Vitamins, Minerals & GLP-1 Medications: Can Supplements Help Fill the Gap?
You’re eating smaller portions, feeling fuller sooner and making progress with your weight management. But if your appetite has changed considerably, you may also be wondering whether you are getting enough nourishment.
It is a sensible question. When we eat less food, we can take in fewer vitamins and minerals, particularly if meals become repetitive or entire food groups disappear.
Medicines such as Mounjaro and Wegovy can make this worth paying attention to. Supplements may help bridge a dietary gap, but choosing the right support means understanding what is missing and why.
Let’s look at how treatment can affect everyday eating, which nutrients deserve consideration and how to use supplements sensibly whilst keeping food at the centre of your plan.
Why can GLP-1 treatment change what we eat?
Wegovy contains semaglutide, which acts on GLP-1 receptors. Mounjaro contains tirzepatide, which acts on both GIP and GLP-1 receptors, although it is often grouped with GLP-1 medicines in everyday conversation.
These treatments affect appetite and fullness, helping many people reduce their food intake. They can also slow stomach emptying. Nausea, vomiting, diarrhoea and constipation are recognised side effects that may influence what you feel able to eat. [1,2]
You might find that your usual lunch feels too large, breakfast becomes less appealing or rich foods no longer agree with you. Occasionally, people settle into eating only the few foods they currently tolerate.
The practical question is whether your smaller intake still provides enough nourishment. Appetite control should be discussed alongside how comfortably you can eat and drink.
Do these medicines automatically cause vitamin deficiencies?
No. Reduced food intake and a diagnosed deficiency are different things.
Eating less of a nutrient may increase the risk of inadequate intake over time, but it does not prove that your body is deficient. Your previous diet, nutrient stores, health conditions and the duration of any restriction all matter.
There is no established rule that everyone taking Mounjaro or Wegovy needs the same supplement package. A 2025 joint expert advisory highlights nutrition assessment and preventing deficiencies during GLP-1 treatment, rather than treating supplementation as a substitute for dietary support. [3]
These medicines should not be described as routinely blocking the absorption of all vitamins and minerals. If a deficiency is identified, other explanations may need investigating too.
For example, someone could already have low iron stores before starting treatment. Another person may have a condition affecting absorption. Assuming that medication explains everything can delay appropriate care.
Why do vitamins and minerals still matter during weight loss?
Vitamins and minerals are often called micronutrients because we need them in relatively small amounts. Small does not mean unimportant.
They support normal body functions, including blood formation, bone health and the nervous system. Different nutrients have different jobs, which is why a varied diet matters. The NHS advises that most people should obtain what they need through balanced eating, although some need supplements. [4]
It can help to think beyond the calorie total. A day that fits a weight-loss target may still offer little variety if it consists mainly of toast, biscuits and a small evening meal.
Try asking: have I included different food groups, or have I simply eaten less of the same two or three things? That question can be more useful than searching immediately for a “GLP-1 vitamin”.
Weight management should leave room for nourishment, enjoyment and an eating pattern you can maintain.
Which nutrients are worth thinking about?
There is no single deficiency profile shared by everyone using these medicines. The food groups you are eating less often provide a better starting point than a long shopping list of supplements.
Iron: meat, beans, nuts and fortified cereals can contribute. People with heavy periods have a higher risk of iron deficiency, so their history matters as well as their diet. [5]
Vitamin B12 and folate: B12 is found in animal foods and appropriate fortified products; leafy vegetables, beans and fortified cereals can provide folate. Avoiding several of these foods may make intake less reliable. [6]
Calcium and vitamin D: consider these if dairy foods or fortified alternatives have become uncommon. Vitamin D also deserves attention because UK sunlight is limited during autumn and winter. [7,8]
Zinc, magnesium and iodine: these may be overlooked when dietary variety becomes narrow. Nuts, pulses and wholegrains contribute magnesium; zinc comes from foods including meat, dairy and cereals; dairy foods and sea fish are iodine sources. [9]
This is a prompt to review your eating pattern, rather than a recommendation to buy a separate bottle for every nutrient.
What about vitamin D in the UK?
Vitamin D supports the regulation of calcium and phosphate, which are important for bones, teeth and muscles.
The NHS advises everyone to consider a daily supplement containing 10 micrograms, equivalent to 400 IU, during autumn and winter. Some people should consider year-round supplementation, including those with dark skin or limited sunlight exposure. [8]
This advice applies independently of weight-management medication. Taking Mounjaro or Wegovy does not, by itself, mean that you need a higher dose.
Check whether a multivitamin already contains vitamin D before adding another product. The amount on the label is usually stated per recommended daily serving, which may involve more than one tablet.
A clinician may recommend a different dose when treating a confirmed deficiency. That treatment is separate from the usual preventive advice; high-dose products should not become an everyday habit without guidance.
Can a multivitamin help fill a dietary gap?
It can be a useful option for some people when food intake is limited or lacks variety. An appropriate multivitamin and mineral supplement may provide several nutrients in a manageable daily serving whilst you work on improving meals. [3,4]
The benefit is supplying nutrients you are not reliably obtaining elsewhere. It is not a guarantee of better weight loss, more energy or prevention of every side effect.
A general supplement also does not automatically contain enough of a nutrient to treat a diagnosed deficiency. Some products contain little calcium, and a gummy marketed as a multivitamin may include few minerals.
Look at the actual contents rather than the front-of-pack promise. A pharmacist can help you compare options and decide whether a standard product is appropriate for your circumstances.
If your appetite has been poor for weeks, adding a tablet should sit alongside a review of the reason you are struggling to eat. It should not become a way of postponing that conversation.
When is a targeted supplement more useful?
Sometimes the need is specific. Vitamin D may be appropriate under UK seasonal advice; a reliable B12 source is particularly important for someone following a vegan diet. Iron may be needed when a clinician identifies iron deficiency. [5,8,10]
A targeted approach lets the dose and duration match the problem. It also makes it easier to review whether treatment has worked and whether it is still needed.
If tests confirm a deficiency, ask what caused it, what treatment is recommended and when follow-up should happen. Correction may require a prescribed dose or another treatment route, rather than a standard shop-bought multivitamin.
Keep a simple list of what you take, including the brand, daily dose and start date. Bring it to appointments. “I take vitamins” gives your clinician much less information than a photograph of the label.
Treatment works best when everyone involved can see the whole picture.
Why not start iron just in case?
Iron deficiency deserves treatment, but unexplained tiredness is not enough to diagnose it.
Iron supplements can cause nausea, constipation and abdominal discomfort, which may be particularly unwelcome if you already have digestive symptoms. Excess iron can be harmful. [5]
Your clinician may consider a full blood count and iron studies, depending on your symptoms and history. The cause matters: inadequate intake, heavy periods and other sources of blood loss need different attention.
Avoid treating hair shedding or fatigue with a high-dose iron product simply because someone online says it helped them. Those symptoms have several possible explanations.
If iron is recommended, ask how to take it, what side effects to expect and when your response will be reviewed. Keep all iron products safely away from children.
Does eating a vegetarian or vegan diet change the advice?
A well-planned vegetarian or vegan diet can support weight management. The important point is planning, particularly when your portions become smaller.
For a vegan diet, the NHS highlights nutrients including B12, vitamin D, iodine, selenium and calcium that may require fortified foods or supplements. Do not assume that an unfortified plant drink provides the same nutrients as milk. [10]
Check labels for the nutrients you are trying to replace. A plant drink may contain calcium but no iodine; products vary.
If appetite is low, consider whether the foods you still enjoy cover your usual sources. Someone who has stopped eating beans, tofu and fortified products may benefit from more individual support than a generic meal plan provides.
The same principle applies to allergies, intolerances and other dietary restrictions. Supplements should fit your diet and health needs, and their ingredients should be checked too.
How can I make smaller meals more nourishing?
Start with manageable changes, rather than trying to rebuild your entire diet overnight.
A small bowl of yoghurt with oats and berries offers a different mix of foods from yoghurt alone. Adding beans to soup or an egg to toast can make a familiar meal more varied without turning it into a large plate.
For lunch or dinner, try a modest serving of fish, chicken, tofu or pulses alongside vegetables and a starchy food you tolerate. Frozen vegetables, tinned beans and simple leftovers can reduce the effort involved.
These are meal ideas, not a fixed prescription or a claim that one plate meets every requirement. Adjust them for allergies, preferences and any medical dietary advice.
The NHS Eatwell Guide encourages variety across food groups and balance over a day or week. You do not have to make every meal perfect. [11]
If a particular food makes you feel uncomfortable, discuss alternatives. A useful plan is one you can actually eat.
Can supplements replace meals or protein?
A vitamin tablet cannot replace the energy, protein and fibre supplied by food. Those needs still deserve attention even when your appetite is small.
If you have begun skipping most meals, the answer should involve reviewing your intake and treatment rather than relying on a larger supplement collection.
Protein powders and nutritional drinks are also different from multivitamins. A protein product may provide protein with little micronutrient content; a fortified nutritional drink may offer a broader mix. Read the label and discuss suitability if ordinary meals are difficult.
A registered dietitian can help turn vague advice such as “eat more protein” into portions and choices that fit your appetite, preferences and medical history.
Keep an eye on everyday function too. Tell your clinician if you are feeling weaker, struggling with usual activities or finding eating increasingly difficult. Progress should be discussed in terms of wellbeing as well as the number on the scales.
How do I choose supplements safely?
Choose a product with clearly stated ingredients and daily amounts. For general supplementation, discuss an ordinary formulation with a pharmacist rather than assuming that higher doses are better.
The percentage Nutrient Reference Value, or NRV, is a labelling guide. It does not tell you whether you personally have a deficiency or what dose would treat one.
Avoid stacking several overlapping products, such as a multivitamin, a hair supplement and a separate B-complex, without checking the totals. Vitamin B6 is one example where excess supplementation can damage nerves; the NHS advises against more than 10 mg daily in supplements unless a doctor recommends it. [6]
Tell your pharmacist about prescribed medicines and medical conditions before buying.
Calcium, iron and other supplements can affect how some medicines are taken, so timing may matter.
Special care is needed with kidney disease, pregnancy plans or existing vitamin treatment. Keep the packaging, follow the recommended dose and arrange a review if you are taking something for a specific problem.
Do I need a blood test?
Not everyone taking Mounjaro or Wegovy needs a large panel of vitamin tests. Your symptoms, diet and medical history should guide which investigations are useful.
If you have persistent fatigue, a sore tongue, tingling or other concerning changes, contact your GP or prescribing team. Blood tests can help assess suspected B12 or folate deficiency, but results need interpreting alongside symptoms. [12]
Share how long you have been eating less, what a typical day looks like and which supplements you already take. Mention heavy periods, dietary restrictions, recent illness and previous deficiencies.
A brief food diary can make that conversation easier. Record food, drinks and any nausea or vomiting for a few representative days without trying to make the entries look ideal.
The aim is to identify the next useful step. That might be dietary advice, a targeted test, treatment of a deficiency or a review of medication tolerability.
When should I contact my prescribing team promptly?
Seek advice promptly if you are repeatedly vomiting, struggling to eat enough or having difficulty keeping fluids down. Vomiting and diarrhoea can cause dehydration, and the medicine leaflets warn that this can affect kidney function. [1,2]
Marked dizziness, very little urine or feeling significantly unwell needs urgent assessment.
Severe, persistent abdominal pain, especially with vomiting, also needs urgent medical attention because it may indicate a serious problem. Do not try to manage these symptoms with vitamins.
If side effects are limiting your intake, speak to your prescribing team before any planned dose increase. Your treatment plan may need reviewing.
You do not need to wait until a symptom is unbearable to ask for support. An early conversation can help you describe what has changed and agree a practical response.
Supporting your health throughout your weight-management journey
Supplements can have a useful role when they meet a real need: bridging an identified dietary gap, following UK vitamin D advice or treating a deficiency under clinical guidance.
The best starting point is a clear picture of what you are eating and how you are feeling. Smaller portions can still offer variety, and support can help when they do not.
At AJ Hill Aesthetics, we encourage you to raise questions about appetite, nutrition and side effects during your reviews. Bring your supplement list and tell us if meals are becoming difficult.
Your plan should support your health whilst you work towards your weight-management goals. Food, suitable supplementation and individual clinical advice can all play a part.
This article provides general information and does not replace an individual assessment or your medicine’s patient information leaflet.
Sources & further reading
Information checked: 13 October 2026.
