What Supplements to Take on a GLP-1

I get asked this more than any other question, and the honest answer is shorter and duller than people want. Most of the supplement industry’s interest in GLP-1 users is opportunistic. A small part of it is genuinely useful, and the useful part is mostly cheap.

Here is how I think about it.

The problem is volume, not appetite

The drug works by making you not want food. That is the therapeutic effect and it is doing its job. The side effect of the therapeutic effect is that total intake commonly falls by something like 30–50%, and it falls across the board — you do not eat proportionally less of everything except the iron.

Your requirements do not fall with your intake. You still need roughly 2.4 mcg of B12 a day, 8 mg of iron if you are a man and 18 mg if you are a premenopausal woman, 310–420 mg of magnesium, 600–800 IU of vitamin D. Those numbers were written for someone eating a normal volume of food. You are not.

So the whole supplement question reduces to one thing: nutrient density per bite has to go up, because the number of bites went down. Everything below is a consequence of that.

The second consequence is lean tissue. Body-composition substudies of the pivotal trials report lean mass making up roughly a quarter to 40% of total weight lost, which is broadly what any rapid weight loss does — but the weight loss here is not modest. STEP 1 reported a mean 14.9% at 68 weeks; SURMOUNT-1 reported 20.9% at 72 weeks on the top tirzepatide dose. A quarter of 20% is a lot of muscle. I have written about why that matters in muscle is the whole game.

The short list

Four things. This is the part I would defend to a colleague.

1. Protein. Target about 1.2–1.6 g per kg of body weight per day, spread across the meals you do eat, with roughly 25–30 g at a sitting so each one crosses the leucine threshold that actually triggers muscle protein synthesis. On 800 kcal a day this is arithmetically hard from food alone, which is the entire argument for a powder: it is the most protein you can get into the smallest volume. See the protein powder rankings.

2. Creatine, 3–5 g a day. Monohydrate, no loading phase needed, one of the best-evidenced and cheapest supplements in existence. It supports strength work, which is what actually preserves lean mass. One thing nobody tells you: it raises serum creatinine without harming the kidney, which can look like falling kidney function on a routine panel. That is worth knowing before your next blood test, and it is covered in the creatine rankings.

3. A soluble fiber. Constipation is the most durable side effect on these drugs — nausea fades, constipation often does not — and it is partly a food-volume problem. Less food means less fiber and less bulk. Psyllium or partially hydrolysed guar gum, started low, taken with real fluid. Not insoluble bran, which on a stomach that is already emptying slowly tends to make bloating worse. See the fiber rankings.

Creatine and electrolytes are increasingly sold together in one scoop, which is a sensible response to the fact that both go short for the same reason — Minome’s GLP-1 Foundation is the version of that I rate highest, and it places second in both rankings.

4. Fluid, with electrolytes when you need them. Thirst cues get quieter along with hunger cues, and a chunk of daily fluid normally comes from food you are no longer eating. On an ordinary week, water is fine. During a week with vomiting or diarrhea, an oral rehydration formulation is not a wellness product, it is the correct medical response — the electrolyte rankings explain why the sachet with the glucose in it beats the one without.

Tier two: reasonable, conditional

Each of those has its own ranking: multivitamins, magnesium and probiotics, where I have tried to be honest about how thin the evidence gets at the bottom of the list.

The distinction in that last column is the one that matters. A multivitamin is insurance. A specific nutrient is treatment, and treatment gets dosed against a number and re-checked. Iron in particular: taking it without knowing your ferritin is how people spend six months treating the wrong thing, or occasionally how they cause harm. Reading your own labs covers which numbers to ask for.

What I do not recommend

• High-dose biotin. It does nothing for hair unless you are frankly deficient, which is rare, and it interferes with a long list of immunoassays including troponin and thyroid function. A biotin-driven false troponin result in an emergency department is a genuinely dangerous thing to carry around in your bloodstream. The FDA has issued a safety communication about it.
• Anything positioned as doing what your prescription does. Berberine is not a GLP-1, and “nature’s Ozempic” is marketing rather than pharmacology — no supplement produces the 15–20% weight loss these drugs produce in trials. Berberine does have its own modest evidence for glucose and lipids, separate from that claim, and I have ranked it on those terms in the blood-sugar rankings. What to avoid is the product that implies you could take it instead.
• Detox and cleanse products, on a drug whose common adverse effects already include diarrhea and dehydration.
• Anything you cannot name the dose of. Proprietary blends exist so you cannot tell how little is in them.
• Appetite suppressants. You are on the most effective appetite suppressant ever brought to market. Stacking is not the problem you have.

Taking them when your stomach is slow

Delayed gastric emptying changes the practical side of this more than people expect.

• Large capsules are harder. Powders, liquids and chewables go down more easily; a two-a-day multivitamin in small capsules beats one horse tablet.
• Split doses. Two smaller doses land better than one big one on a stomach holding food longer than it used to.
• Iron and calcium compete, and both compete with the thyroid replacement you may also be taking. Space them by at least four hours.
• Take them with the meal you actually finish, which for most people is not dinner.
• On injection day and the day after, consider moving anything that reliably makes you queasy — often iron, sometimes fish oil — to the far end of the dosing week.

The order I would add them in

If you start everything at once and something makes you feel worse, you will not know what it was. So: protein first, for a fortnight. Then fiber, started at a third of the label dose and worked up over two weeks. Then creatine. Then a multivitamin. Then, only after a blood test, whatever the blood test said.

Two problems get left out of that sequence on purpose, because they are the two people most want a supplement for and the two where supplements do least: facial volume loss and hair shedding. Both have their own article, and both start by explaining what is actually happening before recommending anything.

Three of the tier-two items now have rankings of their own: vitamin D, omega-3 and iron — the last of which comes with a firm precondition about testing first.

If you came here for a symptom

Most people arrive at this page with one specific problem rather than a general question. The rankings are organised that way too:

That sequence takes about two months. It is slower than buying six bottles on a Sunday evening, and it is the difference between knowing what is helping you and hoping.

None of this is medical advice for you specifically, and every item here is worth running past your own prescriber and pharmacist — particularly if you take thyroid replacement, an anticoagulant, insulin or a sulfonylurea, where the interactions are real rather than theoretical.