What you should know about raspberry ketones

raspberry-ketonesRaspberry ketones are marketed as a natural weight loss supplement for revving up metabolism and burning fat more efficiently, but the active compounds used in these formulas are created synthetically, and no evidence exists they can do what manufacturers claim.

With only a third of Americans standing on the “normal” side of the body weight dividing line, millions carrying excess fat are desperately seeking any help they can get.

If you’re reading this, you may be one of them.

Failed efforts to follow weight-loss plans and claim the rewards of a thinner body and better health is a common disappointment in the modern world.

Statistics gathered by the Boston Medical Hospital indicate close to 50 million Americans embark on a diet each year, spending a total of $33 million annually on weight-loss products. (1)

According to the World Health Organization, Southeast Asia has the lowest percentage of overweight people, but a staggering half-billion worldwide were classified as obese in 2008, and the problem just keeps getting bigger. Women are more likely to be overweight and obese than men. (2)

No wonder there are so many buyers for the latest and greatest weight-loss supplement.

Unfortunately, many of the products available aren’t effective, and it appears raspberry ketones is among them.

Experimental Chemistry

Reducing appetite and enhancing the body’s ability to burn fat are the two most popular selling points for weight-loss supplements.

Raspberry ketones claim the latter effect; while it’s true that genuine, natural raspberry ketones pack a whallop, it’s not in the way you’d want to help you lose weight.

What they’re really best for is flavoring processed foods like ice cream and soft drinks, as well as imparting scent (and sometimes flavor) to certain cosmetic products. (3)

When you think about the exhilarating smell of fresh raspberries, to say nothing of the way they taste, it’s easy to understand how the substance responsible for those qualities would tempt researchers to figure out a way to isolate it, which they did.

A little of that powerful stuff goes a long way, which is a good thing, since raspberry ketones occur in minute quantities naturally at somewhere between 0.0001% and 0.0004% by weight. It would take 90 pounds of raspberries to make a single dose of the real stuff, which would obviously make it pricey.

The evolution of chemistry gets the credit for synthetically created raspberry ketones, which make the compound an affordable option for anyone who wants to try it as a weight-loss aid. If you’re interested in the details of how it’s accomplished in the lab, you can check out these cited sources. (4, 5, 6)

The molecular structure of natural raspberry ketones originally caught the attention of chemists because of its similarity to capsaicin (found in chili peppers) and synephrine, which is a stimulant. Both of these possess proven effects in ramping up metabolic processes. (7, 8)

Isolated fat cells from rats placed in test tubes with raspberry ketones produced two encouraging results:

  • Fat breakdown, referred to as lipolysis, took place more quickly through a heightened sensitivity of the cells to norepinephrine, which is a fat-burning hormone.
  • Fat cells released larger amounts of adiponectin, a hormone that may help regulate both metabolism and blood sugar levels.

Since overweight people have lower levels of adiponectin that rise when they drop fat (9, 10), researchers concluded raspberry ketones could help herd that particular hormone balance in the right direction.

But there’s no guarantee this can happen with human use.

However, drinking coffee can increase adiponectin levels, and another notable discovery on stimulating production of this hormone included a 268% increase over a week’s time through engaging in exercise. (11, 12)

More rodent studies indicated animals dosed with insanely high amounts of raspberry ketones didn’t gain as much weight on a fattening diet as the ones without it. (13)

But again, this may not hold true for humans.

Besides, it would take a hundred times the recommended dosage of raspberry ketones to match what the rats ate during the study.

Human Studies on Raspberry Ketones

There aren’t any.

The only clinical trial done with humans tested the effect of six substances used together as a weight-loss aid:

  1. Garlic
  2. Capsaicin
  3. Ginger
  4. Caffeine
  5. Synephrine
  6. Raspberry ketones

Spanning 8 weeks, the study divided participants into two groups, with one taking a placebo. They were asked to exercise and reduce caloric intake.

Those using the six-ingredient supplement released nearly 8% of total body fat, while the control group managed to let go of barely more than 2%. (14)

It’s not possible to calculate individual effects of the six ingredients, so there’s no way to tell if the raspberry ketones had anything to do with the respectable trial results.

Synergistic interactions can also boost the effectiveness of substances used together. If you’re feeling adventurous, you may want to try this combo.

Reviews and online forums suggest raspberry ketones have similar success and failure rates to other weight-loss products; some people swear by them and other call it a bust (15).

With so many variables and no human studies, it’s difficult to say whether raspberry ketones can help people lose weight, or if other factors may have influenced success stories.

Future research may provide answers to these questions.

Warnings and Dosage Recommendations

Without human studies, side effects of raspberry ketones, if there are any, can’t be pinpointed.

Unverified reports mention elevated heartbeats and blood pressure, along with feeling jittery, but the lab mice didn’t seem to experience any ill effects on massive doses, for what it’s worth.

Keep in mind that the molecular structure of raspberry ketones used in weight-loss supplements is a product of modern chemistry, not a natural derivative of raspberries.

Dosage recommendations on package labels usually fall between 100 and 400 milligrams, taken either once or twice daily. This doesn’t even come close to the amount that kept rats from gaining as much weight on a fattening diet as the control group.

Summary: Raspberry ketones may not do any harm, but focusing on lifestyle changes that can help you achieve and maintain normal weight might be a better choice.


  1. http://www.bmc.org/nutritionweight/services/weightmanagement.htm
  2. http://www.who.int/gho/ncd/risk_factors/obesity_text/en/
  3. http://examine.com/supplements/raspberry-ketone/
  4. http://www.ncbi.nlm.nih.gov/pubmed/17722151
  5. http://link.springer.com/article/10.1007%2Fs00897960034a
  6. http://pubs.acs.org/doi/abs/10.1021/jo00099a017
  7. http://www.ncbi.nlm.nih.gov/pubmed/17615999
  8. http://www.ncbi.nlm.nih.gov/pubmed/21537493
  9. http://www.ncbi.nlm.nih.gov/pubmed/12611609
  10. http://www.ncbi.nlm.nih.gov/pubmed/18378021
  11. http://care.diabetesjournals.org/content/31/3/504.abstract
  12. http://care.diabetesjournals.org/content/27/2/629.full
  13. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3338106/
  14. http://www.ncbi.nlm.nih.gov/pubmed/23601452
  15. http://healthranks.org/raspberry-ketones
0 comments… add one

Leave a Comment