Natural vs Man Made Synthetic Chemicals Toxicity
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The term ‘chemophobia’ has been used on social media amongst chemists with increasing regularity over the past year. Defined as ‘a fear of chemicals’, more specifically it refers to the growing tendency for the public to be suspicious and critical of the presence of any man-made (synthetic) chemicals in foods or products that they make use of. Sense About Science, a UK-based charitable trust whose mission is ‘to equip people to make sense of science and evidence’, is attempting to combat this with a new free guide, “Making Sense of Chemical Stories”, for which the graphics in this post were made.

In these graphics, I wanted to emphasise the point that whether a chemical is natural or man-made tells us nothing about its toxicity. There are many chemical compounds, found naturally in plants, that are poisonous to humans in small amounts; similarly, there are many man-made compounds which are perfectly harmless unless ingested at very high doses. Although the first of the two graphics sorts natural and man-made chemicals into toxic & non-toxic categories, overall I wanted to show that in reality, this is an impossibility – all chemicals, if taken in a high enough dose, are toxic – even water, which we consider essential to life. “The dose makes the poison” is a rule that applies to all compounds, natural or man-made.

A common argument is that we’ve become accustomed to, and built up tolerance to, naturally-occurring toxic compounds, whereas we haven’t had time to do so with more recent synthetic compounds. However, consider that the most toxic chemical compound known to man is the naturally-occurring botulinum, one teaspoon of which could kill a quarter of the world’s population. It’s been around for millennia – and yet we still haven’t developed resistance to it. Plants, too, are constantly evolving, and producing compounds we’ve never before been exposed to; however, not every new compound produced by a plant is deadly to us just because we’ve never been exposed to it before.

Natural & Man-Made Chemicals - Dose Makes The Poison
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The second of the graphics further emphasises the relationship between dose and toxicity. Many fruits and vegetables contain compounds that have been shown to be toxic to humans. However, they are present in such comparatively minute quantities, that they are nowhere near the dose required for them to cause harmful effects.

In recent years, some groups have been in uproar over the presence of chemicals that are known to be harmful or carcinogenic in everyday cosmetics or foods. As an example, some groups maligned the presence of formaldehyde in some vaccines – despite the fact that there’s more formaldehyde present in your average pear (for the record, the quantity in both is well below the dose needed to cause any harm). The key fact that is often overlooked about chemical testing is that it often involves concentrations of chemicals well above those that we are normally exposed to. Just because a chemical is harmful or carcinogenic at very high doses, does not necessarily mean it will have any ill effects at the doses we experience. Food regulation exists to prevent harmful levels of chemicals from being used in products we buy – if the levels were harmful, they simply wouldn’t be allowed on the shelves.

Another prime example of the spread of chemical misinformation is the self-styled ‘Food Babe’s’ poorly informed attack on the use of azodicarbonamide (unceremoniously dubbed ‘the Yoga Mat chemical’) in Subway’s bread, which is excellently debunked here. It’s a sad state of affairs when someone without a chemistry or food science degree, and with little more than a simple knowledge of the subject, is able to spread such misinformation about chemicals much more easily than those who wish to educate the public to better evaluate such stories for themselves.

That’s why I was eager to get involved and support Sense About Science’s initiative in creating these graphics for their new guide. Whilst, as ever with this kind of information, it’s unlikely to reach those in need of it most, it will hopefully encourage those who do read it to more neutrally evaluate claims about chemicals in their food and personal care products, and to discard their pre-conceived notions about natural and man-made chemicals.

You can view and download the Sense About Science guide on their site here, where you can also download the graphics in this post, or request hard copies. Additionally, I’ve been inspired by the guide to create a few other graphics, unaffiliated with Sense About Science, which I’ll be sharing over the next week or so. Please share their guide far and wide, and help stem the flow of chemical misinformation!

EDIT (07/06/2014): I’ve altered the graphic to remove MSG from from the synthetic section, and replace it with propylene glycol. MSG was included as it was commonly synthetically produced for use as a food additive. However, having been informed that it’s now more commonly produced from bacteria, it doesn’t fit in the man-made section, so I’ve altered the graphic to reflect this.



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The graphic in this article is licensed under a  Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. See the site’s content usage guidelines.

56 CommentsClose Comments


  • G L
    Posted May 19, 2014 at 5:53 pm 0Likes

    I enjoyed the graphics – while I enjoyed the discussion of toxicity, I also have followed the literature on endocrine disrupter and changing fish to female at hormone small doses from endocrine disruption seems to be a similar call to arms as Rachel Carson’s on wasteful pesticide use. Where Parselus’ linear toxicity matches behavior of many substances, other compounds develop a bimodal shape- hormone like potency at small doses, a trough at an intermediate dose, with large doses also exhibiting an effect.

  • Jonathan
    Posted May 23, 2014 at 9:06 am 0Likes

    The article assumes to much . For example : ” Food regulation exists to prevent harmful levels of chemicals from
    being used in products we buy – if the levels were harmful, they simply
    wouldn’t be allowed on the shelves. ”

    That statement alone , is enough to cast doubt on anything said here. Your talking about the same regulators, which allows for pesticide producing plants, plus chemicals soaked into the soil in which they’re raised. We can pick apart every processed food on the shelf, and see its effect on any number of people in a given group.

    And please illustrate that plants are evolving ? This is just ridiculous . I worry for our food supply with people like you at or anywhere near the helm .

    • Compound Interest
      Posted May 23, 2014 at 10:51 am 0Likes

      Having an effect, and having harmful effects, are two very different things. Every single thing that you eat has an effect on your body. These are often benign – for example, compounds in asparagus make your urine smell funny in some cases. However, regulatory bodies exist to ensure that the levels in our food are far below those that could be harmful. Obviously, research is ongoing, and yes, there will occasionally be instances where something new is discovered about a compound that causes laws on levels in food to be re-evaluated. But that’s the point – if something like that happens, it IS re-evaluated. A lot of people don’t appreciate just how stringent these regulations are.

      As for the pesticides argument, of course these are harmful if present in high enough levels, which is again, why regulations exist to prohibit their presence at any level approaching a harmful dose. In fact, research suggests that around 99% of the pesticides you ingest are natural compounds produced by plants, rather than synthetic pesticides (again, worth pointing out here that the levels of these, too, aren’t harmful).

      Of course the chemical industry isn’t perfect, and yes, there will occasionally be mis-steps or mistakes – as in any profession or regulatory body. However, to imply that these bodies are complicit with systematically poisoning the population is a simply incorrect view.

      Finally, everything is evolving. You are. Plants are. Weird and terrifying creatures dwelling in the furthest depths of the ocean are. It’s a long process, sure – but over the course millions of years of human evolution, plants too have evolved, and they’ll inevitably produce new compounds as they do so.

    • Paul Sanders
      Posted April 24, 2015 at 6:28 pm 0Likes

      lol, are you kidding. the FDA is filled with cronies from major corporations. it is a revolving door. they go to work for the FDA. allow the chemical to be used. then go back to the company and get a high paying salary with little to no responsibilities.

      • Tony Wood
        Posted April 18, 2016 at 3:18 pm 0Likes

        I think you need to notify your local politician, newspaper and any other regulatory authority you can get hold of with the names, dates, dollar amounts and any other information you have about your allegations.
        You need to do this as your duty to the wider population.
        By withholding this information you are in effect complicit with these dealings

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  • Éric Lévesque
    Posted June 4, 2014 at 2:08 pm 0Likes

    Monosodium Glutamate (MSG) is not a synthetic substance, it’s a natural amino acid (actually one the the 20 AAs that have a DNA codon for incorporation in proteins)… The fact that a natural compound can also be produced synthetically doesn’t make it less a natural compound, it’s the same molecule with the same properties.

    • Compound Interest
      Posted June 4, 2014 at 4:33 pm 0Likes

      Glutamic acid is, of course, a natural amino acid – MSG is its sodium salt, which is a (minor) difference. However, it does occur naturally in small amounts in a range of foods, including tomatoes and cheeses. It was included on the synthetic side here because most of the MSG we use as a food additive will be synthetically created.

      The point of this graphic was more to point out the meaninglessness of classifying compounds as natural or man-made – I think this proves the perfect case in point!

    • Else Murray Johnski
      Posted November 12, 2014 at 11:03 pm 0Likes

      this is why i prefer the terms naturally sourced and synthesized to avoid confusion on this matter. one might even argue that that synthesized material is a more reliable version of the chemical because it’s production is being more closely monitored and controlled than a naturally sourced material.

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  • Chris
    Posted July 7, 2014 at 2:57 pm 0Likes

    Just because there are toxic things in nature doesn’t make the man made chemicals safe. Take Aspartame as a prime example. While it’s not officially toxic at the levels we would ingest, it still causes cancer at these levels. Same with Caramel food coloring. MSG at normal levels can cause ADHD symptoms to he substantially worse. Artifical food coloring increases cancer risks, ADHD risks and Autism Symptoms but is not technically toxic.

    These are all being backed by more and more scientific evidence every day, which is why people are against man made chemicals in our food supply.

    Again, this is when the chemicals are ingested at normal levels or below normal in many cases.

    But even if we set that aside, most man made chemicals taste nasty or are very addictive, such as high fructose corn syrup which actually is both. Don’t believe me that it tastes nasty? Find an A&W restaurant buy a root beer (not diet) and get bottle of A&W soda. Have someone help you do a blind taste test.

    Most people will pick the restaurant version, a as it uses real sugar and the bottle uses corn syrup.

    • Compound Interest
      Posted July 7, 2014 at 3:58 pm 0Likes

      Hi Chris, thanks for contributing. The point of this graphic isn’t to state that man-made chemicals are all safe, merely that the term ‘natural’ doesn’t always equate to ‘better’.

      I have to take issue with some of your assertions on aspartame and MSG, however. For aspartame, over 200 studies over 40 years have concluded that it causes no harm to health at the levels we ingest – and certainly doesn’t cause cancer. Here’s a recent review as an example:

      As for MSG, again, studies have confirmed that MSG in normal diet concentrations has no effect on the overwhelming majority of people. Here’s a link that goes into a bit more detail on this: Can you link me to any peer-reviewed research that proves a link between MSG and ADHD?

      One factor you are correct on is that artificial food colourings can be carcinogenic compounds – however, for this reasons many of them have been banned from use. This is the great thing about food regulation – if a compound does happen to be harmful, it’ll be removed from foods.

      There are many man-made chemicals that are vital for the supply of food across the world. Without the addition of man-made preservatives to our food, we’d likely have severe difficulties keeping it fresh enough for long enough.

      As for the blind taste test, it is true that some artificial sweeteners can sometimes impart a slightly different taste. There’s nothing wrong with preferring sugar-sweetened drinks to these, but that isn’t the same as saying there’s anything wrong or harmful about them.

      Hope that’s cleared things up a little for you. It’s a long road, but we really need to get away from the automatic classification of ‘natural = good, man-made chemicals = bad.’

  • Chris
    Posted July 7, 2014 at 2:58 pm 0Likes

    Food regulators are also not doing their job or they wouldn’t allow very danger pesticides and pesticide producing plants on the market.

    • Compound Interest
      Posted July 7, 2014 at 4:02 pm 0Likes

      The majority of pesticides you ingest from your food are actually those compounds naturally generated by plants as pesticides. One study puts this figure at around 99%, I’ll try and hunt down the link for you. The concentration of pesticides you ingest from you food is far, far below the concentration which would be able to cause you any harm.

      • Carolyn Hunter Dickerson
        Posted November 30, 2016 at 11:55 pm 0Likes

        Then explain the high incidence of cancer today vs 50 years ago… Glyphosate alone is an endocrine disruptor… and it is prevalent and unavoidable in the standard american diet today.

        • Carolyn Hunter Dickerson
          Posted November 30, 2016 at 11:59 pm 0Likes

          Furthermore, these chemicals you say are in ‘safe amounts’ can build up in the tissues of the body. The more you eat, the more you’re apt to store. Which would bust your argument for safe levels. What happens over time? Who’s done the studies needed to disprove or prove this either way? Usually its the chemical or food industry… and you can’t tell me they aren’t biased.

      • Angela Cunningham
        Posted March 18, 2017 at 9:34 pm 0Likes

        do you realize they use glyphosate (round up), which is considered a pesticide, to dessicate crops? they spray weed killer on crops to dry them out and then we eat the glyphosate. glyphosate has been found in vaccines which are NOT safe and there is an enormous difference between ingesting something and injecting it. the ignorance of the author is unconscionable.

        • Compound Interest
          Posted March 19, 2017 at 12:21 am 0Likes

          I’m entertained by the fact you call me ignorant without citing *any* evidence for the claims you make in your comment.

    • Random Guy
      Posted January 11, 2016 at 3:21 am 0Likes

      Many plants produce pesticides. Coffee is a good example: I personally enjoy the effects of caffeine, in fact I rely on them! So many things can be used as a pesticide and are safe to ingest and normal levels. You presume that a pesticide is naturally dangerous to humans. Some are, both organic and synthetic. Also some break down very quickly, while others do not. Toxicity and application need to be taken into account too.

      What would you consider a dangerous pesticide producing plant?

    • Tony Wood
      Posted April 18, 2016 at 3:21 pm 0Likes

      This probably explains why so many of the population are dying of food poisoning.
      Oh, wait a minute, no they’re not.
      I guess that blasts your argument.

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  • sensorsweep
    Posted October 19, 2014 at 2:03 am 0Likes

    your link to the montreal gazette article above appears to be dead. i think this might be the same article?

    • Compound Interest
      Posted October 19, 2014 at 10:53 am 0Likes

      So it is, the original page I linked must have gone dead. Thanks for the heads up, I’ve now updated the post to include the right link!

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  • Lew
    Posted April 26, 2015 at 1:08 pm 0Likes

    A well written silly analogy spoken narrowly. Nature does it better. Mans constant quest to outdo nature could well be his eventual undoing.

    • nico101
      Posted January 27, 2016 at 6:43 pm 0Likes


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  • achbm
    Posted September 28, 2015 at 6:10 pm 0Likes

    We have a natural tolerance to chemicals in rough proportion to their frequency in nature. O2 is a very reactive gas but we live off it. Botulinum is very rare. In cases such as Botulinum we have (evolved) natural mechanisms (fear of snakes / disgust at bad smells) that aim to protect us. Our suspicion of man made chemicals is part of this emotional built in precautionary principle. Plus we have a history of “experts” telling us not to worry about all sorts of things that eventually turn out to be poisonous. Here’s a quote from a Lancet article from 1967 “On the other hand, there is a danger that workers’ representatives may overrate the dangers of dealing with asbestos under good conditions. It would be ludicrous to outlaw this valuable and often irreplaceable material in all circumstances.”

    • Compound Interest
      Posted September 30, 2015 at 7:24 am 0Likes

      I’m not sure there’s any research out there showing a link between natural abundance of a compound and its toxicity. If you’re aware of any, please point me in its direction.

      I do agree that the attitudes of chemical companies, particularly in the mid-20th century, hasn’t helped with people’s suspicions of chemicals. It’s the nature of the problem that a small handful of stories such as the one you quote tend to dominate people’s perceptions (though I would be interested in seeing the entire context of that quote before condemning it).

      I suppose what it does show is exactly what’s emphasised here; that testing on compounds where we suspect problems with toxicity may occur is constantly ongoing. Problems might not necessarily be identified immediately, but if they are, whether it’s a ‘man-made’ or ‘natural’ compound sadly still seems to sway people’s opinions on them.

      • achbm
        Posted September 30, 2015 at 2:23 pm 0Likes

        We put man made chemicals in the same box as “rare therefore potentially toxic”.

        Your botulinum example (and other on that list) is misleading as we are mighty afraid of anything that may contain botulinum (our fear of germs, disgust and high smell sensitivity at everything contaminated by bacteria etc). We don’t eat rotten meat because it is “natural”. In fact our suspicion at things potentially contaminated by bacteria is orders of magnitude higher than our suspicion at potentially toxic materials and it reflects exactly the potential higher lethal potential you show in your table.

        It is easy to belittle people’s suspicion (I’ve done it in the past and still do in regards to things like GMO’s or vaccines which fall in the same category).

        Take benzene for example It was initially shown toxic to bone marrow in late 1800’s. The first restrictions were put in place in 1946 at 100 ppm, which later came down to 50, 35, 25 and 1 ppm by 1987. Later it was shown to be unsafe even in 1 ppm concentrations. Think about the possibility of one member of your family getting cancer or some other condition like infertility due to exposure to benzene during this time (many people did). Whether we talk radiation, lead, asbestos, PCB’s, Benzene etc there were always decades between the moment the initial alarm signals were drawn to the moment some actions were taken to protect people. Decades during which we accumulated scientific evidence of harm while people got sick.

        The Lancet quote is from an otherwise logical article in favor of implementing some control measures for asbestos but is even more relevant because it shows how you can argue with good intentions, out of ignorance, in favor of something harmful. The full picture of how harmful asbestos is was not available in 1967 so of course it sounded reasonable not to freak out about it.

        Most man made chemicals are not toxic. State of CA compiled 23 lists and came up with about 2,200 potentially toxic man made chemicals out of the around 30,000 chemicals said to be in production somewhere in the world at any given time. That’s about 7%. The question is who has the burden of proof and how should we go about ensuring safety.

  • crissy jo
    Posted October 13, 2015 at 9:09 pm 0Likes

    i am recearching this topic for my chemistry class and i have found it verry intresting yet not verry helpfull

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  • Anita
    Posted January 30, 2016 at 3:59 am 0Likes

    Good info. Thank you. I really wish you’d use nonsexist language. Lots of alternatives to manmade include human made, synthetic, manufactured, artificial, handmade, handcrafted, constructed, processed, hand built, machine made, and of human origin. It’s easy to avoid offending 51% of the population.

    • dart
      Posted November 29, 2016 at 8:52 pm 0Likes

      wow chill out its just a phrase there is no harm done and no one that’s not a feminist cunt would ever think that

    • Chuck
      Posted January 15, 2017 at 4:50 am 0Likes

      Non sexist language what are you a f ing feminist I suppose you think doctors assign genders to baby’s when there born too don’t you. 51% of the population affended get real it’s people like you that affend 98% of the population! Go back to your safe space.

      • Anita
        Posted January 15, 2017 at 7:33 am 0Likes

        You sound sweet.

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  • Shea O'Neil
    Posted September 13, 2016 at 12:53 am 0Likes

    I became allergic to apples and pears (also grapes, peaches, plums, nuts) not long after major intestinal surgery from ulcerative colitis when I was 13, and I am still allergic today. I think some people are more sensitive to chemicals, poisons, etc, like those with damaged systems, those in recovery from illness or surgery, and babies, also those going through stressful bodily changes… puberty, pregnancy, highly stressed, and elderly. I feel like if everything has a little poison in it, it will add up in peoples systems too and could cause problems. Vaccines are going into babies.. Can’t they make them WITHOUT formeldahyde? Not all baby’s will get sick but if you take a new immune system and vaccinate, it is fighting the disease, it is fighting the formaldehyde, and maybe it lives in a home with cats and its fighting parasites, and maybe its mom didnt breastfeed and it isn’t getting the best nutrition and maybe its infant formula is from Walmart and expired, or is soy based and drastically genetically altered in an inflammatory way, and maybe the baby is going to a daycare where they only wash their hands after diaper changes when state inspectors are coming by, and there are a bunch of other sick babies there with no sanitary knowledge, then they get sick and go to a doctors office full of sick people. Certainly if you lab study science project separate these variables you will never know which if these separate seemingly harmless things got the baby sick with autism or asthma or immune disease, but it doesn’t sound fun to be that baby… I think we need to stop isolating variables and start trying to make things better.

    • Compound Interest
      Posted January 15, 2017 at 10:20 am 0Likes

      Just a quick point on the formaldehyde in vaccines you mention – there’s actually much more formaldehyde (naturally!) in many fruits that there is in vaccines. In fact, in a pear, there’s 600 TIMES more formaldehyde than could be found in vaccines. Of course, we don’t consider the amount present in fruits to be harmful, and the amount in vaccines is much, much lower.

      • Compound Interest
        Posted January 15, 2017 at 10:23 am 0Likes

        Also, not ALL vaccines contain formaldehyde. Those that do use it to kill or inactivate the bacteria or viruses being used to make the vaccine. This is a pretty vital step, or you’d be injecting full-strength pathogens into your bloodstream, which would essentially just give you the disease you were trying to prevent.

  • Shea O'Neil
    Posted September 13, 2016 at 12:59 am 0Likes

    OH and I think natural IS better because it has a balancing component to its “poison” often, like if it is a fruitfruit it might be high in vitamin c, it may have a seed with stuff that is difficult too digest so it can reproduce, it us a living vital force with life’s intelligence and billions of years of evolution and natural balance with its ecosystem… I do not know about your 20 year study in a lab…

  • Olivier Clarisse
    Posted November 13, 2016 at 12:34 pm 0Likes

    This article reads like propaganda:
    Not scientifically sound yet glistering with science terms.
    Their is no comparison possible between toxicity from injection versus from food digestion, their is additionally no valid model of the entire human digestion system available yet (from scientific studies), yet this aarticl juxtaposes statements mixing both and implying analogy!

    • Compound Interest
      Posted November 13, 2016 at 2:57 pm 0Likes

      I can assure you the article is scientifically sound, but if you want more detail on a particular point made please specify and I’d be happy to discuss.

      There are a range of ways in which compounds can be tested, which give us a very good idea of what happens to them when ingested or when added to the blood stream. While you are of course correct in stating that this still isn’t a 100% perfect model of the human body, the evidence from these tests is sound enough for us to be able to state confidently whether or not a compound is harmful to humans.

      In addition, studies can be and are done in humans; this is a necessity in the testing of medicines, which must pass human trials before they become available commercially. We can say confidently from these tests how well a drug is absorbed, how it is eliminated from the body, and what side effects it has.

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