What a Surgeon Sees When He Reads Your Supplement Label

Written by Dr Jatin Joshi, co-founder and Chief Medical and Scientific Officer of Personally, and a researcher at the University of Oxford's Centre for Evidence-Based Medicine. I have a financial stake in this company, and you should weigh what follows with that in mind.

A note before we start: I co-founded Personally, and I make money if you buy it. Read everything below with that in mind, and hold the last section to a higher standard than the first five.

You have a shelf of bottles. Some you take out of habit, some because a podcast said to, and a few you would struggle to explain if someone asked. If a quiet part of you suspects half of them might be doing nothing, you are not being cynical. You are being observant.

I am a surgeon, and for most of my career I was more sceptical about supplements than you are. Then Crohn's disease cost me six feet of my intestine, and I lost the ability to absorb what I needed from food. Supplements stopped being optional for me. They became the thing I depend on to stay well. That is when I started reading the labels the way I read everything else in medicine: looking for the evidence, and noticing where it was not.

The short version. Before I take any supplement, I ask it five questions. Does the label tell me the dose, or hide it? Is there evidence for this exact thing, or for something that merely resembles it? Was the amount studied the amount in the bottle? Has anyone checked it against everything else I take? And was it built for a population, or for me? Very few products answer all five. Here is how to run the same five questions yourself, in the time it takes to turn a bottle around.

Turn the bottle around and look for the words "proprietary blend." It sounds like a mark of quality. It is closer to the opposite. A proprietary blend names the ingredients but not how much of each one is inside. You are told there is green tea extract and a dozen other things, and the total weight, but not whether the ingredient you actually care about is a real dose or a pinch added so it can appear on the label. In medicine, a dose you cannot see is a dose you cannot trust. If a product will not tell you how much of something it contains, treat that silence as your answer.

This is the one that catches almost everyone, because it is built to. A label points to a study. Read who the study was actually in. A great deal of supplement science is done in test tubes or in animals and never repeated in people. Some is done in people who are ill, then sold to people who are well. The mechanism sounds convincing, the reference looks real, and the leap from one to the other is quietly enormous.

There is a related idea worth putting down here, which is the assumption that natural means safe, or that because your body already makes something, more of it must be better. Neither holds. Digitalis is natural. So is arsenic. Something your body produces can still do you harm in the wrong amount. Natural tells you where a substance came from. It tells you nothing about whether it works, and nothing about whether it is safe at the dose in front of you.

If you have ever taken something faithfully for months, felt nothing, and quietly wondered whether the problem was you, this one is for you. Usually it was not you. A label can cite a real human trial, in the right people, with a real result, and still put a fraction of that dose in the bottle. The study is honest. The reference is real. The product simply holds too little to do what the study showed. You did everything right. It was never going to work.

You only have to set the two numbers next to each other to see it, and that is the point: you can only do that if the product tells you both. A product that shows you its doses is one you can check. A product that does not is asking you to take its word.

If you have ever stood at the counter holding a new bottle, wondering whether it is safe alongside your prescription, and had no real way to find out, that instinct was correct. Ingredients do not act alone. Some block the absorption of others when they share a pill. Some interact with prescription medicines. If you take anything for your thyroid, your mood, your blood pressure, or your blood sugar, the supplement you add on top is not a separate decision. It is part of the same picture. This is the question the industry asks least, and as a doctor it is the one that worries me most.

Most supplement doses trace back to the Recommended Daily Allowances, which began as a wartime public-health exercise in the 1940s. They have been rebuilt since, and rebuilt carefully, but the design has not changed in the one respect that matters to you. They are still a single number, set high enough to cover almost everyone in a large group of healthy people, precisely because requirements vary so much between individuals. That is a good and useful thing to have. It is not a description of you. And for a good many nutrients the underlying evidence is thin enough that the number is a considered estimate rather than a measured requirement.

You are not a population. You never were. A single fixed dose, sold to everyone, is an average, and the average person does not exist. This is the deepest problem of the five, and the one you cannot solve by shopping more carefully, because the whole shelf is built the same way: fixed units, made for the average, unchanged from the month you buy them to the month you stop.

Put them together and a pattern appears. Most supplements would not survive the standard we apply to medicines. Not because the ingredients are worthless, but because the product was built to be bought, not to be right. The dose is hidden, the evidence is borrowed, the amount is too small, nothing was checked against your prescriptions, and it was made for a population instead of a person. Once you have seen it, you cannot unsee it. It is why I stopped choosing supplements and started building them.

It would be a poor sort of honesty to hold every other supplement to those five questions and not answer them ourselves. So, plainly.

One. We name every ingredient and every dose. You can see exactly what is in your formula and how much.

Two. We assess the evidence for every ingredient in our library, and we say where it is strong and where it is not. Where the evidence is thin, we tell you it is thin rather than dressing it up.

Three. Because we publish every dose, you can run this question on us as easily as on anyone else. Set our number against the study and see for yourself. Most products make that impossible. We think being checkable is the point.

Four. We ask what medications you take, from a validated list rather than a text box, and we screen your formula against them before we build it. That is not a safety guarantee and it does not replace your doctor or pharmacist. It means the question that matters most is actually being asked, which is more than most of the shelf can say.

Five. We build your formula around you, from over seventy evidence-assessed ingredients, and rebuild it as your body changes.

That is the whole point of the company: to be the supplement that can be held to its own test.

You do not need to become a surgeon to ask these five questions. You need to know they exist, and to notice when a product avoids answering them. That noticing is most of the protection, and it is yours to keep whether you ever use Personally or not.