Labdoor analyzed 24 of the best-selling glucosamine supplements in the United States for glucosamine, chondroitin, and MSM (methylsulfonylmethane) content as well as heavy metal (arsenic, cadmium, lead, mercury) contamination.
Labdoor's analysis found that about two-thirds of the tested products (17 of 24) recorded glucosamine doses of at least 1500 mg per day, the lowest level at which glucosamine has been found in research studies to improve joint pain and function. 16 products also listed chondroitin; only 3 recorded effective chondroitin levels. 19 products also listed MSM; only 3 recorded effective MSM levels. Most products were fairly accurate in their label claims for glucosamine and MSM (within 10%). 6 products were missing more than 80% of the chondroitin they claimed. All but one product passed heavy metal screens, and flagged additives were rare. Shellfish is a common source for glucosamine supplements. For people who are allergic to shellfish, note that 6 products are shellfish-free.
Analytical Chemistry Methods: CE (glucosamine); HPLC (chondroitin); GC (MSM); ICP-MS (arsenic, cadmium, lead, mercury).
Lab-tested glucosamine content ranged from -4% to +41% vs. product label claims.
Products in general were fairly accurate in their label claims for glucosamine; measured values deviated from label claims by an average of 6%. In contrast, in the 16 products with chondroitin, products ranged from having -97% to +30% vs. their respective chondroitin label claims; 6 of them had less than 20% of the total chondroitin they claimed. 19 products claimed MSM, with measured amounts deviating an average of 23% from their label claims. 3 products claimed unquantified proprietary blends.
All but one product passed heavy metal screens for arsenic, cadmium, lead, and mercury.
All but one product passed heavy metal screens. This means that each product's heavy metal recordings per serving fell below California Proposition 65's proposed and established MADLs (Maximum Allowable Dose Levels) and NSRLs (No Significant Risk Levels): no more than 10 mcg/day of inorganic arsenic, 4.1 mcg/day of cadmium, 0.5 mcg/day of lead, and 0.3 mcg/day of mercury (proposed). Amazing Nutrition Glucosamine + Chondroitin + MSM exceeded the lead MADL in one serving.
Glucosamine products averaged a 100 (out of 100) in Nutritional Value scores.
Glucosamine products in this batch recorded minimal quantities of calories, fats, carbohydrates, and sugars. 8 products recorded sodium, ranging from 28 to 100 mg per serving. Additionally, the 3 most commonly recorded vitamins and minerals in this batch were potassium, manganese, and vitamin C.
Glucosamine, chondroitin, and MSM can interact negatively with certain medications and health conditions. Please consult a physician before supplementation.
Currently, there is no established Tolerable Upper Intake Level (UL) for glucosamine, chondroitin, or MSM as side effects are rare. The most recently established Observed Safe Levels (OSL) for glucosamine and chondroitin are 2000 mg/day and 1200 mg/day, respectively. An OSL is defined as "the highest intake with convincing evidence of safety, even if there are no established adverse effects at any level". 4 products exceeded at least one of these thresholds.
Reported side effects from glucosamine, chondroitin, and MSM supplements include stomach upset, nausea, headache, skin rash, and allergy. There is some concern over liver damage with glucosamine use, even at recommended doses. The Osteoarthritis Research Society International (OARSI) has recommended discontinuation of glucosamine supplement use if no visible benefit occurs after 6 months. Some research states concerns over chondroitin with respect to impacts on blood clotting, musculoskeletal disorders, and liver damage. Manganese levels can also be a concern with chondroitin supplements. However, levels of manganese per serving recorded in this analysis did not exceed the UL for manganese.
No synthetic sweeteners, artificial colors, or controversial preservatives were recorded in this batch.
Please consult your physician before and during supplementation, especially if you have a medical condition, are pregnant, or are taking any other drugs or dietary supplements.
On average, products measured 1417 mg of glucosamine per serving.
Products in this analysis recorded an average of 1417 mg of glucosamine per serving, ranging from 686 mg in Nature's Bounty Glucosamine Chondroitin Complex to 2100 mg in Dr. Tobias Hip Knee & Joint. 16 products recorded chondroitin and 19 products recorded MSM on top of glucosamine. On average, products with chondroitin recorded 450 mg of chondroitin per serving, and products with MSM recorded 899 mg of MSM per serving.
Research on glucosamine, chondroitin, and MSM is currently very limited and dosing studies are lacking. In a review of the research, 1500 mg/day seems to be the lowest effective dose of glucosamine for helping with joint pain and function in the average person. In one 24-week study, benefits from 1500 mg/day of glucosamine were similar to 200 mg/day of the pain medication, celecoxib. Clinical research does not yet show any efficacy difference between glucosamine HCl and glucosamine sulfate.
Adding MSM to glucosamine may yield some additional joint benefits. The lowest effective dose of MSM seems to be 1500 mg per day. In the case of chondroitin, current research shows that there is some minimal efficacy to taking chondroitin alone at doses as low as 800 mg per day. However, when this is added to an effective dose of glucosamine, no additional benefits are seen as compared to the same dose of glucosamine alone. Further research needs to be performed to clarify whether a combination of glucosamine and chondroitin is more effective than glucosamine alone.