Taking vitamins with Wegovy: what actually matters

Why appetite suppression changes your micronutrient picture

One thing people rarely consider when starting Wegovy is that eating significantly less food also means eating significantly fewer vitamins and minerals. The appetite-suppressing effect of semaglutide is, for most people, quite pronounced in the early months. Meals shrink. Snacks disappear. And with them go the incidental nutrients that would ordinarily come from a varied diet.

This is worth taking seriously. Protein adequacy gets most of the attention, and rightly so, but fat-soluble vitamins (A, D, E and K) depend on dietary fat for absorption. If fat intake drops sharply because portion sizes fall, even a supplement taken on schedule may not absorb as efficiently as it would on a fuller meal. The practical implication: take fat-soluble vitamins with whichever meal contains the most fat, even if that meal is now small.

Water-soluble vitamins, including vitamin C and the B-group vitamins, are less affected by meal composition, though B12 deserves specific attention. People eating smaller amounts of meat, fish and dairy can slide into suboptimal B12 status over months, quietly. A daily B12 supplement or a good B-complex is a sensible precaution for many people on calorie-restricted treatment. The duration of Wegovy treatment matters here too: a brief course carries a different nutritional risk profile to a year-long programme.

Vitamin D is the other one to watch. Most people in the UK are already below optimal levels for at least part of the year, and reduced dietary intake makes that gap wider. A daily 10 micrograms of vitamin D3 is consistent with NHS guidance for adults generally; during weight-loss treatment there is a reasonable case for checking your baseline level with your GP.

Does Wegovy interact with vitamins or standard supplements?

There is a misconception that runs through supplement forums: that GLP-1 medicines interact badly with vitamins in a pharmacological sense, the way some drugs interact with grapefruit or warfarin. That is not the picture the evidence supports.

The NHS patient information for semaglutide does flag that Wegovy slows gastric emptying, which can theoretically alter the absorption rate of other medicines taken at the same time. For most vitamins, this is a minor timing issue rather than an interaction that changes efficacy. Standard multivitamins, vitamin C, zinc, magnesium and similar supplements do not appear on the list of medicines that require special attention alongside semaglutide.

Where timing genuinely matters is with anything formulated to release slowly over hours (extended-release capsules in particular) because a slower gastric transit time could alter how they behave. Oral medicines and specific supplement formulations in that category are worth mentioning to your prescriber, who can advise on timing or flag whether the format matters for your specific supplement.

People taking iron supplements should also know that semaglutide's effect on gastric pH and transit could affect iron absorption. If you are taking therapeutic-dose iron on medical advice, let your prescriber know when you discuss starting Wegovy. For the purpose of an eligibility assessment for Wegovy, your current medications and supplements form part of that conversation.

Collagen, creatine and the supplements that get asked about most

Beyond multivitamins, a few specific supplements come up regularly in questions from people starting semaglutide therapy. Collagen peptides are popular among people concerned about skin during rapid weight loss, and there is no reason to stop them on Wegovy, they are a protein source, effectively, and protein is precisely what you want to be maintaining. You can read more about the specific evidence picture on our collagen and Wegovy page.

Creatine is another one that comes up, particularly among people who are keeping up resistance training during treatment. Again, there is no known interaction with semaglutide, and maintaining muscle mass during weight loss is genuinely worth supporting. The creatine and Wegovy page covers this in detail if you want to go further.

What you can reasonably do right now: audit what you are currently taking, consider whether fat-soluble vitamins are timed with your largest meal, and make sure vitamin D and B12 are covered. If you are on anything prescribed by your GP (iron, folate, therapeutic-dose vitamins) mention that when you complete your consultation. Our prescribers read every response personally; supplement and medication lists are part of the clinical picture they assess. You can find detail on how BMI and other eligibility factors work for Wegovy on the relevant page.

Supplements can also interact with other medicines you might use alongside Wegovy. If you are wondering about common over-the-counter medicines in that mix, our page on antihistamines and semaglutide covers how to think about that category, and the naproxen and Wegovy page addresses pain relief specifically.

One thing worth looking at if you are considering treatment is the weight-loss treatments overview, which sets out what is included in a nume consultation and what happens after approval.