What it is
Cayenne is a dried, ground hot chilli. Its pungency is measured in Scoville heat units (SHU); typical cayenne is 30,000–50,000 SHU.
What the research says
Metabolism and appetite
LimitedCapsaicin may slightly increase heat production and fat burning and reduce appetite. Reviews describe the effects as small and variable.
Blood pressure
LimitedOne study found a reduction; a systematic review found no effect.
Amounts used in studies
Studies vary widely, from a few milligrams of capsaicin to several grams of chilli a day.
Who should avoid it
- Stomach ulcers, reflux or irritable bowel flare-ups.
- Pregnancy and breastfeeding (skin reactions reported in breastfed babies).
- Uncontrolled high blood pressure or heart conditions.
Medicines to watch
- ACE-inhibitor blood-pressure medicines: may worsen the dry cough they cause.
- Ciclosporin (transplant patients): avoid.
- Blood thinners and anti-platelets: possible effect.
What to look for when buying
- Ask for the SHU rating; heat varies a lot between batches.
- Chilli is prone to aflatoxin contamination. Ask for a test result.
Common questions
Will it burn?
Not in the mouth. Some people feel warmth or discomfort in the stomach; always take it with food.
Will it help me lose weight?
The measured effects are too small to matter much on their own.
Sources
Last reviewed 19 October 2026 by Spicewell editorial team. How we write our guides
This guide is general information, not medical advice. Speak to a doctor or pharmacist before starting any supplement, especially if you are pregnant, breastfeeding, under 18 or taking medication.