Do Supplements Actually Do Anything for Pain?

Walk down the supplement aisle of any Canadian pharmacy and the bottles make a coherent-sounding case: glucosamine for worn joints, turmeric for inflammation, collagen for cartilage, magnesium for aching muscles. A few of those products have real trials behind them. Most have marketing that borrowed the vocabulary of real trials. Knowing which is which is worth doing before the money goes out, because the honest answer is neither “supplements work” nor “supplements are useless” — it is that two or three of them do something modest for particular conditions, and the rest do very little for anyone.

What the licence on the label actually means

Anything sold legally as a supplement in Canada carries an eight-digit Natural Product Number (NPN), or a DIN-HM if it is homeopathic. The number means Health Canada has reviewed the product and listed it in the Licensed Natural Health Products Database, which anyone can search by product or company name.

That is worth more than nothing. It means someone checked the ingredients, the dose and the wording of the claim. But the standard of evidence a claim has to meet is not the standard a prescription drug meets. For many herbal ingredients, a licensed claim can rest on documented traditional use rather than on a clinical trial. So a licence tells you the product is what the label says and is unlikely to hurt most people at that dose. It does not tell you the product will help your pain.

A product with no NPN at all has not been reviewed by anyone. That includes a good deal of what is sold online and shipped from outside the country.

The ones with something behind them

Omega-3 (fish oil)

This is the strongest case on the shelf, and it is a narrow one. In rheumatoid arthritis — an inflammatory disease, not a wear-and-tear one — trials have fairly consistently found modest reductions in joint tenderness and morning stiffness, and, more reliably than the pain results themselves, a reduction in how many anti-inflammatories people take. The effect is real but small, it takes around three months to appear, and the doses used in trials are well above what a single capsule provides.

None of that carries over to osteoarthritis, which is the far more common condition and a different problem. If your diagnosis is knee or hip osteoarthritis, fish oil is not the thing to try first.

Vitamin D

Vitamin D matters here, but not in the way it is usually sold. Correcting a genuine deficiency is worth doing — it affects bone health, and Canadian winters make deficiency common. Topping up someone who already has enough has not reliably reduced pain in trials.

Health Canada advises everyone over 50 to take 400 IU a day, on the grounds that skin makes vitamin D less efficiently with age. Osteoporosis Canada recommends more — 800 to 2000 IU daily for adults over 50. Either is cheap and sensible. Neither should be expected to change how much your knees hurt.

Turmeric and curcumin

Several randomised trials have found that curcumin extracts reduce knee osteoarthritis pain over four to eight weeks, in a couple of cases about as much as ibuprofen. That sounds impressive until you look at the trials: they are small, short, use a dozen different proprietary formulations that are not interchangeable, and a large share are funded by the companies selling the extract. Reviewers who pool them keep reaching the same two-part conclusion — the signal is there, the quality of the evidence is too low to lean on.

There is also a safety point that has changed recently. Health Canada completed a safety review of turmeric and curcuminoid products and found a possible link to liver injury — rare, unpredictable, and occasionally serious. Licensed products are now expected to carry a warning about it. This applies to concentrated supplements, not to turmeric used as a spice in cooking.

The ones that mostly don’t

Glucosamine and chondroitin are the best-studied supplements in this category and the clearest disappointment. The large American GAIT trial compared glucosamine, chondroitin, the combination and placebo in knee osteoarthritis and found no overall advantage for any of them. Later reviews have gone the same way often enough that the American College of Rheumatology recommends against glucosamine for hand, hip and knee osteoarthritis, and Arthritis Society Canada describes the research as showing no clear or consistent benefit.

Collagen, MSM and magnesium are all sold hard for joint pain and all sit on much thinner evidence than glucosamine does — a scattering of small trials, mostly funded by manufacturers, with inconsistent results. Magnesium is genuinely useful for a deficiency and for some kinds of cramp; it has not been established as a treatment for chronic pain.

Why one can feel like it is working anyway

Plenty of people are certain a supplement helped them, and they are not being foolish. Chronic pain moves in cycles. People usually start something new during a bad stretch, which is exactly the point at which pain is most likely to improve on its own — not because of the capsule but because bad stretches end. Add the genuine placebo response, which is unusually strong for pain, and the fact that anyone spending forty dollars a month tends to also be walking more and sleeping better that month, and you have a reliable recipe for a treatment that feels effective without being effective.

This is precisely why trials use a placebo group. It is also why personal experience, yours or a friend’s, is weak evidence about a supplement even when it is strong evidence about how you felt.

The risks people underrate

Supplements get treated as automatically gentle because they are sold beside the vitamins rather than behind the counter. Several of the popular ones interact with prescriptions. Glucosamine and high-dose fish oil both interact with warfarin and other blood thinners. Glucosamine is commonly made from shellfish, which matters if you have that allergy. Concentrated turmeric now carries its liver warning. And taking four or five products at once multiplies the chance of an interaction while making it impossible to work out which one caused a problem.

What it costs, and what the money buys instead

Supplements are paid out of pocket. Provincial drug plans do not cover them, and most extended health benefits through work do not either. A single product typically runs $25 to $60 a month, and people rarely stop at one — two or three at once is common, which is several hundred dollars a year.

That is the comparison worth making. The same money over a year covers a block of physiotherapy sessions, a season of aquafit at a municipal pool, a decent pair of shoes and a cane fitted properly. Every one of those has better evidence behind it for chronic pain than anything on the supplement shelf.

If you want to try one, test it properly

There is nothing wrong with trying something the evidence is lukewarm about, as long as it is safe and you are honest about the result. The way to get a real answer is to run it like a small experiment.

• One product at a time. Starting three at once guarantees you learn nothing about any of them.
• Pick the measure before you start — minutes you can walk, stairs without stopping, how often pain wakes you — and write down where it is now.
• Give it eight to twelve weeks. Most of these are slow if they work at all, and anything that helps within three days is telling you about the week, not the capsule.
• Decide the stopping rule in advance: if the number has not moved by the end date, the bottle goes in the bin rather than into a subscription.
• Change nothing else major during the trial, or you will not know what did it.

That approach costs one product’s price to get an answer, instead of an indefinite monthly payment for a maybe.

A supplement that is genuinely working will still be working in three months, and you will be able to point at something that changed.

The short version: fish oil has a modest case in rheumatoid arthritis, vitamin D is worth taking if you are short of it or over 50, curcumin might do a little for knee osteoarthritis and now carries a liver caution, and glucosamine has been studied enough to conclude it mostly does not help. None of them is doing what a walking programme, a strength routine or a sensible pacing plan does. Supplements are the last five percent of a plan, not the first step of one.