Update 9/14/19. What are raspberry ketones and do they work? Well, if you watch the Dr. Oz Show, you may have heard Dr. Oz call raspberry ketones “The #1 miracle in a bottle to burn your fat.” Since he made that bold statement, I've heard that raspberry ketone supplements are sold so fast that vitamin stores can't keep them on the shelves! So, what I'd like to do is review the raspberry ketone research — minus the hype that you have already heard about. Only in this way can you make an informed decision about whether raspberry ketone is right for you. Other names for this supplement include red raspberry ketone, and European red raspberry, as well as the more scientific names Rubus idaeus, Rubus strigosus and Framboise Rouge. I'm telling you these other names because if you just searched for “raspberry ketone” you may not find all of the information available. For this review, I'm pretty much going to stick to just calling it raspberry ketone.
What Are Raspberry Ketones?
Red raspberry ketones are one of many compounds in raspberries and are what gives raspberries their unique smell. Like all things that come from fruits and vegetables, raspberries contain a lot of substances that are healthy —including anthocyanins, vitamin C and beta carotene. As such, raspberry ketones are also antioxidants.
Raspberry ketones also “look” similar to synephrine and capsicum — two ingredients that have been used in many weight loss supplements over the years such as the fat burner promoted by Jillian Michaels. This similarity is likely why scientists considered raspberry ketones as a weight loss agent itself.
Ketone trivia. The name ketone is a chemistry term. That's not important. I just thought people might like to know where the word came from. On some websites they spell ketone as “keytone” but this is an incorrect spelling of the word. Again, not important.
Tip. Keep in mind as you read this review that raspberry ketones are not the same thing as ketones that are made when people go on low-carb diets or in people who are diabetic. Those ketones are not the same as raspberry ketones.
Raspberry Ketones And Weight Loss
When Dr. Oz asked his fitness expert, Lisa Lynn (more about her below) on TV, how she found out about the weight loss properties of raspberry ketones, Lisa said “Research research research.” So, I looked up the research on raspberry ketones and this is what I discovered.
In a study published in 2005, called the Anti Obesity Action of Raspberry Ketone, raspberry ketones were given to mice that were fed a high-fat diet for several weeks. Mice were split into different groups, each getting the same calories but getting different amounts of raspberry ketones (either 0.5%, 1% or 2%).
The diets were about 40% fat in each group. Researchers noted that raspberry ketones — that made up between 1% and 2% of total calories — caused a reduction in body weight and fat buildup in the livers of mice after 10 weeks of use, compared to mice that only were fed a high-fat diet.
Norepinephrine (also called noradrenaline ) is a chemical made in the adrenal glands that act as a neurotransmitter and does many things, one of which includes helping to burn fat. This study also incubated isolated mouse fat cells in norepinephrine along with raspberry ketones to see what would happen.
The researchers observed that the combination of raspberry ketones and norepinephrine caused more fat to leave the fat cells than norepinephrine alone.
This is why Dr. Oz said raspberry ketones cause fat cells to shrink.
I'm telling you this because various websites claim that raspberry ketones increase levels of norepinephrine. However, this study did not show that.
Rather, the researches only showed that raspberry ketones appeared to improve the fat-burning ability of norepinephrine.
This is actually a good thing because too much norepinephrine can be bad. For example norepinephrine can raise blood pressure.
Oddly, this study noted that while a 1% intake of raspberry ketones tended to raise triglyceride levels in the mice, eating it at a concentration of 5% of total calories tended to reduce triglycerides.
These researchers also quoted previous studies noting that raspberry ketones raised metabolic rates—in rats. That's interesting, but where's the proof that raspberry ketones raise metabolism in people?
Bottom Line: This was just a mouse study —and a small study at that! Each group only had 6 mice.
Also, if we really want to be technical, all the mice were male. What about female mice? Would raspberry ketones have the same weight loss effects in female mice —or more importantly —women?
In another study, published in 2010, researchers found that red raspberry ketones inhibited weight gain and improved fat burning in mice that were fed a high-fat diet. Researchers also noted that raspberry ketones increase levels of adiponectin, a hormone made in fat cells.
The Wikipedia page on adiponectin goes into more detail, discussing how the hormone does a variety of things including improving the sensitivity of insulin— (good for diabetics).
Dr. Oz said that Adiponectin was the “hormone that tricks the body into thinking it's thin.”When we put on weight, we reduce the ability of the adiponectin hormone to work.”
Sounds good, but red raspberries have only been shown to reduce adiponectin in mice. What about people? Have raspberry ketone supplements been proven to help people lose weight by raising adiponectin levels? Nope. Not yet.
Tip. There is more evidence that exercise raises adiponectin levels than for raspberry ketones —and exercise has been shown to work in people!
One study from 2013 appeared to show that a supplement – containing raspberry ketones – helped weight loss. But there were several ingredients in that supplement. Also, of the 70 people who originally signed up, only 45 people made it to the end. That's a big drop amount.
There is a study published in 2017 that noted, that raspberry ketones might reduce food intake in mice who were fed a high-fat diet. Again, this is a mouse study.
So, what's the evidence for raspberry ketones and weight loss? It looks like some mouse studies. What about people?
Are Raspberry Ketones Better With Capsaicin?
Capsaicin is found in chili peppers and synephrine is an extract from oranges. Both have been used in weight loss products in the past. Because raspberry ketones “look” like both capsicum and synephrine, I predict that you will see weight loss products that have all three of these ingredients.
But, would they all work better together? I don't know because there is no proof either way. Because of that, I recommend you save your money on weight loss pills that combine (“stack”) capsaicin, synephrine, and raspberry ketones.
Synephrine, in particular, is not without problems. It can raise heart rate and blood pressure which can make it dangerous for a lot of people.
Who Is Lisa Lynn?
Dr. Oz called Lisa Lynn a “fitness expert” on his TV show when he did a segment on this supplement— but who is she? I checked into her background and found her website (LynFit.com) that notes that Lisa Lynn was the personal trainer of Martha Stewart.
Her website does indicate that Lisa holds multiple personal training certifications.
All this is fine but on her website, we see Lisa Lynn also has her own line of supplements (called “Lyn Fit”) She even has a raspberry ketone supplement on her website.
In a previous segment of the Dr. Oz show, Lisa Lynn also extolled the virtues of the metabolism booster/weight loss supplement, Coleus Forskohlii. Lisa has this supplement on her website also.
See the review on Coleus Forskohlii for more information.
Look, I'm sure she's a nice person and a great personal trainer —and I am all for capitalism – but where is all the raspberry ketone research? As far as I see, it's just some mouse studies.
How Much Raspberry Ketones Do You Need?
If raspberry ketones help people lose weight, how much works? Nobody knows because there are no human studies of raspberry ketones and weight loss. If we believe the mouse studies (which I don't), it appears that a concentration of 1% of total calorie intake might help weight loss. If that is correct, then the number of raspberry ketones needed would be different for different calorie intakes.
For example, a person who consumes 1800 calories per day would need less than a person who eats 2000 calories per day.
When asked “how much works” on the Dr. Oz Show, Lisa Lynn said to take 100 mg at breakfast— and if that didn't help, to go to 200 mg. Where did she get these numbers from? She doesn't tell us.
I guessing that this might be the human dose, extrapolated from what researchers gave the lab mice? But, I see no good proof that 100-200 mg of raspberry ketones per day helps people lose weight. It might—but I just don't know.
In this toxicology report on raspberry ketones, the authors mention a dosage of 100-1400 mg per day is often mentioned on the internet. That is a pretty big range, which again, says to me, nobody has any idea.
Raspberry Ketones And Appetite
Various websites make the claim that supplements can reduce appetite. But I see no proof of this. Even the mouse studies, do not state that raspberry ketone supplements suppress appetite.
Anti-Aging Effects Of Raspberry Ketones
Can raspberry ketone supplements slow down the aging process? Do they reduce wrinkles? Well, red raspberry ketones do have some antioxidant effects but it's a long shot to go from that to say that they are “anti-aging.”
Raspberry ketones may be found in some cosmetics because they seem to have a skin whitening effect —at least in skins of mice. That's fine, but I recommend you save your money on raspberry ketone anti-aging supplements. They are not an “anti-aging superfood.”
For those who really want a “superfood,” eat raspberries! Here's why: antioxidants work best in small amounts and when they are eaten in combination with the other ingredients in food. Because of this fact, raspberries are better than raspberry ketone supplements when it comes to being healthy.
Raspberry Ketone Side Effects
In healthy people, raspberry ketones are probably safe. That said, those who are not healthy or take medications should speak to their doctor/pharmacist first. Here are a few things to consider when taking this supplement. This list is not complete.
- Start with less than recommended for the first week
- Pregnant or nursing women should also speak to their doctor
- Stop taking the product at least 2 weeks before having surgery
There are only trace amounts of raspberry ketones in raspberries so they are no the same thing as supplements. This toxicology report states that there is only 4.3 mg per 2.2 pounds of raspberries. Just because raspberries are safe does not mean concentrated supplements of raspberry ketones are also safe.
One of the mouse studies summarized above noted that raspberry ketones raised triglyceride levels. Does this mean they also raise triglycerides and cholesterol levels in people?
Since raspberry ketones appear to have some chemical similarity to synephrine, be careful if you have high blood pressure or heart conditions. Synephrine might raise blood pressure and heart rate.
A report from Denmark publishedhas raised some concerns that the supplement may have toxic potential but there is little human evidence for this.
Some have speculated that these supplements may be inappropriate for those with cancers that are sensitive to estrogen levels. This is based on a concern that raspberry ketones may have estrogen-like properties. Cancers that might be affected by this include breast cancer, fibroids of the uterus, endometrium cancer, and uterine cancer.
In the book Herbs of Choice raspberry leaf is said to help with pregnancy issues such as morning sickness and labor pains. The book also notes (p. 140) that raspberry appears to promote contraction of the uterus. That would not be good for pregnant women. Would the same be true for raspberry ketone supplements? I don't know.
Do these supplements raise blood pressure? I do not know, but if the leaf of raspberries cause the muscles of the uterus to contract, what effect would they have on the muscles of the blood vessels? Would they also contract (and raise blood pressure) or would they relax (and decrease blood pressure)? I don't know.
Remember, some raspberry ketone supplements may contain more than just raspberry ketones. Always check the labels to see what other ingredients a supplement may contain.
See What Weight Loss Supplements Work for a list of things I feel have evidence
Do Raspberry Ketones Work?
The research on raspberry ketones for weight loss is in its infancy. As such, I just don't know if this supplement helps people lose weight or not. The majority of research is a lab rat and lab mice research. Raspberry ketones may benefit in mice but what about humans? I'd like to see a real-life study of of 100 people followed for at least 6 months under real-life (not laboratory) conditions to judge its weight loss power.
If you are still thinking about trying raspberry ketones to help you lose weight, I suggest you go to your doctor and get your blood work done first —cholesterol, blood pressure, weight, liver enzymes, the works—and then get it done again in a couple of months to see if anything has changed.
There are a LOT of websites that sell raspberry ketones. If you read the comments here, you'll see how some people talk about how their credit card was charged more than once after they purchased a product. Know who you deal with. Make sure the raspberry ketone websites you deal with have a contact phone number with customer support people who can help you have questions.
If they are going to work, keep in mind that it might take 6 months before raspberry ketones help you lose weight. Oh, and if you watched the Dr. Oz show, you also heard that you still have to exercise and watch what you eat too. So, you have to eat right and exercise as well as take raspberry ketones. That sounds less like “a miracle in a bottle to burn fat” and more like common sense.