Most Metabolism Boosters Are BS

Most Metabolism Boosters Are BS

Thanks to Brilliant for supporting this whole
week of SciShow. Go to to learn more. [♪ INTRO] Take a stroll into any nutrition store and
you’ll see displays stacked to the ceilings with products that
claim to “boost” your metabolism. Whether they’re marketed as “Metabol Burn”
or “VitaGainzzzz” or something equally absurd, there’s one thing that they have in common:
They don’t really work. Decades of research show that making any meaningful
change in your metabolism is really hard to do, so a powder or pill
won’t turn you into a calorie burning machine. Most supplements can’t really boost your
metabolism, and the actual changes we can make to it are
pretty limited. Contrary to what the supplements might lead
you to believe, metabolism isn’t just the ability to burn
off energy from food. The actual claims are all over the place, but in general when a product says it “boosts”
your metabolism, that’s code for burning more calories or
fat. Using calories is a part of metabolism, but even that process is affected by your
physiology, like enzymes and hormones. When scientists talk about metabolism, they use it as a broader term for all of a
cell or body’s processes. Which is a pretty big concept, and not very
informative on its own. So since that’s such a broad definition, researchers
usually break it down into smaller components. The biggest slice of the metabolic pie is
something called basal metabolic rate, or BMR, and it’s the energy your body uses
at rest. But even that comes with an asterisk. True BMR is measured when the subject is at
rest, at a certain temperature, not digesting food, and not pregnant, because
all of those things can nudge your energy consumption one way
or the other. Fun fact: growing a whole other human inside
of you changes your energy needs. Furthermore, different parts of the body have
different metabolic rates. Gram for gram, your kidneys and heart consume
the most calories, followed by your brain and liver. Towards the bottom of that list is muscle
and fat. But no one is advocating taking on an extra
kidney to try to raise your rate of calorie burn. Instead, researchers focus on two tissues
that we can tweak: fat and muscle. Fat, or adipose tissue, is one of the ways
your body stores energy long term, so it makes sense that it doesn’t take a
lot of energy to store energy. Muscle, on the other hand, has the opposite
job. When you exercise, it uses quite a bit of
energy and oxygen, but even at rest, its caloric needs are higher
than fat. And sure enough, people with a higher proportion
of muscle mass tend to have higher basal metabolic rates
than people with more fat mass. That is, they burn more calories per gram
of body weight even when they’re resting. Now the second slice of the metabolic pie is energy
used during exercise, but again, with an asterisk. Yes, when you exercise, you use a few more
calories for a short period of time, but even a thirty minute workout burns a pretty
small number of calories compared to your BMR. So researchers also look at how exercise affects
something called resting energy expenditure, which is just a more relaxed way to measure
overall metabolism than the super-specific BMR. Multiple research groups have found that aerobic
exercise, whether it’s long and slow like riding a
stationary bike, or short bursts of intense exercise like sprinting,
all elevate metabolism temporarily after exercise. Likewise, lifting weights also leaves you
with a slightly boosted metabolism after the workout. And long term, those bulkier muscles are probably
what make the biggest difference in your metabolism. One 2008 study on diet and exercise in overweight
women found that resistance training allowed participants to keep their metabolisms
elevated even after the diet, while the ones who just cut calories ended
up slowing their metabolisms. But even if you’re not hitting the gym,
you still have the third slice of the metabolic pie: non-exercise activity thermogenesis, which
makes for a neat acronym. It encompasses all of your day-to-day, moving-around-but-not-exercising
activities, like walking around the house, or doing the
dishes, or watering the plants. That adds up to a good chunk of metabolism,
but it varies a lot depending on your lifestyle. Now this last way our bodies burn calories
actually has a lot to do with how we eat calories. It takes energy to digest, absorb, and get
rid of food, so we call those calories the thermic effect
of food. High-protein foods take a bit more work to
digest than others, so your steak has a higher thermic effect
than a bag of chips. But even something like ice water has a thermogenic
effect thanks to our bodies warming it up, which
takes energy. Now, it’s easy to think of our meat sack
bodies as simple calorie-burning engines, but metabolism happens at the cellular level, which is where supplements might claim their
products work. For instance, after eating and digesting a
piece of fruit, the simple sugar glucose is released into
your bloodstream. This is our bodies’ main energy currency. But it still needs to get into the cell so that cellular
machinery can turn it into usable energy. And it’s a big molecule by cell standards,
so it doesn’t just seep right in. Which is why our bodies produce insulin, a hormone that binds to receptors on our cells
and shuttles glucose inside of them. Without insulin, we could still digest food
and get glucose into our bloodstream, but we wouldn’t be able to process it into
energy since it couldn’t enter the cell, which is exactly what happens in diabetes! Your body either can’t make enough insulin,
or has trouble importing enough sugar into cells. But glucose isn’t the only nutrient our
body uses for fuel. And chances are that if a product is marketed
as a metabolism booster, it’s concerned with one nutrient: fat. Now, fat is utilized in a complex chain of
chemical events that I’m not gonna explain here. But at rest, your body typically doesn’t
use fat for energy. That’s supposed to be stored energy, whereas the glucose that’s floating in your
blood is ready to use right away. Before resorting to breaking down fat, your
body will typically tap the stored glucose in your muscles and liver,
called glycogen. And to complicate things further, your body
never only uses fat or only glucose as a fuel source. It’s a mixture of both. So hopefully you’re starting to see that
your metabolism has lots of moving pieces to it, and if a product says it can change your metabolism,
that’s a pretty bold claim. Despite the lack of evidence backing them,
pharmacies still keep these products in stock, even as some researchers have voiced concerns
about their safety. These products are available over the counter,
at least in the US, but they’re not regulated as tightly as
proper pharmaceuticals. Now, there are a few ingredients that can
increase resting energy expenditure, but that doesn’t mean a supplement will
boost your metabolism long term. Like capsaicin, the same molecule that gives
red pepper its spiciness. This ingredient has been used to suppress
appetite in the past, but it can also increase energy expenditure
and shift your body towards burning fat. It does this by kicking off a chain of events that
eventually stimulates the sympathetic nervous system, which is the same system that’s activated
during the fight or flight response. This part of your nervous system is responsible
for basic bodily functions like regulating heart rate and basal metabolic
rate. So when we see a chemical that stimulates
the sympathetic nervous system, we generally associate that with an increase
in metabolism. When researchers looked into capsaicin, they saw it activate a receptor called TRPV1,
which is an important part of fat oxidation. And it might also help you process glucose
more efficiently by toning down the inflammatory response often associated
with obesity. When used according to protocol, capsaicin has the potential to help you burn
an extra 50 calories a day; that’s according to a literature review
published in 2012. But whether you stick to protocol or not is
a whole different issue. Whether or not the subjects actually followed
directions usually determined any metabolic results. And as can be the case with diet and supplement
research, the dosage of capsaicin varies widely from
study to study. Some studies used pure capsaicin capsules
as high as 150 milligrams, while others sprinkled less than a milligram’s
worth of red pepper on someone’s food. Surprisingly though, this is consistent with
how much variation there is in our diets. The average capsaicin intake in Europe is
1.5 milligrams a day. Meanwhile, in countries with spicier cuisines,
like India or Mexico, it’s anywhere from 25-200 mg. Now another metabolism boosting ingredient
that’s present in most countries’ diets is caffeine. There’s extensive data supporting caffeine’s
ability to raise energy expenditure, and it’s not because it keeps you awake
and jittery all night. Caffeine ends up stimulating the same sympathetic
nervous system, but through a different mechanism than capsaicin. It also has the ability to activate an enzyme
called lipase, which promotes the breakdown of fat. And caffeine comes in many different forms,
from pills to candy bars to coffee. And despite all the other ingredients that
manufacturers throw into energy drinks and other caffeinated products, caffeine seems to be the only one that does
anything useful for metabolism. A 2014 article from the journal Obesity reported
that a commercially available energy drink raised subjects’ energy expenditures, but
a regular mixture of water and caffeine did the same thing. This suggests that all those other ingredients,
usually some B vitamins, don’t have any noticeable effect in these
products. Plus, the increase in fat burning ability might actually be canceled out if the caffeine
interrupts your sleep. One study in 2013 gave a moderate dose of
caffeine to young men who didn’t normally consume
that much. And while their resting energy expenditures
didn’t change, they got less sleep. Caffeine might be one of the reasons that
our final ingredient, green tea, is such a common ingredient in
metabolism supplements as well. Green tea extract is exactly what it sounds
like: compounds taken from green tea. That usually includes caffeine as well as
a group of chemicals called catechins. In cell, animal, and human studies, researchers
have seen increased resting energy expenditure after
giving subjects doses of green tea. One study back in 2005 gave participants capsules
of EGCG, one of the green tea catechins, with caffeine and saw an increase in energy
expenditure of about 180 calories. But the metabolic claims don’t stop there. Green tea supposedly helps bump up your fat
burning too, although there’s not a lot of direct evidence
in human studies to support it. Supposedly, the catechins within green tea
inhibit an enzyme that degrades neurotransmitters like dopamine and
epinephrine. And just like capsaicin and caffeine, this
means stimulation of the sympathetic nervous system, which raises energy
expenditure. But it’s also been implied from these studies
that long term green tea use might change our gene expression towards a
slight bump in fat metabolism. But again, we need more evidence from human
studies. At the same time, we’re still trying to
work out details on how to use it. There are trials where researchers gave green tea
extract to participants and saw no noteworthy results. So all of these ingredients have some evidence
to back them up, but there’s a big difference from experimental
conditions to how you use the products at home. Ultimately, one of the best metabolism boosters,
other than increasing muscle mass, is a totally free product that you won’t
see on any nutrition store shelves: sleep. For decades, we’ve known that sleep deprivation
can impair metabolism. And it does this by messing around with certain
hormones that control energy intake and storage. Research published in 2010 hooked subjects
up to a steady drip of glucose overnight and cut their sleep to four hours per night
for two nights, and then had them sleep ten hours per night
for another two nights. And they found that ghrelin, a hormone that
signals hunger, was increased by 28%, while leptin, a hormone that signals fullness,
dropped 18%, even after the participants got two nights
of make-up sleep. This went along with an increase in appetite
rating as well, which you’re probably familiar with if you’ve
pulled an all-nighter. Plus, sleep deprivation harms your insulin’s
ability to respond to glucose. So while you might think you’re more active
while you’re awake into the wee hours of the night, you’re doing your metabolism
more harm than good. So can those flashy products in nutrition
stores actually boost your metabolism? Well, there’s some truth to their claims,
but clearly, it’s not that straightforward. Some work in specific conditions, while some
may actually be dangerous in large amounts. And obviously, if you’re thinking about trying any
of these things, check with your doctor first. On the other hand, if you feel like you’re
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100 thoughts on “Most Metabolism Boosters Are BS

  1. Go to to try out Brilliant’s Daily Challenges. The first 200 subscribers get 20% off an annual Premium subscription.

  2. sorry if this has already been done but i've heard that other people in other country's really don't like drinking or eating cold things thinking it will hurt you from a "shock" to your system would be interesting to hear about this and if it's true or not

  3. I'm pretty sure large doses of caffeine, speed, cocaine, and smoking increases your metabolism, unless you die. Dying dramatically lowers your metabolism.

  4. Ok so all you need to do is market an energy drink called fat burn x with capsaicin, green tea extract and caffine. BRB making a millions of doll hairs

  5. Rub lye on your body. Get rid of that fat and make soap at the same time!

    I do hope it goes without saying you shouldn’t do that…

  6. Huh, I'd always heard the brain uses up some 20% of your bodily energy. So the kidneys use more than that? I'll have to do some reading.

  7. can you please do a video on Garcinia Cambogia? And those pills that bind to fat and make you excrete it out? Do they work?

  8. Ephedra, when combined with aspirin and caffeine was the best fat burner we had. Unfortunately, if not managed properly it can have serious side effects. If it were a pharmaceutical instead of an herbal supplement, ephedra would still be on the market, prescribed by doctors.

  9. I started reading studies more closely when I happened to read one about alcohol and testosterone. Turns out the researchers considered keeping the rats at a .24 BAC 24/7 was moderate consumption. Light consumption was I believe around .12 BAC, so constantly legally drunk still. Heavy consumption was something ridiculous like .45 BAC 24/7, not even sure how those rats lived that long. Not sure how much I'd trust that study.

  10. Just overlooked that B-Vitamins might be taken for brain clearancy…don‘t know if this wasn‘t said by purpose or not, but makes me question the rest of the video. But otherwise seems ok 🙂

  11. Most effective way to increase your metabolic rate: put on a bunch of weight and just have more cells to keep alive

  12. Body building, toning, athleticism etc is 99% genetics and 1% diet. I can eat pizzas, McDonald's, KFC with Coke or Pepsi and drink full cream milk all week long and not gain an ounce of fat. I go through a bottle of whiskey every weekend and bounce back only a few hours later, with no hangover. I don't even have to lift to stay muscular it's insane. My girlfriend thinks I'm not human. So I reckon I'm either going to live forever.. or drop stone dead in a few years, we'll see lol.

  13. Question: Why is calorie used to measured weight gain/loss instead of mass of the food? Also, how is mass (specifically fat) released from the body after the energy from it has been used? This comes from the mismatch of the saying Burning Energy → Weight Loss

  14. Not quite accurate. We can make huge changes to our metabolism with a pill. Try taking something for chronic Lyrica, Gabapentin or antidepressant. Guaranteed to hugely slow your metabolism and make you gain weight really fast!
    Something that does the opposite?
    Sadly the only thing that helps there is old fashioned healthy eating and exercise. Although building muscle is great because muscle burns fat….
    As always the easy way only goes one way. Oh well…🤷‍♀️

  15. Using sliced habanero as your go-to snack helps curb your hunger. Eat a bowl and you'll be too busy nursing your tongue to have time to eat

  16. Then there's 2,4-Dinitrophenol which works very well but has the unfortunate disadvantage of sometimes killing you.

  17. I bothered to read the ingredients on all those meta boosters at my local store, and there was one common ingredient among them all. Caffeine in large doses. Like above what you'd get out of drinking a 1 liter energy drink can. Some had twice that. Everything else in them was either just a stimulant, or something to make it feel like it was working. Seriously if anyone in the comments reads this, please stay away from those products if you're already drinking sodas with caffeine, energy drinks, or pre-workouts, or a combo of all the above. You're already getting all you will from the caffeine in your other products, and more than you actually need in a day. Do not underestimate caffeine's ability to make you over dose on it. You will go from feeling an adrenaline like amp(what pre-workout makes you feel) to being on the ground with heart failure.

  18. It's SEXIST!!! to use the term bullsh*t when she cows go poop, too.

    And, it's also SPECIESIST!!! because non-bovine animals also expel digestion remnants through their anal orifice.

    In the future, instead of saying "bullsh*t", please say "Non-gender specific non-species specific animal excrement".

    And instead of using "BS", please use "NSNSAE".

    Thank you for your cooperation.

    And do i really HAVE to say anything about the usage of the term "horsesh*t"?

  19. Looks like you had the "soften" attribute in Premiere's ultra key turned up a little too high. His hair looks like a gray blob.

  20. Long story short, to save you time from watching this video, you can't lose weight and you'll stay fat for the rest of your life.

  21. as a guy with hyperparathyroidism or graves. my metabolism is very high naturally. mess with it even a little… and i could drop dead on the spot. even in now knowing most off shelf boosters are BS, i still shouldn't risk it.

  22. In New Mexico, chili, green and red are staples. Jalapenos (whole, fresh) with every meal. I knew an old man who had a tortilla covered with chili and a dash of salt as a mid morning snack and drank coffee all day. That man lived into his late 90s on a small ranch in the middle of no where.

  23. Exercise (weight training), amount of calories, and type of calories all impact metabolism. I really see it better/clearer since I started Keto and IF.

  24. Can y’all talk about how CLA works? I work at GNC and we basically make it out to be this godly fat burner but I don’t believe it.

  25. White fat to brown. 

    Journal of Diabetes Research

    Volume 2018, Article ID 9713259, 11 pages

    Research Article

    Pycnogenol® Induces Browning of White Adipose Tissue through the PKA Signaling Pathway in Apolipoprotein E-Deficient Mice

    Huiying Cong,1,2 Wenxia Zhong,1,2 Yiying Wang,1,2 Shoichiro Ikuyama

    ,3 Bin Fan

    ,4 and Jianqiu Gu


    1Department of Endocrinology and Metabolism, The First Hospital of China Medical University, No. 155 Nanjing North Street, Shenyang 110001, China

    2The Endocrine Institute and the Liaoning Provincial Key Laboratory of Endocrine Diseases, The First Hospital of China Medical University, No. 155 Nanjing North Street, Shenyang 110001, China

    3Department of Clinical Investigation, Department of Diabetes, Endocrine and Rheumatic Diseases, Oita San-ai Medical Center, 1213 Ichi, Oita 870-1151, Japan

    4Department of Neurology, Shengjing Hospital, China Medical University, No. 39 Huaxiang Road, Shenyang 110022, China

    Correspondence should be addressed to Bin Fan; [email protected] and Jianqiu Gu; [email protected]

    Received 27 June 2017; Revised 2 October 2017; Accepted 26 October 2017; Published 17 January 2018

    Academic Editor: Hiroshi Okamoto

    Copyright © 2018 Huiying Cong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


    Beige adipocytes in white adipose tissue (WAT) have received considerable recognition because of their potential protective effect against obesity. Pycnogenol (PYC), extracted from French maritime pine bark, has anti-inflammatory and antioxidant properties and can improve lipid profiles. However, the effect of PYC on obesity has never been explored. In this study, we investigated the effects of PYC on obesity and WAT browning in apolipoprotein E- (ApoE-) deficient mice. The results showed that PYC treatment clearly reversed body weight and the mass of eWAT gain resulting from a high-cholesterol and high-fat diet (HCD), but no difference in food intake.

    The morphology results showed that the size of the adipocytes in the PYC-treated mice was obviously smaller than that in the HCD-fed mice. Next, we found that PYC upregulated the expression of genes related to lipolysis (ATGL and HSL), while it decreased the mRNA level of PLIN1. PYC significantly increased the expression of UCP1 and other genes related to beige adipogenesis. Additionally, PYC increased the expression of proteins related to the protein kinase A (PKA) signaling pathway. The findings suggested that PYC decreased obesity by promoting lipolysis and WAT browning. Thus, PYC may be a novel therapeutic target for obesity.

  26. White fat to brown fat. 

    Mol Cell Biochem. 2016 May;416(1-2):131-9. doi: 10.1007/s11010-016-2702-5. Epub 2016 Apr 11.

    Cannabidiol promotes browning in 3T3-L1 adipocytes.

    Parray HA1, Yun JW2.

    Author information


    Recruitment of the brown-like phenotype in white adipocytes (browning) and activation of existing brown adipocytes are currently being investigated as a means to combat obesity. Thus, a wide variety of dietary agents that contribute to browning of white adipocytes have been identified. The present study was designed to investigate the effects of cannabidiol (CBD), a major nonpsychotropic phytocannabinoid of Cannabis sativa, on induction of browning in 3T3-L1 adipocytes. 

    CBD enhanced expression of a core set of brown fat-specific marker genes (Ucp1, Cited1, Tmem26, Prdm16, Cidea, Tbx1, Fgf21, and Pgc-1α) and proteins (UCP1, PRDM16, and PGC-1α). Increased expression of UCP1 and other brown fat-specific markers contributed to the browning of 3T3-L1 adipocytes possibly via activation of PPARγ and PI3K. In addition, CBD increased protein expression levels of CPT1, ACSL, SIRT1, and PLIN while down-regulating JNK2, SREBP1, and LPL. 

    These data suggest possible roles for CBD in browning of white adipocytes, augmentation of lipolysis, thermogenesis, and reduction of lipogenesis. In conclusion, the current data suggest that CBD plays dual modulatory roles in the form of inducing the brown-like phenotype as well as promoting lipid metabolism. Thus, CBD may be explored as a potentially promising therapeutic agent for the prevention of obesity.


    Browning; Cannabidiol; Lipogenesis; Thermogenesis

  27. Not even mentioning DNP in the category of "boosting resting energy expenditure" For shame sci-show. You could have even gone into why it's so dangerous!

  28. How does the claim at 10:36, that sleep deprivation harms insulin's ability to respond to glucose, work? Insulin is a specific protein, and glucose is a specific carbohydrate. How does something as physiologically high-level as a lack of sleep interfere with the chemical interactions between two well-defined molecules?

  29. @6:45 capsaicin helps burn an extra 50 calories a day…. actual calories or kcal/food calories? 50 actual calories is a rounding error. 50 kcal/food calories out of Fitbit's 4000 calories I burn a day isnt really a whole lot either.

  30. DNP is a metabolism worker and 100% works. It's also very easy to overdose on where you cook yourself to from the inside, and this process is irreversible. This is why it's illegal, but they DO exist.

  31. The video is about nothing. Marketing is lies? No way! Of course nothing you eat will make you leaner alone. But combine with excersize, sleep and fasting and the result will come.

  32. I'll back the caffeine one. I drink 4 sodas a day and eat basically whenever I want and am only right at average weight. Though I'm an insomniac so I can't really back the sleep one. Even when not on caffeine I still can't sleep. I only get dreams like once a month if even and when I wake up I usually feel worse than when I went to sleep (but that goes away after about 15-30 minutes). Possibly connected to me never really feeling tired. I just sleep when I want to. Have gone more than 24 hours and only stopped when my eyes started to dry out. But hey I stay out a solid 10-18 hours afterwards.

  33. What about SLOWING DOWN your metabolism?
    Sleep deprivation definitely isn't working for me as I've slept an average of 5 hours a night most of my life. I've always been underweight for my height and have wanted to change that for a long time.
    Is there any hope for skinny guys like me out there?

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