Supplements to take on Wegovy: what the evidence actually supports

Why Wegovy increases your risk of nutritional shortfalls

The GLP-1 trial evidence gives a useful starting point here. In STEP 1, published in the New England Journal of Medicine, participants taking semaglutide 2.4 mg lost an average of around 15% of body weight over 68 weeks. That's a meaningful reduction, and it is driven largely by a sustained fall in appetite and food intake. When you consistently eat less, the overall volume of vitamins and minerals entering your body drops too, even if the quality of your remaining diet is good. Protein deserves the most urgent attention. Rapid weight loss without adequate protein tends to take muscle along with fat, which undermines long-term metabolic health and can leave you feeling weaker than expected. Most clinical dietitians working in weight management suggest aiming for roughly 1.2–1.6 g of protein per kilogram of body weight per day during active weight loss, a target that becomes harder to hit naturally when appetite is suppressed. A good-quality protein supplement (whey, soy, or pea-based, depending on preference and tolerance) can be a practical bridge when meals feel small. The NHS semaglutide patient information also notes that following a balanced diet remains important throughout treatment, which makes monitoring your nutritional intake genuinely worthwhile rather than an afterthought.

The micronutrients most worth tracking on semaglutide

Vitamin D is one of the first worth discussing with your GP or prescriber. UK population surveys consistently show widespread deficiency, and the NHS already recommends that most adults consider a daily supplement of 10 micrograms (400 IU) through autumn and winter. Eating less food reduces dietary vitamin D further, so a year-round supplement at this dose is reasonable for most people on Wegovy, and worth checking via a blood test if you haven't done so recently. Vitamin B12 merits attention for a different reason. Semaglutide slows gastric emptying, which affects how well some oral medicines and nutrients are absorbed; B12 in particular depends on adequate stomach acid for absorption. A standard multivitamin or dedicated B12 supplement is low-risk and sensible for most patients. Iron is another common gap, particularly in women of reproductive age, and it is one that reduced food volume can worsen noticeably. You can find a more detailed look at how Wegovy interacts with iron levels on our page covering Wegovy and iron supplements. Omega-3 fatty acids round out the core list: oily fish consumption often falls when appetite drops, and omega-3s have well-documented cardiovascular benefits that matter for a population managing obesity-related conditions. A standard fish-oil or algae-based omega-3 capsule (1–2 g daily) is widely recommended alongside weight-management medicines. If hair thinning is something you're concerned about, zinc and biotin are sometimes suggested, for more on that, our guide to Wegovy and hair loss covers the evidence in full.

What to be careful about: interactions and things to avoid

Not everything sold in the supplement aisle is harmless alongside a prescription medicine. A few practical cautions are worth knowing. Fat-soluble vitamins (A, D, E and K) accumulate in the body, so very high-dose supplements of these carry a genuine risk of toxicity, stick to standard doses unless a clinician has recommended otherwise based on your bloodwork. St John's Wort is a common one to watch: it interacts with a wide range of prescription medicines and should not be taken without your prescriber's knowledge. Similarly, high-dose calcium supplements taken at the wrong time of day can interfere with the absorption of other nutrients and some medicines. For a fuller list of what to avoid, our page on supplements to avoid on semaglutide goes through the risk categories clearly. The general principle is simple: keep your supplements in a separate, accessible spot (the shelf above the fridge, say, rather than buried in a gym bag) so you actually take them consistently, and let your prescriber know everything you're using. That conversation is easiest during a clinical review, where your weight progress and any side effects can be assessed at the same time. If you're thinking about the broader cost picture of private Wegovy treatment, our Wegovy prices page sets out what a private prescription typically involves in the UK.

Getting a supplement plan that fits your situation

The supplements worth taking on semaglutide are not the same for everyone. Someone with a varied, protein-rich diet and recent normal bloods has different needs from someone who has eaten a restricted diet for years or has a history of anaemia. A registered dietitian is the most qualified person to build a personalised plan alongside your prescriber. More detailed breakdowns of specific supplement combinations are available on our pages covering the best supplements during Wegovy treatment and supplements for semaglutide users more broadly. The core starting point (protein, vitamin D, B12, omega-3s, iron where indicated) is consistent across most clinical guidance and is a reasonable default while you arrange a more tailored review. If you are ready to start Wegovy through a regulated UK pharmacy with prescriber oversight built in from day one, check your eligibility with our clinical team.