Can You Take Melatonin With Wegovy? What the Evidence Says

What official guidance and the SmPC actually say about this combination

The Wegovy SmPC, published on the electronic Medicines Compendium, lists the medicines and substance classes that require caution or are contraindicated with semaglutide. Melatonin does not feature on that list. This is consistent with what the NHS medicines page for semaglutide describes: the main drug-interaction concern with Wegovy is not any specific supplement but rather the general effect of delayed gastric emptying on other oral medicines, particularly those with a narrow therapeutic window or time-sensitive absorption profile.

That gastric-emptying effect is worth pausing on. Semaglutide slows the rate at which the stomach empties into the small intestine, which is part of how it reduces appetite and blunts post-meal glucose spikes. For an oral supplement taken at night, this could in theory mean slightly slower or altered absorption, not necessarily harmful, but a practical reason to flag it rather than assume nothing changes.

Melatonin itself has a short half-life and is generally regarded as having a low interaction potential. It is available in the UK both as a licensed medicine (Circadin, 2mg prolonged-release, prescription-only for adults over 55 with primary insomnia) and as an over-the-counter food supplement in lower doses. Which form you are taking matters, because licensed melatonin comes with a prescriber conversation built in; supplement melatonin often does not.

The blood-glucose angle, worth noting if you have diabetes or prediabetes

Melatonin receptors are found in pancreatic beta cells, and research published in journals including The BMJ has explored links between melatonin signalling and insulin secretion. The evidence is not settled, but one consistent finding is that high-dose melatonin may suppress insulin release, at least transiently in some individuals. For most people taking a low-dose supplement for occasional sleep support, this is unlikely to be clinically significant. For people with type 2 diabetes or prediabetes (a group who may also be taking Wegovy for weight management) it is a more relevant question.

Semaglutide itself improves blood-glucose control as part of its mechanism of action. Layering anything that could, even modestly, affect glucose or insulin on top of that is worth discussing with a prescriber, not because the risk is high, but because it belongs in the clinical picture. If you are also taking other glucose-lowering medicines alongside Wegovy, the conversation becomes more important still.

A question our prescribers hear fairly often is whether someone can keep taking the supplements they rely on once they start Wegovy. The honest answer is: usually yes, but the combination should be reviewed rather than assumed. That applies to melatonin as much as to any other regular supplement, and our dedicated page on melatonin and Wegovy goes into further detail for anyone who wants a closer look at the evidence.

How semaglutide's gastric effects can change supplement timing

Even where there is no direct pharmacological interaction, the slowed gastric emptying associated with semaglutide means that oral supplements may not absorb in the way you are used to. Melatonin is typically taken 30 to 60 minutes before sleep, and timing is part of its intended effect, it works partly by signalling to the brain that darkness and rest are approaching. If absorption is delayed, the sleep-timing benefit might shift slightly.

This is a practical rather than a safety concern for most people. The simplest approach is to mention it at your Wegovy consultation so that your prescriber can factor it into the review. There is more detail on the broader question of what to avoid taking alongside semaglutide that is worth reading if you take several regular medicines or supplements.

For context on the treatment itself, the Wegovy overview covers how semaglutide works, what the licensed eligibility criteria are, and what the clinical trial results showed. Understanding the medicine as a whole makes these narrower questions easier to place.

Practical steps before combining melatonin and Wegovy

The short version: there is no formal contraindication, but the combination deserves a brief clinical conversation rather than a silent assumption. Sleep is genuinely relevant to weight management, poor sleep raises ghrelin (the hunger hormone) and lowers leptin, working against the appetite regulation that Wegovy supports. So if melatonin is helping your sleep, that may actually be complementary to your treatment goals, and your prescriber is well placed to say so explicitly.

A few practical points worth knowing. First, tell your prescriber about all supplements you take, not just prescription medicines, this is part of the standard consultation at nume. Second, if you use licensed melatonin (Circadin) prescribed by a GP, your GP should know you are starting Wegovy, and our prescribers notify your GP as part of our standard process. Third, if you notice any change in how you feel after adding or stopping melatonin while on Wegovy, log it and mention it at your next review.

For those comparing GLP-1 medicines more broadly, there is a useful summary of medicines to discuss before starting Wegovy, and a separate page on whether statins can be taken alongside Wegovy, a common question given that cardiovascular risk and weight often overlap. Those pages draw on the same clinical sources as this one, so the principles are consistent. If you are currently weighing up costs and timing, it is also worth checking whether our Wegovy Black Friday offers are relevant to your situation before you start.