By Dr Elena Seranova, PhD (Stem Cell Biology), Founder of NMN Bio. Updated November 2026.
Quick answer. On a GLP-1 medicine such as Mounjaro, Ozempic, Wegovy or Zepbound, the supplements worth your money are the ones that cover what the drug quietly takes away: protein (food first, powder if you can't manage it), creatine for muscle, vitamin D and calcium for bone, electrolytes and magnesium for hydration and energy, and vitamin B12 with a simple multivitamin while your plate is small. Add fibre if things have ground to a halt. Skip anything sold as "natural Ozempic", and talk to your prescriber before adding berberine.
The injection does one job very well. It turns the volume down on hunger. Everything else your body needs to stay strong while you lose weight is still your job, and you now have to do it on half the food.
Why GLP-1 users need a different supplement plan
Most supplement advice assumes you eat a normal amount of food. On a GLP-1 medicine you don't. Many people drop to a third or half of their usual intake, and some days, especially the day or two after the injection, it is closer to nothing.
Less food means fewer nutrients. And the body, given a steep deficit, does not take all of the loss from fat. In the STEP 1 trial body-scan sub-study, roughly two fifths of the weight lost on semaglutide (Ozempic and Wegovy) was lean mass. On tirzepatide (Mounjaro and Zepbound) in SURMOUNT-1 it was about a quarter. Lean mass is not all muscle, but a good part of it is, and muscle is the tissue you most want to keep at 45 or 60.
In 2025 four US societies (the American Society for Nutrition, the American College of Lifestyle Medicine, the Obesity Medicine Association and The Obesity Society) published a joint advisory on nutrition for people on these drugs. Their priorities were blunt: protect protein, lift weights, watch for micronutrient gaps, and manage the gut side effects. That is the backbone of the list below.
1. Protein: the one you cannot skip
Not a pill, but it comes first because nothing else on this list works without it. Muscle is built from amino acids, and if they don't arrive, the body borrows them from your thighs.
Guidance for people losing weight usually lands around 1.2 to 1.6 g of protein per kilo of body weight a day. For an 80 kg adult that is roughly 95 to 130 g. On a suppressed appetite that is hard, so stack the odds:
- Eat the protein on your plate first, before the carbs fill you up.
- Spread it across the day. Three or four smaller hits of 25 to 30 g beat one big meal you can't finish.
- Use a protein shake or Greek yoghurt on the days solid food feels impossible. Liquids often go down when chewing doesn't.
2. Creatine: the most underrated GLP-1 supplement
Creatine is the best-studied sports supplement there is, and the case for it on a GLP-1 medicine is strong. It helps muscle hold on to energy and water, and alongside resistance training it supports strength. In older adults this is an authorised claim in the UK and EU: 3 g a day of creatine, with resistance training, increases muscle strength in adults over 55.
How to take it: 3 to 5 g of creatine monohydrate a day, any time, mixed into water or a shake. No loading phase needed. It takes about four weeks to fill your muscle stores, so start early rather than waiting until you notice your strength slipping.
One caveat. Creatine raises blood creatinine, the marker doctors use to estimate kidney function. That is a lab effect, not kidney damage, but it can make a blood test look worse than it is. Tell your doctor you take it. If you already have kidney disease, ask before you start.
3. Vitamin D and calcium: protect the bone you don't see
Rapid weight loss costs bone as well as muscle. Less load on the skeleton plus less calcium coming in from food is a poor combination, especially for women around and after menopause.
Vitamin D helps you absorb calcium and keep muscles working normally. Most people in the UK are short of it from October to March anyway. A daily 10 to 25 µg (400 to 1,000 IU) of vitamin D3 is a sensible default. Get calcium from dairy, fortified plant milk, tinned fish with bones or tofu where you can, and top up with a supplement only if your intake is clearly low.
4. Electrolytes and magnesium: the fix for "Mounjaro fatigue"
Ask people on these drugs what surprised them and fatigue comes up again and again. Part of it is simply eating less. A big part is fluid. You eat less food (which carries a lot of your water and salt), you may feel too queasy to drink, and nausea or diarrhoea pull more fluid out.
Mild dehydration feels like tiredness, headaches, dizziness when you stand up, and cramps. An electrolyte drink with sodium and potassium, sipped through the day, fixes more "Mounjaro fatigue" than any energy supplement. Choose a sugar-free one.
Magnesium is the electrolyte people forget. It contributes to normal muscle function and to reducing tiredness and fatigue, and many adults run low even on a full diet. On a reduced intake the gap widens. A glycinate or taurate form is gentle on the gut, which matters when your gut is already doing a lot. If you take it in the evening, it also helps with the broken sleep some people get on these drugs. Our Oh!Mg evening magnesium combines bisglycinate, taurate and lactate for exactly that reason.
5. Vitamin B12 and a basic multivitamin
When you eat half as much, you get roughly half the vitamins and minerals. A plain once-daily multivitamin is cheap insurance while your plate is small. Look for one with B12, folate, zinc, iron (if you are a menstruating woman) and selenium.
B12 deserves a separate mention. Many people on GLP-1 medicines for type 2 diabetes also take metformin, which lowers B12 over time. Low B12 shows up as tiredness, low mood, pins and needles and brain fog, all easy to blame on the injection. Ask for a blood test if you take both.
6. Fibre: for the side effect nobody posts about
Constipation is one of the most common GLP-1 side effects. The drug slows the gut, and eating less means less fibre moving through it. A daily spoon of psyllium husk in a large glass of water helps, as do oats, chia, beans and berries when you can face them. Drink more as you add fibre or it will make things worse, not better.
What about Mounjaro hair loss?
Hair shedding two to four months after starting a GLP-1 medicine is common, and it is almost always telogen effluvium: a temporary shed triggered by rapid weight loss and a sudden drop in calories and protein, not by the drug acting on hair directly. It usually settles within six months once weight loss slows.
The best defence is the boring list above: enough protein, and no gaps in iron, zinc or vitamin D. Biotin gummies only help if you are actually deficient, which is rare. If shedding is heavy, ask your GP to check ferritin (your iron stores) and thyroid function.
What to skip, and what to be careful with
- "Natural GLP-1" or "nature's Ozempic" products. If you are already on the real drug, a supplement that claims to copy it adds nothing but cost.
- Berberine, without a word with your prescriber. NMN Bio does offer berberine and it has been proven to be quite efficient, but it lowers blood sugar and can upset the gut. Stacked on a GLP-1 medicine, especially alongside insulin or a sulfonylurea, it adds to the glucose-lowering effect and to the nausea. It is a good alternative for some people; it is not an automatic add-on. (More in Berberine vs Ozempic.)
- Fat burners and stimulant blends. They raise heart rate and suppress appetite further, which is the last thing you need when you are already struggling to eat enough protein.
- Megadoses of anything. Keep total vitamin D under 100 µg (4,000 IU) a day unless a doctor has told you otherwise, and don't double up on zinc or B6 across several products without adding up the totals.
A simple daily GLP-1 supplement routine
| When | What | Why |
|---|---|---|
| Morning | Multivitamin with B12, vitamin D3 10 to 25 µg | Covers the gaps from eating less; bone and muscle function |
| With your biggest protein meal | Creatine 3 to 5 g | Muscle energy and strength, alongside training |
| Through the day | Sugar-free electrolytes, 1.5 to 2 litres of fluid | Hydration, fewer headaches and less fatigue |
| Daily, with plenty of water | Psyllium husk, 5 g | Keeps the gut moving |
| Evening | Magnesium glycinate or taurate | Muscle function, tiredness, sleep |
Plan around your injection. The day of the jab and the two days after are usually the hardest for appetite and nausea. Front-load protein on the days before, keep shakes and electrolytes ready for the days after, and don't skip your supplements just because you skipped a meal. Most of them don't need food to work.
And lift something. Two short strength sessions a week, even with bands at home, tell your body the muscle is still in use. Supplements make that easier. They don't replace it. For more on this, read Ozempic and Mounjaro muscle loss: how to keep the muscle and lose the fat.
The bigger picture
GLP-1 medicines are the most effective weight-loss tool medicine has ever had. But the goal was never a smaller number on the scale. It was a body that works better for longer: stronger legs, steadier energy, bones that hold up at 75. The drug takes the weight. Keeping the rest is up to you.
We are working on something built specifically for people on GLP-1 medicines. If you want to hear about it first, join the NMN Bio list using the sign-up at the bottom of this page.
Frequently asked questions
What supplements should I take on Mounjaro?
Prioritise protein, then creatine (3 to 5 g a day), vitamin D, electrolytes, magnesium and a basic multivitamin with B12. Add psyllium fibre if you are constipated. The same list applies to Ozempic, Wegovy and Zepbound.
Can I take creatine on Mounjaro or Ozempic?
Yes, for most healthy adults. There is no known interaction between creatine and GLP-1 medicines. Creatine can raise blood creatinine on lab tests, so tell your doctor you take it, and check first if you have kidney disease.
Should I take electrolytes on Mounjaro?
Often, yes. Eating less, drinking less and gut side effects all push you towards mild dehydration, which feels like fatigue and headaches. A sugar-free electrolyte drink through the day helps many people.
Why am I so tired on Mounjaro?
Usually a mix of low calorie intake, too little protein, mild dehydration and, for some, low B12 or iron. Fix fluids and electrolytes first, then protein, then ask for a blood test if the tiredness lasts.
Do I need a multivitamin on a GLP-1?
It is sensible while your food intake is well below normal. A standard once-daily multivitamin covers most gaps. It doesn't replace protein.
Can I take berberine with Ozempic or Mounjaro?
Speak to your prescriber first. Both lower blood sugar and both can cause gut side effects, so the combination needs supervision, especially if you also take insulin or a sulfonylurea.
This article is for education and does not replace advice from your doctor or pharmacist. If you are on a GLP-1 medicine for diabetes, take other prescription medicines, have kidney disease, or are pregnant or breastfeeding, check with your healthcare team before starting any supplement.
References
- Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med 2021;384:989-1002.
- Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med 2022;387:205-216.
- Mozaffarian D et al. 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. 2025.
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific opinion on creatine in combination with resistance training and improvement in muscle strength. EFSA Journal 2016;14(2):4400.
- Aroda VR et al. Long-term metformin use and vitamin B12 deficiency in the Diabetes Prevention Program Outcomes Study. J Clin Endocrinol Metab 2016;101(4):1754-1761.
