Fat loss supplements: what works and what does not

Worth considering

• Protein powder. Not a fat burner, but a convenient way to hit your protein target, which helps protect muscle and control hunger while dieting. Whey, milk-based and plant blends all work. See protein shakes.
• Caffeine. Found in coffee, tea and many pre-workouts. It can modestly increase energy expenditure, may take the edge off appetite for some people and improves training performance. Keep intake sensible and avoid it late in the day. See caffeine and training.
• Creatine monohydrate. One of the most researched supplements there is. It supports strength and power training, which helps you keep muscle in a deficit. It does not burn fat, and it may add 1 to 2 kg of water to your muscles at first, which is harmless but worth knowing. See creatine explained.
• Vitamin D. Not for fat loss, but the NHS advises everyone in the UK to consider a daily 10 microgram supplement in autumn and winter.
• Fibre supplements such as psyllium husk can help some people feel fuller and support digestion, although whole foods are better where possible.

Notice that none of these works by melting fat. They either make the diet easier to follow or make your training better, and those are the only two routes that really matter.

Little or no evidence

These are among the most heavily marketed fat loss supplements. At best, they have effects too small to show up on the scales. At worst, they waste your money.

• Green tea extract. Very small effects at most, and high-dose extracts have been linked to liver problems in rare cases.
• Raspberry ketones. No good evidence in humans.
• Garcinia cambogia. Trials show little or no meaningful effect.
• CLA (conjugated linoleic acid). Small and inconsistent effects in studies.
• Apple cider vinegar. Any effect on weight appears small, and taken undiluted it can damage tooth enamel and irritate the throat.
• Fat burners. Usually a blend of caffeine and plant extracts, often at undisclosed doses. Any effect mostly comes from the caffeine, which a coffee provides for far less money.
• Detox teas. Most contain laxatives or diuretics. The weight you lose is water and bowel contents, which returns quickly, and regular laxative use can cause dehydration and gut problems.

Genuinely dangerous products

Some diet pills sold online are not just useless but dangerous. DNP (2,4-dinitrophenol), an industrial chemical sold illegally as a fat burner, has caused deaths in the UK, and the Food Standards Agency has repeatedly warned people not to take it. Other slimming products bought from unregulated websites or social media have been found to contain undeclared prescription drugs or banned stimulants.

The rules are simple. Do not buy slimming pills from websites, social media accounts or gym contacts that are not registered pharmacies. If a product claims dramatic results, has no clear ingredient list or is sold as a research chemical, do not take it. If you have taken something and feel unwell, with symptoms such as a very high temperature, a racing heart, heavy sweating or confusion, call 999 or go to A&E.

Prescription weight loss medicines

Prescription weight loss medicines are a completely separate category from supplements. Newer medicines such as semaglutide (Wegovy) and tirzepatide (Mounjaro) work on appetite and can lead to substantial weight loss for some people. They are licensed medicines with real side effects and specific eligibility criteria, and they should only be obtained through your GP, an NHS service or a registered pharmacy with a proper consultation.

If you are prescribed one, strength training and enough protein become more important, not less. Rapid weight loss can include a lot of muscle, and lifting weights with a good protein intake is the best way to protect it. Our guide to starting fat loss when you have a lot to lose covers other NHS support you can ask about.

How to judge any new product

New fat loss products appear every few months. A few quick questions sort most of them out:

• Is there good evidence in humans, not just in cells or animals?
• Is the effect big enough to matter, or a few extra kcal a day at best?
• Are the ingredients and doses clearly listed?
• Is it sold by a reputable UK retailer or pharmacy?
• Would the money do more if spent on food, shoes or coaching?

If the honest answers are no, tiny, no, no and yes, you already know what to do.

Where to spend your money instead

• Good food: lean protein, vegetables, fruit and wholegrains. A weekly shop built around protein and fibre does more than any tub.
• A kitchen scale and a tape measure.
• Decent walking shoes.
• Coaching and a training environment that keeps you consistent.

Our guide to fat loss myths covers more of the marketing claims worth ignoring. If you want a plan built around food and training rather than products, Lycan Strength offers nutrition and accountability coaching alongside its classes.