Compare thermogenic supplements on the caffeine per serving, the other ingredients and their amounts, and the cost per serving. "Thermogenic" is a marketing term for stimulant-based formulas, and we don't claim any product here causes weight loss.
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What is a thermogenic supplement?
A thermogenic supplement is a product, usually built around caffeine, that's marketed for dieting. "Thermogenesis" means heat production in the body, but caffeine has no authorised health claims in Great Britain, and the word on a label doesn't mean a product has been shown to change body weight.
The US National Institutes of Health says caffeine might help you lose a little weight or gain less weight over time, and that tolerance can reduce this. The NHS approach is to aim to lose 0.5 to 1kg a week through diet and activity. See weight management for more.
How much caffeine is in a thermogenic?
It varies, so check the caffeine per full serving and add it to your coffee, tea and energy drinks. EFSA says single doses of up to 200mg and up to 400mg a day from all sources do not raise safety concerns for healthy adults, and up to 200mg a day in pregnancy. It also says 100mg close to bedtime may affect sleep in some adults.
"Customers need to understand what they're taking, how much they're taking and whether the ingredients suit their individual needs," says Andy Arshad, who runs SupplementHQ. If you're sensitive to caffeine, look at stimulant-free products instead.
Are thermogenics safe?
They can cause side effects, mostly from caffeine. The International Society of Sports Nutrition lists faster heart rate, palpitations, anxiety, headaches and poorer sleep among commonly reported caffeine side effects, increasing with dose.
Speak to your GP or pharmacist first if you're pregnant or breastfeeding, have a heart condition or high blood pressure, or take medication. Supplements for under-18s should be discussed with a GP or pharmacist.
We sell the products on this page. That's our commercial interest, and it's why we show the evidence alongside them. This page is general information for adults, not personalised medical advice. Food supplements should not replace a varied, balanced diet.
Written by Andy Arshad, SupplementHQ. Last reviewed 11 October 2026.