Glucosamine is currently the most common bone and joint health supplement (often with chondroitin or non-denatured type II collagen), and is also an essential ingredient for the formation of hyaluronic acid, and it is estimated that 59% of the population who have used alternative therapies have used glucosamine
What are the effects of glucosamine in empirical medicine? Are there any side effects or contraindications? For details, please refer to the latest empirical discussion in the text
What is glucosamine?
Glucosamine is a natural amino acid monosaccharide found in the body’s connective tissue, cartilage, ligaments and other structures, and helps maintain strength, flexibility and elasticity in these areas.
Numerous studies have also pointed out that it has antioxidant and anti-inflammatory effects, so it is beneficial for diseases related to inflammation. Note 8
When to eat glucosamine? What is the dose?
To prevent stomach upset, glucosamine is best supplemented with food (preferably with meals).
In most clinical studies for the treatment of osteoarthritis, 3 – 300 mg is taken 500 times a day, for a total dose of about 900 – 1500 mg per day.
What are the proven efficacy benefits of glucosamine?
1. Glucosamine is beneficial to temporomandibular joint dysfunction
Temporomandibular disorder (TMD) is a musculoskeletal disorder characterized by persistent pain in the temporomandibular joint, masticatory muscles, and periauricular area. The incidence ranged from 21.5% to 50.5%, with a higher incidence in women than in men.
One of the common clinical manifestations is pain, which can affect the ears, eyes or throat, causing neck pain, facial pain and headaches, affecting an individual’s sleep, quality of life and mental health.
A meta-analysis (including 3 randomized controlled trials of temporomandibular joint dysfunction) suggested that chondroitin sulfate and glucosamine supplementation helped improve maximum mouth opening. Note 1
In addition, there was no statistically significant difference in pain reduction compared to the analgesic tramadol.
*Conclusion: For temporomandibular joint dysfunction, glucosamine supplementation with chondroitin sulfate may bring positive help, but limited by the small sample size, more studies are still needed to support it
2. Glucosamine improves osteoarthritis
Osteoarthritis is the most common degenerative joint disease, affecting joints such as the hips, knees, hands and feet, affecting more than 18% of people over the age of 25.
Pathological changes include progressive loss and destruction of articular cartilage, such as: thickening of subchondral bone, osteophyte formation, synovial inflammation, degeneration of ligaments and meniscus of the knee, enlargement of the joint capsule.
Key clinical symptoms include chronic pain, joint instability, stiffness, and narrowing of the joint space, and the causes are multifactorial, including joint injury, obesity, aging, and genetics.
A meta-analysis (18 randomised placebo-controlled trials associated with osteoarthritis) noted that oral glucosamine was helpful for pain relief compared with placebo (as measured by VAS pain score/visual analogue pain score and JKOM/JKOM/Japanese knee osteoarthritis scale), but had limited effect. Note 1
Another meta-analysis (17 randomised placebo-controlled trials of osteoarthritis, 2212 participants) suggests that oral glucosamine may have a small to moderate effect in reducing osteoarthritis-related pain, but has little effect on joint space narrowing. Note 2
In addition, smaller doses several times a day had a greater analgesic effect than large doses (1500 mg) once a day, suggesting that dosing schedules are important.
*Conclusion: To date, there is insufficient evidence to support that oral glucosamine can delay the natural course of joint degeneration, but may be somewhat helpful for pain relief
3. Glucosamine reduces the risk of colorectal cancer
Colorectal cancer is the third most common cancer in the United States and the third leading cause of cancer death, with about 1 in 18 people developing colorectal cancer in their lifetime.
Although survival rates vary widely depending on the stage of the disease, 5-year survival rates of up to 90% are reported if colorectal cancer is diagnosed early.
Currently, several colorectal cancer screening strategies are available to reduce morbidity and mortality, including fecal occult blood testing (FOBT), barium enema photography, flexible sigmoidoscopy, colonoscopy, virtual colonoscopy, and a combination of these tests.
A cohort study (113,067 participants) pointed out that compared with people who had not used glucosamine health products, some users could reduce the risk of colorectal cancer by about 17%, especially short-term use (less than 2 years), and long-term continuous use was less related. Note 3
The mechanism behind it is thought to be related to the anti-inflammatory effect of glucosamine (can inhibit inflammatory transcription factor/NF-kappaB and other pro-inflammatory hormones, such as tumor necrosis factor (TNF-a), interleukin-6 (IL-6), cyclooxygenase (COX-2), prostaglandin E-2 (PGE2)), which in turn affects cell growth, proliferation and survival.
*Conclusion: Population observations have found that oral glucosamine is associated with a lower incidence of colorectal cancer, but more randomized controlled trials are needed to support this
4. Glucosamine improves vascular endothelial function
Vascular endothelial cells run through the entire circulatory system, from the heart to the smallest capillaries, and these cells have unique functions that are essential for vascular biology.
These include regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammation and immune response, and cell growth.
If endothelial cells are dysfunctional, it is easy to cause hypertension, coronary artery disease, chronic heart failure, peripheral vascular disease, diabetes, chronic renal failure and severe viral infections.
A controlled study (4 weeks, 39 male volunteers) showed that taking glucosamine significantly increased flow-mediated vasodilation, but also improved intracellular total glutathione, reduced glutathione, reduced and oxidized glutathione ratios (intraerythrocyte GSH/GSSG). Note 5
*Conclusion: Oral glucosamine can improve vascular endothelial function by regulating intracellular redox state, but more large-scale studies are still needed to further validate.
5. Glucosamine reduces the risk of lung cancer
Lung cancer accounts for 17% and 9% of all cancers in men and women, respectively, and 19% of all cancer-related deaths, with the main types being adenocarcinoma, squamous cell carcinoma, small cell carcinoma and large cell carcinoma.
Major causative factors include smoking, exposure to secondhand smoke, occupational exposure to agents such as asbestos, nickel, chromium, arsenic, exposure to radiation, including radon gas in households and mines, and exposure to indoor and outdoor air pollution.
A follow-up study (Cohort Study, 76,904 participants) noted that long-term glucosamine use (≥ four times a week for more than 3 years) was associated with a lower risk of lung cancer (limited to adenocarcinoma). Note 6
*Conclusion: It has been found that subjects who take glucosamine daily have a lower risk of lung cancer, but more studies are needed to confirm the causal relationship
Does oral glucosamine affect blood sugar?
Glucosamine belongs to a type of aminomonosaccharide derivative and is a precursor to mucopolysaccharides and proteoglycans.
So there are some doubts that it may affect glucose metabolism and lead to insulin resistance, which has been demonstrated only in animal experiments.
A double-blind, placebo-controlled study (6.5 years, 407 middle-aged women, BMI ≥ 27 kg/m2) noted that oral glucosamine not only had no effect on mean glycated hemoglobin levels (HbA1c), but also did not cause hyperglycated hemoglobin or new-onset diabetes events in participants with normal baseline glycosylated haemoglobin levels. Note 4
However, for those with high glycated hemoglobin levels at baseline, although there was an impact on the observed values (increased HbA1c), it was not statistically significant.
*Conclusion: For non-diabetic patients, oral glucosamine does not affect glycosylated hemoglobin levels or increases the risk of new diabetes, but more studies are needed to confirm whether it has an effect on diabetics
Are there any side effects of glucosamine?
Oral glucosamine is highly safe for healthy adults, but mild side effects have been reported, mostly associated with gastrointestinal discomfort such as nausea, heartburn, diarrhea and indigestion, so it is recommended to be used with food to help reduce these conditions.
In addition, rare side effects include drowsiness, allergic skin reactions, and headache.
Safety precautions (11 contraindications to use)
1. May affect blood sugar and blood pressure (although not proven), so patients or those taking related hypoglycemic and blood pressure-lowering drugs, herbs or health products should be careful and be sure to monitor blood sugar and blood pressure regularly
2. Glucosamine products are mostly extracted from shrimp and crab carapaces, so people who are allergic to seafood may induce allergic reactions
3. May have a blood-thinning effect, so please use with caution if you have poor blood clotting function, take anticoagulants, or want to undergo surgery (need to stop 2 weeks before surgery)
4. Do not use by pregnant and nursing mothers (due to unknown safety)
5. May induce asthma, asthma patients please use with caution
6. Glucosamine sulfate contains high amounts of sodium or potassium, such as those who are on a restricted diet (limiting the amount of sodium in the diet) or taking potassium-sparing diuretics, please use with caution
7. Do not use it with anticancer drugs (such as Doxorubicin, Etoposide, Teniposide), which may affect the effect of the drug
8. Patients with glaucoma or high intraocular pressure should be careful, as a small study suggests that intraocular pressure may be raised. Note 7
9. Do not use in combination with the anti-inflammatory analgesic Acetaminophen (acetaminophen), which may affect the efficacy of the drug
10. For patients with chronic liver disease, there have been a few cases where it may increase the liver test index after taking it: Aspartine transamase (Asparate-Aminotransferase: AST). Note 9
11. There have been rare cases of drug-induced cholestasis taking chondroitin sulfate plus glucosamine, and the patient has no history of chronic liver disease. Note 1
What dosage forms are available for glucosamine?
The roughly visible on the market are glucosamine hydrochloride, glucosamine sulfate (usually using potassium chloride as a stabilizer), crystalline glucosamine sulfate.
N-acetyl glucosamine is another available form of salt, but it appears to have no clinical activity compared to other forms and is therefore rarely used.
Summary: Although glucosamine has the effect of lubricating joints and reducing joint pain, it is not suitable for all joint pain diseases (such as: rheumatoid arthritis, gout and infection, etc.), if the joint pain for unknown reasons for more than 1 week, please first find a doctor to diagnose, determine that it is the initial degenerative arthritis before considering taking it for a period of time, if it is effective, it is necessary to return to the doctor regularly to achieve the best treatment effect.