Nobody knows the full side-effect profile of raspberry ketone, because its safety at supplement doses of 100 to 1,400 mg a day has never been evaluated in humans. The best-documented human problem is a single case report of a racing heart, a sharp rise in blood pressure, sweating and diarrhea within hours of a first dose. Many other reported effects, such as jitters and poor sleep, are well-known effects of the caffeine and other stimulants that raspberry ketone products often contain.
Key Takeaways
- The NIH says the safety of raspberry ketone at supplement doses has never been evaluated in humans.
- Food supplies only a few milligrams a day; supplements provide 100 to 1,400 mg, and toxicologists have called that gap a cause for concern.
- One published case linked a first dose to a racing heart, a blood pressure spike and spasm of the heart's arteries; cause and effect was not proven.
- In mice, very high single doses caused deaths and changes in blood and immune cells; these doses are far above what people take.
- Many products pair raspberry ketone with caffeine, bitter orange or green tea extract, which have their own side effects.
- Ask your doctor or pharmacist first if you are pregnant, breastfeeding, have a heart or blood pressure concern, or take prescription medicines.
Evidence grade: Emerging. Human safety data are limited to one small eight-week trial of a combination product and a single case report; the rest comes from rat and mouse toxicity studies and computer modeling.
This article focuses on safety. For what raspberry ketone is, what human trials measured and the doses studied, see raspberry ketone benefits: what the research says.
Why the Safety Picture Is Unclear
Raspberry ketone is added to some foods as a flavoring, where intake is tiny. Raspberries contain up to 4.3 mg per kilogram, and typical diets provide only a few milligrams a day. Supplements deliver 100 to 1,400 mg, and those doses have not been safety-tested in people.
A 2015 review by researchers at the Technical University of Denmark's National Food Institute found that toxicology data were limited to short-term rat studies. Even the lowest common dose, 100 mg, was 56 times the threshold of toxicological concern used for this class of compounds. Based on the highest dose that caused no adverse effect in rats (280 mg per kg of body weight a day), the margin of safety was 165 at 100 mg a day but only 12 at 1,400 mg a day. Computer models (QSAR) also flagged possible effects on the heart and on reproduction and development. These are predictions, not proof, but they have not been ruled out by real studies.
Side Effects Reported in People
The 2020 case report
Doctors in the United Kingdom described a 47-year-old woman who took two raspberry ketone tablets for the first time. About two hours later she had sudden diarrhea, sweating and malaise, a heart rate of 137 beats per minute and a blood pressure of 197/130. Over the next two days she had several brief episodes of chest pain with heart-tracing changes that the doctors attributed to coronary vasospasm, a temporary tightening of the heart's arteries. Imaging showed her arteries were not blocked.
The authors proposed a possible link because raspberry ketone's structure resembles synephrine, a stimulant, but they did not prove the supplement caused it. She smoked and had other medical problems at the same time, and the tablets' dose was not reported.
What the human trials reported
In a 2013 trial of 70 adults, a combination product containing raspberry ketone, caffeine and bitter orange was taken for eight weeks. The researchers reported no serious adverse events, minor complaints such as stomach upset at similar rates in both groups, and no differences in resting heart rate or blood pressure. However, 25 of the 70 participants dropped out and results were reported only for those who finished. A trial of this size and length cannot detect rare or long-term problems.
Jitters, poor sleep and palpitations
Online articles often list sleep problems, heart palpitations, nervousness and raised blood pressure as raspberry ketone side effects. We could not find a study that measured these effects for raspberry ketone alone. They are, however, signs of too much caffeine listed by the FDA, and many raspberry ketone products contain caffeine. If you feel shaky or wired or cannot sleep, check the label for caffeine first. Our article on the impact of caffeine on sleep patterns explains why timing matters.
What Animal Studies Show
- Single high doses in mice (2020): one oral dose of 640 mg per kg of body weight killed 6 of 14 male mice within two days. Survivors showed shrinkage of fat tissue, spleen and thymus changes, and lower white blood cell counts. Lower doses reduced food intake.
- Ten days in mice with diet-induced weight gain (2021): doses of 330 and 500 mg per kg killed 67.6% and 50% of the mice. Raspberry ketone also raised the liver enzyme ALT and raised blood glucose in every group given raspberry ketone.
- Fourteen days in mice (2020): 400 mg per kg a day reduced weight gain and lowered blood pressure, while 200 mg per kg had mixed effects on eating patterns. The authors concluded that the effects depend on dose.
For perspective, a 500 mg dose in a 70 kg (154 lb) adult is about 7 mg per kg. Mice and people handle compounds differently, so these results cannot be converted directly into human risk. They do show that raspberry ketone is biologically active and that more is not better.
Skin Contact and Topical Products
Laboratory research notes that skin exposure to raspberry ketone is known to cause chemical or occupational leukoderma, a loss of skin color. A closely related compound, rhododendrol, caused this reaction in consumers who used a skin-lightening cosmetic in 2013. Raspberry ketone can be turned into reactive compounds by the pigment enzyme tyrosinase, which may damage pigment cells. If you use a skin product with raspberry ketone and notice light patches, stop and see a dermatologist. More on topical use is in what raspberry ketone does for skin.
Combination Products: Check Every Ingredient
Raspberry ketone is rarely sold alone, so the other ingredients often matter as much as the ketone:
- Caffeine: the FDA cites 400 mg a day as an amount not generally associated with negative effects for most adults. Add up coffee, tea, energy drinks and supplements.
- Bitter orange (synephrine): NCCIH says the evidence on the heart is inconclusive; some studies show raised heart rate and blood pressure and others do not. It may not be safe during pregnancy or breastfeeding.
- Green tea extract: NCCIH lists nausea, constipation, stomach discomfort and increased blood pressure as side effects, and notes that liver injury, although uncommon, has been reported, mainly with extract capsules and tablets.
For example, OPA Raspberry Ketone Ultra provides 500 mg of raspberry ketones per two-capsule serving, along with 300 mg of African mango and a 400 mg blend that includes green tea extract and caffeine anhydrous. Because it contains caffeine, count it toward your daily total. If you are considering a formula with African mango, see our guide to African mango side effects.
Safety and Interactions
No published study has tested raspberry ketone together with any medication, so interactions are unknown rather than ruled out. Based on its stimulant-like structure, the animal findings and the ingredients it is usually combined with, talk to your doctor or pharmacist before using raspberry ketone if you:
- Are pregnant or breastfeeding: there are no human safety data.
- Take stimulant medicines, because raspberry ketone resembles synephrine and many products add caffeine.
- Take blood pressure or heart rhythm medicines. NCCIH notes that green tea in high amounts lowers blood levels of nadolol, a beta-blocker.
- Take blood-sugar-lowering medicines. Raspberry ketone raised blood glucose in mice, and its effect in people is unknown.
- Take blood thinners such as warfarin. Online claims that raspberry ketone changes warfarin are not backed by any published study we could find, but it has never been tested, so tell the clinician who manages your warfarin about every supplement you take.
- Have a liver concern or take medicines that affect the liver, especially if the product contains green tea extract.
Stop using the product and seek medical care if you have chest pain, a pounding or irregular heartbeat, fainting, severe headache, or yellowing of the skin or eyes. If you do use raspberry ketone, use the lowest label dose, avoid stacking it with other stimulant products, and see when to take raspberry ketones for timing tips.
Frequently Asked Questions
What are the side effects of raspberry ketones?
No study has measured side effects of raspberry ketone alone in people. A single case report described a racing heart, a blood pressure spike, sweating, diarrhea and spasm of the heart's arteries after a first dose. Jitters, poor sleep and palpitations are common with the caffeine found in many raspberry ketone products.
Can raspberry ketones interact with medications?
Possibly, but it has never been studied. Because raspberry ketone resembles the stimulant synephrine and is often combined with caffeine or green tea extract, ask your pharmacist before combining it with stimulants, heart or blood pressure medicines, blood-sugar-lowering medicines or blood thinners.
Are raspberry ketones safe to take every day?
Long-term daily use has not been studied. The longest human trial lasted eight weeks and used a combination product. The NIH says the safety of supplement doses has never been evaluated in humans, so daily use is a decision to make with your healthcare provider.
Can I take raspberry ketones if I am pregnant or breastfeeding?
There are no safety data for pregnancy or breastfeeding, and NCCIH says bitter orange, a common companion ingredient, may not be safe during these times. Avoid raspberry ketone unless your healthcare provider advises otherwise.
Do raspberry ketones raise blood pressure?
The evidence is mixed. In the 2013 trial, blood pressure did not differ from placebo over eight weeks, and in mice a high dose lowered blood pressure. One case report described a sudden spike after a first dose. Caffeine and bitter orange in combination products can raise blood pressure in some people.
Do raspberry ketones damage the liver?
There are no human reports of liver injury from raspberry ketone alone in the studies we reviewed. In mice, it raised the liver enzyme ALT. Green tea extract, a common companion ingredient, has been linked to uncommon cases of liver injury.
Sources
- NIH Office of Dietary Supplements. Dietary Supplements for Weight Loss: Fact Sheet for Health Professionals (Raspberry Ketone section). 2022.
- Bredsdorff L, Wedebye EB, Nikolov NG, et al. Raspberry ketone in food supplements--High intake, few toxicity data--A cause for safety concern? Regul Toxicol Pharmacol. 2015.
- Khattar A, Beeton I. Coronary vasospasm and raspberry ketones weight-loss supplement: Is there a connection? Anatol J Cardiol. 2020.
- 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. J Int Soc Sports Nutr. 2013.
- Hao L, Kshatriya D, Li X, et al. Acute feeding suppression and toxicity of raspberry ketone [4-(4-hydroxyphenyl)-2-butanone] in mice. Food Chem Toxicol. 2020.
- Mir TM, Ma G, Ali Z, et al. Effect of Raspberry Ketone on Normal, Obese and Health-Compromised Obese Mice: A Preliminary Study. J Diet Suppl. 2021.
- Kshatriya D, Hao L, Li X, Bello NT. Raspberry Ketone [4-(4-Hydroxyphenyl)-2-Butanone] Differentially Effects Meal Patterns and Cardiovascular Parameters in Mice. Nutrients. 2020.
- Ito S, Hinoshita M, Suzuki E, et al. Tyrosinase-Catalyzed Oxidation of the Leukoderma-Inducing Agent Raspberry Ketone Produces (E)-4-(3-Oxo-1-butenyl)-1,2-benzoquinone: Implications for Melanocyte Toxicity. Chem Res Toxicol. 2017.
- Morimoto C, Satoh Y, Hara M, et al. Anti-obese action of raspberry ketone. Life Sci. 2005.
- U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? 2024.
- National Center for Complementary and Integrative Health. Bitter Orange: Usefulness and Safety.
- National Center for Complementary and Integrative Health. Green Tea: Usefulness and Safety.
Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.
Written and reviewed by Michael Gonzales, Founder, OPA Nutrition · Last reviewed: · How OPA researches and writes
