Raspberry ketones
No controlled human trial of raspberry ketone alone was located. One 8-week trial of a six-ingredient product with caffeine and bitter orange reported more weight and fat loss than placebo, sponsored by a supplement company. Toxicity data are limited to rat studies. Case reports describe coronary vasospasm and a resistant ventricular arrhythmia in women taking raspberry ketone products.
- Status
- Dietary supplement in the US. In the UK the pure compound is regarded as a novel food requiring authorization before marketing.
- Also called
- raspberry ketone, rheosmin, 4-(4-hydroxyphenyl)-2-butanone, frambinone, raspberry ketone plus
- Taken for
- weight loss, fat loss, metabolism, fat burning
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help0
No benefit shown in research yet.
Reported risks2
What people take it for, and what was found
Mixed results1
Weight loss with a multi-ingredient product containing raspberry ketone
One maker-sponsored trial of a blend with caffeine and bitter orange found weight fell 2.0% against 0.5%, so the effect cannot be assigned to raspberry ketone.
The numbers and sources
- Effect
- In 70 obese adults on a calorie-restricted diet and exercise program, a product containing raspberry ketone, caffeine, capsaicin, garlic, ginger and Citrus aurantium was compared with placebo for 8 weeks. Among the 45 who finished, body weight fell 2.0% against 0.5%, fat mass 7.8% against 2.8%, and waist girth 2.0% against 0.2%. Lean mass rose 3.4% against 0.8% [1].
- Population
- 45 completers, 27 on the product and 18 on placebo [1].
- Sources
- [1]
- Caveats
- The study was sponsored by Ultimate Wellness Systems, Inc., and two authors reported funding from or consulting for supplement companies including the sponsor. The product contained caffeine and bitter orange, so the effect cannot be assigned to raspberry ketone. 25 of 70 participants did not finish [1].
Claimed, not studied in people2
Weight loss with raspberry ketone alone
Not studied in people. In mice on a high-fat diet, raspberry ketone limited weight and fat gain, but higher doses killed half or more of obese mice.
No study in people. This rests on animal studies.
The numbers and sources
- Effect
- In mice fed a high-fat diet with 0.5 to 2% raspberry ketone for 10 weeks, it prevented the rise in body weight, liver weight and visceral fat, and reduced them when added after 6 weeks of high-fat feeding [5]. In obese mice given raspberry ketone for 10 days, weight gain slowed at 165, 330 and 500 mg/kg, but 330 and 500 mg/kg killed 67.6% and 50% of the mice, and ALT and blood glucose rose [6].
- Population
- Mice on high-fat diets [5][6].
- Sources
- [5], [6]
- Caveats
- Mouse studies only. The second study was designed to look for harm, and the deaths occurred at doses that slowed weight gain [6]. No trial of raspberry ketone alone in people was located.
Metabolic rate
Not studied in people. In the lab, raspberry ketone increased fat breakdown in rat fat cells and raised brown-fat markers in mouse fat cells.
No study in people. This rests on lab studies, how it acts in the body.
The numbers and sources
- Effect
- Raspberry ketone increased norepinephrine-induced fat breakdown in rat fat cells, with hormone-sensitive lipase moving to the fat droplets [5]. In cultured mouse fat cells, it raised FNDC5 and the brown-fat markers PRDM16, CD137 and UCP1, but did not change irisin released into the medium [7].
- Population
- Rat epididymal fat cells [5]. Mouse 3T3-L1 fat cells in culture [7].
- Sources
- [5], [7]
- Caveats
- Cell studies only. Neither study measured energy expenditure in an animal or a person, and no human study of metabolic rate on raspberry ketone was located.
Doses studied
The one controlled trial gave four capsules a day of the multi-ingredient product, two at breakfast and two at lunch, and its abstract and tables do not give the raspberry ketone amount [1]. Products sold online listed intakes of 100 to 1,400 mg of raspberry ketone a day, against up to 4.3 mg/kg naturally present in raspberries [2].
Risks
Reported risks2
Heart rhythm and coronary vasospasm case reports
Case reports: two women had a cardiac arrest with dangerous heart rhythms, or chest pain with suspected coronary spasm, after raspberry ketone products.
The numbers and sources
- Effect
- A 32-year-old woman with no cardiac risk factors had a pulseless electrical activity arrest and then polymorphic ventricular tachycardia that needed 33 shocks and temporary overdrive pacing. No clear cause was found, and she had recently started an over-the-counter weight loss product containing raspberry ketones [3]. A 47-year-old woman developed sweating, a heart rate of 137 and blood pressure of 197/130 about two hours after a first dose of two raspberry ketone tablets. On the following days she had six episodes of chest pain with transient ST elevation, and CT showed unobstructed coronary arteries. The report raises coronary vasospasm linked to raspberry ketones as a question [4].
- Population
- Two case reports [3][4].
- Sources
- [3], [4]
- Caveats
- Single cases cannot establish cause. The first patient was in hospital for a perianal abscess [3]. The second had anemia, a duodenal ulcer and pulmonary emboli during the same admission [4].
Few toxicity data at supplement doses
Animal studies only: rat data give a margin of safety of 165 at 100 mg but 12 at 1,400 mg. No human toxicity study was located.
The numbers and sources
- Effect
- Toxicology studies of raspberry ketone are limited to acute and subchronic studies in rats. The lowest marketed dose of 100 mg is 56 times the threshold of toxicological concern of 1,800 µg a day for its chemical class. Based on a rat no-observed-adverse-effect level of 280 mg/kg a day, the margin of safety was 165 at 100 mg and 12 at 1,400 mg. Computer structure-activity models flagged potential cardiotoxic and reproductive or developmental effects [2].
- Population
- Animal and in silico data [2].
- Sources
- [2]
- Caveats
- No human toxicity study was located. The models predict hazards and do not measure them.
Checked, no increase found1
Side effects in the controlled trial
One small maker-sponsored trial found heart rate, blood pressure, blood tests and adverse events no different from placebo over 8 weeks.
Sources
- Lopez HL, Ziegenfuss TN, Hofheins JE, et al. Eight weeks of supplementation with a multi-ingredient weight loss product enhances body composition, reduces hip and waist girth, and increases energy levels in overweight men and women. Journal of the International Society of Sports Nutrition. 2013. https://doi.org/10.1186/1550-2783-10-22
- Bredsdorff L, Wedebye EB, Nikolov NG, et al. Raspberry ketone in food supplements. High intake, few toxicity data. A cause for safety concern? Regulatory Toxicology and Pharmacology. 2015. https://doi.org/10.1016/j.yrtph.2015.06.022
- Ansari SA, Patel F, Ashouri D, et al. Resistant Polymorphic Ventricular Tachycardia in a Patient Taking Raspberry Ketones Weight Loss Supplement. Cureus. 2022. https://doi.org/10.7759/cureus.33089
- Khattar A. Coronary vasospasm and raspberry ketones weight-loss supplement: Is there a connection? The Anatolian Journal of Cardiology. 2020. https://doi.org/10.14744/anatoljcardiol.2020.53496
- Morimoto C, Satoh Y, Hara M, et al. Anti-obese action of raspberry ketone. Life Sciences. 2005. https://doi.org/10.1016/j.lfs.2004.12.029
- Mir TM, Ma G, Ali Z, et al. Effect of Raspberry Ketone on Normal, Obese and Health-Compromised Obese Mice: A Preliminary Study. Journal of Dietary Supplements. 2021. https://doi.org/10.1080/19390211.2019.1674996
- Tsai YC, Chen JH, Lee YM, et al. Raspberry ketone promotes FNDC5 protein expression via HO-1 upregulation in 3T3-L1 adipocytes. Chinese Journal of Physiology. 2022. https://doi.org/10.4103/cjp.cjp_95_21