Continuous glucose monitors were, not long ago, a clinical tool for people managing type 1 diabetes or unstable type 2. Now they are being advertised on Instagram, sold through wellness subscription services, and worn by healthy thirtysomethings who want to understand their “metabolic health”. In the UK, companies like Levels, Zoe and Supersapiens have made CGM for non-diabetics a genuine consumer category, with prices typically starting around £99 to £200 per month depending on the service. That is real money for what, in many cases, amounts to real-time blood glucose data that a healthy person may have no clinical need for.
I want to be clear upfront: this is not an attack on the technology. CGMs are genuinely impressive medical devices, and the data they produce is real. The question is whether the interpretation layers being sold alongside them, and the lifestyle changes being recommended on the basis of individual glucose responses, are justified by the evidence we actually have.
What CGMs are approved to do in the UK
The MHRA regulates CGMs as medical devices under the UK Medical Devices Regulations 2002 (as amended). Devices like the Abbott FreeStyle Libre, which is also available on NHS prescription for eligible patients with diabetes, are approved as aids for glucose monitoring in people with diabetes. They are not approved as metabolic optimisation tools for healthy adults. That distinction matters, because it means the claims made in wellness marketing sit outside the scope of what regulators have actually evaluated.
The Advertising Standards Authority has already taken action against some health brands for making unsubstantiated claims. If you see a CGM subscription service promising it will help you “unlock fat burning” or “end energy crashes”, those are marketing claims, not clinical findings. Treat them accordingly.
What does the research actually say about CGM for non-diabetics?
The honest answer is: not much, and what exists is mixed. A 2023 study published in Nature Medicine (the Stanford-led DIETFITS follow-up work examining glycaemic variability) found that individual glucose responses to food varied considerably even among healthy people. That finding has been heavily used by CGM companies to argue that personalised nutrition guidance, informed by your own glucose data, produces better outcomes. But the leap from “glucose responses vary” to “wearing a CGM will improve your health or performance” is not supported by robust clinical trials in non-diabetic populations.
A 2024 review in The Lancet Diabetes & Endocrinology noted that while CGMs generate large volumes of data in healthy individuals, there is currently insufficient evidence that acting on that data produces meaningful improvements in weight, cardiovascular risk, or athletic performance compared to established dietary approaches. The reviewers called for randomised controlled trials in non-clinical populations before widespread recommendation. We are still waiting for those trials.
In healthy adults, blood glucose generally stays within a tight range regardless of what you eat. The dramatic-looking spikes that some CGM apps flag as alarming are often physiologically normal. A glucose rise after a bowl of porridge is not the same thing as the sustained hyperglycaemia seen in diabetes. Yet some CGM coaching services treat any excursion above a certain threshold as a problem to be solved through dietary restriction, which risks encouraging unnecessary anxiety about food.
The performance claims deserve particular scrutiny
Supersapiens, which markets its CGM service specifically to athletes, has attracted a following among cyclists, runners, and endurance competitors. The premise is that knowing your glucose in real time helps you fuel more precisely during training and racing. I find this genuinely interesting as a concept. Sports nutrition is a field where small margins matter, and glucose management during prolonged effort is well established as important.
But “interesting concept” and “proven performance advantage” are different things. The peer-reviewed evidence base for CGM-guided fuelling in non-diabetic athletes is thin. Most sports nutrition guidance from bodies like the British Dietetic Association still centres on periodised carbohydrate intake based on training load and intensity, not real-time glucose response. Until we have properly controlled studies showing CGM-guided fuelling outperforms standard evidence-based nutrition practice in healthy athletes, the claims should be held lightly.
Who might genuinely benefit from CGM data outside a diabetes diagnosis?
This is where it gets more constructive. There are populations where CGM use in non-diabetic contexts has real clinical logic. People with prediabetes, those with a strong family history of type 2 diabetes, women with a history of gestational diabetes, and people with polycystic ovary syndrome (PCOS) all have elevated risk profiles where understanding glucose variability has some clinical rationale. For these groups, the conversation belongs with a GP or endocrinologist, not a wellness app.
If you are curious about your metabolic health and you fall into one of these categories, that is worth raising with your NHS GP rather than self-directing via a subscription service. Given how the NHS waiting list pressures are already pushing people towards self-diagnosis, the last thing anyone needs is another layer of uninterpreted data creating unnecessary worry or driving inappropriate dietary restriction.
The supplement and nutrition industry connection
CGM services rarely exist in isolation. Most are bundled with dietary coaching, meal planning, and frequently supplements. Once a company has your glucose data, they have a compelling hook for selling you products designed to “smooth” your glucose response: berberine, cinnamon extract, chromium, and various fibre supplements appear regularly in CGM-adjacent marketing. Some of these have limited supporting evidence in clinical populations; most are sold well beyond what the evidence justifies.
I came across a comparison tool from Nusan whilst researching how UK consumers are trying to make sense of health product claims more broadly, and the pattern is consistent: the supplement market tends to rush into spaces where clinical data is incomplete and consumer interest is high. CGM is no different. If you are being told by a CGM service that you need specific supplements based on your glucose patterns, ask for the clinical evidence before spending your money.
This also connects to what I have written previously about the supplement boom needing more scrutiny in the UK generally. The CGM category is just the newest entry point.
What about Zoe specifically?
Zoe is the highest-profile CGM-adjacent wellness company in the UK, co-founded by Professor Tim Spector of King’s College London. Their programme involves a CGM, gut microbiome testing, and personalised dietary recommendations. Zoe has published peer-reviewed research, including a 2024 paper in Nature Medicine suggesting their personalised dietary programme outperformed standard healthy eating guidance for certain metabolic markers. That is genuinely more rigorous than most commercial wellness programmes.
But even here, the research involves Zoe’s own programme participants and has not yet been independently replicated at scale. The scientific advisory involvement does not mean every claim in their marketing is substantiated. The NHS guidance on CGM remains focused on people with diabetes and does not endorse its use in healthy adults for weight or performance management.
The psychological risk nobody talks about
One concern I have not seen discussed enough is the psychological effect of continuous metabolic monitoring on people who do not have a clinical reason for it. Wearing a device that generates a new data point every few minutes, and then receiving alerts about “high” readings, could reasonably increase health anxiety in some people. There is also a risk of what researchers call “orthorexic” thinking: becoming so focused on optimising food choices around a metric that eating becomes a source of stress rather than pleasure or nourishment.
If you are already prone to metabolic health anxiety or have a history of disordered eating, a CGM subscription service is not where I would start. Talk to your GP first.
The bottom line
CGMs are legitimate, well-engineered medical devices. The data they produce is real. For people managing diabetes, they are genuinely life-changing. For healthy adults with no clinical indication, the evidence that wearing one and adjusting behaviour accordingly produces meaningful health outcomes is currently insufficient to justify the cost, the anxiety, or the supplement spending that tends to follow. The commercial ecosystem around CGM for non-diabetics has moved considerably faster than the science. That gap is worth understanding before you subscribe.
Frequently Asked Questions
Can I get a CGM on the NHS if I don't have diabetes?
Generally no. NHS CGM prescriptions are reserved for people with type 1 diabetes and some people with type 2 diabetes who meet specific clinical criteria. If you are interested in CGM for metabolic monitoring without a diabetes diagnosis, you would need to purchase it privately through a commercial service.
Is it safe to use a CGM if I am not diabetic?
The devices themselves are safe for most people; they involve a small sensor inserted just under the skin. The main risks for non-diabetic users are psychological, including health anxiety from misinterpreting normal glucose fluctuations, and financial, given the ongoing subscription costs. If you have a history of disordered eating, speak to a GP before using one.
Do CGMs actually help with weight loss in healthy people?
Current evidence does not support CGM use as an effective weight loss tool in people without diabetes or prediabetes. A 2024 Lancet review found insufficient evidence that acting on CGM data in healthy adults produces better weight outcomes than established dietary approaches. The personalised nutrition framing is compelling, but the clinical proof is not there yet.