FlexGuard Official Website › How It Works
How It WorksHow Does FlexGuard Work? Three Ideas in One Capsule
FlexGuard works by combining three approaches in one daily capsule.
Glucosamine and chondroitin supply materials cartilage is built from. Boswellia, turmeric, quercetin and bromelain act on inflammatory signalling, and MSM and methionine supply sulfur.
Three mechanisms, described the way the published work describes them, then the honest question of how much of each a 699 mg capsule can deliver.
The first FlexGuard pathway: supplying what cartilage is made of
The oldest idea in the category, and the one with the largest pile of trials.
Cartilage is a matrix of collagen and proteoglycans holding a great deal of water, and it has no blood supply of its own. Glucosamine is an amino sugar the body uses to build the glycosaminoglycan chains in that matrix; chondroitin sulfate is one of those chains.
The idea that taking them by mouth supports the tissue is fifty years old and has been tested more than any other proposition in this category. GAIT randomised 1,583 people to glucosamine, chondroitin, both, celecoxib or placebo. Neither supplement arm separated significantly from placebo for the group as a whole. A separate three-year trial of glucosamine sulfate at 1,500 mg a day reported changes in symptoms and in joint space width.
Between those two results sits a long argument about preparation, dose and which patients were studied. NCCIH's summary is the fairest short account of it, and its conclusion is that the evidence is mixed rather than settled in either direction.
What matters for this bottle is the amount. Every trial in that literature used 1,500 mg of glucosamine a day, usually with 1,200 mg of chondroitin. A FlexGuard capsule carries 500 mg and 50 mg.
An ingredient at a third of its trial amount is not a third as likely to work; it is simply untested at that amount. Nobody has run a randomised trial of 500 mg of glucosamine a day, so the honest position is that this row sits outside the evidence rather than against it. The ingredients page sets every row out the same way.
The second FlexGuard pathway: the four plant rows
Four botanicals, one of which is present at an amount its own trials would recognise.
Boswellia, turmeric, quercetin and bromelain are on this panel for a different reason. None of them is a building block; all four are proposed to act on the signalling that produces everyday joint discomfort.
Boswellia serrata, 67 mg
Boswellic acids, and AKBA in particular, are studied for their effect on the 5-lipoxygenase pathway. The 90-day trial of a 30 per cent AKBA extract reported improvements at 100 mg and 250 mg a day, and this row is the closest on the panel to a researched amount.
Turmeric root, 50 mg
Curcuminoids act on several inflammatory signalling pathways in laboratory work. The joint meta-analysis drew on trials using around 1,000 mg a day of curcuminoids, and NCCIH notes that curcumin taken alone is poorly absorbed. Root is not extract.
Quercetin, 8 mg
A flavonoid with antioxidant activity in the laboratory and limited human work at supplement doses. Its absorption is low and variable, which is part of why the human studies use several hundred milligrams rather than single ones.
Bromelain, 8 mg
Proteolytic enzymes with an anti-swelling reputation from post-surgical use. The osteoarthritis review found small trials at doses in the hundreds of milligrams. Enzyme preparations are usually sold by activity rather than by weight, and no activity figure is printed here.
Taken together these four contribute 133 mg of the capsule, of which boswellia is half. If this formula has a plant story, boswellia is it, and the other three are company.
The third FlexGuard pathway: sulfur, and the compound people confuse it with
Two rows, two common misreadings, and one of them is worth correcting plainly.
Sulfur turns up twice on this panel, in MSM and in methionine, and both rows are commonly misread.
MSM is an organic sulfur compound with a real joint literature. A 2017 review describes trials running from about 1.5 g to 6 g a day. Every published study measured its dose in grams; this panel measures it in single milligrams, and the difference is three orders of magnitude.
Methionine is an essential amino acid, and the confusion is with SAMe. The body converts methionine into S-adenosylmethionine, and the SAMe meta-analysis found that compound comparable to anti-inflammatories at about 1,200 mg a day. Supplying 8 mg of the precursor is not the same as supplying the product, and nothing on this label claims it is.
Sulfur is not in short supply in an ordinary diet. Eggs, meat, fish, garlic, onions and brassicas all carry sulfur amino acids in amounts a capsule cannot approach.
What one FlexGuard capsule actually delivers
The blunt part of this page, kept in one section rather than spread through it.
| Row | In one capsule | In the trials | What that means |
|---|---|---|---|
| Glucosamine sulfate | 500 mg | 1,500 mg a day | One third |
| Boswellia serrata | 67 mg | 100 to 250 mg of a standardised extract | The closest row on the panel |
| Chondroitin sulfate | 50 mg | 800 to 1,200 mg a day | About a sixteenth |
| Turmeric root | 50 mg | About 1,000 mg a day of curcuminoids | Root, not extract |
| Quercetin | 8 mg | 250 mg a day and upward | Below a dietary intake |
| Methionine | 8 mg | No trial of methionine alone | Untested at any amount |
| MSM | 8 mg | 1.5 to 6 g a day | Grams against milligrams |
| Bromelain | 8 mg | Hundreds of milligrams a day | A fraction |
A capsule is not a sum of eight separate products, and nothing here predicts what a blend does. The table exists so nobody has to take a marketing sentence on trust.
One row of the eight is in the neighbourhood of its own research. One is at a third. Six are well below. That is the shape of this capsule, and it follows directly from putting eight ingredients into one 699 mg dose rather than two ingredients into four capsules.
What FlexGuard cannot do, stated plainly
One section, so the rest of this page does not have to hedge.
It does not treat, prevent or manage arthritis, osteoarthritis or any other named condition. It is not a painkiller and it does not act within an hour. It does not rebuild cartilage.
Those are not modest disclaimers; they are what a dietary supplement is. The 2019 American College of Rheumatology guideline reviewed this ingredient class at full trial doses for diagnosed osteoarthritis and recommended against glucosamine, which is a conclusion about a medical question rather than about a comfort claim.
What the seller claims is joint comfort, mobility and support through everyday joint stress. The benefits page takes those three apart one at a time.
How FlexGuard works: short answers
How does FlexGuard work in the body?
Three ways, on paper. Glucosamine and chondroitin supply cartilage components; boswellia, turmeric, quercetin and bromelain act on inflammatory signalling; MSM and methionine supply sulfur. How much of each the capsule delivers is the separate question.
Does it work faster on an empty stomach?
Nothing on this panel needs one. The label gives no instruction either way, and bromelain is a digestive enzyme, so some people prefer it with food.
Why is it one capsule when other products are three?
Because the amounts are smaller. A product carrying 1,500 mg of glucosamine cannot fit it into one capsule; this one carries 500 mg and does.
Does FlexGuard rebuild cartilage?
No. No dietary supplement may claim that, and cartilage that has thinned does not thicken because a capsule contains one of its components.
Who publishes this FlexGuard website?
- 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(8):795-808. PMID 16495392. https://pubmed.ncbi.nlm.nih.gov/16495392/
- Reginster JY, Deroisy R, Rovati LC, et al. Long-term effects of glucosamine sulphate on osteoarthritis progression: a randomised, placebo-controlled clinical trial. Lancet. 2001;357(9252):251-6. PMID 11214126. https://pubmed.ncbi.nlm.nih.gov/11214126/
- National Center for Complementary and Integrative Health. Glucosamine and Chondroitin for Osteoarthritis: What You Need To Know. https://www.nccih.nih.gov/health/glucosamine-and-chondroitin-for-osteoarthritis
- Sengupta K, Alluri KV, Satish AR, et al. A double blind, randomized, placebo controlled study of the efficacy and safety of 5-Loxin for treatment of osteoarthritis of the knee. Arthritis Res Ther. 2008;10(4):R85. PMID 18667054. https://pubmed.ncbi.nlm.nih.gov/18667054/
- Daily JW, Yang M, Park S. Efficacy of turmeric extracts and curcumin for alleviating the symptoms of joint arthritis: a systematic review and meta-analysis of randomized clinical trials. J Med Food. 2016;19(8):717-29. PMID 27533649. https://pubmed.ncbi.nlm.nih.gov/27533649/
- National Center for Complementary and Integrative Health. Turmeric: Usefulness and Safety. https://www.nccih.nih.gov/health/turmeric
- Guo Y, Bruno RS. Endogenous and exogenous mediators of quercetin bioavailability. J Nutr Biochem. 2015;26(3):201-10. PMID 25468612. https://pubmed.ncbi.nlm.nih.gov/25468612/
- Brien S, Lewith G, Walker A, et al. Bromelain as a treatment for osteoarthritis: a review of clinical studies. Evid Based Complement Alternat Med. 2004;1(3):251-257. PMID 15841258. https://pubmed.ncbi.nlm.nih.gov/15841258/
- Butawan M, Benjamin RL, Bloomer RJ. Methylsulfonylmethane: applications and safety of a novel dietary supplement. Nutrients. 2017;9(3). PMID 28300758. https://pubmed.ncbi.nlm.nih.gov/28300758/
- Soeken KL, Lee WL, Bausell RB, et al. Safety and efficacy of S-adenosylmethionine (SAMe) for osteoarthritis. J Fam Pract. 2002;51(5):425-30. PMID 12019049. https://pubmed.ncbi.nlm.nih.gov/12019049/
- Kolasinski SL, Neogi T, Hochberg MC, et al. 2019 American College of Rheumatology/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee. Arthritis Rheumatol. 2020;72(2):220-233. PMID 31908163. https://pubmed.ncbi.nlm.nih.gov/31908163/
See the FlexGuard panel before you decide
Three mechanisms, eight rows, and one printed number against each. Sixty days from purchase to change your mind.
Two bottles $158 · six bottles $294 · 60 days from purchase
Order FlexGuard On The Official WebsiteOne capsule a day · 30 per bottle · lot FLE-26/FL-2166
