6 min read
Three bites into lunch, you are done. Not “trying to be good” done, genuinely full. For a lot of people starting semaglutide or tirzepatide, that is the moment a new question shows up: if I am eating this much less, am I still getting what my body needs? And are there vitamins to take on Ozempic, or is food enough?
It is a smart question to ask early. These medications work in part by turning down appetite, which is the point. But a smaller plate also leaves less room for protein, vitamins, and minerals, so what you do eat starts to matter more.
Quick answer: There is no single list of vitamins to take on Ozempic that fits everyone. The priorities experts emphasize are enough protein, nutrient-dense food, fluids, and strength training to protect muscle and bone. A basic multivitamin may help cover gaps when you are eating much less, but ask your prescribing clinician first, and consider blood work for nutrients like vitamin D, B12, and iron rather than guessing.
[IMAGE: Small plate with salmon, vegetables, and Greek yogurt on a kitchen table next to a glass of water | alt: small high-protein meal for someone asking what vitamins to take on Ozempic]
You Are in Very Large Company
If it feels like everyone is talking about these drugs, they are. Pew Research Center found that 53% of Americans hear or read about Ozempic, Wegovy, and similar drugs extremely or very often. In a November 2025 KFF Health Tracking Poll, 12% of adults said they were currently taking a GLP-1 drug, and 18% said they had taken one at some point.
Side effects are common, too. A 2025 RAND survey found that about half of current users reported nausea. That matters for nutrition, because it is hard to eat a balanced meal when food sounds unappealing.
Why Eating Less Changes the Nutrition Math
When you eat less, you take in less of everything. Calories drop, and so do protein, fiber, calcium, iron, and B vitamins. If most of your reduced intake comes from crackers and toast on queasy days, the gap widens further.
In 2025, four professional groups (the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society) published a joint advisory on nutrition for GLP-1 therapy. Their priorities include preventing nutrient deficiencies, preserving muscle and bone through resistance training and appropriate diet, and managing gastrointestinal side effects. That is a helpful checklist for anyone on these drugs.
What Vitamins to Take on Ozempic: What the Research Suggests
The research here is young, so it is worth being careful. A 2026 narrative review in Clinical Obesity pulled together six observational studies of adults on GLP-1 medications. Vitamin D deficiency was the most common problem, seen in 7.5% of users at 6 months and 13.6% at 12 months. The review also found that more than 60% of users took in too little calcium and iron, and that thiamine and B12 shortfalls increased over time.
The authors are clear that causality is uncertain, since the studies were observational. In plain English: we know people on these drugs often eat less of certain nutrients, but we cannot say exactly how much the medication itself is responsible. The practical takeaway is to test rather than assume.
- Vitamin D: a blood test tells you whether you need more. Our post on signs of vitamin D deficiency covers what to watch for.
- Vitamin B12: especially worth checking if you also take metformin or an acid reducer. We explained why in Common Medications That Can Lower Your Vitamin Levels.
- Iron: ask about a ferritin test instead of adding iron on your own, since too much iron causes its own problems.
- Calcium: dairy, fortified plant milks, canned salmon with bones, and tofu made with calcium are compact sources that fit a small appetite.
Protein Comes First
If there is one nutrient to put at the top of your list, it is protein. When you lose weight quickly, some of that weight can come from muscle, and the joint advisory specifically calls out preserving muscle and bone. Protein, together with resistance training, is how you do that.
With a small appetite, a few tactics help:
- Eat protein first. Start each meal with the fish, eggs, chicken, tofu, or beans before you fill up on anything else.
- Choose dense, easy foods. Greek yogurt, cottage cheese, eggs, and milk deliver a lot of protein in a few bites.
- Spread it out. Several small protein servings through the day are easier than one big one.
- Lift something. Two or three strength sessions a week give your muscles a reason to stay.
Your protein target depends on your size, activity, and kidney health, so ask your clinician or a registered dietitian for a number. For a sense of how protein targets work in practice, see our guide to nutrition for men over 40, which walks through the math for an active adult.
Eating Well on Queasy Days
Nausea can make it surprisingly hard to keep up with nutrition on these medications. A few simple habits often help: eat smaller meals, stop at the first sign of fullness, go easy on greasy or very rich foods, and sip fluids through the day instead of gulping a large glass with meals. Eating less food also means getting less water from food, so keep a bottle nearby.
If nausea, vomiting, or diarrhea keeps you from eating or drinking normally for more than a day or two, call your prescriber. That is a dosing conversation, not something to push through.
Skip the “GLP-1” Supplements
Store shelves now carry products with “GLP-1” in the name. According to Harvard T.H. Chan School of Public Health, these supplements do not work like prescription GLP-1 drugs, even though the packaging may suggest otherwise, and supplements do not go through the kind of safety review that prescription drugs do before they are sold. If a label promises Ozempic-like results, that is your cue to put it back. Our guide on how to read a supplement label can help you spot the red flags.
Where a Multivitamin Fits
Many people on GLP-1 medications ask whether a daily multivitamin makes sense, and it can be a reasonable way to help fill gaps while you are eating less. Check with your prescriber, especially if you have kidney disease or other conditions. If you both decide it fits, a plain formula near 100% of the Daily Value, such as Vitamin100, is one option. It leaves out iron and vitamin D so those can be dosed based on your blood work.
Frequently Asked Questions
What vitamins should I take on Ozempic?
There is no universal list. Research points to vitamin D, iron, calcium, B12, and thiamine as nutrients to watch, so the best approach is blood work plus a nutrient-dense diet. A basic multivitamin may help, but decide with your prescriber.
How much protein should I eat on a GLP-1?
It depends on your body size, activity level, and kidney function, so ask your clinician or a registered dietitian for a personal target. In practice, putting protein first at every meal and adding strength training are the two habits that matter most.
Are GLP-1 supplements real?
Products labeled “GLP-1” are dietary supplements, not medications. Harvard experts note they do not work like prescription GLP-1 drugs, and they are not reviewed for safety before sale the way drugs are.
Should I get blood work while on a GLP-1?
It is a good idea to ask. Since observational studies show vitamin D deficiency and other shortfalls becoming more common over the first year, periodic labs can catch problems early. Your prescriber can decide which tests make sense for you.
The Bottom Line
A GLP-1 medication changes how much you eat, so it is worth changing how you think about what you eat. Put protein first, keep your plate colorful, stay hydrated, lift a few times a week, and ask your clinician about blood work. Supplements can play a small supporting role, but your food and your care team are doing the heavy lifting.
Sources
- 6 facts about obesity and weight-loss drugs in the U.S., Pew Research Center, 2026
- KFF Health Tracking Poll: 1 in 8 Adults Say They Are Currently Taking a GLP-1 Drug, KFF, 2025
- Nearly 12 Percent of Americans Have Used GLP-1 Drugs for Weight Loss, RAND, 2025
- Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory, ACLM, ASN, OMA, and The Obesity Society (via PubMed), 2025
- Ozempic, Wegovy inspire wave of GLP-1 supplements, but are they safe or effective?, Harvard T.H. Chan School of Public Health, 2025
- Micronutrient and Nutritional Deficiencies Associated With GLP-1 Receptor Agonist Therapy: A Narrative Review, Clinical Obesity, 2026
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for general education and is not a substitute for advice from your healthcare provider.