Capsaicin (Cayenne Pepper)
The compound that makes chilli peppers hot. At supplement doses, capsaicin modestly increases the amount of energy your body burns. The effect is real but small — roughly equivalent to the calories in one biscuit per day — and not sufficient on its own to produce meaningful weight loss.
Quick read · 3 min
- •Evidence: Weak — limited or inconsistent trial data
- •Research reviewed by the NIH Office of Dietary Supplements shows that capsaicin modestly increases energy expenditure — by roughly 50 kilocalories per day.
- •Generally safe at supplement doses (typically up to 33 mg capsaicin/day).
- •Prescription weight loss drugs produce 7–21% weight loss in trials. Most supplements in this category produce less than 2 kg.
Based on clinical trials · No rankings · Every claim linked to source
Last reviewed: March 2026
How it works
Capsaicin activates TRPV1 receptors on nerve endings, triggering a thermogenic (heat-producing) response. This temporarily increases metabolic rate and may promote fat oxidation. The effect is real but short-lived — the body adapts over time. Some evidence also suggests a mild appetite-suppressing effect.
What the evidence shows
Research reviewed by the NIH Office of Dietary Supplements shows that capsaicin modestly increases energy expenditure — by roughly 50 kilocalories per day. This is the equivalent of walking about 10 minutes. By itself, this is not a meaningful amount for weight loss. Most individual trials show statistically significant but clinically small effects. Capsaicin works better as one component of a broader weight management approach than as a standalone treatment.
Safety
Generally safe at supplement doses (typically up to 33 mg capsaicin/day). Stomach irritation and heartburn are the most common side effects. People with irritable bowel syndrome (IBS) or GORD (acid reflux) may find capsaicin worsens their symptoms. At food amounts in cooking, it is safe for most people. Supplement doses are considerably higher than food amounts.
Community insights
These are personal experiences shared in public online communities — not medical advice.
“Take it with food — on an empty stomach it causes significant GI discomfort for many people.”
“The thermogenic effect is real but tiny — think of it as helping a little bit at the margins, not a shortcut. Don't pay a lot for it.”
Common questions
After reading this page, most people compare this with other supplements, look at prescription options, or check what they can do today without a prescription.