Glucosamine is a natural compound found in cartilage — the tough tissue that cushions joints.

In supplement form, glucosamine is harvested from shells of shellfish or made in a lab. There are several forms of glucosamine, including glucosamine sulfate, glucosamine hydrochloride and N-acetyl glucosamine. These supplements are not considered interchangeable.

People use glucosamine sulfate orally to treat a painful condition caused by the inflammation, breakdown and eventual loss of cartilage (osteoarthritis).

Research on glucosamine use for specific conditions shows:

  • Osteoarthritis. Oral use of glucosamine sulfate might provide some pain relief for people with osteoarthritis of the knee, hip or spine.
  • Rheumatoid arthritis. Early research suggests that oral use of glucosamine hydrochloride might reduce pain related to rheumatoid arthritis when compared with placebo, an inactive substance. However, researchers didn't see an improvement in inflammation or the number of painful or swollen joints.

When considering glucosamine, read product labels carefully to make sure you choose the correct form. While glucosamine sulfate has been studied for treatment of arthritis, there's no clinical evidence to support the use of N-acetyl glucosamine in treating arthritis.

Generally safe

Glucosamine sulfate might provide pain relief for people with osteoarthritis. The supplement appears to be safe and might be a helpful option for people who can't take nonsteroidal anti-inflammatory drugs (NSAIDs). While study results are mixed, glucosamine sulfate might be worth a try.

When taken in appropriate amounts, glucosamine sulfate appears to be safe. Oral use of glucosamine sulfate can cause:

  • Nausea
  • Heartburn
  • Diarrhea
  • Constipation
  • Drowsiness
  • Skin reactions
  • Headache

Because glucosamine products might be derived from the shells of shellfish, there is concern that the supplement could cause an allergic reaction in people with shellfish allergies.

Glucosamine might worsen asthma.

It's possible that glucosamine sulfate might affect your blood sugar levels, which might interfere with blood sugar control during and after surgery. Stop taking glucosamine sulfate two weeks before an elective surgery.

Possible interactions include:

  • Acetaminophen (Tylenol, others). Taking glucosamine sulfate and acetaminophen together might reduce the effectiveness of both the supplement and medication.
  • Warfarin (Coumadin, Jantoven). Taking glucosamine alone or in combination with the supplement chondroitin might increase the effects of the anticoagulant warfarin. This can increase your risk of bleeding.
Oct. 14, 2017