The market is full of miracle weight loss cures, be it some herb or drug in the form of pills, tablets or powders; or some snake oil salesman selling you oils, gels, heat belts or creams; or it can be dietitian or slimming centre selling you a ‘zero effort’ instant weight loss and spot reduction. But there is just one thing common in them – none of these work, and they are all part of the big lies being spread by these ‘run-of-the-mill’ companies. Just like I have been exposing a number of supplements in the market, another useless junk in the arsenal is raspberry ketones.
US researcher Jungmin Lee, in a 2016 study in the Nutrition & Food Science Journal, suggested that raspberry ketone was discovered in 1903, and its chemical structure was first identified in 1951 from raspberries. Pure raspberry ketone is a powder of translucent white, short needle-shaped crystals, and considered the main constituent of raspberry aroma.
According to an Iraqi research team, led by Faris Abdul Karim Khazaal, in the 2015 study in the International Journal of Pharmaceutical Sciences Review & Research, Raspberry ketones are primarily used as a scenting and flavouring agent in cosmetics and foods. They are also found in cranberries, blackberries and other fruits. The structure of Raspberry ketone has a vaguely similar structure to Ephedrine and Synephrine (similar to ephedrine but less potent, also called ‘bitter orange’). There is also some structural similarity to capsaicin (compounds found in hot chillies and peppers).
But this supplement, which was never even considered for weight loss, became a buzzword in the supplement market after a February 2012 segment of the Dr. Oz Show suggested they’re basically a miracle product for fast and safe weight loss. This is the same TV doctor who has been warned, fined and ridiculed multiple times for his fake claims on many such useless supplements like garcinia cambogia and green coffee bean extract.
In a 2013 study in the Journal of International Society of Sports Nutrition, US researcher Hector Lopez & team determined the safety and efficacy of a multi-ingredient supplement containing primarily raspberry ketone, caffeine, capsaicin, garlic, ginger and Citrus aurantium, in an 8-week weight loss program.
According to Lopez, Raspberry ketone (4-(4-hydroxyphenyl) butan- 2-one), which is a naturally occurring phenolic compound in red raspberry that has been shown to enhance norepinephrine-induced lipolysis in adipocytes, prevent high-fat diet-induced body weight gain in mice and increase adiponectin gene expression and secretion in adipocytes in culture.
Lopez quoted two studies for proving the above point:
- A 2010 study in the journal Planta Medica, by a Korean research team, led by K.S. Park, showed that treatment with raspberry ketones increased the fatty acid oxidation and suppressed lipid accumulation, in mice.
- A 2005 study in the journal Life Sciences, by Japanese researcher C. Marimoto & team, found that raspberry ketones, in mice, prevented the high-fat-diet-induced elevations in body weight and body fat, thus prevents and improves obesity and fatty liver.
Korean researcher K.S. Park in a 2015 study in the journal Pharmaceutical Biology, found that raspberry ketone increased the activation of several genes involved in lipolysis, including adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL).
However, there are no human studies on this supplement. The one by Lopez & team, where they found a fat loss of 7.8% relative to the 2.8% in placebo, and weight loss of 2% relative to 0.5% in placebo, without detectable differences in caloric intake, was actually due to the other ingredients in the supplement like caffeine, capsaicin, garlic, ginger and Citrus aurantium. So, raspberry ketones cannot be given credit for this.
In a 2017 study in the Journal of Food & Function, US researcher B.M. Cotton & team, investigated the effect of raspberry ketones on the accumulation of adipose mass, liver fat storage, and levels of adiponectin in mice fed a high-fat diet, for five weeks. Researchers found that raspberry ketone supplementation did not show any noticeable fat loss or change in liver fat storage. There was a slight reduction seen in energy intake.
In a 2016 study in the FASEB (Federation of American Societies of Experimental Biology) Journal, US researcher John Carbone & team, 5 obese young adults (4 women, 1 man) consumed 200mg raspberry ketones daily for 6 weeks. Their diet and activity records were strictly maintained. After 6 weeks, however, there was no change seen in %body weight or %body fat in young adults. The results of this pilot study suggested that raspberry ketone supplementation is not an effective weight loss aid.
There may be other areas of research on raspberry ketones, which are being researched. For e.g. in a 2008 study in the journal Growth Hormone & IGF Research, a Japanese team led by N. Harada suggested that raspberry ketones might increase dermal IGF-I production through sensory neuron activation, thereby promoting hair growth and increasing skin elasticity.
However, there are studies questioning the safety of these ketone supplements. In a 2015 study in the journal Regulatory Toxicology & Pharmacology, a Danish research team, led by L. Bredsdorff, suggests that raspberry ketone is marketed on the Internet as a food supplement. The recommended intake is between 100 and 1400mg/day. The substance is naturally occurring in raspberries (up to 4.3mg/kg). When the lowest recommended daily dose of raspberry ketone (100mg) as a food supplement is consumed, it is 56 times the established threshold of toxicological concerning limit.
According to Lee, raspberry ketone has held GRAS (Generally Recognized as Safe) status since 1965 as an ingredient for use in food, drug, or cosmetic and is listed under synthetic flavouring substances with the instruction to use a minimum quantity that produces intended effect. For his 2016 study, Lee purchased random raspberry ketone supplements from the market. The information printed on bottle labels suggested consuming much more than what has been studied in humans. One manufacturer-recommended taking 300mg twice a day (total 600mg), while the other proposed one 500mg capsule daily, with neither label describing such dosage in relation to the GRAS advised minimum level of raspberry ketone that achieves raspberry flavour and aroma.
According to Dr. Axe, the raspberry ketone is actually one of the most expensive products used in the food industry — the natural compound can cost as much as $20,000 per kilogram. Plus, the extraction of pure raspberry ketone requires an insane number of raspberries. Extraction occurs through hydrogenation and takes about a kilogram of raspberries (over 2 pounds) to make 1.4mg of raspberry ketones. Considering a standard supplemental dose for humans is around 100–200mg, that’s a lot of raspberries! This is exactly why some supplement companies use synthetic raspberry ketone, which is much cheaper.
Independent research site examine.com, on raspberry ketones, suggests that there is no human evidence for the effects of raspberry ketones. Studies on rats have used a dosage range of .545-2.18g/kg, which correlates to a human estimated dose of 80-340mg/kg for humans. This dose is very high compared to other fat-burning compounds, so for that reason, the standard supplemental dose of raspberry ketones for humans is in the 100-200mg range. There is no solid evidence for the effectiveness of the doses listed below. Rat dosages correlate to the following human doses:
- 870-3,700mg for a 150lb person
- 1,100-5,000mg for a 200lb person
- 1,500-6,200mg for a 250lb person
Therefore, just like other useless supplements, raspberry ketones are just another weight loss scam.