Glucosamine, chondroitin and MSM: tested on the wrong people

Every grappler over 30 has a jar of these somewhere. Knees that complain on the stairs, a shoulder that clicks, hands that took 8 weeks of bag work and have opinions about it. The joint aisle is aimed precisely at that.

So let me tell you who the research was done on, because it was not you.

The population problem

Almost the entire evidence base for glucosamine and chondroitin comes from patients with diagnosed osteoarthritis of the knee or hip.

That is a degenerative disease, usually in older adults, in which cartilage has already been lost and the joint space has narrowed. It is a different problem from a 26 year old wrestler whose knees ache because he trains twice a day on a mat.

Whatever those trials found, they were not measuring your situation. Hold that thought, because what they found makes the transfer question largely academic.

The big independent trial

The Glucosamine/Chondroitin Arthritis Intervention Trial, known as GAIT, was funded by the United States National Institutes of Health. No supplement company paid for it.

The programme cost around 12.5 million dollars and ran across several years, with the main intervention lasting 24 weeks.

It enrolled 1,583 patients, randomised to glucosamine at 1,500 mg a day, chondroitin at 1,200 mg a day, both together, celecoxib at 200 mg a day, or placebo.

For the study population as a whole, the supplements were ineffective.

The comparison arm is what makes that finding stick. Celecoxib, an actual anti-inflammatory drug, produced significant relief: 70.1 percent of that group achieved a 20 percent or greater reduction in pain, against 60.1 percent on placebo, p = 0.008.

The trial was capable of detecting a real effect. It detected one. It simply was not the supplements.

The number that should change how you read this aisle

A network meta-analysis published in the BMJ pooled 10 large randomised trials covering 3,803 patients with knee or hip osteoarthritis.

On a 10 centimetre pain scale, the difference against placebo came out at 0.4 cm for glucosamine, 0.3 cm for chondroitin, and 0.5 cm for the combination.

None of those estimates crossed the threshold of the minimal clinically important difference. Measurable on paper. Too small for a patient to feel.

Then the finding that reframes the rest of this page.

The authors ran a subgroup analysis by funding source. Trials independent of industry showed smaller effects than trials paid for by the companies selling the product, and the interaction was significant at p = 0.02.

Who paid for the study predicted how well the supplement performed. Better than the dose did. Better than the duration did.

MSM

Methylsulfonylmethane is the third name on these labels, usually stacked with the other two.

The best-known trial in an exercise population followed half-marathon runners taking 3 g a day for 21 days before the race and 2 days after. Post-race muscle and joint pain was reduced at a level the authors called clinically but not statistically significant. No outcome reached statistical significance in the time-by-treatment analysis, and there was no effect on oxidative stress or muscle damage markers.

There were 11 people in each group.

The declared conflict of interest states that the lead author was employed by the manufacturer of the MSM product used during the study period, though not paid by them to conduct it.

An earlier pilot in healthy men found trends toward reduced soreness and fatigue that did not reach significance either.

Two small pilots, trends rather than results, and the same funding shadow across the top. MSM may still turn out to do something; so far nobody has shown that it does much, in anybody, at any dose.

What this means for a fighter

Put the three findings side by side. The research population is not you. The effects measured in that population sat below what a patient would notice.

And the size of those effects tracked who paid for the trial.

For a healthy athlete whose joints ache from training load rather than from cartilage disease, the honest expectation from this aisle is close to nothing, and the mechanism by which it would help your specific problem has never been demonstrated.

I have watched fighters spend 40 or 50 a month on this for years. I have never once seen it change a training week.

What actually helps a fighter's joints

Less satisfying than a jar. It works.

Training load first. Joint pain in a camp is nearly always a volume and surface problem before it is a nutritional one, and the answer usually lives in the training plan rather than in the kitchen.

Body mass second. Every kilogram you carry through a session is loaded through the same knee. A fighter walking around 15 kilograms above fight weight asks more of those joints than one walking around 8 kilograms above, every day of camp, before any supplement enters the conversation.

That is one more argument for choosing a weight class you can actually hold.

Then collagen, and specifically the protocol rather than the product. The research effect depends on loading the tissue you care about roughly an hour after the dose. Without the loading, the studies found almost nothing.

It is the one item in this general area with a tested protocol behind it.

And if a joint is injured rather than sore, that is a physiotherapist and a diagnosis. No supplement substitutes for knowing what is actually wrong, and nutrition during an injury is a separate job from preventing one.

Who I would say yes to

• Nobody, on the evidence as it stands, purely for joint protection or performance in a healthy athlete.
• A fighter over 40, or one with diagnosed osteoarthritis, sits closer to the studied population and should have that conversation with a doctor rather than with a shop assistant.
• If somebody has taken it for years, believes it helps, tolerates it well and the product is certified, I am not going to spend a consultation arguing about it. There are larger problems in most plans.

Who I would say no to

• Anyone buying it instead of addressing training volume.
• Anyone buying it expecting it to fix an injury.
• Anyone buying it uncertified. It carries the same exposure as everything else: in one analysis of 200 products bought from ordinary retailers, 70 contained a substance prohibited by WADA, and 57 percent of those did not declare it on the label.

The pattern across this whole shelf

Something deserves naming, because it has now appeared 3 times in this series.

The original ZMA testosterone study was paid for by the patent holder, and an independent replication found nothing. The most eye-catching HMB result was excluded from a later meta-analysis for sitting implausibly far from a normal training response.

And here, across 10 trials and nearly 4,000 patients, effect size moved with the funding source.

When a supplement's evidence is strongest in the studies its manufacturer paid for, that is itself the finding. Read the funding statement before the abstract, and read both before the label.