Supplements on GLP-1 medicines
Quick answer. In a 2026 consumer survey in Europe, protein, vitamin D, a multivitamin and fiber were the supplements GLP-1 users most often said they take or consider taking, each named by roughly half of respondents. The Atlas found no randomized trial that tested any of these supplements in people taking semaglutide or tirzepatide. Expert guidance says supplements can be considered for nutrients at risk of running short, such as vitamin D, calcium and B12, and tailored to each person.
What it is
When appetite drops, people look for ways to cover what they are not eating. That is why supplements come up so often around these medicines. This page separates what people say they use from what has been tested and what experts advise. For food-first advice see eating enough and avoiding nutrient gaps, and for protein amounts see the protein page.
What trials show
The Atlas searched PubMed on November 3, 2026 for randomized trials that paired protein, vitamin D, probiotics, creatine or HMB with semaglutide or tirzepatide, and found none. That does not prove none exist, only that the Atlas did not find one. The big medicine trials gave people the drug alongside a reduced-calorie diet and counseling, and they did not test add-on supplements.
The closest evidence comes from other groups. A 2022 review of 10 trials in postmenopausal women found that whey protein added to resistance training improved lower-limb lean mass and biceps strength, while whey protein without resistance training did not make a significant difference. A 2026 pooled analysis of 20 randomized trials found that lifestyle programs with resistance training lost a smaller share of weight as lean mass (17.5%) than those without (26.2%). Neither tested people on these medicines. The muscle page has the details.
What experts say about supplements
The 2025 joint advisory from four professional societies says supplements can be proactively considered for at-risk nutrients, such as vitamin D, calcium and B12, tailored to each person. It does not say everyone needs them. For constipation, it lists magnesium, fiber supplements or capsules and polyethylene glycol 3350 as options if food changes are not enough. The Atlas found no trial or guideline recommending electrolyte supplements for people on these medicines.
A 2025 narrative review went further. It said multivitamins can address deficiencies and low intake, protein supplements can help people reach 1.2 to 2.0 g/kg a day, whey protein combined with resistance training can help preserve lean mass during weight loss, creatine and HMB may add strength benefits, and fiber and probiotics may improve bowel regularity. Two cautions apply. It is a narrative review and not a trial in people on these medicines, and all four authors are affiliated with GNC, a supplement retailer.
What people report: the 2026 survey
The most recent numbers come from consumer research by Lumina Intelligence, a market research firm, reported by the trade publication NutraIngredients on October 28, 2026. It surveyed consumers across Europe. Nearly 60% said their supplement use went up after starting a GLP-1 medicine, although the article does not make clear whether that means how much they take or how much they spend. Among current users, these were the supplements they said they take or consider taking:
| Supplement | Share who take or consider taking it |
|---|---|
| Protein | 50.6% |
| Vitamin D | 49.7% |
| Multivitamin | 48.3% |
| Fiber | 45.9% |
| Probiotics | 36.9% |
| Creatine | 31.7% |
| HMB | 14.6% |
Respondents also reported side effects: nausea (about 27%), constipation (about 25%), mood changes (about 22%) and fatigue or low energy (about 22%). About 12% reported losing muscle or strength.
Read this with care. The article gives no sample size and no list of countries, only "across Europe." Answers are self-reported, "consider taking" is not the same as taking, and the Atlas read the survey through the trade-press article and not the original report. It shows what is popular. It does not show that any supplement works. Many supplement products are marketed to people on these medicines, and marketing claims are not evidence.
Supplement by supplement
| Supplement | Tested in people on these medicines? | What guidance says |
|---|---|---|
| Protein | No trial of a protein amount or protein supplement found | The advisory proposes 1.2 to 1.6 g/kg a day and says extra protein alone is likely not enough without strength training. See the protein page. |
| Vitamin D | No trial found | The advisory names vitamin D as an at-risk nutrient to consider, tailored to the person. |
| Multivitamin | No trial found | The 2025 review (GNC authors) says multivitamins can address individual deficiencies. The advisory does not recommend them for everyone. |
| Fiber | No trial found | The advisory lists fiber supplements as an option for constipation after food changes. See the constipation page. |
| Probiotics | No trial found | The 2025 review says they may improve bowel regularity. The Atlas found no guideline that recommends them. |
| Creatine | No trial found | The 2025 review says creatine may add strength benefits alongside resistance training. That is a review claim, not a result in these users. |
| HMB | No trial found | Same 2025 review, same limits. |
Who needs to be careful
- Anyone with kidney disease or a history of kidney stones, who should ask about protein, magnesium and other supplements first.
- Anyone taking prescription medicines, since some supplements can change how other medicines are absorbed or act. A pharmacist can check this.
- Anyone with severe or lasting digestive symptoms, who should call the prescriber instead of adding products.
- Anyone with a bowel condition, past bowel surgery or a history of blockage, before adding fiber.
Questions to bring to a clinician or dietitian
- Which nutrient levels, such as vitamin D or B12, should be checked before I add anything?
- Are any supplements I take a problem with my other medicines?
- How much protein should I aim for, and is food enough?
- What should I do about nausea or constipation before reaching for a product?
What is still unknown
- Whether routine supplements improve any outcome in people on these medicines is untested.
- Whether creatine, HMB or probiotics do anything for muscle or digestion in this group is untested.
- The survey has no published sample size, and what "consider taking" means in practice is unclear.
- How often nutrient deficiencies occur in people on these medicines is not clearly measured in the sources reviewed.
Related pages
Back to eating and exercise | What to eat on a GLP-1 medicine: a sourced food list
Sources
- GLP-1 user data indicates white space opportunity for sports and active innovators Hancocks N. NutraIngredients, October 28, 2026, reporting Lumina Intelligence consumer research. Sample size and countries not stated in the article. Funding: Not stated. Trade press, secondary source
- Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and the Obesity Society Mozaffarian D, et al. Obes Pillars. 2025;15:100181. PMID 40673264. Funding: Professional societies; several authors report industry relationships. Journal article
- Dietary supplement considerations during glucagon-like peptide-1 receptor agonist treatment: a narrative review Johnson BVB, et al. Obes Pillars. 2025;16:100209. PMID 41368199. Funding: Not stated in the abstract; all authors are affiliated with GNC, a supplement retailer. Journal article, narrative review
- Effect of whey protein supplementation in postmenopausal women: a systematic review and meta-analysis Kuo YY, et al. Nutrients. 2022;14(19):4210. PMID 36235862. Funding: Not stated in the abstract. Journal article
- Lean mass changes with incretin therapy versus lifestyle intervention: a systematic review and meta-analysis of randomised controlled trials Eisa N, Barood O. Diabetes Obes Metab. 2026;28(6):4818-4827. PMID 41877354. Funding: Not stated in the abstract. Journal article