GLP-1 medications (semaglutide, tirzepatide, and related drugs) work partly by slowing how quickly the stomach empties and by reducing appetite — that mechanism is behind the weight loss, and it's also why several common side effects (nausea, feeling full quickly, changes in bowel habits) show up for many users.
Rapid weight loss on a GLP-1 can include a meaningful amount of lean muscle, not just fat — clinical guidance for this population recommends 1.2–1.6 g of protein per kilogram of body weight per day specifically to help preserve muscle during active weight loss.
Protein powder — A well-dosed, tolerable protein powder is the most direct way to hit the 1.2–1.6 g/kg/day target described above.
Creatine — Creatine monohydrate is the best-studied, reference-standard form for preserving strength during weight loss — general-population evidence only; no direct GLP-1 trials exist yet.
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Digestive side effects
Slowed digestion is a documented, mechanism-level effect of GLP-1 medications, and it's the reason nausea, feeling overly full, and changes in bowel habits (including constipation) are common, especially early in treatment or after a dose increase.
Fiber — Soluble fiber (psyllium, PHGG) tends to sit easier alongside a GLP-1's slower digestion than insoluble, bulk-forming fiber.
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Eating less overall
Appetite suppression means many users simply eat less food overall — which can be the intended effect, but it also reduces total nutrient intake. In one study of adults on GLP-1 therapy, vitamin D deficiency was the most common nutrient abnormality found, present in 7.5% of patients at 6 months and 13.6% at 12 months.
Multivitamin — A daily multivitamin with adequate vitamin D3 covers the most commonly documented nutrient gap in GLP-1 users, described above.
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Nausea, vomiting, and diarrhea
Nausea, vomiting, and diarrhea are the most commonly reported GLP-1 side effects, especially early in treatment or after a dose increase. Clinical guidance for managing them is behavioral first: for nausea, increase fluid intake in small sips without over-filling; for vomiting, prioritize hydration; for diarrhea, hydrate generously with water (plain, or with lemon and a pinch of bicarbonate) and specifically avoid sports-style isotonic drinks. Severe or persistent symptoms are a conversation for your prescriber, not a product page.
Electrolytes — Where reduced eating and fluid loss make electrolytes relevant, a clean-label formula (moderate sodium, potassium, and magnesium, no added sugar) can support the hydration guidance above — though no GLP-1-specific clinical guideline sets exact targets, and our scoring criteria say so plainly (see the electrolytes category page).
THE CURRENT STACK
One category at a time.
Ranked independently from store availability. Scores reproduce from public data.
Protein powder88
P
Top verified pick
The Isopure Company Isopure Whey Protein Isolate Unflavored
Every product in every category is scored the same way: how well-dosed it is against a clinical reference amount, whether the form is a good one, whether an independent lab has verified what's on the label, how clearly the label discloses every ingredient, and price per effective dose — plus one GLP-1-specific check per category (see that category's own page for what it checks). Every score is public and reproducible from the same two data sources anyone can check.
It depends on what a real gap looks like for you — not everyone on a GLP-1 develops one (see the standing disclosure on this page). Where we can score with confidence (protein, creatine, fiber, omega-3 today), we publish a top pick per category; where we can't yet (electrolytes, multivitamin), we publish criteria instead of guessing. Full methodology, axis weights, and changelog: /glp-1-supplements/methodology/.
Complete supplement stack for GLP-1 weight loss — what do I actually need?
We score six categories relevant to GLP-1 users — protein, creatine, fiber, electrolytes, multivitamin, omega-3 — each on the same five weighted scoring factors plus a category-specific GLP-1-specific check. This page shows the current pick (or an honest 'not confident yet' state) per slot; every score is priced for roughly half the top candidates so far — unpriced products show value as unverified, and picks may reorder as pricing coverage grows. Full methodology, axis weights, and changelog: /glp-1-supplements/methodology/.