Cleansing and Detox Don’t Work and Are Pseudo-Health Practices

Green smoothie with a strawberry as garnish

“Cleansing” is the practice of using a special diet for several days or even weeks with the end of cleansing the body of toxins, a “detox”. Unfortunately, the evidence for any benefit is limited or non-existent. Cleansing and detox don’t work and are pseudo-health practices.

The idea behind cleansing

If we need to be “cleansed”, that implies that we’re dirty or fouled in some way. In most cases, it’s claimed that the practice of “cleansing” rids our bodies of “toxins”.

However, what these toxins are never seems to be quite explained. Some some sort of vague bad stuff that our bodies can’t rid themselves of on their own.

The body does have mechanisms to rid itself of toxins. The most important organs for that process are the liver, kidneys, and intestines. On the cellular/molecular level, various classes of enzymes such as cytochrome P450 and phase II enzymes perform tasks like neutralizing drugs or toxins and preparing them for excretion.

In a normally healthy human, these mechanisms are at work constantly. Some interventions notably increase the activity of Nrf2, the regulator of phase II enzymes, and these include exercise, fasting, and certain phytochemicals such as resveratrol and curcumin.

Another important way that cells cleanse themselves is through the process of autophagy, in which molecules and cellular organelles that have become degraded through passage of time are broken down and recycled. In this case, however, we can’t really call these things toxins, since they’re normal, but worn-out, cellular constituents.

The practice of cleansing

The practice of cleansing has many variations, such as vegan cleansing and juice fasting, and programs vary greatly depending on who’s advocating them.

Absence of animal foods is prominent in most of them, as well as refraining from alcohol and caffeine, with addition of lots of high-fiber fruits and vegetables, so we may be able to generalize cleansing diets as low-calorie, high fiber, and vegan. Juicing is also prominent.

For example, Dr. Mehmet Oz claims that his cleanse “optimizes” the  body’s detoxification system, although he presents no evidence that it does. Among the foods he recommends are quinoa with prunes for breakfast, and a “revitalizing fruit smoothie” for lunch. Oprah tried a 21-day vegan cleanse, and didn’t like it much.

Other cleansing systems promote foods like “green smoothies” and “beet burgers”.

Cleansing promotes an almost magical or mystical belief in the power of fruits and vegetables. While fruits and vegetables may have benefits – though I’ve become more agnostic on that front – the idea that consuming super-high amounts of them while refraining from animal products confers extra benefits seems without foundation. If 5 servings of them a day is good (maybe), it doesn’t follow that 20 is better.

Smoothies are an artificial form of food, since food in its natural form must be chewed or chewable to be healthy. If fruits and vegetables are healthy, turning them into smoothies could very well make them unhealthy in general, or diminish their health benefits. It’s rather odd that with all the emphasis on greens and naturalness that you need a blender to cleanse.

The thinking behind cleansing (if there is any) harks back to the idea that we can return to the Garden of Eden, where we lived in peace and harmony and in good health, committed no violence, and all creatures were happy.

Puritanism is also strong here. One aspect of cleansing is a focus on bowel movements, hence all the high-fiber foods. Supposedly, this cleans our colons. In reality, some who practice cleansing report day-long watery diarrhea from all that quinoa and other stuff. (Personal correspondence.) Refraining from alcohol and caffeine also reflect puritanism, although of course doing that may confer benefits.

The good, the bad, and the ugly of cleansing and detox

Could cleansing and detox have a good side? Sure, and as usual, it all depends on context.

If someone were eating large amounts of processed, junk food, and refrained from that for awhile and ate more fruits and vegetables, that might be beneficial. Likewise, a cleanse functions as a low-calorie diet, so it might have the same advantages as a crash diet for an obese or diabetic person. (I’m struggling to think of other benefits.)

But junk food typically means sugar, refined carbohydrates, and vegetable (seed) oils. Animal products such as meat, eggs, and cheese are not junk, yet cleansing emphasizes not eating them.

However, there are much better ways of accomplishing these goals than a cleanse, which in any case is supposed to “detox”, a phantom goal.

The downsides of cleansing are many.

One is muscle loss. If you eat a low-calorie, low-protein vegan diet for any length of time, and lose weight, much of that weigh loss will be muscle, which should be avoided at all costs. A rule of thumb in weight-loss diets is that from 1/4 to 1/2 of weight lost will be muscle, unless you take in extra protein and lift weights.

Another downside is that people commonly report feeling awful on a cleanse, with fatigue, headaches, and diarrhea being prominent.

Cleansing and detox are pseudo-health practices.

True cleansing

As noted above, the process of autophagy breaks down cellular junk for recycling. As it happens, we have the means at our disposal to increase autophagy, which declines in aging. That means is via fasting.

Intermittent fasting strongly increases the process of autophagy; when the body senses that no nutrients are available, it breaks down cellular components to get them. When you eat again, the body rebuilds them anew. Cleansing may actually diminish autophagy, especially if you’re drinking smoothies, which if made from fruit have a high sugar content and raise insulin levels, cutting off autophagy.

Ketogenic diets may have nearly the same effect as fasting.

Exercise increases the activity of Nrf2, which leads to more of the important, detoxifying antioxidant enzymes such as superoxide dismutase and catalase. Exercise is arguably the most important thing you can do to make your body stress-resistant and toxin proof.


Cleansing and detox are pseudo-health practices that have little to no scientific backing. In some cases, they may do the opposite of what’s intended.

PS: For practices that will genuinely improve your health, see my book, Stop the Clock.

PPS: Check out my Supplements Buying Guide for Men.

Share this post with your friends

Want to permanently lose 20-50 pounds in 12 weeks?

Without going hungry, counting calories or doing cardio


  1. PJ Pires says:

    So people are making millions of dollars using pseudo-health methods?

    I cannot believe it mate xD.

    Sometimes I think people love to be foolished…

  2. BC says:

    Whenever I hear of some magical routine that will cure or otherwise make up for an overall unhealthy lifestyle, I always remember the following quote:

    “People don’t want to exercise. They don’t want to eat healthy food. They don’t want to stop drinking; they don’t want to stop smoking; they don’t want to stop having dangerous sex. They want to take a pill. Well, good luck.”
    – Richard Veech, National Institute on Alcohol Abuse and Alcoholism

    If 90% of your lifestyle (eating, sleeping, exercise) habits are good, you can be rather lax on the remaining 10% and still come out quite good. The problem is that people want to be lax on 90%, and then do some small 10% thing that makes everything okay. In the words of Mr. Veech above, “Well, good luck.”

    • Drifter says:

      While it may seem reasonable on the surface to think that peoiple are lazy gluttons, I don’t think the best evidence supports this, since the dramatic declines in health have largely taken place since around 1980 and it’s unlikely people suddenly had a drop in character then. I think a better explanation is that most people actually do try to eat in a healthy way, but the official recommendations for what is healthy, as Dennis has extensively described, are largely a guide as to how to ruin health.

  3. Drifter says:

    I think, part of the belief in these methods is that they are elimination diets in disguise. If a diet causes someone to give up grains or nightshades or some other food that many people have issues with, then many people will benefit, even if it was not for the advertised reason.

  4. Robert says:

    Ive been doing sauna sessions lately, as it seems to improve my skin, and Ive read it can also raise growth hormone production.

    Its also commonly regarded as a cleansing activity by sweating out “toxins”, but do you know if theres any scientific basis to that?

    • Nick says:

      Guess it depends on what are meant as toxins. Certainly sweat does not consist solely of water and salt.

      Do we have any reason to think sweating in a sauna is different than sweating in the gym? (No trick question about a sauna in a gym!)

      Then again, it might explain that particular sauna stink.

    • P. D. Mangan says:

      Hi Robert – it seems doubtful to me that you would be sweating out any appreciable amount of toxins. Most of the important ones that persist in the body, such as dioxin or organic mercury, are found in fat tissue, since they’re more lipophilic, not hydrophilic. So, sweat shouldn’t contain appreciable amounts of toxins, because if they’re water soluble, kidneys should be clearing most of them from the body. For example, phthalates from plastic or personal care products are toxins, but body levels seem to drop dramatically within days of stopping their ingestion, so they must be water soluble. For most toxins of concern then, one requirement for low levels is to have low levels of body fat.

    • Lowell says:

      Google Lymphatic detox!!

  5. three says:

    Detox does work I do it twice a year.
    I would never use products endorsed by celebrities.
    You can do it on a cheap.
    Benefits: clear mind, overall great energy throughout the day and weight lose.

  6. Mike says:

    Thank you Mr. Mangan for this post. I never thought of cleanses in that way before. Definitely something to ponder.

  7. brbr says:

    Sorry for the Off topic, do you recommend your dietary tips for people with hypertriglyceridemia? any tips for controlling triglycerides?

    And last, what do you think of that swedish study about aspirins leading to heart problems (if people stop taking them)?

    • P. D. Mangan says:

      Carbohydrates elevate triglycerides, so the best way to lower them is to stop eating refined carbs and sugar. Fish oil can also lower triglycerides.

      The study on aspirin was in high-risk people and showed that they should not stop taking aspirin; aspirin didn’t cause their heart attacks. Link. Study concludes:

      In long-term users, discontinuation of low-dose aspirin in the absence of major surgery or bleeding was associated with a >30% increased risk of cardiovascular events. Adherence to low-dose aspirin treatment in the absence of major surgery or bleeding is likely an important treatment goal.

  8. Montgomery says:

    True, but there are (very minor) other things about “detox”:

    1. “The Russian Method”
    The human body has no effective mechanism to get rid of radiation poisons (breathed-in or eaten radioactive matter) and certain toxins (for example lead and cadmium).
    The elimination of those toxins can be sped up by a zero-calorie diet until the patient is only a few weeks from death due starvation, then he his re-fed until he is normal weight, and then the cycle is repeated as needed.
    The breakdown and rebuilding of bodily matter is the only effective way to reduce the internal radioactivity and toxin load of some classes of toxins. Obviously, it is restricted to extreme cases, because it is very unpleasurable and takes much time (up to a year or longer to go through some cycles).

    2. Extremely fast weight loss
    There are special cases where obese patients, for example due to other medical conditions, lose a lot (50kg or more) body fat in a short time.
    Fat-soluble toxins, but also normal vitamins are dissolved in that body fat; when the fat phase of that fat-water mix that constitutes a human body chemically, is reduced in volume that much and that fast, the concentration of fat-soluble vitamins like E and D, which the body has no elimination mechanisms for, in the water phase, that is, lymph water and blood, can rise to levels that are clearly toxic. There were a few rare cases where this was an issue, contributing to life-threatening effects.

    3. Effects from the Distribution Law for reducing toxin load
    The human body produces no known (at least to me) toxins it hasn’t evolved mechanisms to get rid off.
    This, however, is not true for some evolutionary novel external toxins;
    this includes, for example, some pesticides, and a lot of other modern chemicals that are not realistically to avoid in modern life.
    They are ubiquitously detectable in human blood, fat, and breast milk for feeding babies.
    Some of them are either not “recognized” by our evolved toxin-removal mechanisms, or their concentration is to low to activate specialized immune processes to do so. Therefore, those chemicals accumulate in human bodies (to the degree that modern human’s corpses are classified as dangerous chemical waste in some cases).
    These external, tissue-enriching chemicals can be expected to be harmful.
    How to get rid of them, or at least reduce their concentration?
    Drink more (reasonably pure, that is, with a low or zero load of such toxins) water.
    The Distribution Law makes sure, even if there are no detoxification mechanism for those chemicals in the human biochemistry, that the concentration of the vast majority of those chemicals is reduces substantially.
    A liter or two more of a reasonably clean drink more per day may make a big difference after months and years towards a lower load of those toxins.

  9. Ric Flair says:

    I believe that Rapamycin may cause autophagy.

  10. ConantheContrarian says:

    Many decades ago when I had severe acne well into my twenties, I initiated what booklet called a “cleanse”. “Cleanse” is what I call it today. It consisted of a three day fast of water, lemon juice and honey (to keep up energy). The next six days involved raw fruit and vegetables working up to meat. On the twelfth day it was how you were supposed to eat the rest of your life. No processed foods, no processed sugar. My cystic acne was gone within 30 days. It never came back. Knowing what I know now, I wonder if the whole ordeal cause my body to shift to ketogenic. Or something. What would you call it. But it worked. Does that make any sense?

    • P. D. Mangan says:

      Hi Conan – that makes sense. Sounds low calorie enough the first 6 days that you’d be in ketosis after a few days. You got rid of your cystic acne not by getting rid of toxins, but by getting rid of processed, insulinogenic foods.

    • Montgomery says:

      I am certain that a connection between food and skin clarity exists.

      When we “overeat”, that is, consume many extra calories, the body temperature rises, as increased metabolism and “burning” – wasting – of surplus calories for heat happens.
      You probably have felt it often – after a huge meal you get warm, hot even, while when you starve, you tend to feel cold – because body temperature is indeed lowered.

      The increased body temperature after overeating also reaches the skin – leading to better conditions for bacteria (and other things like amoeba) to grow and spread faster; this leads to bacterial overgrowth in the pores and then often leads to pimples and other effects of that kind.
      Warmer = better conditions for microorganisms to grow and multiply.

      Another effect is that after overeating sebaceous glands also exploit the sudden increased availability of energy and nutrients and increase their production of sebum – exactly the material the very same microorganisms that are now thermally induced to grow need to feed themselves.

      So, when overeating, you first get warmer; then you produce more skin grease, deep in the pores as well as on the skin’s surface; then a growth explosion of microorganisms is fueled by that; then that overgrowth leads to clogged pores and inflammation, and that is known as having bad skin.

      I am not certain, but suspect that effect is stronger when eating loads of carbs – I have noticed that my skin produces more sebum “per calorie eaten” from sweets and starches than from fats and proteins.
      Sometimes, when I squeeze certain areas of my nose in front of the mirror, “worms” of sebum emerge from my pores – and soon I experience more pimple growth.
      When I fast for some days or eat low-carb, those “worms” and the pimple growth fail to show up, my skin clears up.

      However, do not try to clean the microbes off your skin:
      You need them, direly. They form a biofilm on your skin, making sure that no other microorganisms – harmful bacteria, fungi etc. – can attack your skin. Actually, you live in symbiosis with those microorganisms, they protect your skin from colonization by harmful ones.
      Actually, our immune systems, by action of secreting chemicals through pores on the skin, allow certain
      microbes to exist, while attacking others.
      This is the reason humans smell differently – while fresh sweat is odorless, and the chemicals secreted are very similar, our immune systems are different – allowing different kinds of bacteria spectra to live on our skin, and those bacteria process our sweat in different ways chemically, leading to differences in smell.
      This is not just a curious thing, but actually a mechanism for our sexual selection:
      Women instinctively choose men who have a different immune system – and they analyse that by smelling the men, instinctively sampling a man’s smell, that is, information about his immune system makeup compared to hers (women often bury their noses in or near men’s armpits or chest area instinctively, enjoying the smell). Different, recombined immune systems in offspring make sure that pathogens and parasites have to deal with novel immune systems in every generation and, ideally, every human, decreasing the odds that mass-infections can happen (Microorganisms have an evolutionary adaption advantage here: Their inter-generational distance is hours, while ours is decades – they can adapt more quickly to us then we can adapt to them. Thefore, mixing up our immune systems is extra important for our species.)
      So, gentlemen, if a woman does not like you, she may not even be able to consciously give reasons why, for her reproductive instincts just tell her that your immune system is too closely matched with hers – she cannot “smell” you – not your fault, just a random effect.

  11. Joel says:

    My cleanse story:

    As this article was published, I was literally in the middle of my first-ever 5-day “cleanse.” While others were ready to pass out under the calorie restriction, I think my Keto/Paleo tolerance and general fitness level made the actual process pretty easy for me…or so I thought.

    In addition to daily doses of wheat grass, Udo’s oil and other vegan “delights,” I decided to add on a “colon cleanse” where they irrigate your colon for 45 minutes. (While I now know that I deserve “not the sharpest knife in the drawer” status, just know that I’m basically willing to try almost anything once or twice!)

    Result: Easy-peasy during the 5 days. The first few days afterwards…a few soft stools, but nothing crazy. Then 3 days after, diarrhea nearly 20x per day for 3 days & nights straight (I was so alarmed at the frequency, I kept track in Evernote so that I could show my doctor…who shook his head at me and informed me that there was nothing much they could do.)

    I’m still dealing with the diarrhea 10 days after this thing. Fortunately, I’m improving, but I’ve lost time in the gym (and 10 lbs), lost time at work, and lost 10 days of life enjoyment. It’s literally one of the dumbest things I’ve ever done in my life in the name of “health.”

  12. ConantheContrarian says:

    Dennis, what you say seems to make sense now…today. At the time I seemed to need something, like an extended fast, to get me over that hump and on the road to healing my skin problems…and it worked.

  13. pzo says:

    Whenever I hear someone talk about toxins or cleansing, I want to scream. And I know I’m dealing with a scientific illiterate.

    Juice fast? It has calories. Not a fast.

    When did smoothies become as necessary and routine as a bowel movement? “What do you put in your smoothie?” Who says I make them? Why would you want to pre-masticate your food? When they find a blender in some cave with early hominid bones, I’ll reconsider my stance.

Leave a Reply

Your email address will not be published. Required fields are marked *