Glucosamine occurs naturally in the fluid around the joints, in animal bones, bone marrow, shellfish, and fungi. It plays a vital role in building cartilage, and many people take it as a supplement to treat arthritis and osteoarthritis.
Glucosamine, especially glucosamine sulfate, is taken from the shells of shellfish and put into dietary supplements. A synthetic form is also be made in laboratories.
Contents of this article:
What is glucosamine?
Glucosamine sulfate is a popular supplement.
Glucosamine is normally taken by mouth, and it comes in different forms.
- Glucosamine sulfate
- Glucosamine hydrochloride
Although similar, they may have different effects when used as dietary supplements.
Most studies into the potential health benefits of glucosamine have focused on glucosamine sulfate.
Glucosamine may be combined with other ingredients in dietary supplements, including chondroitin sulfate, MSM, or shark cartilage.
Some people claim that the combinations help, but researchers say that scientific proof is lacking.
The NIH points out that glucosamine sulfate products do not always contain the ingredients listed on their label. Tests have shown that glucosamine content can range from 0 percent to 100 percent, or that when the label claimed the product had glucosamine hydrochloride, it was really glucosamine sulfate.
Why do we need glucosamine?
Glucosamine is vital for building cartilage. Cartilage is a flexible, tough connective tissue found in several parts of the body. This fine, rubbery tissue functions as padding, a cushion for bones and joints.
Joint cartilage requires glucosamine because it is needed to produce glycosaminoglycans, a major component of joint cartilage.
Sulfur needs to be incorporated into cartilage in order to make and repair it. Glucosamine plays a crucial role in incorporating sulfur into cartilage.
As people age, glucosamine levels fall. In time, this can lead to joint deterioration.
Why do people take glucosamine supplements?
According to the National Center for Complementary and Alternative Therapy, a 2007 National Health Interview Survey found that 17.7 percent of adults in the United States regularly took some type of dietary supplement.
People take glucosamine in the hope that it will prevent joint pain.
Of those, 19.9 percent took glucosamine. It was the second most popular dietary supplement after fish oil, omega 3, or DHA, used by 37.4 percent of those who took supplements.
The National Institutes of Health (NIH) list the following reasons why people use glucosamine sulfate:
- Osteoarthritis (OA)
- Weight loss
- Interstitial cystitis, a bladder condition
- Jaw pain
- Joint paint knee pain
- Back pain
- Multiple sclerosis
- HIV and AIDS.
Glucosamine supplements are also used by people with inflammatory bowel disease (IBD), and ulcerative colitis.
Does glucosamine help with osteoarthritis?
Many people take glucosamine supplements for OA, and especially OA of the hip or knee.
Some studies suggest that glucosamine may:
- Reduce osteoarthritis-related pain, stiffness, and swelling in the joints
- Improve function in patients with knee or hip osteoarthritis
- Provide continued relief of symptoms for up to 3 months after patients stop treatment.
However, the Glucosamine and chondroitin Arthritis Intervention Trial (GAIT), which surveyed 1,600 participants in 16 locations across the U.S., found that glucosamine plus chondroitin sulfate did not provide significant relief from osteoarthritis.
Some participants with moderate-to-severe pain reported significant relief when they took the combination of glucosamine and chondroitin.
While this combination, or glucosamine alone, may relieve moderate to severe pain in patients with osteoporosis, overall, it appears to be no more effective than a placebo in slowing the loss of cartilage in knee osteoarthritis.
The score is based on reviews of a number of trials.
In a review of 18 trials in 2005, some indicated that glucosamine or glucosamine sulfate may benefit people with osteoarthritis, while others did not find it significantly effective.
A review of two trials for glucosamine hydrochloride in 2010 did not reveal a clinically significant improvement in joint pain or condition.
The NIH point out that while some people use creams containing glucosamine for arthritis pain, these creams usually contain other substances, such as camphor, and it may be these substances that relieve the pain. There is no evidence that glucosamine can be absorbed through the skin.
Other potential uses of glucosamine
Some studies have suggested that a form of glucosamine may help people with inflammatory bowel disease (IBD).
Glucosamine may help to prevent the autoimmune reaction involved in MS.
Scientists at the University of California, Irvine, found that N-acetyl glucosamine (GlcNAc) supplements suppressed the damaging autoimmune response that occurs in MS.
It appears that GlcNAc may inhibit the growth and function of abnormal T-cells that mistakenly cause a patient's immune system to attack and destroy myelin, the tissue that insulates nerves.
These findings were supported by a mouse study at Jefferson Medical College. The team found that over-the-counter (OTC) glucosamine helped delay the onset of MS symptoms in mice, and that it improved their ability to move and walk.
One study found that glucosamine may have a carry-over effect when used with ibuprofen to reduce pain levels in people with temporomandibular joint (TMJ) problems.
No evidence to support many uses
Glucosamine has been recommended for a range of conditions and illnesses, but studies have tended to be inconclusive, or have found it ineffective, or possibly harmful, for example, in people with an allergy.
Glucosamine side effects and safety concerns
Side effects are reported to be mild and infrequent, but include:note that glucosamine is "likely safe" when used properly by adults, but that some people have experienced mild side effects, including drowsiness, skin reactions, and headache.
The effect of glucosamine during pregnancy or breastfeeding is unknown, so it is not advisable to use it at these times.
Some people take glucosamine to treat allergies, but glucosamine products that are derived from shellfish may trigger allergies in people who are susceptible. People with a shellfish allergy are advised to avoid this type of glucosamine supplement.