Glucosamine and Chondroitin

Glucosamine has been on shelves for decades and the evidence still hasn't settled. These are the questions our naturopaths ask in store.

A good fit if

• You have ongoing knee discomfort and you'll give it a few months
• You want glucosamine sulfate specifically, which is the form with the encouraging evidence
• You avoid shellfish and want the corn-fermented version
• You'd rather understand mixed evidence than be sold a certainty

Check with us first if

• You have asthma. It's named as a group to take care, alongside shellfish allergy.
• You take warfarin. Caution is advised, although one review found no significant interaction.
• You take diabetes medicine. Caution is advised, although the trial evidence was reassuring.
• You have kidney disease or take heart or blood pressure medicine, and the product is the potassium chloride form.
• You're pregnant or breastfeeding. There's no warning on Australia's permitted ingredients list, but there's no safety information either.

• Glucosamine sulfate (item 2368). Best known for: The salt the long-term trials used. Absorption: Permitted listed with no conditions. Typical use: The form to pick if you're following the evidence that favours glucosamine.
• Glucosamine sulfate potassium chloride (item 2369). Best known for: A stabilised sulfate salt, very common on shelf. Absorption: Potassium chloride is a mandatory component. Typical use: Carries a kidney and heart warning, and a 550 mg potassium limit for oral use.
• Glucosamine sulfate sodium chloride (item 2370). Best known for: The sodium-stabilised equivalent. Absorption: Permitted listed with no conditions. Typical use: An alternative if potassium is a concern for you.
• Glucosamine hydrochloride. Best known for: A different salt with a different evidence picture. Absorption: Not interchangeable with the sulfate evidence. Typical use: Check which salt a product actually uses.
• Corn-fermented glucosamine. Best known for: Made without crustacean shell. Absorption: The route around the shellfish question. Typical use: The option if allergy or a vegetarian diet rules out shellfish-derived.

Reference values. There's no recommended intake for glucosamine, because it isn't a nutrient.

Typical supplemental range. Australian labels usually suggest around 1,500 mg a day, the dose most trials used, taken in one go or split. The long-term trials ran for one to four years, and the highest dose used in a human trial we reviewed was 3,000 mg a day of corn-fermented glucosamine.

Upper level. Australia's permitted ingredients list (Schedule 1) sets no upper limit for any form of glucosamine, and the NHMRC has no reference value for it. The one firm number applies to glucosamine sulfate potassium chloride: taken by mouth, it's only allowed in medicines containing less than 550 mg of potassium chloride.

Worth knowing. If you're going to try it, give it months rather than weeks. The trials that found an effect ran for a year or longer. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• None meaningful: glucosamine isn't obtained in useful amounts from food; supplements are manufactured

This list is the part of the page we will not shorten. If any of it applies to you, talk to one of our naturopaths or your doctor before starting.

• Shellfish allergy. Most glucosamine is made from crustacean shell. Of 366 Australian adverse reaction reports on glucosamine and chondroitin preparations between 2000 and 2011, 263 (71.85%) were hypersensitivity reactions.
• Asthma. Named alongside shellfish allergy as a caution group.
• Warfarin. Caution advised, though the same review states no significant supplement-drug interaction was found. Evidence is not settled.
• Diabetes medicines. Named as a caution group, though 90 days of glucosamine hydrochloride with chondroitin was reassuring on glycaemic control.
• Kidney disease, or taking heart or blood pressure medicines. Mandatory Schedule 1 warning on glucosamine sulfate potassium chloride (item 2369).
• Pregnancy and breastfeeding. No warning is recorded against any glucosamine item in Schedule 1, and no safety data was located either.
• Children. No paediatric restriction on glucosamine items, but sodium chondroitin sulfate (item 4582) mandates "Adults only", and joint indications commonly carry age restrictions.
• Non-pharmaceutical-grade product. Post-marketing surveillance lists adverse events specifically for non-pharmaceutical-grade glucosamine and chondroitin.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.