Supplements and GLP-1 Medications: What You Need to Know
If you're one of the millions of Americans currently taking a GLP-1 medication drugs like semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound), you've probably already navigated a fair number of questions. How to manage side effects. What to eat. How to stay on track.
But there's one question that doesn't get asked nearly enough: How do GLP-1 medications affect the supplements I'm taking?
It's an important question. And the answer is more nuanced than most people realize.
At RYOS, we believe you deserve clear, pharmacist-reviewed guidance, especially when your health involves both prescription medications and supplements. So let's walk through what the research tells us, what to watch for, and how to take your next step with confidence.
GLP-1 Medications: A Quick Overview
GLP-1 receptor agonists mimic a natural hormone called glucagon-like peptide-1, which helps regulate blood sugar, slow digestion, and reduce appetite. Originally developed to treat type 2 diabetes, these medications are now widely prescribed for weight management as well.
The numbers reflect just how quickly adoption has grown. According to a 2025 KFF Health Tracking Poll¹, approximately one in eight U.S. adults reported currently taking a GLP-1 medication, with usage highest among adults between the ages of 50 and 64. Industry projections estimate that roughly 10 million Americans were on GLP-1 treatment in 2025, a figure expected to climb to 25 million by 2030 as oral formulations and broader insurance coverage expand access.
These medications work. But like any powerful tool, they come with effects that goes beyond their primary purpose including how your body absorbs nutrients and supplements.
How GLP-1 Medications Can Affect Supplement Absorption
One of the primary ways GLP-1 medications work is by slowing gastric emptying, the rate at which food and other substances move from your stomach into your small intestine. This is what helps you feel full longer, but it also means that anything you take by mouth, including supplements, may be absorbed differently.
According to the FDA-approved prescribing information for both Wegovy and Zepbound, these medications delay gastric emptying and have the potential to affect the absorption of other oral medications taken at the same time. Research published in Pharmacotherapy (Hooper et al., 2025)² used pharmacokinetic modeling to show that GLP-1-related delays in gastric emptying led to meaningful changes in absorption for several commonly co-administered medications, including shifts in both total exposure and time to peak concentration.
What does this mean for supplements? While formal interaction studies between GLP-1 medications and dietary supplements are still limited, the same physiological mechanism applies. Fat-soluble vitamins, minerals like iron and calcium, and other oral supplements may be absorbed at different rates or to different degrees when gastric emptying is delayed.
This isn't cause for alarm. But it is cause for awareness.
Nutrient Deficiencies: A Growing Concern for GLP-1 Users
Beyond absorption timing, there's another layer to consider: GLP-1 medications significantly reduce appetite. That's a feature, not a bug, but eating less also means taking in fewer vitamins and minerals from food. The research on this front is becoming hard to ignore.
A 2026 narrative review published in Clinical Obesity (Urbina et al.)³ examined six studies involving over 480,000 adults taking GLP-1 medications. The findings were striking: vitamin D deficiency was the most common nutritional issue, affecting approximately 13.6% of participants after 12 months of treatment. Iron depletion was also frequent, with GLP-1 users showing 26–30% lower ferritin levels compared to those on other diabetes medications. B vitamin deficiencies, dehydration, and mineral shortfalls in calcium, selenium, and zinc also increased over time.
A separate Harvard Health⁴ report highlighted these same patterns, noting that researchers concluded doctors should consider nutritional deficiencies "a common consequence" of GLP-1 therapy rather than a rare side effect.
In a smaller dietary analysis of 69 GLP-1 users, 72% consumed less than recommended amounts of calcium, nearly two-thirds fell short on iron, and only 1.4% met vitamin D intake recommendations.
The takeaway? If you're on a GLP-1 medication, nutritional support isn't optional, it's essential.
Supplements That Deserve Extra Attention on GLP-1 Therapy
Not every supplement raises a red flag when taken alongside a GLP-1 medication. But some categories deserve closer consideration.
Vitamin D is the most common deficiency among GLP-1 users. Because it's fat-soluble and GLP-1 medications often lead to reduced fat intake, absorption can drop even if you're supplementing. Timing matters. Taking vitamin D with your largest meal of the day (one that includes some dietary fat) can support better uptake.
Iron absorption may also be affected. A pilot study (Melis et al., 2025)⁵ published in Diabetes, Obesity and Metabolism specifically investigated the effect of semaglutide on intestinal iron absorption and found meaningful reductions. If you're already at risk for iron deficiency, especially if you're a woman of reproductive age, this warrants a conversation with your healthcare provider.
B vitamins, including B12 and thiamine, have emerged as another area of concern. Case reports have linked GLP-1 use with severe thiamine deficiency, including cases of Wernicke encephalopathy, a serious neurological condition during periods of significant caloric restriction.
Calcium and magnesium intake frequently falls below recommended levels in GLP-1 users simply because overall food intake drops. This can have downstream effects on bone health, muscle function, and metabolic balance.
Protein supplements have become a common addition for GLP-1 users seeking to preserve lean muscle mass during weight loss. Research shows that weight loss from GLP-1 medications is predominantly fat loss, but some muscle mass is also lost in the process⁵. Adequate protein intake and supplementation where needed can help protect against this.
Supplements to Approach With Caution
Some popular supplements may require extra care when you're taking a GLP-1 medication.
Berberine, a plant-derived compound sometimes called "nature's Ozempic," works through different metabolic pathways than GLP-1 medications but shares some overlapping effects on blood sugar regulation. Berberine can also interfere with liver enzymes (CYP3A4, CYP2D6, and CYP2C9) that metabolize many medications. Both berberine and GLP-1 medications can cause gastrointestinal side effects so combining them may amplify nausea, diarrhea, or abdominal discomfort.
Curcumin (turmeric) has shown some evidence of influencing GLP-1 secretion in animal and laboratory studies, but human data is minimal. The concern isn't necessarily a dangerous interaction but that combining curcumin with a GLP-1 medication without guidance adds an uncontrolled variable to your regimen.
Blood-sugar-lowering supplements in general including chromium, alpha-lipoic acid, and cinnamon extracts deserve caution when combined with GLP-1 therapy because of the potential for additive effects on glucose levels. Excessive blood sugar reduction can lead to hypoglycemia, particularly in people also taking insulin or sulfonylureas.
Fiber supplements like psyllium can further slow gastric motility when combined with GLP-1 medications. While fiber is important for digestive health, timing and dosage should be discussed with a pharmacist or physician to avoid compounding the gastrointestinal effects.
Timing Matters: How to Take Supplements on GLP-1 Therapy
Because GLP-1 medications slow the movement of substances through your digestive tract, when you take your supplements can be just as important as which ones you take. A few general tips to keep in mind:
Separate your supplements from other medications by at least 30 to 60 minutes when possible, especially if you're taking medications with a narrow therapeutic window. Take fat-soluble vitamins (A, D, E, K) with a meal that contains some dietary fat to support absorption. If you experience nausea from your GLP-1 medication, which is common, particularly during dose escalation, consider taking supplements at a different time of day than when nausea tends to peak. And always talk to your pharmacist or prescriber before adding, removing, or changing the timing of any supplement.
The RYOS Approach: Medication-Aware Supplements
This is exactly why RYOS exists.
Most supplement brands don't consider what medications you might be taking. They aren't designed with drug-nutrient interactions in mind. And they don't involve a pharmacist in the formulation process.
RYOS supplements are pharmacist-reviewed to identify known drug-nutrient interactions against the most commonly prescribed medications for chronic conditions tracked by the CDC. That means our formulations are reviewed through the lens of medication safety so you can be more informed for discussions with your physician. Results are published upfront before you buy.
Whether you're taking a GLP-1 medication, a statin, a blood pressure medication, or a combination of all three, we believe you deserve supplements that account for the full picture of your health. Not just the ingredients on the label but how those ingredients work alongside everything else you take.
That's wellness with clarity, that's RYOS.
Key Takeaways
GLP-1 medications slow gastric emptying, which can change how and when oral supplements are absorbed. Research shows that nutrient deficiencies, especially in vitamin D, iron, and B vitamins, are a common consequence of GLP-1 therapy, not a rare side effect. Some supplements, including berberine, curcumin, and blood-sugar-lowering compounds, deserve extra caution when combined with GLP-1 medications. Timing your supplements thoughtfully and working with a pharmacist can help you get the most from both your medications and your supplements. RYOS supplements are pharmacist-reviewed with medication interactions in mind, offering an added layer of confidence for people managing complex health regimens.
Frequently Asked Questions
Can I take supplements while on Ozempic or Wegovy? Yes, many supplements can be taken alongside GLP-1 medications. However, because these drugs slow gastric emptying and reduce appetite, absorption and nutrient intake can be affected. It's important to work with your pharmacist or healthcare provider to choose supplements that are appropriate for your specific medication regimen and to time them effectively.
What vitamins should I take while on a GLP-1 medication? Research suggests that GLP-1 users are commonly deficient in vitamin D, iron, and B vitamins (including B12 and thiamine). Calcium, magnesium, and protein intake also frequently fall short. A high-quality multivitamin or targeted supplementation plan developed with your healthcare provider can help fill these gaps.
Does Ozempic affect how supplements are absorbed? It can. GLP-1 medications delay gastric emptying, which affects the rate and extent of absorption for oral substances, including supplements. Fat-soluble vitamins and minerals like iron may be particularly affected. Taking supplements with food and separating them from your GLP-1 dose can help.
Is it safe to take berberine with a GLP-1 medication? Berberine and GLP-1 medications work through different pathways, so a direct pharmacokinetic interaction is unlikely. However, both can lower blood sugar and cause gastrointestinal side effects, so combining them may increase the risk of hypoglycemia or digestive discomfort. Always consult your healthcare provider before combining them.
What makes RYOS different for someone on GLP-1 therapy? RYOS supplements are pharmacist-reviewed to identify known drug-nutrient interactions. This means our formulations are reviewed with medication safety in mind, an important distinction for anyone managing both prescriptions and supplements.
Reviewed by Sunny Chow, RPh, Registered Pharmacist
Contributing Author, Kyle Chu
This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider or pharmacist before making changes to your medication or supplement regimen.
Sources
KFF Health Tracking Poll. "1 in 8 Adults Say They Are Currently Taking a GLP-1 Drug." November 2025.
Hooper N, et al. "GLP-1RA-Induced Delays in Gastrointestinal Motility: Predicted Effects on Coadministered Drug Absorption by PBPK Analysis." Pharmacotherapy. 2025.
Urbina J, Salinas-Ruiz LE, Valenciano C, Clapp B. "Micronutrient and Nutritional Deficiencies Associated With GLP-1 Receptor Agonist Therapy: A Narrative Review." Clinical Obesity. 2026;16(1):e70070.
Harvard Health Publishing. "Study: Taking GLP-1 Drugs May Increase Risk of Key Nutrient Deficiencies." March 2026.
Melis P, Lucijanic M, Kranjcec B, et al. "The Effect of Semaglutide on Intestinal Iron Absorption in Patients With Type 2 Diabetes Mellitus: A Pilot Study." Diabetes, Obesity and Metabolism. 2025;27(6):3542–3545.
Additional Sources
Butsch WS, Sulo S, Chang AT, et al. "Nutritional Deficiencies and Muscle Loss in Adults With Type 2 Diabetes Using GLP-1 Receptor Agonists: A Retrospective Observational Study." Obesity Pillars. 2025;7:100237.
Johnson B, Milstead M, Thomas O, et al. "Investigating Nutrient Intake During Use of Glucagon-Like Peptide-1 Receptor Agonist: A Cross-Sectional Study." Frontiers in Nutrition. 2025;12:1566498.
RAND Corporation. "Nearly 12 Percent of Americans Have Used GLP-1 Weight Loss Drugs." August 2025.
J.P. Morgan Research. "How Supply and Demand for Weight Loss Drugs Is Playing Out in 2026." 2026.
Jensterle M, et al. "Semaglutide Delays 4-Hour Gastric Emptying in Women With Polycystic Ovary Syndrome and Obesity." Diabetes, Obesity and Metabolism. 2023.
Wegovy (semaglutide) Prescribing Information. Novo Nordisk.
Zepbound (tirzepatide) Prescribing Information. Eli Lilly.