Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

Flexezy-ER Ingredients & Drug Interactions

by Physician's Signature

Flexezy-ER label
See full label image
Other (e.g. Tea Bag) Category: Non-nutrient/non-botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Flexezy-ER against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Flexezy-ER is a dietary supplement by Physician's Signature with 2 active ingredients. Its ingredients are commonly taken for osteoarthritis joint pain, joint stiffness, cartilage support.Based on those ingredients, 170 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Glucosamine Sulfate, Chondroitin Sulfate. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Flexezy-ER by Physician's Signature

Ask about any prescription or over-the-counter medication and we check it for interactions with Flexezy-ER by Physician's Signature — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
Prefer a human? Send your question to our licensed pharmacists — free, answered by email within 24 hours.

HelloPharmacist Scorecard of Flexezy-ER by Physician's Signature

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 30, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 2 active ingredients.
  • “Flexezy Proprietary Blend” is a proprietary blend — the label gives one combined amount (660 mg) without saying how much of each component you get.

Flexezy-ER contains 2 active ingredients: chondroitin sulfate and glucosamine sulfate. These are naturally occurring compounds that may support joint cartilage and are commonly combined in osteoarthritis products.

The product also contains several inactive ingredients — dicalcium phosphate, hypromellose, microcrystalline cellulose, a film coat, stearic acid, magnesium stearate, and silica — which serve as binders, fillers, and capsule materials.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: joint pain and cartilage support.
  • We looked for evidence on: Osteoarthritis, Joint pain, Knee pain, Back pain, Aromatase inhibitor-induced arthralgia, cartilage degradation — and 1 related terms.
  • The strongest evidence on file: Glucosamine is rated "Likely Effective" for Osteoarthritis (Natural Medicines).
  • Also on file: Chondroitin Sulfate is rated "Possibly Effective" for Osteoarthritis.
  • Also on file: Chondroitin Sulfate is rated "Insufficient Reliable Evidence To Rate" for Aromatase inhibitor-induced arthralgia.

Glucosamine sulfate is rated Likely Effective for osteoarthritis, meaning the evidence supporting its use for joint pain and function is reasonably solid. Chondroitin sulfate is rated Possibly Effective for both osteoarthritis and cataracts, meaning the evidence is encouraging but not yet conclusive.

For aging skin, osteoporosis, high cholesterol (hyperlipidemia), and colorectal adenoma, the evidence on chondroitin is insufficient to rate it — we don't have enough reliable data to say whether it works or doesn't. The same is true for glucosamine and aging skin, back pain, colorectal cancer, and metabolic dysfunction-associated steatotic liver disease (MASLD).

The evidence, ingredient by ingredient Chondroitin Sulfate Glucosamine

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Both chondroitin sulfate and glucosamine sulfate are generally well tolerated by most adults when taken by mouth, though quality and benefit vary between products. Common side effects from either ingredient include bloating, constipation, cramps, diarrhea, heartburn, and nausea.

Rarely, chondroitin has been linked to liver damage (hepatotoxicity) and skin symptoms like swelling of the eyelids, rash, or hives. Glucosamine has rare reports of severe side effects and allergic reactions, including in a small number of cases anaphylaxis (a serious whole-body allergic reaction); one review found that 72% of reported glucosamine adverse events involved hypersensitivity reactions.

Both ingredients carry a caution about varying quality and uncertain benefit for short-term use. Neither ingredient has enough safety data during pregnancy or breastfeeding — the safety information advises against using either while pregnant or nursing unless your doctor says otherwise.

Side effects, ingredient by ingredient Chondroitin Sulfate Glucosamine

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Chondroitin Sulfate, Glucosamine.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications.
  • For scale: 170 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking Flexezy-ER, double-check with your doctor or pharmacist if you take warfarin (Coumadin) or other blood thinners — glucosamine and chondroitin may increase their effect. Also flag any topoisomerase II inhibitor chemotherapy drugs (like etoposide or doxorubicin), diabetes medications, or regular acetaminophen use.

These combinations carry documented interactions we need to review with your personal medical history.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with clinical evidence supporting its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

Flexezy-ER may be worth considering if you have osteoarthritis and want to try glucosamine and chondroitin, which have some solid or encouraging evidence behind them. If you take warfarin or any other blood thinner, have diabetes, use topoisomerase II inhibitor chemotherapy, or regularly take acetaminophen, talk with your doctor or pharmacist before starting — these combinations need careful review.

Pregnant or breastfeeding? The safety data isn't there; check with your doctor or pharmacist first.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Sep 21, 2018.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Flexezy-ER, straight from the product label.

Brand Physician's Signature
Net contents 120 Caplet(s)
Market status On market
Date entered into DSLD Sep 21, 2018
DSLD ID 181013
Product type Non-nutrient/non-botanical
Supplement form Other (e.g. Tea Bag)
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Flexezy-ER by Physician's Signature, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
2 Caplet(s)
Maximum serving Sizes:
2 Caplet(s)
Servings per container
60
IngredientAmount% DV
Chondroitin Sulfate0 NP--
Glucosamine Sulfate0 NP--
Flexezy Proprietary Blend660 mg--

Other ingredients: Dicalcium Phosphate, Hypromellose, Microcrystalline Cellulose, Film Coat, Stearic Acid, Magnesium Stearate, Silica

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Brand IP Statement(s)

Each Flexezy-ER caplet is made to slowly release glucosamine and chondroitin over a 12 hour period.

Suggested/Recommended/Usage/Directions

Directions: Take two caplets in the morning and two caplets in the evening or as directed by your healthcare provider until results are achieved. Thereafter, you may continue the above serving or decrease to one caplet in the morning and one in the evening. Caplets may be taken with or without food.

Precautions

Caution: For adults only.

Consult your physician prior to using this product if you are pregnant, nursing or have any pre-existing conditions.

Warning: This product contains a chemical known to the state of California to cause birth defects or other reproductive harm.

Keep out of the reach of children

Do not use if seal is broken

Contains: Crustacean Shellfish (Crab & Shrimp).

Storage

Store in a cool, dry place

General Statements

Serving your family with pride since 1889 Rawleigh

Item# 102021 310E1261201/241016/9102021B

By W.T. Rawleigh

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Formula

Extended release Glucosamiine and Chondroitin Sulfate

Contains: Crustacean Shellfish (Crab & Shrimp).

FDA Statement of Identity

Dietary Supplements

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Flexezy-ER by Physician's Signature label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Flexezy-ER label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Flexezy-ER by Physician's Signature

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Caplet(s) Dosage formOther (e.g. Tea Bag) Servings per container60 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Flexezy Proprietary Blend

660 mg per serving

Other (inactive) ingredients: Dicalcium Phosphate, Hypromellose, Microcrystalline Cellulose, Film Coat, Stearic Acid, Magnesium Stearate, Silica. These complete the product’s ingredient list but are not active constituents.

Interaction report

Flexezy-ER by Physician's Signature Drug Interactions

Want to check YOUR meds against Flexezy-ER?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
170Drugs
2 Major 13 Moderate 155 Minor

Ingredients driving the most interactions

Glucosamine Sulfate 170
Chondroitin Sulfate 2

Individual Drug Interactions

The ingredients in Flexezy-ER interact with 170 drugs. Click any drug to see the details.

2 of the 2 ingredients in Flexezy-ER interact with drugs. Each result below shows which ingredient is responsible. Glucosamine Sulfate Chondroitin Sulfate

Each ingredient & the kinds of drugs it affects

For each ingredient in Flexezy-ER with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Glucosamine Sulfate4 drug types · 170 drugs

Warfarin (Coumadin)

Glucosamine might increase the anticoagulant effects of warfarin and increase the risk of bruising and bleeding.
In two individual case reports, glucosamine/chondroitin combinations were associated with a significant increase in international normalized ratio (INR) in patients previously stabilized on warfarin. In one case, the increase in INR occurred only after tripling the dose of a glucosamine/chondroitin supplement from 500 mg/400 mg daily to 1500/1200 mg daily. Additionally, 20 voluntary case reports to the U.S. Food & Drug Administration (FDA) have linked glucosamine plus chondroitin with increased INR, bruising, and bleeding in patients who were also taking warfarin. There have also been 20 additional case reports to the World Health Organization (WHO) that link glucosamine alone to increased INR in patients taking warfarin. The mechanism of this interaction is unclear. Glucosamine is a small component of heparin, but is not thought to have anticoagulant activity; however, animal research suggests that it might have antiplatelet activity.

Likelihood Probable Evidence D
Topoisomerase Ii Inhibitors

Theoretically glucosamine may induce resistance to topoisomerase II inhibitors.
In vitro research suggests that glucosamine might induce resistance to etoposide (VP16, VePesid) and doxorubicin (Adriamycin) by reducing inhibition of topoisomerase II, an enzyme required for DNA replication in tumor cells. This effect has not been reported in humans.

Likelihood Possible Evidence D
Acetaminophen (Tylenol, Others)

Acetaminophen might interfere with the activity of glucosamine sulfate by interacting with the sulfate portion.
Anecdotal reports suggest that adding glucosamine to an acetaminophen regimen might decrease pain control in patients with osteoarthritis. Some research suggests that the sulfate portion of glucosamine sulfate might contribute to its effect in osteoarthritis. Since acetaminophen metabolism requires sulfur and reduces serum sulfate concentrations, acetaminophen could theoretically interfere with the action of glucosamine sulfate. Conversely, the administration of sulfate could theoretically decrease the effectiveness of acetaminophen in sulfate-deficient people by increasing its clearance.

Likelihood Possible Evidence B
Antidiabetes Drugs

Despite initial concerns, it is unlikely that glucosamine will interfere with the effects of antidiabetes drugs.
In vitro and animal research has suggested that glucosamine might increase insulin resistance or decrease insulin production. This has raised concerns that taking glucosamine might worsen diabetes and decrease the effectiveness of diabetes drugs. However, clinical research suggests that glucosamine does not have adverse effects on blood glucose or glycated hemoglobin (HbA1C) in healthy, obese, or type 2 diabetes patients.

Likelihood Unlikely Evidence B
Glucosamine Sulfate full monograph & interactions

Chondroitin Sulfate1 drug type · 2 drugs

Warfarin (Coumadin)

Taking chondroitin in combination with glucosamine might increase the anticoagulant effects of warfarin. However, the effect of chondroitin alone is unclear.
There have been multiple reports of increased international normalized ratio (INR) in patients taking warfarin with glucosamine, with or without chondroitin. The lack of reports with chondroitin alone seem to suggest that the interactions occurring in these reports may have been due to glucosamine. In two individual case reports, glucosamine/chondroitin combinations were associated with a significant increase in INR in patients previously stabilized on warfarin. Additionally, 20 voluntary case reports to the US Food & Drug Administration (FDA) have linked glucosamine plus chondroitin with increased INR, bruising, and bleeding in patients who were also taking warfarin. There have also been 20 additional case reports to the World Health Organization (WHO) that link glucosamine alone, without chondroitin, to increased INR in patients taking warfarin.

Likelihood Unlikely Evidence D
Chondroitin Sulfate full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Flexezy-ER, from the product label.

Physician's Signature

See all Physician's Signature products
Name
Vitamins Direct
City
West Palm Beach
State
FL
ZipCode
33407
Phone Number
866-354-8384
Web Address
www.vitaminsdirectonline.com
Pharmacist Counseling Corner

Flexezy-ER by Physician's Signature: Common Questions

Does Flexezy-ER by Physician's Signature interact with any medications?
Yes. Based on its ingredients, Flexezy-ER has a known interaction with 170 medications, including 2 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Flexezy-ER contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
What is chondroitin sulfate and what does it do in this product?
Chondroitin sulfate is a naturally occurring compound found in cartilage. It's included here because evidence suggests it's possibly effective for osteoarthritis and cataracts, though the benefit isn't guaranteed and quality varies between products.
What is glucosamine sulfate and what does it do in this product?
Glucosamine sulfate is another naturally occurring compound that supports cartilage. It's rated likely effective for osteoarthritis, meaning the evidence that it may help joint pain and function is reasonably strong.
Can I take Flexezy-ER if I'm pregnant or breastfeeding?
The safety data isn't there for either ingredient during pregnancy or breastfeeding. The safety information advises against use in both situations unless your doctor advises otherwise — talk with your doctor or pharmacist before taking it.
What are the most common side effects I might experience?
The most common side effects from either glucosamine or chondroitin are bloating, constipation, cramps, diarrhea, heartburn, and nausea. Serious side effects are rare but have included liver damage and allergic reactions.
Does Flexezy-ER have any fillers or inactive ingredients?
Yes — it contains dicalcium phosphate, hypromellose, microcrystalline cellulose, a film coat, stearic acid, magnesium stearate, and silica as inactive ingredients to bind, fill, and form the capsule.
Is this product safe to take with acetaminophen?
There's a documented Minor-severity interaction between glucosamine and acetaminophen — in some cases acetaminophen may reduce glucosamine's effect on pain control. Check with your doctor or pharmacist about whether this product works well with your acetaminophen routine.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if Flexezy-ER is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Flexezy-ER label
Go deeper

The Full Monographs Behind Flexezy-ER’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Chondroitin Sulfate

Interacts with 2 drugs

Chondroitin sulfate is a naturally occurring building block of cartilage that is widely taken, often with glucosamine, for osteoarthritis joint pain. The evidence is mixed—some people report...

Read the full Chondroitin Sulfate monograph → Herb & supplement monograph

Glucosamine

Interacts with 170 drugs

Glucosamine is a natural compound found in cartilage and joint fluid, and it is one of the most popular supplements for osteoarthritis, especially of the knee. The evidence is mixed, with so...

Read the full Glucosamine monograph →
Sources

Sources & How We Checked

Flexezy-ER's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 80 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Chondroitin Sulfate 22 references
  1. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  2. Tallia AF, Cardone DA. Asthma exacerbation associated with glucosamine-chondroitin supplement. J Am Board Fam Pract 2002;15:481-4..
  3. Danao-Camara T. Potential side effects of treatment with glucosamine and chondroitin. Arthritis Rheum 2000;43:2853. PubMed
  4. Rozenfeld V, Crain JL, Callahan AK. Possible augmentation of warfarin effect by glucosamine-chondroitin. Am J Health Syst Pharm 2004;61:306-307. PubMed
  5. Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med 2006;354:795-808. DOI
  6. Knudsen J, Sokol GH. Potential glucosamine-warfarin interaction resulting in increased international normalized ratio: Case report and review of the literature and MedWatch database. Pharmacotherapy 2008;28:540-8. PubMed
  7. Yue QY, Strandell J, Myrberg O. Concomitant use of glucosamine potentiates the effect of warfarin. Jan 2006. Drug Safety 29(10):911-1010. DOI
  8. Nordling, J. and van, Ophoven A. Intravesical glycosaminoglycan replenishment with chondroitin sulphate in chronic forms of cystitis. A multi-national, multi-centre, prospective observational clinical trial. Arzneimittelforschung. 2008;58(7):328-335. PubMed
  9. Nickel, J. C., Egerdie, B., Downey, J., Singh, R., Skehan, A., Carr, L., and Irvine-Bird, K. A real-life multicentre clinical practice study to evaluate the efficacy and safety of intravesical chondroitin sulphate for the treatment of interstitial cystit
  10. Oliviero, U., Sorrentino, G. P., De Paola, P., Tranfaglia, E., D'Alessandro, A., Carifi, S., Porfido, F. A., Cerio, R., Grasso, A. M., Policicchio, D., and . Effects of the treatment with matrix on elderly people with chronic articular degeneration. Drug
  11. Crowley, D. C., Lau, F. C., Sharma, P., Evans, M., Guthrie, N., Bagchi, M., Bagchi, D., Dey, D. K., and Raychaudhuri, S. P. Safety and efficacy of undenatured type II collagen in the treatment of osteoarthritis of the knee: a clinical trial. Int.J.Med.Sc PubMed
  12. Nickel, J. C., Egerdie, R. B., Steinhoff, G., Palmer, B., and Hanno, P. A multicenter, randomized, double-blind, parallel group pilot evaluation of the efficacy and safety of intravesical sodium chondroitin sulfate versus vehicle control in patients with
  13. Sawitzke, A. D., Shi, H., Finco, M. F., Dunlop, D. D., Harris, C. L., Singer, N. G., Bradley, J. D., Silver, D., Jackson, C. G., Lane, N. E., Oddis, C. V., Wolfe, F., Lisse, J., Furst, D. E., Bingham, C. O., Reda, D. J., Moskowitz, R. W., Williams, H. J.
  14. Wildi, L. M., Raynauld, J. P., Martel-Pelletier, J., Beaulieu, A., Bessette, L., Morin, F., Abram, F., Dorais, M., and Pelletier, J. P. Chondroitin sulphate reduces both cartilage volume loss and bone marrow lesions in knee osteoarthritis patients starti
  15. Pavelka and et al. Double-blind, dose effect study of oral cs 4 & 6 1200mg, 800mg, 200mg against placebo in the treatment of femorotibial osteoarthritis. Wular Rheumatol Liter 1998;27(suppl 2):63.
  16. Cerda C, Bruguera M, Parés A. Hepatotoxicity associated with glucosamine and chondroitin sulfate in patients with chronic liver disease. World J Gastroenterol 2013;19(32):5381-4. PubMed
  17. von Felden J, Montani M, Kessebohm K, Stickel F. Drug-induced acute liver injury mimicking autoimmune hepatitis after intake of dietary supplements containing glucosamine and chondroitin sulfate. Int J Clin Pharmacol Ther 2013;51(3):219-23. PubMed
  18. Provenza JR, Shinjo SK, Silva JM, Peron CR, Rocha FA. Combined glucosamine and chondroitin sulfate, once or three times daily, provides clinically relevant analgesia in knee osteoarthritis. Clin Rheumatol 2015;34:1455-62. PubMed
  19. Ossendza RA, Grandval P, Chinoune F, Rocher F, Chapel F, Bernardini D. [Acute cholestatic hepatitis due to glucosamine forte]. Gastroenterol Clin Biol. 2007 Apr;31(4):449-50.
  20. Greenlee H, Crew KD, Shao T, Kranwinkel G, Kalinsky K, Maurer M, Brafman L, Insel B, Tsai WY, Hershman DL. Phase II study of glucosamine with chondroitin on aromatase inhibitor-associated joint symptoms in women with breast cancer. Support Care Cancer 201 PubMed
  21. Chu EC, Huang KHK, Cheung G, Ng G, Lin A. Delayed Skin Allergy to Glucosamine Chondroitin Supplement. Cureus 2023;15(3):e36310. PubMed
  22. Lila AM, Alekseeva LI, Baranov AA, et al. Chondroitin sulfate and glucosamine combination in patients with knee and hip osteoarthritis: A long-term observational study in Russia. World J Orthop 2023;14(6):443-457. PubMed

See these in context on the Chondroitin Sulfate monograph →

Glucosamine 58 references
  1. Adams ME. Hype about glucosamine. Lancet 1999;354:353-4. PubMed
  2. Balkan B, Dunning BE. Glucosamine inhibits glucokinase in vitro and produces a glucose-specific impairment of in vivo insulin secretion in rats. Diabetes 1994;43:1173-9. PubMed
  3. Giaccari A, Morviducci L, Zorretta D, et al. In vivo effects of glucosamine on insulin secretion and insulin sensitivity in the rat: possible relevance to the maladaptive responses to chronic hyperglycaemia. Diabetologia 1995;38:518-24. PubMed
  4. Holmang A, Nilsson C, Niklasson M, et al. Induction of insulin resistance by glucosamine reduces blood flow but not interstitial levels of either glucose or insulin. Diabetes 1999;48:106-11. PubMed
  5. Houpt JB, McMillan R, Wein C, Paget-Dellio SD. Effect of glucosamine hydrochloride in the treatment of pain of osteoarthritis of the knee. J Rheumatol 1999;26:2423-30.
  6. Barclay TS, Tsourounis C, McCart GM. Glucosamine. Ann Pharmacother 1998;32:574-9.
  7. Shankar RR, Zhu JS, Baron AD. Glucosamine infusion in rats mimics the beta-cell dysfunction of non-insulin-dependent diabetes mellitus. Metabolism 1998;47:573-7.
  8. Almada A, Harvey P, Platt K. Effects of chronic oral glucosamine sulfate on fasting insulin resistance index (FIRI) in non-diabetic individuals. FASEB J 2000;14:A750.
  9. Reginster JY, Deroisy R, Rovati LC, et al. Long-term effects of glucosamine sulfate on osteoarthritis progression: a randomised, placebo-controlled trial. Lancet 2001;357:251-6.
  10. Does glucosamine increase serum lipid levels and blood pressure? Pharmacist's Letter/Prescriber's Letter 2001;17(11):171115.
  11. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
  12. Monauni T, Zenti MG, Cretti A, et al. Effects of glucosamine infusion on insulin secretion and insulin action in humans. Diabetes 2000;49:926-35. PubMed
  13. Pouwels MJ, Jacobs JR, Span PN, et al. Short-term glucosamine infusion does not affect insulin sensitivity in humans. J Clin Endocrinol Metab 2001;86:2099-103. DOI
  14. Yun J, Tomida A, Nagata K, Tsuruo T. Glucose-regulated stresses confer resistance to VP-16 in human cancer cells through a decreased expression of DNA topoisomerase II. Oncol Res 1995;7:583-90.
  15. Pavelka K, Gatterova J, Olejarova M, et al. Glucosamine sulfate use and delay of progression of knee osteoarthritis: A 3-year, randomized, placebo-controlled, double-blind study. Arch Intern Med 2002;162:2113-23. PubMed
  16. Tallia AF, Cardone DA. Asthma exacerbation associated with glucosamine-chondroitin supplement. J Am Board Fam Pract 2002;15:481-4..
  17. Scroggie DA, Albright A, Harris MD. The effect of glucosamine-chondroitin supplementation on glycosylated hemoglobin levels in patients with type 2 diabetes mellitus: a placebo-controlled, double-blinded, randomized clinical trial. Arch Intern Med 2003; PubMed
  18. Hoffer LJ, Kaplan LN, Hamadeh MJ, et al. Sulfate could mediate the therapeutic effect of glucosamine sulfate. Metabolism 2001;50:767-70.. PubMed
  19. Yu JG, Boies SM, Olefsky JM. The effect of oral glucosamine sulfate on insulin sensitivity in human subjects. Diabetes Care 2003;26:1941-2. PubMed
  20. Danao-Camara T. Potential side effects of treatment with glucosamine and chondroitin. Arthritis Rheum 2000;43:2853. PubMed
  21. Guillaume MP, Peretz A. Possible association between glucosamine treatment and renal toxicity: comment on the letter by Danao-Camara. Arthritis Rheum 2001;44:2943-4. PubMed
  22. Rozenfeld V, Crain JL, Callahan AK. Possible augmentation of warfarin effect by glucosamine-chondroitin. Am J Health Syst Pharm 2004;61:306-307. PubMed
  23. Tannis AJ, Barban J, Conquer JA. Effect of glucosamine supplementation on fasting and non-fasting plasma glucose and serum insulin concentrations in healthy individuals. Osteoarthritis Cartilage 2004;12:506-11. PubMed
  24. Bush TM, Rayburn KS, Holloway SW, et al. Adverse interactions between herbal and dietary substances and prescription medications: a clinical survey. Altern Ther Health Med 2007;13:30-5.
  25. Stumpf JL, Lin SW. Effect of glucosamine on glucose control. Ann Pharmacother 2006;40:694-8. PubMed
  26. Pham T, Cornea A, Blick KE, et al. Oral glucosamine in doses used to treat osteoarthritis worsens insulin resistance. Am J Med Sci 2007;333:333-9. PubMed
  27. Muniyappa R, Karne RJ, Hall G, et al. Oral glucosamine for 6 weeks at standard doses does not cause or worsen insulin resistance or endothelial dysfunction in lean or obese subjects. Diabetes 2006;55:3142-50. PubMed
  28. Knudsen J, Sokol GH. Potential glucosamine-warfarin interaction resulting in increased international normalized ratio: Case report and review of the literature and MedWatch database. Pharmacotherapy 2008;28:540-8. PubMed
  29. Yue QY, Strandell J, Myrberg O. Concomitant use of glucosamine potentiates the effect of warfarin. Jan 2006. Drug Safety 29(10):911-1010. DOI
  30. Rozendaal RM, Koes BW, van Osch GJVM, et al. Effect of glucosamine sulfate on hip osteoarthritis: A randomized trial. Ann Intern Med 2008;148:268-77. PubMed
  31. Baron AD, Zhu JS, Zhu JH, et al. Glucosamine induces insulin resistance in vivo by affecting GLUT 4 translocation in skeletal muscle. Implications for glucose toxicity. J Clin Invest 1995;96(6):2792-801. PubMed
  32. Nelson BA, Robinson KA, Buse MG. High glucose and glucosamine induce insulin resistance via different mechanisms in 3T3-L1 adipocytes. Diabetes 2000;49(6):981-91. PubMed
  33. Giordano N, Fioravanti A, Papakostas P, et al. The efficacy and tolerability of glucosamine sulfate in the treatment of knee osteoarthritis: a randomized, double-blind, placebo-controlled trial. Curr Ther Res Clin Exp 2009;70(3):185-196. PubMed
  34. Shaygannejad, V., Janghorbani, M., Savoj, M. R., and Ashtari, F. Effects of adjunct glucosamine sulfate on relapsing-remitting multiple sclerosis progression: preliminary findings of a randomized, placebo-controlled trial. Neurol Res 2010;32(9):981-985. PubMed
  35. Cahlin, B. J. and Dahlstrom, L. No effect of glucosamine sulfate on osteoarthritis in the temporomandibular joints--a randomized, controlled, short-term study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112(6):760-766. PubMed
  36. Cerda C, Bruguera M, Parés A. Hepatotoxicity associated with glucosamine and chondroitin sulfate in patients with chronic liver disease. World J Gastroenterol 2013;19(32):5381-4. PubMed
  37. Hochberg MC, Martel-Pelletier J, Monfort J, Möller I, Castillo JR, Arden N,Berenbaum F, Blanco FJ, Conaghan PG, Doménech G, Henrotin Y, Pap T, Richette P, Sawitzke A, du Souich P, Pelletier JP; on behalf of the MOVES Investigation Group. Combined chondroi
  38. von Felden J, Montani M, Kessebohm K, Stickel F. Drug-induced acute liver injury mimicking autoimmune hepatitis after intake of dietary supplements containing glucosamine and chondroitin sulfate. Int J Clin Pharmacol Ther 2013;51(3):219-23. PubMed
  39. Provenza JR, Shinjo SK, Silva JM, Peron CR, Rocha FA. Combined glucosamine and chondroitin sulfate, once or three times daily, provides clinically relevant analgesia in knee osteoarthritis. Clin Rheumatol 2015;34:1455-62. PubMed
  40. Ossendza RA, Grandval P, Chinoune F, Rocher F, Chapel F, Bernardini D. [Acute cholestatic hepatitis due to glucosamine forte]. Gastroenterol Clin Biol. 2007 Apr;31(4):449-50.
  41. Audimoolam VK, Bhandari S. Acute interstitial nephritis induced by glucosamine. Nephrol Dial Transplant 2006;21(7):2031. PubMed
  42. Greenlee H, Crew KD, Shao T, Kranwinkel G, Kalinsky K, Maurer M, Brafman L, Insel B, Tsai WY, Hershman DL. Phase II study of glucosamine with chondroitin on aromatase inhibitor-associated joint symptoms in women with breast cancer. Support Care Cancer 201 PubMed
  43. Wilkens, P., Scheel, I. B., Grundnes, O., Hellum, C., and Storheim, K. Effect of glucosamine on pain-related disability in patients with chronic low back pain and degenerative lumbar osteoarthritis: a randomized controlled trial. JAMA 2010;304(1):45-52. PubMed
  44. Simon RR, Marks V, Leeds AR, Anderson JW. A comprehensive review of oral glucosamine use and effects on glucose metabolism in normal and diabetic individuals. Diabetes Metab Res Rev 2011;27(1):14-27. PubMed
  45. Smidt D, Torpet LA, Nauntofte B, Heegaard KM, Pedersen AM. Associations between labial and whole salivary flow rates, systemic diseases and medications in a sample of older people. Community Dent Oral Epidemiol 2010;38(5):422-35. PubMed
  46. Wangroongsub Y, Tanavalee A, Wilairatana V, Ngarmukos S. Comparable clinical outcomes between glucosamine sulfate-potassium chloride and glucosamine sulfate sodium chloride in patients with mild and moderate knee osteoarthritis: a randomized, double-blind
  47. Chopra A, Saluja M, Tillu G, Venugopalan A, Sarmukaddam S, Raut AK, Bichile L, Narsimulu G, Handa R, Patwardhan B. A Randomized Controlled Exploratory Evaluation of Standardized Ayurvedic Formulations in Symptomatic Osteoarthritis Knees: A Government of I
  48. Swinburne LM. Glucosamine sulphate and osteoarthritis. Lancet 2001;357(9268):1617. PubMed
  49. Murphy RK, Ketzler L, Rice RD, Johnson SM, Doss MS, Jaccoma EH. Oral glucosamine supplements as a possible ocular hypertensive agent. JAMA Ophthalmol 2013;131(7):955-7. PubMed
  50. Kimball AB, Kaczvinsky JR, Li J, et al. Reduction in the appearance of facial hyperpigmentation after use of moisturizers with a combination of topical niacinamide and N-acetyl glucosamine: results of a randomized, double-blind, vehicle-controlled trial.
  51. Ma H, Li X, Sun D, et al. Association of habitual glucosamine use with risk of cardiovascular disease: prospective study in UK Biobank. BMJ. 2019 May 14;365:l1628. PubMed
  52. Hoban C, Byard R, Musgrave I. Hypersensitive adverse drug reactions to glucosamine and chondroitin preparations in Australia between 2000 and 2011. Postgrad Med J. 2019 Oct 9. pii: postgradmedj-2019-136957. PubMed
  53. Tenti S, Veronese N, Cheleschi S, et al. Prescription-grade crystalline glucosamine sulfate as an add-on therapy to conventional treatments in erosive osteoarthritis of the hand: results from a 6-month observational retrospective study. Aging Clin Exp Res PubMed
  54. Yu H, Wu J, Chen H, et al. Glucosamine use is associated with a higher risk of cardiovascular diseases in patients with osteoarthritis: results from a large study in 685,778 subjects. Nutrients 2022;14(18):3694. PubMed
  55. Chu EC, Huang KHK, Cheung G, Ng G, Lin A. Delayed Skin Allergy to Glucosamine Chondroitin Supplement. Cureus 2023;15(3):e36310. PubMed
  56. Lila AM, Alekseeva LI, Baranov AA, et al. Chondroitin sulfate and glucosamine combination in patients with knee and hip osteoarthritis: A long-term observational study in Russia. World J Orthop 2023;14(6):443-457. PubMed
  57. Lehrer S, Morello T, Karrasch C, Rheinstein PH, Danias J. Effect of Glucosamine on Intraocular Pressure and Risk of Developing Glaucoma. J Glaucoma 2023. PubMed
  58. Rabade A, Viswanatha GL, Nandakumar K, Kishore A. Evaluation of efficacy and safety of glucosamine sulfate, chondroitin sulfate, and their combination regimen in the management of knee osteoarthritis: a systematic review and meta-analysis. Inflammopharmac PubMed

See these in context on the Glucosamine monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Supplement interaction checker › Check any supplement or product against your medications Drug–drug interactions › Check two or more of your medications against each other Browse medications A–Z › Every drug we've checked against herbs & supplements NDC & pricing lookup › Find a drug’s NDCs, packaging and costs Ask a pharmacist › Free, personal answer from our licensed team