What vitamins should I take on Ozempic?

No vitamin is required with Ozempic. A 2025 joint advisory from four US nutrition and obesity societies says vitamin D, calcium and B12 can be considered if you're at risk, and a basic multivitamin-mineral can cover gaps when you eat very little. Base doses on blood tests and your prescriber's advice.

Can I take a multivitamin while on Ozempic?

Yes, for most people. A standard multivitamin-mineral at around 100% of daily values is a reasonable safety net when you eat under about 1,200 calories (women) or 1,800 (men). Tell your prescriber, since the label asks you to list all vitamins and supplements.

Do I need vitamin B12 on Ozempic?

Not automatically. Adults need 2.4 mcg a day, and you can get that from fish, meat, eggs, dairy or a multivitamin. Ask for a B12 test if you also take metformin, eat little animal food, or have numbness, tingling or unusual fatigue.

Should I take vitamin D on Ozempic?

Many people can, especially if a blood test shows low levels. The RDA is 600 IU (15 mcg) a day to age 70 and 800 IU (20 mcg) after, and the upper limit is 4,000 IU. Go higher only if your doctor recommends it.

Can supplements interfere with Ozempic?

Standard vitamins aren't known to change how semaglutide works. But semaglutide slows stomach emptying, which may affect how oral medicines are absorbed, so list every supplement for your prescriber and skip weight-loss or stimulant products.

Does Ozempic cause hair loss, and can supplements help?

Hair shedding can follow fast weight loss. No supplement is proven to prevent it, but low protein, iron or zinc can make it worse, so get those checked rather than taking high doses blindly.

What blood tests should I get on Ozempic?

Common ones to ask about are vitamin D (25-OH), vitamin B12, a complete blood count with ferritin, a basic metabolic panel for kidney function and electrolytes, and HbA1c. Your prescriber decides what you need.

Vitamins and Supplements to Take With Ozempic

There's no vitamin you're required to take with Ozempic. The 2025 joint advisory on nutrition for GLP-1 therapy says vitamin D, calcium and vitamin B12 can be considered for people at risk, and a basic multivitamin-mineral can fill gaps when you're eating very little.

The bigger gap for most people is protein: about 80-120 g a day. Get blood work, then let the results decide the doses. Talk to your prescriber before you add anything.

Key takeaways

Protein first: the advisory suggests 1.2-1.6 g per kg of body weight a day during active weight loss, or a simple 80-120 g.
A multivitamin is a fair safety net if you eat under about 1,200 calories (women) or 1,800 (men).
Vitamin D: the RDA is 600 IU a day to age 70 and 800 IU after. The upper limit is 4,000 IU.
Test before you take iron. Too much is harmful, and many people don't need it.
Skip weight-loss and stimulant supplements. They add risk and nothing the medication isn't already doing.

Why Ozempic can leave nutrient gaps

Semaglutide (Ozempic, Wegovy) cuts appetite and slows stomach emptying. The joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society reports that GLP-1 drugs lower energy intake by 16-39%.

Eating that much less makes it harder to cover every nutrient. The advisory flags the risk as highest below about 1,200 calories a day for women and 1,800 for men, and lists these nutrients of concern: iron, calcium, magnesium, zinc, and vitamins A, D, E, K, B1, B12 and C.

Side effects add to it. Nausea can push protein-rich foods off the plate, and vomiting or diarrhea can lead to dehydration. The FDA label notes kidney injury has been reported in people who got dehydrated from these side effects, so fluids matter as much as any pill.

Vitamins and supplements to consider on Ozempic

Adult daily amounts below are the Recommended Dietary Allowances (RDAs), not treatment doses. If a blood test shows a deficiency, your doctor may prescribe more.

Supplement	Why it comes up on Ozempic	Adult daily amount (RDA)	Notes
Protein (food, shakes)	Lean mass loss during fast weight loss	80-120 g, or 1.2-1.6 g/kg	Food first; shakes when appetite is low
Multivitamin-mineral	Low total food intake	About 100% of daily values	A safety net, not a fix for a deficiency
Vitamin D	Named in the 2025 advisory	600 IU (15 mcg) to age 70; 800 IU (20 mcg) after	Upper limit 4,000 IU (100 mcg)
Calcium	Named in the 2025 advisory; bone health	1,000-1,200 mg for most adults	Count dairy and fortified foods first
Vitamin B12	Named in the 2025 advisory	2.4 mcg	Test if you take metformin or eat little animal food
Iron	Nutrient of concern	18 mg women 19-50; 8 mg men and women 51+	Only if a test shows you need it
Magnesium	Nutrient of concern	310-320 mg women; 400-420 mg men	Food first; magnesium laxatives count too

Protein

Protein isn't a vitamin, but it's the gap that matters most. In the STEP 1 trial of semaglutide 2.4 mg (the Wegovy dose), about 38% of the weight people lost was lean mass (5.3 kg of 13.6 kg), and the advisory's authors estimate about half of that was muscle.

The advisory suggests 1.2-1.6 g of protein per kg of body weight a day while you're actively losing weight, or a simpler fixed target of 80-120 g. It also says shakes, bars and fortified foods are a fair way to close the gap. See how much protein you need on Ozempic for the full breakdown, or get a number from the protein calculator.

Multivitamin-mineral

A standard multivitamin at roughly 100% of daily values is the simplest way to cover the long list of nutrients of concern. It won't correct a real deficiency, and it isn't needed if you still eat a varied diet at a moderate intake. Avoid "mega-dose" formulas unless a doctor prescribes them.

Vitamin D and calcium

The advisory names both. The Institute of Medicine set the vitamin D RDA at 600 IU (15 mcg) a day for ages 1-70 and 800 IU (20 mcg) for 71 and older, and found that higher blood levels weren't consistently better. The upper limit for adults is 4,000 IU.

Get calcium from dairy, fortified plant milk, tofu set with calcium and canned fish with bones first, then supplement the difference if you fall short.

Vitamin B12

Adults need 2.4 mcg a day. If you still eat fish, meat, eggs or dairy, or take a multivitamin, you're likely covered. Ask for a test if you also take metformin, which is linked to lower B12, or if you eat few animal foods. Tingling, numbness and unusual fatigue are worth mentioning to your doctor.

Iron

The RDA is 18 mg a day for women 19-50 and 8 mg for men and for women over 50. Iron supplements can cause constipation, which is already a common Ozempic side effect, and excess iron is harmful. Take iron only if a ferritin or iron test says you need it, and ask your pharmacist how to time it around calcium and your other supplements.

Magnesium

Adult RDAs are 310-320 mg for women and 400-420 mg for men. Nuts, seeds, beans and whole grains are the best food sources. If you use a magnesium-based laxative for constipation, count it, since supplements and laxatives are where excess magnesium usually comes from.

Fiber

Constipation is one of the most common side effects. The advisory recommends fluids and gradually more fiber from food. Our guide to Ozempic constipation and fiber covers which foods help. Ask your prescriber before adding a fiber supplement.

Creatine and omega-3

Neither has been tested much in GLP-1 users specifically. Creatine monohydrate at 3-5 g a day is the standard dose in the International Society of Sports Nutrition position stand, and it pairs with strength training, not instead of it. Fish twice a week is a simpler way to get omega-3s than a capsule.

Supplements to skip or ask about first

Weight-loss supplements and fat burners. They add risk and duplicate what the medication already does.
Stimulant pre-workouts and high-caffeine products. They can make nausea and a racing heart worse.
High-dose single nutrients without a test, especially iron and preformed vitamin A.
Anything you haven't told your prescriber about. Semaglutide slows stomach emptying, and the label warns it may affect how oral medicines are absorbed. The patient information asks you to list all vitamins and herbal supplements.

Blood tests to ask your doctor about

A baseline panel lets you supplement what you're actually low in instead of guessing. Common tests to ask about:

Vitamin D (25-hydroxyvitamin D)
Vitamin B12
Complete blood count and ferritin (iron stores)
Basic or comprehensive metabolic panel (kidney function, potassium, sodium)
Magnesium
HbA1c and fasting glucose

Repeat tests are worth discussing after several months of fast weight loss or if you're eating far less than before. For what each deficiency looks like, see GLP-1 nutrient deficiencies.

Does Ozempic cause hair loss?

Hair shedding can follow any fast weight loss, with or without medication. No supplement has been shown to prevent it in GLP-1 users. Low protein, iron or zinc can make shedding worse, which is one more reason to test instead of taking high doses of "hair" supplements. Hitting your protein target is the most useful step you control.

Track what you actually eat

Supplements only fill gaps you can see. Because appetite drops so much, many people on Ozempic don't realize how little protein they're getting until they log a few days.

Nutrify lets you log meals from a photo or a quick search and shows your protein against your target each day. It has a 7-day free trial, then a paid subscription. For meal ideas built around protein, see what to eat on Ozempic and our list of high-protein foods for GLP-1 users.