The Complete Evidence-Based Supplement Guide for GLP-1 Users
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GLP-1 receptor agonists (i.e. semaglutide (Ozempic®, Wegovy®) and tirzepatide (Mounjaro®, Zepbound®), have transformed the landscape of metabolic health and weight management. By mimicking natural hormones, these medications slow digestion, increase feelings of fullness, and significantly reduce appetite.
However, the same mechanisms that make GLP-1 medications effective can also create nutritional challenges. When your appetite drops and you eat significantly less, it becomes difficult to consume the essential amino acids, vitamins, minerals, and fatty acids your body needs to function optimally. Without intentional nutrition, rapid weight loss can lead to muscle depletion, fatigue, gastrointestinal distress, and nutrient deficiencies.
To protect your lean mass, support your metabolism, and mitigate common side effects, a targeted supplement strategy is highly recommended. Below is a comprehensive, evidence-based guide to the best supplements to take while on GLP-1 medications.
Disclaimer: The information provided in this guide is for educational purposes only and is not intended as medical advice. Always consult with your prescribing physician or a registered dietitian before starting any new dietary supplements, especially when taking prescription medications.
Quick Comparison: Best Supplements for GLP-1 Users
Essential Supplements to Take While on GLP-1 Medications
1. Protein (Whey Isolate or Plant-Based)
When taking a GLP-1 medication, protein is arguably the most critical macronutrient to monitor. Because these drugs suppress appetite, many users inadvertently under-eat protein. Clinical analyses estimate that up to 20–50% of the weight lost on GLP-1 therapies can come from lean body mass (muscle and bone) rather than fat tissue. (Ida et al. 2021, as cited in Frontiers in Nutrition 2025) (Heymsfield et al., Obesity Reviews 2014).
The GLP-1 Mechanism: Adequate protein intake stimulates muscle protein synthesis, which is essential to counteract the catabolic (muscle-breakdown) effect of a severe calorie deficit.
Evidence-Based Dosing: To protect lean mass during GLP-1-driven weight loss, evidence strongly supports consuming 1.6 to 2.2 grams of protein per kilogram of body weight daily, ideally paired with resistance training.
Who Benefits Most: Everyone on a GLP-1 medication, particularly those who are strength training, older adults at risk for sarcopenia, and anyone struggling to eat full meals.
Caution Notes: If you have pre-existing kidney disease, consult your nephrologist before adopting a high-protein diet.
Recommendation: A high-quality, easily digestible protein powder like Momentous Whey Protein is an efficient way to hit your daily targets without feeling overly full.
2. Fiber
Gastrointestinal side effects, particularly constipation, are among the most common complaints from GLP-1 users, largely due to the medication's effect on slowing gastric emptying. But fiber does more than just keep you regular; it works synergistically with your medication.
The GLP-1 Mechanism: When you consume fermentable fibers, the bacteria in your gut microbiome break them down into short-chain fatty acids (SCFAs) like butyrate. These SCFAs bind to receptors in the gut, which naturally stimulates your body's endogenous (internal) secretion of GLP-1 and PYY (peptide YY). This means the right fiber supplement can actually support and enhance the natural satiety pathways your medication is targeting.
Evidence-Based Dosing: Aim for 25–30g of total daily fiber. If supplementing, start with 5–10g and titrate up.
Who Benefits Most: Users experiencing constipation, those struggling with gut health, and individuals looking to maximize natural metabolic signaling.
Caution Notes: Introduce fiber slowly. Increasing fiber intake too rapidly while gastric emptying is slowed can cause bloating and gas. Always drink plenty of water.
Recommendation: A targeted prebiotic blend like Momentous Fiber+ provides the specific fermentable fibers needed to produce SCFAs and support natural GLP-1 release.
3. Omega-3 Fatty Acids
Omega-3s (specifically EPA and DHA) are foundational for cellular health, but they take on added importance during periods of metabolic shift and weight loss.
The GLP-1 Mechanism: Omega-3s help modulate the body's inflammatory response and support cardiovascular health, which is a primary goal for many individuals prescribed GLP-1s for metabolic syndrome or obesity.
Evidence-Based Dosing: 1–2 grams of combined EPA and DHA daily.
Who Benefits Most: Individuals who do not consume 2–3 servings of fatty fish per week, and those focused on long-term heart and brain health.
Caution Notes: High doses of Omega-3s can have a mild blood-thinning effect. Consult your doctor if you are on anticoagulant medications.
Recommendation: Look for a highly bioavailable, sustainably sourced option like Momentous Omega-3.
4. Magnesium
Magnesium is involved in over 300 enzymatic reactions in the body, including energy production and muscle function. Because GLP-1 users often eat smaller portions, magnesium intake frequently falls below optimal levels — in one 2025 analysis of three-day food records from GLP-1 users, 89.9% of participants fell below the reference intake for magnesium, averaging 266mg against a 420mg reference.
The GLP-1 Mechanism: Magnesium helps relax smooth muscle tissue. This is highly beneficial for GLP-1 users dealing with GI sluggishness (constipation), muscle cramps from dehydration, or sleep disturbances.
Evidence-Based Dosing: 300–400mg daily, depending on the form (e.g., Magnesium Threonate for brain health, Magnesium Malate for energy, Magnesium Bisglycinate for sleep, or Magnesium Citrate for bowel regularity).
Who Benefits Most: Users experiencing fatigue, muscle cramps, poor sleep, or mild constipation.
Caution Notes: Certain forms of magnesium (like oxide or high-dose citrate) can cause loose stools. Use caution if you have impaired kidney function. Most multivitamins contain only a partial dose of magnesium, so a standalone product is usually still needed.
Recommendation: A highly absorbable form, such as Momentous Magnesium, ensures you get the cellular benefits without unwanted GI distress.
5. Collagen Peptides
Rapid weight loss often brings an unwanted side effect: skin laxity, sometimes colloquially referred to as "Ozempic face" or body skin sagging.
The GLP-1 Mechanism: While collagen won't prevent all skin changes associated with rapid fat loss, supplementing with specific collagen peptides provides the amino acid building blocks (glycine, proline, hydroxyproline) required to support skin elasticity, dermal density, and joint matrix health and can help minimize some of the impacts.
Evidence-Based Dosing: 10–15g daily.
Who Benefits Most: Individuals experiencing rapid weight loss who want to proactively support skin elasticity and joint health.
Caution Notes: Collagen is an incomplete protein. It should not be counted toward your primary muscle-building protein goals (like Whey).
Recommendation: Momentous Collagen is optimized for absorption and can be easily mixed into your daily protein shake or coffee.
6. Multivitamin
Here is the arithmetic problem at the center of GLP-1 nutrition: your micronutrient requirements don't shrink when your appetite does. The Dietary Reference Intakes are set by age and sex, not by how many calories you eat. Cut your food volume by a third and you cut your vitamin and mineral intake by roughly a third, while your requirement stays exactly where it was.
The data bears this out. A 2025 study in Frontiers in Nutrition had 69 GLP-1 users complete three-day food records and compared the results against the DRI. Average intake landed below the reference for calcium, iron, magnesium, potassium, choline, and vitamins A, C, D, E, and K. Vitamin D was the standout failure: 98.6% of participants fell short, and only 1.4% hit 100% of the reference intake. Magnesium, 89.9% short. Iron, 88.4%.
Just as important is what wasn't short. B vitamins, zinc, selenium, copper, and phosphorus came in adequate — B12 and riboflavin were well above the reference. This is the detail most guides get backwards, and it changes what a multivitamin needs to do. The job isn't blanket coverage. It's closing a specific, identifiable set of gaps.
Deficiency diagnoses track the intake data. A retrospective analysis of insurance claims from 461,382 adults newly prescribed GLP-1s (Butsch et al., Obesity Pillars, 2025) found a nutritional deficiency diagnosed in 12.7% of patients within six months and 22.4% within twelve. Vitamin D was again the most common, at 13.6% by the one-year mark.
Where expert consensus sits: In 2025, four bodies (the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society) issued a joint advisory on nutrition during GLP-1 therapy. It states that supplements can be proactively considered for at-risk nutrients including vitamin D, calcium, B12, or a multivitamin-mineral, dosed to the individual. Unlike bariatric surgery, where multivitamin supplementation is protocol, no formal consensus mandates it for GLP-1 users. "Proactively considered" is the current standard — not "required."
The GLP-1 Mechanism: Two things are happening at once. First, reduced total food volume mechanically reduces micronutrient intake. Second, appetite suppression, nausea, and shifts in food preference tend to narrow dietary variety. The food groups that drop first (fruit, vegetables, dairy) are the ones carrying vitamin C, potassium, calcium, and carotenoids. GLP-1s do not cause malabsorption the way gastric bypass does; the problem is intake, not uptake. That distinction matters, because it means the fix is straightforward.
Evidence-Based Dosing: Follow the label dose. For Momentous Multivitamin, that's 4 capsules daily, split as 2 in the morning and 2 in the evening, taken with food. Splitting the dose improves absorption and reduces the chance of stomach discomfort, worth doing when gastric emptying is already slowed.
Who Benefits Most: Anyone eating meaningfully less than they used to, which is most people on a GLP-1. The case is strongest for those more than six months into treatment, anyone averaging under 1,500 calories a day, older adults, and people who menstruate (iron and calcium risk runs higher in both groups).
Caution Notes: A multivitamin is a floor, not a ceiling. It won't supply your protein target, and it typically contains only a fraction of the magnesium you need, so keep your standalone magnesium. It also contains no iron, which is deliberate and consistent with the guidance below: iron worsens constipation, and you shouldn't be supplementing it without bloodwork. Two more things to watch. First, calcium: the joint advisory flags it as an at-risk nutrient, and most performance multivitamins (including this one, at 50mg) carry only a token amount. If your dairy and leafy green intake has dropped, discuss calcium with your clinician separately. Second, if you're taking a multivitamin alongside standalone vitamin D or a fat-soluble vitamin, add up your total dose rather than assuming each product is independent.
Recommendation: Momentous Multivitamin is built for exactly this gap profile. It delivers 2,000 IU of vitamin D, 400mg vitamin C, 1,500mcg vitamin A, and a full B-complex in bioactive forms (B12 as methylcobalamin, folate as 5-MTHF), so absorption doesn't depend on your body converting them first. Minerals come chelated (zinc bisglycinate, copper bisglycinate) for better uptake. It's delivered in loose-powder capsules rather than compressed tablets, which dissolve more readily — a practical advantage when digestion is slowed. And it's NSF Certified for Sport®: every batch independently tested for purity, potency, and label accuracy.
What Not to Take: Interactions and Cautions on GLP-1s
Because GLP-1 medications fundamentally alter your digestion by slowing gastric emptying, they change how your body absorbs both food and oral supplements. Here is what you need to be cautious of:
1. High-Dose Fat-Soluble Vitamins (A, D, E, K)
Because food sits in the stomach longer, the absorption curve of fat-soluble vitamins can be altered. Taking massive bolus doses of Vitamins A, D, E, or K without medical supervision can increase the risk of toxicity, as these vitamins are stored in the liver and fatty tissues rather than excreted in urine like water-soluble vitamins. Stick to standard daily doses unless directed otherwise by bloodwork.
2. Standalone Iron Supplements (Without Medical Need)
Iron supplements are notorious for causing gastrointestinal irritation and severe constipation. Because GLP-1 medications already increase the risk of constipation and slow bowel motility, adding unnecessary iron can compound these side effects significantly. Only take iron if a blood test confirms a deficiency, and work with your doctor on a gentle formulation.
3. Unverified "Weight Loss" Supplements or Stimulants
Avoid over-the-counter fat burners, metabolism boosters, or supplements containing heavy stimulants (like ephedra, synephrine, or high-dose caffeine). GLP-1 medications can sometimes increase resting heart rate; adding unregulated stimulants places unnecessary stress on your cardiovascular system and can exacerbate nausea.
4. Timing Conflicts with Prescription Medications
Slowed gastric emptying doesn't just affect supplements; it affects oral prescription drugs (like birth control, thyroid medication, or blood pressure meds). Taking supplements at the exact same time as your oral prescriptions may alter their absorption. Always ask your pharmacist or prescriber if you need to space out your supplements and oral medications.
FAQ: Supplements and GLP-1 Medications
What are the best supplements to take on Ozempic?
The best supplements to take while on Ozempic (or any semaglutide/tirzepatide medication) are those that address the specific nutritional gaps and side effects caused by the drug. High-quality protein (like whey isolate) is essential to prevent muscle loss. A prebiotic fiber supplement helps manage constipation and supports natural satiety hormones. Magnesium and Omega-3s support muscle function, sleep, and cardiovascular health while in a calorie deficit. A multivitamin closes the micronutrient gaps — vitamin D above all — that open when total food intake drops.
Which nutrients are GLP-1 users most likely to be low in?
Vitamin D is the clearest and most consistent gap. In a 2025 analysis of three-day food records from GLP-1 users, 98.6% fell below the reference intake for vitamin D and only 1.4% met it. Potassium (98.6% below), choline (94.2%), magnesium (89.9%), and iron (88.4%) followed. Calcium, and vitamins A, C, E, and K also came in under reference. Notably, B vitamins, zinc, selenium, and copper were adequate in the same sample — so the common advice to take a multivitamin "for the B vitamins" is aimed at the wrong nutrients. In parallel, claims data from 461,382 GLP-1 patients found 22.4% received a nutritional deficiency diagnosis within twelve months of starting treatment, most often vitamin D.
Do you need a multivitamin on GLP-1 medications?
Not strictly, but the case is strong. A 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society lists a multivitamin-mineral among the supplements to proactively consider during GLP-1 therapy, alongside vitamin D, calcium, and B12. There is no formal mandate the way there is after bariatric surgery. That said, micronutrient requirements are set by age and sex, not calorie intake — so eating less doesn't lower what your body needs, and the intake data shows most GLP-1 users are falling short on several nutrients at once. A multivitamin is the most efficient way to close that spread. It is not a substitute for protein, magnesium, or omega-3s, which require doses no multivitamin can carry.
When should I take a multivitamin on a GLP-1?
With food, and split across the day if your product allows it. Momentous Multivitamin is dosed as 4 capsules — 2 in the morning, 2 in the evening — which improves absorption and reduces the chance of nausea. Because slowed gastric emptying can affect the absorption of oral prescriptions, ask your pharmacist whether to space your supplements apart from any oral medications you take.
Aston Dommel, PhD, RD, CSSD
Aston Dommel, PhD, RD, CSSD, holds a PhD in Nutrition Sciences. A dietitian with 7+ years experience, he's worked with special operations, collegiate, and pro athletes. He's now with Momentous working in product science.
