studies; low-certainty evidence; I² 91%) was found; for physical function, there was no significant difference in the comparison in which chondroitin was used with glucosamine or another supplement (1% lower, 95% CI 6% lower to 3% higher; 5 studies; moderate-certainty evidence). The review’s conclusion, based on low-quality studies, is that chondroitin improves pain compared with placebo in the short term, that the benefit is between small and moderate, and that it persisted in some sensitivity analyses and not in others. ^[2]

Honvo meta-analysis (2019)

In the analysis pooling 18 placebo-controlled studies in knee osteoarthritis only, chondroitin sulfate reduced pain significantly but inconsistently (SMD −0.63; 95% CI −0.91 to −0.35; I² 94%) and improved function (SMD −0.82; −1.31 to −0.33; I² 95%). In studies at low risk of bias, SMD for pain was −0.25 (−0.34 to −0.16) for pharmaceutical-grade chondroitin from a single source and −0.08 (−0.19 to +0.02) for other preparations. A strong association between effect size and study size was found (rS=0.93 for pain), and when the smallest studies were removed, no heterogeneity remained. According to the article’s funding section, the analysis was supported by an unconditional educational grant from the manufacturer of the pharmaceutical-grade product that stood out in the studies at low risk of bias. ^[3] NCCIH also relays the same analysis, with a note of major inconsistency in study results. ^[1]

Large studies

In GAIT (1,583 patients, 24 weeks), the response rate in the chondroitin sulfate group was 5.3 points higher than with placebo (P=0.17; placebo 60.1%); the difference was not significant. ^[4] In Wandel’s network meta-analysis (10 studies, 3,803 patients), chondroitin’s pain difference was −0.3 cm (95% credible interval −0.7 to 0.0) and did not reach the prespecified clinical importance threshold of −0.9 cm. ^[10]

Does chondroitin protect joint structure?

Structural results are inconsistent. In Cochrane, in 2 studies (high-certainty evidence), minimum joint space loss was 4.7% less in the chondroitin group (95% CI 1.6%–7.8%). ^[2] NCCIH relays that in two 2-year studies of 622 and 300 participants, chondroitin improved joint space compared with placebo, but that no such effect was found for chondroitin alone in the GAIT study in the US and the LEGS study in Australia. ^[1] In the 24-month substudy of GAIT (572 patients), no treatment group had a significant joint space difference from placebo. ^[5] In LEGS (605 participants, 2 years; 800 mg/day chondroitin sulfate), no significant structural effect was found for chondroitin alone; in the combination the difference was 0.10 mm (95% CI 0.002–0.20). ^[6]

Does chondroitin work in hand osteoarthritis?

In the single-center, double-blind RCT by Gabay and colleagues, 162 patients with radiographic hand osteoarthritis and marked pain received 800 mg/day of chondroitin sulfate (n=80) or placebo (n=82) for 6 months. The fall in global hand pain was greater in the chondroitin group (VAS difference −8.7 mm; P=0.016) and hand function improved more (FIHOA difference −2.14; P=0.008); there was no difference in grip strength and acetaminophen consumption. ^[9] Because it is a single study, the result awaits confirmation. ACR/AF 2019 conditionally recommends chondroitin sulfate for hand osteoarthritis; the rationale is that it is the only study showing an analgesic effect without evidence of harm. ^[11]

Use with glucosamine: placebo and celecoxib comparisons

In GAIT, the combination increased the response rate by 6.5 points compared with placebo in the overall group (P=0.09); in the subgroup of 354 patients with moderate-to-severe pain it was 79.2% versus 54.3% (P=0.002), and this was an exploratory analysis. ^[4] In LEGS, pain decreased in all four groups and there was no difference between groups (p=0.93). ^[6] In the 6-month study by Roman-Blas and colleagues (164 patients, Kellgren/Lawrence grade 2–3, moderate-to-severe pain), chondroitin sulfate + glucosamine sulfate was not superior to placebo in the modified intention-to-treat analysis; the authors reported that the combination produced less reduction in pain than placebo (did not show superiority), and there was no difference in patients who adhered to the protocol. A correction (erratum) concerning the formatting of the global pain score has been published for the article; for this reason, the scale values are not relayed here. ^[7]

In the MOVES study (606 patients, Kellgren/Lawrence grade 2–3, moderate-to-severe pain, 6 months; chondroitin sulfate + glucosamine hydrochloride compared with celecoxib), the WOMAC pain change was −185.7 with the combination and −186.8 with celecoxib, and the prespecified non-inferiority margin was met. The study has no placebo arm; therefore it gives no information about the superiority of the two treatments over placebo. According to the article’s funding section, the manufacturer of the combination product funded the study, supplied the drugs, and took part in design and data interpretation; some of the authors reported consulting relationships with the same company. ^[8]

What do guidelines say about chondroitin?

Is chondroitin safe?

NCCIH states that no major safety problems were found in large studies of glucosamine and chondroitin; it adds that glucosamine and chondroitin have been associated with increased bleeding risk in people using the anticoagulant warfarin and that little is known about their safety during pregnancy and breastfeeding. ^[1] In Cochrane, chondroitin was associated with a significantly lower likelihood of serious adverse events than placebo (Peto OR 0.40; 95% CI 0.19–0.82; 6 studies; moderate-certainty evidence); there was no difference in the number of adverse events and the number of withdrawals due to adverse events. The same review notes that adverse events were reported in a limited way. ^[2] In GAIT, adverse events were mild, infrequent, and balanced between groups. ^[4]

How is chondroitin regulated in Türkiye?

In Türkiye, food supplements are regulated by the Ministry of Agriculture and Forestry, and Ministry approval is mandatory for every food supplement to be placed on the market. ^[14] In the Restricted Substances List (last updated September 21, 2026), an upper limit of 1,200 mg/day is given for chondroitin sulfate in the “daily intake dose for ages 11 and older” column; the ages 4–10 column is empty. ^[13]

• Chondroitin sulfate from E. coli fermentation: 1,200 mg/day (“for the adult population other than pregnant and breastfeeding women”), July 3, 2026; condition of “compliance with Annex-1 of the Turkish Food Codex Novel Foods Regulation”; the label carries a warning that it is not used by those under 18 or by pregnant and breastfeeding women. ^[13]
• “Other sources” (cattle, chicken, chemical synthesis): 1,200 mg/day; first published January 22, 2016; a note that “if it is proven that it was used in food supplements before December 31, 2025, it will not be evaluated under novel foods”; a glycosaminoglycan claim may be made; the label carries the warnings “18 yaş altı bireylerde kullanılmaz.” (not for use by individuals under 18) and “Bu takviye edici gıdanın 3 aydan fazla kullanılması durumunda doktora danışılmalıdır.” (a doctor should be consulted if this food supplement is used for more than 3 months). ^[13]

This list is an upper limit; it does not mean the product is effective.

Evidence table: claim, population, and limits