The short answer: no weight loss patch is licensed in the UK. Not one. And there's no published evidence that what's in them ever reaches your bloodstream. Supplements are a more mixed picture — a few have modest evidence, most have almost none, and a handful come with real safety warnings. Here's the whole thing, question by question, with the sources at the bottom so you can check us.
First, why we bothered writing this
On one day in August 2025, the Advertising Standards Authority ruled against five different supplement companies. Five. In a single day (ASA, 2025a–e).
That doesn't mean those products are dangerous. It means what they were saying about them had got miles ahead of what they could actually prove.
If you've been staring at weight loss patches, diet pills, fat burners and appetite suppressants trying to work out what's real, you're not being slow. It's genuinely hard to tell.
We're a UK weight management clinic, so we've got a dog in this fight. Read us with that in mind. Everything below has a source.
Part one: patches
Are weight loss patches safe?
This is the question people ask most, so let's start here.
For most healthy adults, a slimming patch is unlikely to cause serious harm. There's a slightly awkward reason for that: the same skin barrier that stops the active ingredients getting into your blood also stops most of them causing problems.
What does come up tends to be local and minor — skin irritation, redness, or an itchy rash where the patch sits. Some people report nausea or stomach upset, though with an unlicensed product it's hard to say what's causing what.
There are three situations where we'd be more careful.
If you have diabetes. Some patches contain ingredients marketed as affecting blood sugar. If any of that were absorbed, it could matter alongside your existing medication. Speak to your diabetes team or your pharmacist first.
If you're pregnant or breastfeeding. These products haven't been tested in pregnancy, because unlicensed products don't get tested in pregnancy.
If you take prescribed medicines. Herbal ingredients interact with prescriptions in ways people rarely expect.
The bigger risk with patches isn't really a physical one. It's that you spend money and months on something that was never going to work, while the thing that would have helped goes unstarted.
Do weight loss patches work?
No. And the reason is simpler than you'd think.
It's not about the ingredients. It's about your skin.
Your skin's whole job is keeping things out, and it's very good at it. For anything to get through and into your bloodstream it has to clear two hurdles. It needs to be a small enough molecule — dermatologists use roughly 500 daltons as the cut-off (Bos and Meinardi, 2000) — and it needs the right balance of fat and water solubility to make the trip.
That's why nicotine patches work and hormone patches work. Small molecules that happen to cross skin well, tested and licensed to prove it.
Most things in slimming patches — plant extracts, fibres, large botanical molecules — don't tick those boxes. And there's no published human study showing they reach the bloodstream in any useful amount.
There is no weight loss patch licensed in the UK. To be licensed, a product has to prove it works. None have.
But others sell them. Doesn't that mean they work?
This is the one that catches most people out, and it's a completely reasonable assumption to make.
Here's what's actually going on.
Weight loss patches and supplements are sold as cosmetics or food, not as medicines. That puts them in a different legal category entirely, governed by food and cosmetic law rather than medicines law.
The consequence is the important bit. A medicine has to satisfy the MHRA that it works and is safe before it can be sold. A food doesn't — because food isn't supposed to be claiming to treat anything in the first place.
That's not a loophole. It's the correct legal box for a food. But it changes what a product being on sale actually tells you:
It doesn't mean it's been tested and passed. It means nobody had to check.
So when a pharmacy stocks a slimming patch, that's a commercial decision about what customers are buying. It isn't a clinical judgement that the product works. The same applies to Superdrug, Holland and Barrett, Amazon and everywhere else. Being available and being effective are unrelated facts.
What is policed is the claims. Sell a food, and you can't legally say it prevents, treats or cures anything. That's precisely what those five companies were ruled against for — not for selling the products, but for what they said about them.
What does the NHS say about weight loss patches?
The NHS doesn't prescribe or recommend weight loss patches, and there's no patch available on the NHS for weight loss.
NHS practice follows NICE, the body that sets clinical standards in England. NICE recommends weight management built on diet, physical activity and behavioural support together, with clinical treatment where it's appropriate for that individual (NICE, 2025). Patches don't appear anywhere in that guidance, because there's no evidence base to put them there.
If you've searched for a patch on the NHS and found nothing, that isn't a gap in the information. That's the answer.
What's actually in weight loss patches?
The most common ingredients in UK slimming patches are moringa, berberine, green tea extract, garcinia cambogia, and various unspecified "fat burning" blends.
Some of these have been studied — but almost always as something you swallow, not something you stick on.
Berberine patches are the clearest example, and currently among the most heavily marketed slimming products in the UK. Several reviews have found small effects on weight and metabolic markers from berberine taken orally, as a capsule (Asbaghi et al., 2020). That research says nothing whatsoever about berberine patches.
This is the single most common way people are misled in this market, so it's worth being clear about. "Does this compound do something in the body?" and "does this compound get into the body through skin?" are two entirely separate questions. A yes to the first tells you nothing at all about the second.
Berberine is small enough to clear the size hurdle, at around 336 daltons. But size isn't the only requirement, and we could find no published human data showing a berberine patch achieves useful blood levels.
Moringa has almost no human weight-loss trial evidence in any form, patch or otherwise.
What are the best weight loss patches?
We get why people search this, but we can't answer it honestly in the way it's usually meant.
There's no meaningful ranking to give you. Comparing slimming patches on effectiveness would mean comparing products that have not demonstrated effectiveness, which produces a league table of nothing. Reviews, star ratings and "best of" lists in this category are measuring how a product was packaged, delivered and marketed — not whether it did anything.
If a patch is something you're set on trying, the only ranking worth applying is a safety one: buy from a UK retailer rather than an overseas marketplace, check the full ingredient list, and avoid anything that won't tell you what's in it.
What are the side effects of weight loss patches?
The ones commonly reported:
- Skin irritation, redness or itching where the patch sits
- Rash, sometimes from the adhesive rather than the ingredients
- Nausea or stomach upset
- Loose stools or diarrhoea, particularly with patches containing plant laxatives
That last one matters more than it sounds. If a product causes diarrhoea, the scale will move within a day or two — and what's moved is fluid and stool, and it comes back. That's very often what people are describing when they say a patch "worked at first".
Stop using it if you get anything beyond mild local irritation, and speak to a pharmacist.
Are patches "for women" any different?
No. There's no biological mechanism by which a patch would behave differently depending on your sex.
Products marketed as "weight loss patches for women" are the same category with different packaging and different advertising. It's a marketing segment, not a clinical one.
How do you use them, and where do you put them?
Instructions usually say clean, dry skin on the upper arm, stomach or inner wrist, changed daily.
We'd be doing you a disservice if we went further than that. There's no correct placement for a product with no evidence of absorption, and no site on your body that turns an ineffective patch into an effective one.
Part two: pills, capsules and supplements
What are the best supplements for weight loss?
If you're looking for the best supplements for weight loss, the honest answer is that the field is a lot thinner than the marketing suggests. A few have something behind them. Most have very little. Nothing here is going to do the work on its own.
Here's the breakdown.
The ones with something behind them
Glucomannan. A soluble fibre that absorbs water and takes up room in your stomach, which is a real mechanism. A systematic review found effects on body weight that were small and not consistent across trials (Onakpoya et al., 2014).
Green tea extract. Studied extensively. A Cochrane review — the most rigorous form of evidence review there is — found the effect on weight was small and mostly not statistically significant (Jurgens et al., 2012). Green tea has been properly tested and came up short.
Caffeine. Genuinely does nudge metabolic rate and appetite. The effect is small, it fades as you become habituated to it, and it costs about £2 in a cup of coffee.
The ones that don't hold up
Raspberry ketones. Apple cider vinegar tablets. Most "fat burning" and "metabolism boosting" blends.
Garcinia cambogia is worth singling out. A systematic review found the effect on weight was small, of questionable clinical relevance, and — this is the telling part — larger in the weaker studies than in the stronger ones (Onakpoya et al., 2011). When that pattern shows up, it usually means the effect isn't real.
Are weight loss supplements safe?
Mostly. But "natural" and "harmless" aren't the same word, and a few are worth knowing about specifically.
Green tea extract has been linked to liver injury at high concentrated doses. The European Food Safety Authority reviewed this and flagged doses of 800mg or more of EGCG per day taken as a supplement (EFSA, 2018). To be clear, that's about concentrated extract — not about drinking tea.
Garcinia cambogia has documented case reports of liver injury in the medical literature (NIDDK, 2020).
Bitter orange, or synephrine, is a stimulant with unresolved questions about cardiovascular safety, particularly when stacked with caffeine.
And more broadly: supplements interact with prescribed medicines and with existing health conditions. Most people never mention them to a clinician, because they don't file them mentally under "medicine".
If you're taking something, say so. Honestly, that's the most useful sentence in this article.
So are patches and supplements a scam?
That's a stronger word than we'd use, and the real picture is more interesting.
Most of these companies aren't knowingly selling something fake. They're selling a food supplement, in a format that looks like medicine, in a market where nobody has to prove anything works before selling it.
But the regulators are paying attention — which is where we started this article. Five rulings in one day is not routine. It tells you the gap between what was being claimed and what could be evidenced had grown wide enough to act on.
What actually shifts the needle?
The boring answer. The one with all the evidence behind it.
A sustained change in the balance between energy in and energy out — and, crucially, something that helps you keep it going. NICE recommends weight management built on diet, activity and behaviour together, with clinical support where it's appropriate (NICE, 2025). Where treatment is clinically right for someone, it sits alongside that foundation. Never instead of it.
Nobody can sell you that in a box. Which is more or less why this market exists.
Four questions that'll save you money
"What should I expect to see, and by when?" If they can't answer that specifically, you've got your answer.
"Is there human evidence, or just lab evidence?" A great deal of this marketing rests on cell studies. Things that work in a dish very often do nothing in a person.
"Is the evidence for this product, in this form?" Pill evidence isn't patch evidence. This is the most common way people are misled.
"Who paid for the study?" Manufacturer-funded supplement trials reliably report larger effects than independent ones do.
If nothing's been working
That's not you failing. Most of these products don't do what the packaging implies, and there's no amount of trying harder that turns an ineffective product into an effective one.
If you'd rather have someone look at your situation properly — your medical history, anything you're already taking, any conditions you have — that's what a consultation is for. It takes about ten minutes to start.
References
Asbaghi, O., Ghanbari, N., Shekari, M., Reiner, Ž., Amirani, E., Hallajzadeh, J., Mirsafaei, L. and Asemi, Z. (2020) 'The effect of berberine supplementation on obesity parameters, inflammation and liver function enzymes: a systematic review and meta-analysis of randomized controlled trials', Clinical Nutrition ESPEN, 38, pp. 43–49.
Advertising Standards Authority (2025a) ASA Ruling on Arrae Inc, 6 August. Available at: https://www.asa.org.uk
Advertising Standards Authority (2025b) ASA Ruling on Evolution Slimming Ltd, 6 August. Available at: https://www.asa.org.uk
Advertising Standards Authority (2025c) ASA Ruling on Myota GmbH, 6 August. Available at: https://www.asa.org.uk
Advertising Standards Authority (2025d) ASA Ruling on Ovira Australia, 6 August. Available at: https://www.asa.org.uk
Advertising Standards Authority (2025e) ASA Ruling on The Clean Supps LLC, 6 August. Available at: https://www.asa.org.uk
Bos, J.D. and Meinardi, M.M.H.M. (2000) 'The 500 Dalton rule for the skin penetration of chemical compounds and drugs', Experimental Dermatology, 9(3), pp. 165–169.
European Food Safety Authority (2018) 'Scientific opinion on the safety of green tea catechins', EFSA Journal, 16(4), 5239.
Jurgens, T.M., Whelan, A.M., MacDonald, L., Lord, L.M., Cooper, K. and Seely, D. (2012) 'Green tea for weight loss and weight maintenance in overweight or obese adults', Cochrane Database of Systematic Reviews, 12, CD008650.
National Institute for Health and Care Excellence (2025) Overweight and obesity management, NICE guideline NG246. London: NICE.
National Institute of Diabetes and Digestive and Kidney Diseases (2020) LiverTox: Clinical and Research Information on Drug-Induced Liver Injury — Garcinia cambogia. Bethesda, MD: NIDDK.
Onakpoya, I., Hung, S.K., Perry, R., Wider, B. and Ernst, E. (2011) 'The use of Garcinia extract (hydroxycitric acid) as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials', Journal of Obesity, 2011, 509038.
Onakpoya, I., Wider, B., Pittler, M.H. and Ernst, E. (2014) 'The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials', Journal of the American College of Nutrition, 33(1), pp. 70–78.
Reviewed by the VSC clinical team. Last updated August 2026.
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