What supplements to take with a GLP-1

Short answer: there is no required list. A 2025 joint advisory from four US medical societies says supplements "can be proactively considered for at-risk nutrients, such as vitamin D, calcium, B12, or a multivitamin-mineral tablet, at appropriate doses and tailored to each person's needs".¹ Beyond those, protein, fiber and electrolytes are the gaps people most often fill. Which ones you need depends on what you eat and what your blood work shows.

Supplements come after food. The food plan is in our guide to what to eat when you're eating less; this page covers what to consider on top of it if you take a GLP-1 medication such as semaglutide or tirzepatide.

Why the question comes up

People on GLP-1 therapy eat 16% to 39% fewer calories.¹ The advisory lists the nutrients most likely to fall short as a result: iron, calcium, magnesium, zinc, and vitamins A, D, E, K, B1, B12 and C.¹ It also notes that many people start treatment already low in some of them.¹

The shortlist

Supplement	Why it comes up	What to know
Multivitamin-mineral	Broad cover when intake is low across the board	Named in the advisory.1 Choose one near 100% of Daily Values, not megadoses.
Vitamin D	Low in many adults before they start2	Adult RDA is 15 mcg (600 IU); upper limit 100 mcg (4,000 IU).3 Best guided by a blood test.
Calcium	Falls with smaller portions of dairy; matters for bone	Adult RDA is 1,000 to 1,200 mg from food and supplements together.4
Vitamin B12	Comes from animal foods; metformin and acid reducers lower absorption5	No upper limit has been set.5
Protein (powder or shake)	Protein targets are hard to reach with a small appetite	Food in convenient form. The advisory mentions shakes and bars as an option.1
Fiber	Less food means less fiber	Start low, add slowly, drink water with it.
Electrolytes	Minerals come from food; fluid losses remove more	Most useful when intake is very low or after fluid loss.
Iron	On the advisory's list of concern1	Only with a confirmed low level. Too much iron is harmful.

Each of these has its own page: what vitamins to take on a GLP-1, how much protein to eat on a GLP-1, fiber and staying regular on a GLP-1, and electrolytes on a GLP-1.

How to decide

1. Look at your plate for a few days. Little dairy points to calcium and vitamin D. Little meat, fish or eggs points to B12, iron and protein. Few fruits, vegetables or beans points to fiber and potassium.
2. Ask for blood work. Vitamin D, B12, iron studies and a basic metabolic panel answer most of the question. The advisory recommends a nutritional assessment at the start of treatment.¹
3. Fill the specific gap. One or two targeted products beat a cupboard of bottles.

What to look for on a label

• Every amount printed. Skip "proprietary blends" that list ingredients without doses.
• Doses near daily reference amounts. More is not better, and several nutrients have upper limits.
• No extras you did not ask for: stimulants, added sugar, or herbs sold on appetite claims.
• Claims that stay in bounds. In the US a supplement cannot legally claim to treat, cure or prevent a disease.

What to avoid, and why

Most coverage of this question is a list of things to take. The list of things not to take is shorter, better supported, and more likely to actually matter.

Stimulant metabolism products

Ephedra, bitter orange, high-dose caffeine blends, garcinia cambogia, concentrated green tea extract. These work, where they work at all, by suppressing appetite — which is the thing your medication is already doing, often more than you want. Adding an appetite suppressant to a GLP-1 pushes intake down further at a point where the problem is usually getting enough in. Several also carry cardiovascular risk, and concentrated green tea extract has been associated with liver injury.

Blood-sugar-lowering supplements

Alpha-lipoic acid, berberine, chromium, cinnamon extract. If you take insulin or a sulfonylurea alongside a GLP-1, adding another agent that lowers blood glucose raises the risk of going too low. Berberine additionally affects the liver enzymes that clear many other drugs, which makes it an interaction problem rather than just an efficacy question.

Viscous fibre supplements — sometimes

The counter-intuitive one, and the entry most "best supplements" lists get backwards. Glucomannan, psyllium and similar fibres work by slowing gastric emptying and increasing fullness. Your medication is already doing that. Layering them can amplify fullness to the point where you eat even less than you were.

This is situational rather than a flat no. For constipation specifically, fibre is often the right answer — see fiber and regularity on a GLP-1. For appetite or fullness, on a GLP-1, it is usually solving a problem you do not have.

Anything with a proprietary blend

Not a safety claim, a knowability one. If the panel gives one total for a blend rather than an amount per ingredient, neither you nor your pharmacist can assess the dose or check it against your other medications.

The honest state of the evidence

Worth saying plainly, because almost nobody selling supplements will: there are no formal supplement recommendations for people taking GLP-1 medications. No medical body has issued a protocol. The 2025 joint advisory goes as far as saying supplements "can be proactively considered for at-risk nutrients, such as vitamin D, calcium, B12, or a multivitamin-mineral tablet", tailored to the individual.¹ That is a considered maybe, not a regimen.

What follows from that is the opposite of what the category sells. The right starting point is not a stack; it is finding out what, if anything, is actually low.

Test before you supplement

This single step is worth more than any product choice on this page, and it is the one most often skipped.

Reasonable things to ask for if you have been eating substantially less for months:

• Complete blood count, and ferritin for iron stores — ferritin falls before haemoglobin does, so a normal CBC alone can miss it.
• Vitamin B12, and folate.
• Vitamin D (25-hydroxyvitamin D).
• A basic metabolic panel, which covers sodium, potassium and calcium; magnesium can be added.

Three reasons this beats guessing. Supplementing a nutrient you are not short of does nothing. Some nutrients are harmful in excess, which is particularly true of the fat-soluble ones. And a symptom like fatigue has many possible causes, so treating the one you guessed at can delay finding the one you have.

Timing and separation from other medicines

A practical point that gets missed. Minerals — calcium, magnesium, iron, zinc — bind to several common drugs in the gut and reduce how much is absorbed. The affected list includes levothyroxine, tetracycline and quinolone antibiotics, and bisphosphonates.

The fix is separation rather than avoidance: take the mineral several hours away from the medication. Your pharmacist can give you the interval for your specific combination, and this is exactly the kind of question pharmacists are both good at and rarely asked.

Iron and calcium also compete with each other, so taking both at the same time gets you less of each than taking them apart.

What supplements cannot do

They do not work like the medication, and they are not a remedy for its unwanted effects. Products marketed as "natural GLP-1" are a separate category we look at in what a "GLP-1 supplement" is.

Where ours fits

Zornava Replenish covers three rows of the table in one drink: electrolytes (sodium, potassium, magnesium, calcium), a prebiotic fiber (partially hydrolyzed guar gum) and a set of vitamins (C, D3, B1, B6, folate, B12) with zinc. It is not a multivitamin: it has no iron and no vitamins A, E or K. It has no protein. What each ingredient is there for is on our ingredients page.

Interactions and cautions

• Thyroid medication, some antibiotics and osteoporosis drugs: calcium, magnesium, iron and zinc bind to them. Take them several hours apart.⁴
• Kidney disease or potassium-affecting drugs: ask before adding electrolytes or magnesium.
• Pregnancy: needs differ; use what your clinician recommends.
• Tell your prescriber everything you take, including powders and gummies.