Supplements: the few that work and the rest
Three have solid evidence, a handful are situationally useful, and the fat-burner aisle is the biggest waste of money in the industry.
6 min read
The supplement industry is worth billions, and the overwhelming majority of that money buys nothing. Not because supplements are a scam in principle — a few are genuinely effective — but because the ones that work are cheap, boring, and impossible to build a marketing story around.
Here is the honest sort.
The three with real evidence
Creatine monohydrate
The most studied sports supplement in existence, with hundreds of trials behind it. It increases the availability of phosphocreatine in your muscles, which improves performance in short, high-intensity efforts — which over months means more total training volume and more muscle.
Dose: 3 to 5 grams a day, every day, timing irrelevant. Loading phases are optional; they saturate your stores in a week rather than a month, and the endpoint is identical.
Form: Monohydrate. The expensive alternatives — HCl, ethyl ester, buffered versions — have never demonstrated superiority over plain monohydrate in a controlled comparison. Monohydrate is also the cheapest by a wide margin.
The water thing: Creatine draws water into muscle cells. You may gain one to two kilos on the scale in the first fortnight. This is intracellular water, not fat, and it is not bloating in the visible sense. Do not panic and stop.
It is safe in healthy people at these doses over long periods. The kidney concerns that circulate have not been substantiated in people with normal renal function.
Protein powder
Not magic. It is food in a convenient format, and its entire value is that it makes hitting a protein target easier when cooking is not practical.
Whey is cheap, complete and well absorbed. Casein is slower-digesting, which matters much less than it was once claimed to. Soy and pea blends work fine for plant-based diets — pea alone is a little low in methionine, so a blend is preferable.
If you comfortably hit your protein target from food, you do not need it. There is no additional benefit to getting protein from a tub.
Caffeine
Reliably improves training performance, endurance and perceived exertion, and mildly suppresses appetite.
Dose: roughly 3 to 6 mg per kilogram of bodyweight, 30 to 60 minutes before training. For an 80 kg person that is 240 to 480 mg — the upper end being quite a lot, equivalent to four or five coffees.
The catch: tolerance builds. If you already drink coffee all day, the pre-workout dose does much less. And caffeine has a half-life of around five hours, so an afternoon dose measurably damages sleep quality even in people who insist it does not. Given how much sleep matters for body composition, that trade is often a net loss.
The four worth considering, situationally
Vitamin D. Not a performance supplement, a deficiency correction. If you live somewhere with limited winter sunlight — the whole of the UK and northern Europe qualifies — deficiency is common. The NHS recommends 10 micrograms (400 IU) daily in autumn and winter. Worth a blood test rather than guessing.
Omega-3 (EPA/DHA). Reasonable evidence for cardiovascular and inflammatory markers. Genuinely useful if you rarely eat oily fish; largely redundant if you eat it twice a week.
Magnesium. Widely marketed for sleep on thin evidence. Genuinely useful if you are deficient, which is not rare given typical diets. Glycinate is better tolerated than oxide, which is poorly absorbed and mostly acts as a laxative.
Psyllium husk. Effective for fibre intake, cholesterol and regularity. Cheap. Covered properly in the fibre article.
That is the list. Everything below is where the money goes.
Fat burners
The category is close to worthless. Most are caffeine plus a proprietary blend of ingredients at doses too low to matter, sold at a very high markup.
The genuinely thermogenic compounds either work so weakly that the effect disappears into daily variation, or work well enough to be dangerous — which is why several have been withdrawn or banned. If a fat burner produced a meaningful metabolic effect, it would be a regulated drug, not a tub sold next to the tills.
The calories you did not eat do the work. Nothing in that aisle changes it.
BCAAs
Branched-chain amino acids had a good run and the evidence has not been kind. If you are eating adequate total protein, BCAAs add nothing — you are already consuming them, in better ratios, as part of complete proteins. Studies showing benefit generally used low-protein control groups.
If your protein intake is adequate, this is money set on fire.
Testosterone boosters
Tribulus, D-aspartic acid, fenugreek and the rest. In men with normal testosterone, these do not produce clinically meaningful increases. Where studies show a rise, it is usually small, temporary, or in men who were deficient to begin with.
If you genuinely suspect low testosterone — persistent fatigue, low libido, loss of morning erections, mood changes — that is a blood test and a GP conversation, not a supplement purchase.
Everything else
Glutamine, ZMA, tart cherry, ashwagandha, collagen, greens powders, apple cider vinegar. Some have small effects in specific contexts. None will be the reason your training does or does not work.
Greens powders deserve a particular mention: they are expensive, they do not replicate what vegetables do, and the dose of any individual nutrient is usually modest. Vegetables are cheaper.
What actually decides the outcome
In rough order: total calories, total protein, resistance training with progressive overload, sleep, consistency over months.
Supplements sit somewhere below all of those. Creatine, at perhaps £10 a month, might contribute a few per cent over a year. Getting an extra hour of sleep contributes more, and costs nothing.
The reason the industry thrives is that buying something feels like taking action, and taking action feels like progress. That feeling is the product. If you are going to spend money on your training, spend it on better food, a gym you will actually attend, or a few sessions with a coach who can fix your technique.
How to read a supplement label
Two things on the packaging tell you most of what you need to know.
Proprietary blends. If the label lists a "blend" with a total weight but not the individual doses, assume the expensive ingredients are present in trace amounts. This is the standard way of appearing to contain something without paying for a meaningful dose of it. A product that works has nothing to hide by listing exact quantities.
The dose against the research. Where a supplement cites a study, check the dose used in that study against the dose in the product. Ingredients that showed an effect at 3 grams frequently appear in products at 200 milligrams. The citation is technically accurate and practically meaningless.
Third-party testing is worth looking for if you compete in a tested sport, since supplement contamination with banned substances is a genuine and well-documented problem. Informed Sport and NSF Certified for Sport are the usual marks.
The regulatory position, briefly
In the UK and the US, supplements are regulated as foods rather than as medicines. That means they do not require pre-market approval for efficacy, and the manufacturer is largely responsible for their own safety and labelling claims.
The practical consequence is that "clinically proven" on a label carries far less weight than it appears to, and that what is in the tub is not independently verified unless the manufacturer has chosen to pay for testing.
This is not an argument that all supplements are contaminated or fraudulent. It is an argument for buying simple, single-ingredient products from large manufacturers with a reputation to protect, and for treating elaborate proprietary formulas with suspicion.
If you buy nothing else
Creatine monohydrate, unflavoured, in a large bag. It is the only supplement where the evidence is strong enough that not taking it is a mild disadvantage, and it costs less than a coffee a week.