Wegovy (semaglutide) is a GLP-1 receptor agonist licensed by the MHRA for chronic weight management in adults with obesity or overweight with weight-related comorbidities. Whilst highly effective for weight loss, Wegovy significantly reduces appetite and food intake, which may increase the risk of nutritional inadequacy. Choosing the best multivitamin while on Wegovy can help bridge the gap between reduced calorie consumption and your body's ongoing micronutrient requirements. This article explores which vitamins and minerals deserve particular attention, how to select an appropriate supplement, and when to seek professional guidance to support your nutritional health during treatment.
Quick Answer: A comprehensive multivitamin providing at least 100% of the Nutrient Reference Value for most vitamins and minerals, with particular attention to B vitamins (especially B12 and thiamine), vitamin D (10 micrograms minimum), and appropriate iron content based on individual needs, is recommended during Wegovy treatment.
Wegovy (semaglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed by the MHRA for chronic weight management in adults with obesity or overweight with weight-related comorbidities. The medication works by mimicking the action of the naturally occurring hormone GLP-1, which regulates appetite and food intake by slowing gastric emptying and enhancing satiety signals in the brain. Whilst this mechanism proves highly effective for weight loss, it also means patients typically consume significantly fewer calories and smaller food portions than before treatment.
This substantial reduction in food intake, whilst beneficial for weight management, may create a risk of nutritional inadequacy for some individuals. When you eat less food overall, you naturally consume fewer vitamins and minerals, even if your diet quality remains good. Research indicates that individuals on very-low-calorie diets or experiencing rapid weight loss may be at increased risk of developing micronutrient deficiencies, which can affect everything from immune function to bone health and energy metabolism.
It's important to note that GLP-1 receptor agonists like Wegovy do not cause nutrient malabsorption; any nutritional challenges are primarily related to reduced food intake and, in some cases, nausea or other gastrointestinal symptoms.
A well-chosen multivitamin supplement can serve as nutritional insurance during Wegovy treatment, helping to bridge the gap between reduced food intake and your body's ongoing micronutrient requirements. This is particularly important during the initial months of treatment when appetite suppression is most pronounced and dietary adjustments are still being established. However, supplements should complement—not replace—a balanced, nutrient-dense diet.
Consider consulting your GP, pharmacist or dietitian about individualising your supplementation approach based on your specific dietary pattern, medical history, and any symptoms you experience while taking Wegovy.
Patients taking Wegovy may face several specific nutritional vulnerabilities that warrant attention. Vitamin B12 deficiency may occur in some patients, primarily due to reduced intake of B12-rich foods like meat, fish, and dairy products, or because of nausea and vomiting affecting overall nutrient intake. Symptoms of B12 deficiency include fatigue, weakness, neurological changes such as pins and needles, and cognitive difficulties. Left untreated, severe deficiency can cause irreversible nerve damage.
Iron deficiency is another potential issue, especially in menstruating women and those consuming less red meat due to reduced appetite. Iron is crucial for haemoglobin production and oxygen transport; deficiency manifests as anaemia, fatigue, pale skin, and reduced exercise tolerance. The reduced food intake on Wegovy may limit dietary iron sources, whilst gastrointestinal side effects like nausea can further compromise intake.
Vitamin D deficiency affects a substantial proportion of the UK population regardless of medication use. The NHS recommends that adults consider taking a daily supplement containing 10 micrograms (400 IU) of vitamin D during autumn and winter months, with year-round supplementation advised for those who have limited sun exposure or are at higher risk. Adequate vitamin D is essential for bone health, immune function, and mood regulation. Calcium intake may also decline when dairy consumption decreases, raising concerns about bone mineral density during weight loss.
Thiamine (vitamin B1) deficiency, whilst less common, can occur with persistent vomiting or severely restricted carbohydrate intake. This requires urgent medical attention if symptoms such as confusion, unsteady gait, abnormal eye movements, or severe weakness develop, as these may indicate Wernicke's encephalopathy, a medical emergency. Other nutrients of concern include folate, important for cell division and particularly crucial for women of childbearing age, and magnesium, which supports muscle function and metabolic health.
Your GP may recommend targeted blood tests based on your symptoms or risk factors during Wegovy treatment. These might include full blood count, ferritin, vitamin B12, folate, or vitamin D levels, allowing for appropriate supplementation beyond a standard multivitamin if needed.
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Start HereSelecting an appropriate multivitamin during Wegovy treatment requires consideration of several factors. Look for a comprehensive formulation that provides at least 100% of the Nutrient Reference Value (NRV) for most vitamins and minerals, but avoid mega-doses that far exceed recommended amounts unless specifically advised by your healthcare provider. Products marketed for general health maintenance are typically sufficient, as GLP-1 receptor agonists do not cause nutrient malabsorption.
Check for adequate B vitamin content, particularly B12 (at least 1.5 micrograms, the UK Reference Nutrient Intake, though many supplements provide 2.5 micrograms based on the NRV), thiamine (1–1.4 mg), and folate (200 micrograms). These water-soluble vitamins are not stored long-term in the body and require regular replenishment. Ensure sufficient vitamin D (10 micrograms or 400 IU minimum), as the NHS recommends this level of supplementation during autumn and winter for most adults, with year-round supplementation advised for those with limited sun exposure.
Consider iron content carefully. Whilst menstruating women and those with documented deficiency benefit from iron supplementation, men and post-menopausal women may not require additional iron and excessive intake can cause gastrointestinal upset or, rarely, iron overload. Some multivitamins offer iron-free formulations as an alternative.
Formulation matters when taking Wegovy. Tablets or capsules are generally well-tolerated, but if you experience persistent nausea, liquid or chewable formulations might be easier to manage. Some patients find that splitting doses (taking half in the morning and half in the evening) reduces gastrointestinal discomfort.
Quality assurance is important. Choose products from reputable manufacturers that follow Good Manufacturing Practice (GMP) standards. Look for products with third-party testing or quality marks from organisations like Informed-Sport if you're an athlete concerned about banned substances. Avoid products making exaggerated health claims or promising to enhance Wegovy's weight loss effects, as these are not evidence-based.
Important safety note: Wegovy is contraindicated during pregnancy and breastfeeding. If you are planning pregnancy, choose a multivitamin without retinol (vitamin A) but containing folic acid (400 micrograms daily), as recommended by the NHS for all women trying to conceive.
Understanding which specific nutrients deserve particular attention can help you make informed choices about supplementation during Wegovy treatment.
B-complex vitamins are crucial for energy metabolism and nervous system function. Vitamin B12 (cobalamin) supports red blood cell formation and neurological health; deficiency risk increases with reduced meat and dairy intake. Thiamine (B1) is essential for carbohydrate metabolism and nerve function. Riboflavin (B2) and niacin (B3) support cellular energy production, whilst B6 (pyridoxine) aids protein metabolism and neurotransmitter synthesis. Folate (B9) is vital for DNA synthesis and cell division.
Fat-soluble vitamins require dietary fat for absorption, which may be affected if your diet becomes very low in fat. Wegovy itself does not cause fat malabsorption, but taking supplements with meals containing some healthy fats can aid absorption. Vitamin D regulates calcium absorption and bone metabolism; the NHS recommends 10 micrograms (400 IU) daily during autumn and winter for most adults. Vitamin A supports vision, immune function, and skin health (note that retinol forms should be avoided during pregnancy). Vitamin E acts as an antioxidant protecting cell membranes. Vitamin K is essential for blood clotting and bone metabolism.
Essential minerals include calcium (700 mg daily for adults) for bone health and muscle function, particularly important during weight loss when bone density may be affected. Iron (8.7 mg for men, 14.8 mg for menstruating women) prevents anaemia and supports oxygen transport. Magnesium (300 mg for men, 270 mg for women) regulates muscle and nerve function, blood glucose, and blood pressure. Zinc (9.5 mg for men, 7 mg for women) supports immune function, wound healing, and protein synthesis.
Selenium (75 μg for men, 60 μg for women) and iodine (140 μg for adults) are trace minerals essential for thyroid function, which regulates metabolism. Adequate intake becomes particularly important during weight loss when metabolic rate may naturally decline.
A quality multivitamin should provide balanced amounts of these nutrients, though individual requirements vary based on age, sex, baseline nutritional status, and the degree of dietary restriction experienced on Wegovy.
Timing your multivitamin intake appropriately can optimise absorption and minimise potential side effects when taking Wegovy.
Wegovy is administered once weekly as a subcutaneous injection, typically on the same day each week. The medication reaches peak concentration in the blood approximately 1–3 days after injection and maintains therapeutic levels throughout the week. Unlike some medications that require specific timing relative to food, Wegovy can be administered at any time of day, with or without meals, providing flexibility in your dosing schedule.
For multivitamin supplementation, most formulations are best taken with food to enhance absorption and reduce the risk of gastrointestinal upset, particularly for fat-soluble vitamins (A, D, E, K) which require dietary fat for optimal absorption. Taking your multivitamin with your largest meal of the day, or a meal containing some healthy fats, generally works well. This might be breakfast, lunch, or dinner depending on your eating pattern and when you experience least nausea from Wegovy.
There is no official guidance requiring separation between Wegovy injection and multivitamin intake, as there are no known direct drug-nutrient interactions that would necessitate timing adjustments. While Wegovy does delay gastric emptying (as noted in the SmPC), this is not known to have clinically relevant effects on multivitamin absorption. However, if you experience nausea—a common side effect of Wegovy, particularly in the first few weeks or after dose increases—you might find it helpful to take your multivitamin at a time of day when nausea is minimal, often later in the day as the medication's peak effects subside.
Consistency matters more than specific timing. Taking your multivitamin at roughly the same time each day helps establish a routine and ensures regular nutrient intake. Some patients find setting a daily reminder helpful, or linking supplementation to an existing habit like morning coffee or evening meal.
If you experience persistent nausea or vomiting that prevents you from taking or retaining your multivitamin, contact your GP or prescribing clinician, as this may indicate the need for dose adjustment or anti-nausea medication.
The NHS provides evidence-based guidance on nutritional supplementation during weight management programmes, which applies to patients taking Wegovy.
NICE guidance on obesity management and the NICE Technology Appraisal for semaglutide emphasise that pharmacological interventions like Wegovy should be part of a comprehensive approach including dietary modification, increased physical activity, and behavioural support. Whilst NICE does not mandate routine multivitamin supplementation for all patients on weight loss medication, it acknowledges that nutritional monitoring is important, particularly when calorie restriction is significant or rapid weight loss occurs.
NHS advice on vitamin D supplementation recommends that adults consider taking a daily supplement containing 10 micrograms (400 IU) of vitamin D during autumn and winter months when sunlight exposure is insufficient for adequate synthesis. Year-round supplementation is advised for people who have limited sun exposure or are at higher risk of deficiency. This guidance applies equally to those taking Wegovy.
For patients on very-low-calorie diets (under 800 calories daily), NHS guidance recommends clinical supervision. Many total diet replacement products are nutritionally complete, but additional supplementation may be advised by your healthcare provider based on individual circumstances. Whilst most Wegovy users consume more than this threshold, those experiencing profound appetite suppression should discuss their nutritional intake with their healthcare provider.
The NHS advises against self-prescribing high-dose supplements without medical supervision, as excessive intake of certain nutrients (particularly fat-soluble vitamins A, D, E, K, and minerals like iron) can cause toxicity. If blood tests reveal specific deficiencies, your GP may prescribe therapeutic doses of individual nutrients rather than relying solely on a multivitamin.
Monitoring should be tailored to individual needs. Your GP or specialist weight management service should offer periodic review including assessment of nutritional status, weight loss progress, and any adverse effects. If you experience symptoms potentially related to nutritional deficiency—such as unusual fatigue, hair loss, muscle cramps, or neurological symptoms—contact your GP promptly rather than simply increasing supplement doses independently.
Remember that supplements complement but cannot replace a varied, balanced diet. Focus on consuming nutrient-dense foods within your reduced calorie intake, including lean proteins, colourful vegetables, fruits, whole grains, and healthy fats, using supplementation as additional nutritional insurance during your weight loss journey.
If you experience any suspected side effects from Wegovy or supplements, report them to the MHRA Yellow Card Scheme, which helps monitor the safety of medicines and supplements in the UK.
Whilst not mandatory, a multivitamin can serve as nutritional insurance during Wegovy treatment, helping to bridge the gap between reduced food intake and your body's micronutrient requirements. This is particularly important during initial months when appetite suppression is most pronounced, though supplements should complement rather than replace a balanced, nutrient-dense diet.
Key nutrients include B vitamins (especially B12 and thiamine), vitamin D (10 micrograms daily as recommended by the NHS), iron (particularly for menstruating women), calcium, folate, and magnesium. These support energy metabolism, bone health, immune function, and nervous system health during reduced calorie intake.
Take your multivitamin with food to enhance absorption and reduce gastrointestinal upset, preferably with your largest meal or a meal containing healthy fats. There are no known interactions requiring specific timing separation from Wegovy injections, though taking supplements when nausea is minimal may improve tolerance.
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