Glucosamine is a popular ingredient in joint-health supplements, available in different forms and from both shellfish and plant-based sources. Here’s what you need to know about the research, dosage, side effects and choosing a glucosamine supplement.
🕒 8 min read
Glucosamine is one of the best-known ingredients used in supplements aimed at people looking after their joints. It occurs naturally in the body and is available in several supplemental forms, including glucosamine hydrochloride (HCl) and glucosamine sulphate.
Glucosamine at a glance
- Glucosamine occurs naturally in the body and is associated with cartilage and other joint structures.
- Supplements commonly contain glucosamine hydrochloride (HCl) or glucosamine sulphate.
- Research into glucosamine for osteoarthritis has produced mixed results.
- Digestive symptoms are among the most commonly reported side effects.
- Glucosamine can interact with warfarin, so anyone taking warfarin should seek medical advice before using it.
What is glucosamine?
Glucosamine is an amino sugar that occurs naturally in the body and is associated with molecules found in cartilage and other connective tissues around the joints.
Glucosamine is also widely available in supplement form and is commonly included in products designed for people looking after their joints. It is frequently combined with other ingredients such as chondroitin.
For more information on that combination, read our guide to glucosamine and chondroitin.
Does glucosamine work?
Glucosamine has been studied extensively, particularly in people with knee osteoarthritis, but research findings remain inconsistent.
What does the research say?
A 2023 systematic review of randomised controlled trials reported some improvements in pain measures among people with osteoarthritis, but also found that improvements across commonly used pain, stiffness and physical-function measures were inconsistent. The authors noted substantial differences between the studies included.1
A 2018 meta-analysis found that glucosamine showed an effect on stiffness compared with placebo, while results differed for other outcomes. The researchers also found insufficient evidence that taking glucosamine together with chondroitin was superior to placebo.2
In the UK, NICE advises against offering glucosamine to manage osteoarthritis because it considers there to be no strong evidence of benefit. NICE notes that the evidence is inconsistent and that larger benefits tended to come from smaller, lower-quality studies.3
Glucosamine should therefore not be considered a proven treatment for osteoarthritis or persistent joint pain. If you have unexplained, recurring or worsening joint pain, speak to a healthcare professional for advice.
What are the different types of glucosamine?
The two forms most commonly found in oral supplements are glucosamine hydrochloride and glucosamine sulphate.
Glucosamine hydrochloride (HCl)
Glucosamine hydrochloride contains a relatively high proportion of glucosamine base by weight and can be sourced from shellfish or produced from plant-derived materials.
Healthspan's Optiflex® glucosamine HCl is produced from a plant-based corn source and is suitable for vegetarians and vegans.
Glucosamine sulphate
Glucosamine sulphate is another commonly used form. A large proportion of the clinical research into glucosamine has investigated glucosamine sulphate rather than HCl.1
Because different forms and formulations have been used in research, findings from one product should not automatically be applied to another.
What about N-acetyl glucosamine?
N-acetyl glucosamine is another form of glucosamine found in some specialist products. It is chemically different from glucosamine HCl and glucosamine sulphate, so the forms should not be treated as interchangeable.
Can you get glucosamine from food?
There are no significant everyday dietary sources of glucosamine. Traditionally, glucosamine used in supplements has often been extracted from crustacean shells, including prawn, crab and lobster shells.
Plant-based alternatives are now available. These produce glucosamine from plant-derived glucose rather than shellfish, making them suitable for people looking for a vegan or shellfish-free source.
Plant-based glucosamine can provide a shellfish-free option for vegetarians, vegans and people wishing to avoid crustacean-derived ingredients.
How is Healthspan's plant-based glucosamine made?
Healthspan's Optiflex® glucosamine HCl uses GlucosaGreen®, a glucosamine ingredient produced by TSI using glucose derived from non-GMO corn and a direct fermentation process.
This removes the need to extract glucosamine from shellfish. TSI reports that its GlucosaGreen® process uses substantially less water and generates less solid waste than conventional shellfish-derived glucosamine production.4
Why use a corn-based source?
GlucosaGreen® provides a plant-based, shellfish-free source of glucosamine. According to its manufacturer, the fermentation process also reduces the environmental impact associated with conventional shellfish-derived production.4
How much glucosamine should I take?
There is no single recommended amount that applies to every glucosamine supplement. Products contain different forms and quantities of glucosamine, so always follow the dosage instructions provided with the individual product.
The way glucosamine strength is expressed can also be confusing. In 2018, the Medicines and Healthcare products Regulatory Agency (MHRA) announced that products supplying at least 1,178 mg per day of base glucosamine would be regarded as medicines. Products below that level can continue to be supplied as food supplements.5
Healthspan's Optiflex® Glucosamine HCl 1325mg provides 1,100 mg of glucosamine base per tablet. Always use the serving instructions stated on the pack rather than applying doses used in clinical trials to a different formulation.
When should I take glucosamine?
There is no established best time of day to take glucosamine. Follow the directions supplied with your individual supplement and take it consistently according to the recommended intake.
Optiflex® Glucosamine HCl 1325mg with Vitamin C
Maximum level of pure glucosamine
- 1325 mg glucosamine HCl per tablet
- Sustainable plant-based source
- Added vitamin C
What are the side effects of glucosamine?
Glucosamine is generally well tolerated in clinical studies, although side effects can occur. Gastrointestinal symptoms are among those most commonly reported.1
Possible glucosamine side effects include:
- Stomach discomfort
- Nausea
- Heartburn or indigestion
- Bloating
- Diarrhoea
If you experience a suspected adverse reaction after taking a supplement, stop taking it and seek advice from a healthcare professional.
Who shouldn't take glucosamine?
If you are pregnant or breastfeeding, take prescribed medication or have an existing medical condition, speak to a healthcare professional before taking a glucosamine supplement.
Taking warfarin?
Glucosamine can interact with warfarin. UK prescribing information reports increased INR in people taking glucosamine and warfarin and states that this combination is not recommended.6
If you have a shellfish allergy, check the source and allergen information on the individual product. Many conventional glucosamine supplements use crustacean-derived ingredients, while plant-based alternatives such as Healthspan Optiflex® are available.
Should you take glucosamine supplements?
Glucosamine remains a popular ingredient in joint-health supplements, but research does not support presenting it as a proven treatment for osteoarthritis or joint pain.
If you choose to take glucosamine, look carefully at the form, source and amount provided and follow the product instructions. Supplements should be considered alongside a balanced diet and healthy lifestyle rather than as a replacement for appropriate medical care.
For people with osteoarthritis, NICE identifies therapeutic exercise and, where appropriate, weight management as core approaches to management.3 Our guide to exercises for healthy joints has practical ideas for keeping active.
What can you take with glucosamine?
Chondroitin
Glucosamine and chondroitin are frequently combined in joint-health supplements. Research into the effectiveness of the combination is mixed, so read our guide to glucosamine and chondroitin for a closer look at the evidence.
Turmeric
Turmeric and glucosamine are also commonly found within the same joint-health routine. Our turmeric vs glucosamine guide explains how they differ and what the research says.
Glucosamine FAQs
What are the most common side effects of glucosamine?
Reported side effects are usually digestive and can include nausea, stomach discomfort, heartburn, bloating and diarrhoea. If you experience a suspected adverse reaction, stop taking the supplement and seek advice from a healthcare professional.
What happens if you take glucosamine every day?
Many glucosamine supplements are designed for daily use. Follow the recommended intake on the individual product and do not exceed it. If you take prescribed medication or have a medical condition, speak to your doctor or pharmacist before using glucosamine regularly.
Why don't doctors recommend glucosamine for osteoarthritis?
NICE advises healthcare professionals not to offer glucosamine to manage osteoarthritis because the evidence is inconsistent and it considers there to be no strong evidence of benefit.3
Which is better: glucosamine HCl or glucosamine sulphate?
They are different forms of glucosamine. HCl contains a higher proportion of glucosamine base by weight, while much of the clinical research has investigated glucosamine sulphate. This does not mean one form is automatically more effective than the other, because results from one formulation cannot necessarily be applied to another.
Can you take glucosamine with warfarin?
Glucosamine can interact with warfarin. Increased INR has been reported when the two are taken together, and UK prescribing information states that the combination is not recommended. Speak to your doctor or pharmacist before taking glucosamine if you use warfarin.6
Can vegans take glucosamine?
Yes, provided the glucosamine is made from a plant-based source. Traditional glucosamine is often derived from crustacean shells, but vegan alternatives made using plant-derived glucose are available. Always check the individual product information.
How long does glucosamine take to work?
Research does not establish a reliable timeframe in which everyone should expect to notice an effect. Clinical studies use different forms, doses and study periods, so it is better to follow the individual product instructions rather than expect a guaranteed result after a set number of weeks.
