Every few weeks a well-meaning person hands me a jar the colour of a traffic light and asks, in a hopeful whisper, whether it works. I turn it over, read the panel, and feel the old familiar sigh gather in my chest like weather. Because the honest answer to do supplements actually work is not the answer anyone selling them would like me to give. The honest answer is: some do, in specific situations, for specific people. Most do very little for a healthy adult who eats reasonably. And a great deal of the industry is a triumph of graphic design over biochemistry.

I am not a doctor. I am a man who keeps goats and reads labels for entertainment, which is a lonelier hobby than it sounds. But I have watched a lot of neighbours spend a lot of money on jars, and I have formed opinions the way one forms a compost heap: slowly, and out of other people's discarded material. So let us sort the shelf together, honestly, and see which supplements are worth your money and which are merely worth someone's.

The uncomfortable first principle

Here is the sentence the industry would prefer you skimmed past: if you eat a broadly varied diet, get outdoors now and then, and are not pregnant, unwell, or on a restrictive regimen, you probably do not need most of what is on the shelf. A supplement, by its own name, supplements. It fills a gap. If there is no gap, you are paying good money to manufacture a very costly and vividly coloured urine, which your body will politely discard within the hour.

This is not cynicism. It is arithmetic. The value of a supplement is not the pill; it is the gap it fills. So the whole game — the entire honest game — is figuring out whether you have a gap, rather than whether the advertisement has a budget.

The short list that tends to earn its keep

There is a small, unglamorous handful of things with reasonable evidence or plain good sense behind them, in the right circumstances. None of these are cures for anything. They support ordinary function when something is genuinely missing. Read that sentence twice, because the marketing depends on you not reading it once.

  • Vitamin D — if you live somewhere grey, work indoors, cover up, or simply see the sun the way one sees an old friend (fondly, rarely), your levels may be low. A modest daily dose is cheap and sensible. A blood test tells you far more than a brochure does.
  • Vitamin B12 — genuinely worth it if you eat little or no animal food, or are older, when absorption quietly declines. If you eat meat and fish weekly, you almost certainly have plenty and a B12 supplement is a donation to the manufacturer.
  • Iron — this one matters and this one bites. Iron is worth it only if you are actually low, which a doctor confirms with a simple test. Do not self-prescribe iron on a hunch. Too much is not a bonus; it is a burden your body cannot easily shed. Test first. Please.
  • Omega-3 — the fatty acids in oily fish support normal function, and if you never eat sardines, mackerel, or their relatives, a supplement is a reasonable stand-in. If you do eat fish a couple of times a week, you are already handsomely supplied.
  • Magnesium — some people, particularly those eating few whole grains, nuts, and greens, run a little short, and topping up is inexpensive and low-drama. It is not a magic calm-in-a-capsule, whatever the moonlit packaging implies.
  • Creatine — the one the gym crowd is actually right about. It is among the most studied sports supplements there is, and for people doing resistance training it reasonably supports strength work. If your training consists of carrying shopping to the car, its benefits to you are more philosophical.
  • Fibre and probiotics — situational. Fibre from actual vegetables is superb and free of both cost and hype; a supplement helps some people whose diets are thin on plants. Probiotics can help in particular circumstances, though the effect is strain-specific and modest, not the internal renaissance the labels suggest.

Notice what this list is: boring, specific, conditional. That is precisely how you know it is honest. Truth in nutrition tends to arrive dressed plainly and slightly apologetic, whereas the miracles come in gold foil.

The theatre of the multivitamin

The multivitamin is the great comfort blanket of the medicine cabinet — a small daily rounding-error of reassurance. For most healthy, well-fed adults it is not harmful, and it is not much use either. It is insurance against a deficiency you likely do not have. If it helps you feel you have done a kind thing for yourself, I will not stand between a person and a small ritual of self-care. But let us not pretend it is doing heavy lifting. It is doing the metabolic equivalent of straightening a cushion.

The hall of expensive urine

And then there is the wing of the shop I visit only to marvel at the confidence of the copywriting. Detox teas that detox nothing (you were issued a liver and two kidneys at the factory, free of charge). "Immune-boosting" everything, as though the immune system were a soufflé that merely needed encouragement. Antioxidant megadoses that studies have repeatedly declined to reward. Fat-burners, brain-optimisers, cellular-rejuvenators, and any word ending in a hyphen and a promise.

The reliable tell is grammatical: the more a product claims to cure, heal, reverse, or boost, the less it does. Real supplements speak in the modest dialect of "supports normal function." Snake oil speaks in exclamation marks.

I bear the shopper no ill will. The industry is engineered to bewilder — that is the product, arguably more than the powder. When a shelf is designed to make an ordinary tired person feel one purchase away from vitality, the confusion is not a personal failing. It is the business model working as intended.

How to actually decide, without me

Here is the whole method, which fits on the back of a seed packet:

  • Test before you guess. A blood panel turns "maybe I'm low" into a fact. Facts are cheaper than years of jars.
  • Talk to a doctor or pharmacist before self-prescribing anything, especially iron, and especially if you take other medication — supplements can interact more than their friendly labels admit.
  • Fix the diet first. A pill is a poor apology for a plate that never sees a vegetable. The food does more, costs less, and tastes better than a capsule.
  • Distrust the adjective. If the front of the box works harder than the ingredients panel, the box is the product.

That is the entire honest science of the medicine cabinet, and it did not cost you a jar.

A small vision, from the goat pen

I dream, in my modest way, of a world where the supplement aisle is legally required to be as boring as it is true — plain panels, honest gaps, no gold foil, and a small sign at the entrance reading most of you are fine, go and eat some fish. I do not expect to see this world. But I intend to keep describing it until enough of us stop paying for the alternative, and the alternative gets quieter. Change, like a good compost heap, is mostly a matter of stubbornness over time.

Until then, spend where there is a real gap, skip where there isn't, and keep the difference. Your body will thank you, and so, discreetly, will your bank.

If you'd like all of this sorted properly — every supplement worth buying, every one that isn't, laid out plainly with no gold foil and no exclamation marks — the good people at NutriPeak have made an honest, instant digital reference called The No-BS Supplement Guide. It is precisely the sort of thing I wish the shop had handed me for free: what has decent support, what's expensive urine, and how to tell before you pay. Payable by card or crypto, delivered at once, and refreshingly short on miracles.