Capsaicin (capsaicinoids and capsinoids)
Summary
Capsaicin, the heat in chili peppers, and its non-hot relatives capsinoids slightly raise energy use and fat burning. Pooled trials found about 0.5 kg extra weight loss with capsaicin (grade C), while capsinoids showed no overall effect. Capsaicin did not change blood pressure or blood sugar, and cholesterol findings were unstable.
Key facts
- The pungent compound in hot peppers; capsinoids such as capsiate are non-pungent analogues[11]
- Resting metabolic rate rose about 34 kcal/day versus placebo in pooled trials[7]
- About 0.51 kg more weight loss than control across 15 RCTs in overweight adults[1]
- One meta-analysis found total cholesterol −10 mg/dL and triglycerides −14 mg/dL in overweight adults; another found the cholesterol effect was not robust[10][4]
- 6 graded human outcomes on this page
- October 13, 2026
How it works
EstablishedCapsaicin and capsinoids activate TRPV1 receptors; capsaicin does so in the mouth and gut, capsinoids only in the gut. Activation is linked to small rises in energy expenditure and fat oxidation and reduced hunger signals in human studies.[11][7]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Weight | Grade C | No effect | Meta-analysis of 13 trials · n = 838 · 2022 | 4 rows |
| Heart & metabolism | Grade C | No effect | Meta-analysis of 13 trials · n = 821 · 2026 | 1 row |
| Appetite | Grade D | Improved | Meta-analysis of 8 trials · n = 191 · 2014 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Body weight and body fat (capsinoids) | No effect | Grade C | Meta-analysis · n = 838 · 2022 Adults in randomized trials Form: Capsinoids (non-pungent capsaicin relatives such as capsiate) · Dose: Varied across trials · Duration: Varied No effect on weight, BMI, waist, fat mass, visceral fat or body-fat percentage overall. A subgroup of trials in overweight people lasting 12 weeks or more showed a modest weight reduction. | 36513480 (opens PubMed)Source [2] |
| Cholesterol, blood pressure and blood sugar (red pepper or capsaicin vs placebo) | No effect | Grade C | Meta-analysis · n = 821 · 2026 Adults in placebo-controlled randomized trials Form: Capsaicin, red pepper or related compounds · Dose: Varied across trials · Duration: Varied Small drops in total cholesterol and diastolic blood pressure disappeared when one study was removed. No effect on triglycerides, LDL, HDL, systolic pressure, glucose, insulin or HbA1c. GRADE certainty low to very low. | 41856833 (opens PubMed)Source [4] |
| Body weight, BMI and waist in overweight adults (capsaicin) | Improved | Grade C | Meta-analysis · n = 762 · 2023 Overweight or obese adults in randomized trials Form: Capsaicin supplements or capsaicin-containing foods · Dose: Varied across trials · Duration: Varied Versus control, body weight fell 0.51 kg, BMI 0.25 and waist 1.12 cm; waist-to-hip ratio did not change. | 36938807 (opens PubMed)Source [1] |
| Calories eaten at a meal after capsaicinoids | Improved | Grade D | Meta-analysis · n = 191 · 2014 Adults in short meal-test studies Form: Capsaicinoids taken before a meal · Dose: About 2 mg or more before the meal · Duration: Single meals Energy intake at the following meal fell about 74 kcal, with high heterogeneity (I² 76%). | 24246368 (opens PubMed)Source [3] |
| Weight regain after a diet (capsaicin, 3 months) | No effect | Grade D | RCT · n = 91 · 2003 Moderately overweight adults after a 4-week very-low-energy diet Form: Capsaicin capsules · Dose: 135 mg/day · Duration: 3 months Weight regain did not differ from placebo (33.3% vs 19.2% of lost weight, P=0.09), though fat oxidation stayed higher with capsaicin. | 13129472 (opens PubMed)Source [6] |
| Weight and abdominal fat (capsinoids, 12 weeks) | Mixed | Grade D | RCT · n = 80 · 2009 Adults with BMI 25–35 Form: Oral capsinoids · Dose: 6 mg/day · Duration: 12 weeks Weight change did not differ from placebo (P=0.86), but abdominal fat fell more (−1.11% vs −0.18%, P=0.049). Fat oxidation was nearly significantly higher. Capsinoids were well tolerated. | 19056576 (opens PubMed)Source [5] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Capsaicin or capsicum extract (pungent) | Varies[11] | Activates TRPV1 receptors in the mouth and gut; its burn limits how much people eat in food form.[11] | Capsaicin causes a burning sensation and pain in the mouth that leads many people to avoid spicy foods.[11] | Weight, appetite and fat-oxidation studies (2–135 mg/day) |
| Capsinoids (capsiate, dihydrocapsiate) | Varies[11] | Activate TRPV1 receptors in the gut but not the mouth, so they are not hot.[11] | 6 mg/day for 12 weeks was well tolerated.[5] | Weight and body-composition trials |
| Red pepper or chili in food | Varies[1][4] | Dose varies with pepper type and amount.[1][4] | Pungency limits intake.[11] | Mixed food and supplement trials in meta-analyses |
Studied doses
Doses studied in human trials ranged from about 2 mg of capsaicinoids before a single meal and 6 mg/day of capsinoids for 12 weeks up to 135 mg/day of capsaicin for 3 months. Lipid effects were larger at 10 mg/day or more.[3][5][6][10]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Heart disease or chest pain
- Case reports describe heart attacks in two men aged 25 and 41 without cardiac risk factors who were taking cayenne pepper pills for weight loss; in one, the cause was coronary artery spasm.[13][14]
- People sensitive to spicy food
- Capsaicin produces a burning, painful sensation; non-pungent capsinoids avoid this in the mouth.[11]
- Weight-loss products generally
- Side effects reported with natural weight-loss supplements were mostly minor gastrointestinal complaints, though rare severe events have been reported across products.[12]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
Cost per studied dose, without the sales pitch
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Cost per studied dose
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Frequently asked questions
Does capsaicin help you lose weight?
Only slightly. Fifteen randomized trials in overweight adults found about 0.5 kg more weight loss than control, and a 3-month trial found it did not stop weight regain after dieting.[1][6]
Do capsaicin supplements boost metabolism?
A little. Pooled placebo-controlled studies found resting metabolic rate rose about 34 kcal a day, with more fat burned.[7]
What are capsinoids?
Non-pungent relatives of capsaicin, such as capsiate, that activate the same receptors in the gut without the burn. Pooled trials found no overall effect on weight.[11][2]
Does capsaicin lower blood pressure or blood sugar?
Pooled trials found no significant effect on blood pressure, heart rate, fasting glucose or insulin.[8][9]
Does capsaicin curb appetite?
Taking about 2 mg or more before a meal reduced intake at that meal by roughly 74 kcal in short studies, with inconsistent results between studies.[3]
Sources
- [1]The effects of capsaicin intake on weight loss among overweight and obese subjects: a systematic review and meta-analysis of randomised controlled trials.. Br J Nutr, 2023. meta-analysis
- [2]The effects of capsinoids supplementation on body composition and anthropometric measures: A systematic review and dose-response meta-analysis of randomized controlled trials.. Clin Nutr ESPEN, 2022. meta-analysis
- [3]Could capsaicinoids help to support weight management? A systematic review and meta-analysis of energy intake data.. Appetite, 2014. meta-analysis
- [4]The effect of red pepper/capsaicin on cardiovascular risk factors: a systematic review, meta-analysis, and GRADE assessment.. Nutr Metab Cardiovasc Dis, 2026. meta-analysis
- [5]Effects of novel capsinoid treatment on fatness and energy metabolism in humans: possible pharmacogenetic implications.. Am J Clin Nutr, 2009. RCT
- [6]Effect of capsaicin on substrate oxidation and weight maintenance after modest body-weight loss in human subjects.. Br J Nutr, 2003. RCT
- [7]The effect of Capsaicinoids or Capsinoids in red pepper on thermogenesis in healthy adults: A systematic review and meta-analysis.. Phytother Res, 2021. meta-analysis
- [8]The effect of red pepper/capsaicin on blood pressure and heart rate: A systematic review and meta-analysis of clinical trials.. Phytother Res, 2021. meta-analysis
- [9]Short- and long-term effects of capsaicin supplementation on glycemic control: a systematic review and meta-analysis of controlled trials.. Food Funct, 2021. meta-analysis
- [10]The effect of capsaicin, capsinoids, and pepper-based interventions on lipid profiles in overweight or obese individuals: a systematic review and meta-analysis of randomized controlled trials.. Diabetes Res Clin Pract, 2025. meta-analysis
- [11]The effects of capsaicin and capsiate on energy balance: critical review and meta-analyses of studies in humans.. Chem Senses, 2012. meta-analysis
- [12]The safety and effectiveness of commonly-marketed natural supplements for weight loss in populations with obesity: A critical review of the literature from 2006 to 2016.. Crit Rev Food Sci Nutr, 2020. review
- [13]Acute myocardial infarction and coronary vasospasm associated with the ingestion of cayenne pepper pills in a 25-year-old male.. Int J Emerg Med, 2012. observational
- [14]A case of acute myocardial infarction due to the use of cayenne pepper pills.. Wien Klin Wochenschr, 2012. observational
What changed
- Independent adversarial review: added two case reports of acute myocardial infarction with cayenne pepper pills (PMIDs 22264348, 22527825) to who should avoid and FAQ.
- Adversarial review pass: every evidence row's numbers re-checked against its abstract (Europe PMC for abstracts PubMed truncates, PMC full text where open), grades checked against the grading rubric, and safety and overclaim wording re-read. No changes needed.
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Strict second-pass self review (no separate reviewer agent was available for this batch): every PMID re-fetched via esummary and every evidence row, dose and safety line re-read against its abstract or fact sheet. No NIH ODS or NCCIH fact sheet covers oral capsaicin. Capsaicin and capsinoid results are kept separate, and the 2026 GRADE meta-analysis is reported as unstable for cholesterol and diastolic pressure. Topical capsaicin (patches, creams) is out of scope. Retraction and erratum flags checked on all PMIDs: none.