Should you take supplements while on Mounjaro or Wegovy?

GLP-1 medications support weight loss mainly by reducing appetite. They don’t have a direct impact on nutrition but because they support you to eat less they can increase your risk of poor nutrition if you don’t eat properly.

GLP-1 medications are officially known as glucagon-like peptide 1 receptor agonists. This means they act similarly to the hormone glucagon-like peptide 1 that’s found naturally in the body.

These GLP-1 medications act on the:

• brain to reduce hunger cues
• stomach to reduce how quickly it empties
• pancreas to increase insulin secretion
• liver to reduce glucose release

Together, this helps to improve the body’s ability to regulate blood sugar levels and to increase fullness. This can help with weight loss because it can lower the amount of food you eat because you will feel fuller for longer. A calorie deficit is also an important aspect of weight loss. This means eating fewer calories than you’re using, causing the body to burn through its fat stores.

Although most people have the energy stores needed to power their body when they’re eating less, it’s not just about calories and energy. Your body also needs lots of essential nutrients to function normally.

Most UK adults can get all the nutrients they need from the food they’re eating if they have a healthy, balanced diet. But if you’re eating significantly less than you have been previously, this may reduce your nutrient intake.

Some people experience side effects when taking GLP-1 medication that can also affect what they’re eating. Side effects like nausea, abdominal pain, vomiting, diarrhoea, and constipation can make it harder to eat or to absorb nutrients from the food you’re eating.

By planning your diet carefully and getting side effects under control, it’s definitely possible to get all the nutrients you need, even when you’re eating less.

Because Mounjaro and Wegovy reduce appetite, they help you eat less. This means you need to make sure you’re getting the same amount of nutrition in a smaller amount of food.

GLP-1 weight loss medications like Wegovy and Mounjaro make you feel fuller for longer and, as a result, less hungry.This means you won’t need to eat as much food to feel full or feel the need to eat so often. This can be really useful for losing weight, but it makes the food you’re eating especially important.

For example, it may be tempting to fill up on quick snacks or sweet treats if you’re eating less. However, not only can this counteract some of the benefits of the medication, it may lead to nutrient deficiencies.

Try to be mindful about the foods you’re eating. Planning your meals out can help you to balance all the major food groups across the day and get enough of all the important nutrients. For example, make sure you are eating:

Fibre

Fibre can support your gut health and help to keep things regular if you’re suffering from medication side effects like constipation. Fibre can be found in fruits, vegetables, whole grains, and pulses.

Protein

Protein is another key aspect of a healthy diet, whether it’s from plant sources, dairy, eggs, fish, or meat. The NHS recommends eating 0.75g of protein per kilogram of body weight a day to keep your body healthy and maintain your muscles.

Although it might be tempting to add some protein powder to your diet, it’s usually better to get your nutrients from whole foods. Food delivers nutrients and fibre in a way that’s natural for your body to digest and absorb.

If you’re struggling to get all the nutrients you need while taking GLP-1 medication, especially if you have other dietary restrictions to consider, it may be worth thinking about supplements.

You might be wondering whether to start supplements if you’ve tried to get your nutrients from your food but you’re worried about becoming deficient.

If you’ve visited your GP and they suspect a deficiency, they can do some tests and recommend which supplements to take.

Remember, it’s always best to seek advice from a healthcare professional before starting any new supplement. We’ve highlighted some of the supplements that can help with common vitamin deficiencies.

Vitamin D

Vitamin D is essential to keep your bones healthy and strong and is mostly produced by absorbing sunlight through the skin. A lack of vitamin D can lead to tiredness, bone or muscle pain, and recurrent infections, amongst other things.

The UK government recommends that everyone should consider taking vitamin D during the autumn and winter when there’s less sunlight. Although you can get some vitamin D from what you eat, it’s difficult to get enough through diet alone.

During the summer and spring, most people get enough vitamin D from the sun and their diet. But, people who are mostly inside, cover most of their skin when outside, or have a darker skin tone may want to take vitamin D supplements the whole year.

If you do take vitamin D supplements, don’t take more than 100 micrograms (4,000 IU) a day as this could be harmful.

Vitamin B12

Vitamin B12 is needed to produce red blood cells, release energy from food, and to support a healthy nervous system. The body needs 1.5 micrograms a day of B12.

Although most people who eat dairy, meat, and/or fish can usually get all the B12 they need from their diet, people eating a plant-based diet may not be getting enough. If this sounds like it applies to you, you might benefit from B12 supplements.

Signs of a B12 deficiency include:

• tiredness
• pins and needles
• a sore, red tongue, and/or mouth ulcers
• muscle weakness
• vision problems
• cognition changes, like low mood or memory loss

If you notice any of these symptoms while taking weight loss medication, contact your GP.

Iron

Iron is also important for making red blood cells which are needed for transporting oxygen around your body. A lack of iron can lead to anaemia, which can cause:

• tiredness
• paleness
• headaches
• shortness of breath
• heart palpitations

Although men only need 8.7mg of iron a day, women need 14.8mg a day on average due to losing iron when they bleed during menstruation. Women with heavy periods are likely to lose even more iron and may benefit from iron supplements, but most people can get enough iron from the foods they eat.

Red meat, pulses (like beans and chickpeas), nuts, and dried fruits are all good iron sources. Many green vegetables also contain lots of iron, but it’s best to eat them with vitamin C-rich foods to improve how much iron your body can absorb.

If you do want to try iron supplements, make sure not to take more than the recommended daily dose. This can cause constipation, nausea, vomiting, and stomach pain.

Most people in the UK can benefit from taking vitamin D during the darker months, so this supplement is one to think about when taking GLP-1 medications. If you’re eating a plant-based diet, you may also want to think about adding in B12 and iodine supplements too.

The NHS doesn’t advise people to take vitamin or mineral supplements unless they are not getting enough of these nutrients in their diet. This means you need to review your diet while taking your weight loss medication and check whether you’re eating a variety of foods that meet your nutritional requirements. If you’re not sure, you can always ask for help.

Some people choose to take multivitamins. Although multivitamins contain a wide spectrum of nutrients, they aren’t a replacement for food. The contents of multivitamins vary a lot, with different vitamins included in varying formulations and concentrations.

Supplements don’t count as medications so they don’t have to go through the same rigorous testing that medications do. They aren’t regulated in the same way, which means you might not always know what you’re taking.

Having said this, multivitamins can help people on low-calorie diets to avoid becoming deficient if they are not getting all the nutrients they need from food. Taking multivitamins is an individual decision, and one that should be made after a discussion with a healthcare professional.

If you’re taking GLP-1 medications and suffering from side effects like vomiting or diarrhoea, you might be getting rid of some of the essential vitamins and minerals your body needs. In this situation, it’s important to drink plenty of fluids to avoid dehydration. You may choose to include electrolyte supplements in your fluids to replace some of the minerals you’re losing. If your vomiting and diarrhoea continues for several days, contact a healthcare professional.

It might be tempting to take supplements as a way to improve your health, but in some cases they can actually cause health problems.

Taking more than the recommended amount of fat-soluble vitamins like vitamins A, D, E, and K can cause them to build up in your body, leading to toxic effects. Toxicity is only a possibility when taking these vitamins as supplements – getting these vitamins from the sun or your diet won’t lead to this problem.

Some supplements can also cause health problems when taken in combination, or stop other vitamins from being absorbed properly. For example, calcium can stop the body from being able to absorb iron effectively. To avoid any problems, don’t combine different supplements without medical guidance.

It’s always best to speak to a professional before starting any new supplements. They’ll be able to take a blood sample to check the levels of different nutrients to see if they’re normal and whether or not you could benefit from supplementation.

"You should get your nutrients from your food where you can. If you need help with planning what you’re eating, a dietitian can support you in building nutrient-dense meal plans that meet your calorific needs. This will ensure you continue to lose weight while getting all the necessary nutrients"

— Dr Zoe Miller, Medical Editor

It’s not generally recommended to take supplements while you’re on medications like Wegovy and Mounjaro. Even when eating less food, it’s usually still possible to get all the nutrients you need from a balanced diet.

But if you’re not able to eat a balanced diet due to not being hungry enough or your medication causing side effects, you might benefit from taking certain supplements. Your doctor can offer personalised advice on your individual requirements. A dietitian can also help you plan your diet so that it contains all the nutrients you need while eating fewer calories.

When taking GLP-1 medications, you’ll be less hungry than before and may become full after eating less food than you normally would. If you’re eating unhealthy, processed, or takeaway foods that are low in nutrients, you might become deficient in certain vitamins or minerals.

A balanced diet ensures you’re getting all the things you need to keep your body healthy, even when you’re eating less.

Can I just take a multivitamin instead of focusing on food?

No. While multivitamins can be taken to supplement your diet in some situations, they shouldn’t be viewed as a replacement for a healthy, balanced diet.

Supplements contain nutrients in an artificial format, and may even contain some vitamins that interfere with your body’s ability to absorb others. Your body will find it easier to absorb nutrients in their natural form as part of the food you’re eating.