Dear Mark: Roundup Safety and Polyamory to Monogamy

Tractor spraying wheat field with sprayerFor today’s edition of Dear Mark, I’m covering two entirely different topics. The first is a fairly familiar topic to readers of this blog—whether a popular pesticide is actually dangerous or not. The reader asking the question thinks the data is clear, and Roundup is safe, but I’m not so sure. Second, I discuss the evolutionary underpinnings of our transition from polyamory to monogamy.

Let’s go:

Moreover, the research they reference has been reviewed to death by every regulatory agency on the planet, and none of them are convinced that glyphosate is dangerous, unless anyone here plans on drinking it.

Humans simply aren’t exposed to enough of the pesticide to experience any negative health effects. See the most recent EPA report on the subject:


Thanks for the pushback. I hear what you’re saying—folks on either side of the issue can really misrepresent the facts. There’s nothing I hate worse than unfounded fear-mongering. And even when the fears aren’t totally unfounded, the amount of worry and stress the mongering provokes can be worse than the thing you’re supposed to be fearing.

But with glyphosate, or more accurately Roundup, I just don’t agree with your assessment.

Pesticides aren’t just single chemicals. They’re actually collections of various chemicals called formulations, which contain the declared active principle (glyphosate) and some adjuvants. The adjuvants are supposed to be inert, but they’re not. Just like the supposedly inactive ingredients in toothpaste can have some physiologically significant effects, the adjuvants in pesticide formulations can alter the effect of the active principles.

If adjuvants were truly inert—if they did nothing—they wouldn’t be included. Everything costs money and everything adds up, especially when you manufacture at scale. So these “inert” adjuvants must be fulfilling an important role. Some are surfactants that allow the pesticide to penetrate the cellular walls of organisms. Others are thickeners or emulsifiers to improve the distribution and resiliency of the pesticide (nothing like a smooth, velvety Roundup reduction) in the face of rain, runoff, or extreme heat. Adjuvants increase dermal absorption, too. In other words, they make pesticides more effective, more resilient, and more damaging to pests. And according to a recent paper, many adjuvants also amplify the toxic effects of pesticides on human health.

Using isolated human cells, the researchers compared the effects of nine popular pesticide formulations with those of their isolated principle ingredients on mitochondrial activity and membrane degradation. In 8 out of 9 instances, the commercial formulations were on average hundreds of times more toxic than the principle alone. Roundup and glyphosate were both tested; the former was 125 times more toxic than the latter.

If the EPA used studies of the commercial formulations in their safety assessments, I’d be more likely to accept them. But they don’t. Most of the safety tests study the active principle, not the full pesticide formulation we’re actually encountering in our food and our environment.

In a 2000 review of the human and animal toxicology evidence that concluded Roundup posed no risk to human health, there were some glaring issues. Out of the dozens of studies they reviewed, the only one that actually used fully-formed commercial Roundup was on dermal absorption. All of the other ones tested glyphosate or one of the “inert” components of Roundup in isolation—never together. That’s not how this works. That’s not how biology works.

This isn’t a new problem, either. Some researchers have criticized allowing largely untested adjuvants into the food system via regulatory backdoors as far back as 2006.

It seems like common sense. If you’re going to talk about the toxicity of Roundup, you have to test the toxicity of Roundup. Right?

Here’s what happens when you do test the commercial formulation against the primary chemical:

Roundup kills rats more quickly and frequently than glyphosate alone.

Roundup kills piglets. Glyphosate does not.

Doesn’t fill me with confidence.

One aspect of ancestral health that I have not seen you address is Sexuality. I am surprised, as I think we can all agree that it is a very important part of our health and well being. I just finished reading the book by Dr Christohper Ryan, “Sex At Dawn” (he also has a TED talk), and I was blown away by the general premise of the book. The book argues, with compelling anthropological evidence, that humans are naturally promiscuous, and that prior to agriculture, human tribes/groups were very egalitarian. According to Dr Ryan, marriage and monogamy are as recent as our agricultural diets. I would love to hear your thoughts on this, and I think that the Primal Lifestyle is missing a cog in the wheel without addressing this important aspect of human health.


I’m a big fan of Christopher Ryan’s podcast, Tangentially Speaking (which I discuss in this post), but oddly enough haven’t read his book yet. I think I’ll do that before I comment on his argument.

However, I can discuss the shift away from polyamory toward monogamy. Why’d it happen?

As is the case with other novel environmental inputs like dairy, there is some degree of genetic adaptation to monogamy. If the society is set up for monogamy, “monogamy genes” will be selected for. That may be what happened in the largely monogamous agricultural societies of Europe and Asia, where land ownership and successful transfer of assets to one’s offspring were the foundation of reproductive success. The more wives you have, the more offspring you’ll have, the more diffuse the inheritance you bequeath. A farm, 300 cattle, and a dairy divided 12 ways isn’t nearly as helpful to your reproductive legacy as a farm, 300 cattle, and a dairy divided two ways.

A recent paper suggests that socially-imposed monogamy arose due to changing disease dynamics. In the smaller group sizes of paleolithic hunter-gatherers, the sexually-transmitted infection burden remained low enough to allow polygamy. As populations settled down and grew, the STI burden increased, making polygamy incredibly dangerous. This was compounded by the shift away from nomadism. If you’re on the move, you’re less likely to get bogged down with disease. Our ancestors in their smaller groups were largely nomadic and thus inoculated from the STI risks of a settled population.

Polyamory isn’t my thing. Whatever your thing is, though, it’s got to come down to basic human decency. Be true to who you are and what you want. Don’t hurt others. Be honest. Be safe.

What more can one say?

That’s it for today, folks. Thanks for reading. I’d love to get your feedback on today’s questions and answers.

I’m especially interested in your experiences or insights into the polyamory/monogamy matter. That could make for an interesting future post.

Be well.


About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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32 thoughts on “Dear Mark: Roundup Safety and Polyamory to Monogamy”

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  1. I don’t have much to say specifically about polyamory/monogamy other than agreeing with Mark’s ‘human decency” comment, but I DO think the entire primal/ancestral health community, in fact all those who understand health and wellness to involve the whole person, to have more discussion and openness around sexuality.

    I feel that in the US we see over-sexualized images and expectations, yet it’s not ok somehow to actually BE overtly interested in sexuality if you’re a heterosexual woman, for example, without bringing up the accusation or label of “slut” or worse. Possibly a throwback to the Puritans? SO we have a cultural dilemma, and the best way to work with it is to openly communicate and to question some of these assumptions and beliefs.

    Many even have trouble with plain, non-sexual nakedness in the everyday kind of way such as – forgot to close the door while changing – I must be an exhibitionist – I have traumatized my kid who just walked by! We don’t hear much about sex in health and wellness other than diseases to avoid, trauma, and vague references to things than increase or decrease libido, etc.

    Would love to hear more about the many positive ways people enhance, heal, support and optimize their sexual expression and general sexuality as an important part of vibrant health (and let’s lose the “weird” vibe and drop the shaming while we’re at it).

    1. My boys run around the neighborhood with bare chests… they way that I did (confession, still do)… the way that my father did… the way that his father did.

      “We make men without chests and expect of them virtue and enterprise. We laugh at honour and are shocked to find traitors in our midst” – C.S. Lewis. The real work in parenting seems to have taken a back seat to comfort.

      Doing my part by shaping my boys… affirming them with such self worth, self acceptance and strength that they come to believe in themselves. It is strength that makes all other values possible… without it, nothing survives in nature.

      I believe that we need to refocus our efforts in raising boys to become men… with virtues that their barbaric forefathers would be proud of. I believe that this is fundamental in then shaping our boys and men to become “good men…” with values that their barbaric foremothers would be proud of.

    2. Kay, I like everything you said. Agreed that in the US people make such a big deal about non sexual nakedness. The human body is beautiful. I just returned from Paleo f(x) and I’m happy to report there were several sessions devoted to sexuality. I was not able to attend those…the three days are so packed that you really need to pick and choose. But glad to see that it was at least part of the discussion.

    3. I am naked as much as possible every day. That means when my son and housemate aren’t home, or even lately when I’m working at my brother’s house while he’s away at work. In the past 3 weeks, I sheet-rocked a ceiling, paneled and painted 4 walls, then sanded and varnished a hardwood floor, all naked. Tough to run the woods naked but, weather permitting, I do it stripped down to a pair of “compression shorts” (and shoes) –until I can toughen up my feet and go barefoot or at least minimalist shoes. But, sharing the ethic Mark outlines above, I will be a devoted monogamous lover of one woman for life. Love is so much more than just sex. And whenever there are people around, I’m pretty well dressed, I spend money on nice clothes as part of the personal transformation that has made Primal living so central in my life.

  2. Regarding polyamory… While getting jiggy with multiple partners would be fun, the benefits I get from a long term relationship with my significant other far outweigh the jiggies.

    Even though it does decrease my testosterone a little!

  3. Even with an open mind and open heart, you just know that something is incredibly wrong with roundup. You just can’t control nature, and if you try to, bad things happen.

    While on the conversation, so many beautiful public spaces, universities and so on all use the stuff. It breaks my heart to see so many young people laying around on the lush green grass, buried in their textbooks, unknowingly bathing in poison. Not sure what needs to be done to stop this madness but I’m pretty sure that articles like this are helping. Thanks for another great post!

  4. Wow! The shift away from polygamy is bound to generate some interesting comments. I’d really like to hear your thoughts, Mark, after you read Ryan’s book.

  5. Next time I get busted with prostitutes I’m going to tell the officer that I was just trying to improve my health by boosting my oxytocin levels!!!

  6. Roundup is desiogned to kill things, mostly weeds but it also kills rats and piglets, piglets might be a touch delicate but rats are pretty tough and resilient; if it will kill them there is almost certainly a level of exposure that will kill humans. We used to think DDT was safe, don’t see much of that any more. Recent history is littered with products sold by big chemical and pharma companies that were supposed to be safe but turned out not to be. Big companies pay huge amounts to lobbyists and also fund sympathetic research to ensutre their products get to market. If hitherto trusted VW can cheat on emissions and design software to help it do so, why would a chemical company, that faces the same shareholder pressures to produce profits be immune from behavious that ensures its product tests favourably. As Mark says the product used is Roundup and it contains adjuvants so test roundup not once chemical in isolation.

  7. RoundUp/Glyphosate is supposed to be harmless to humans because it affects the shikimic pathway in plants which humans don’t have. Genetically modified plants get around the influence on the shikimic pathway which is why RoundUp is used: It kills the weeds but not the GMOs. Most of the testing on Round Up et ali was done before we had any significant knowledge about our gut bacteria and its role in health. Bacteria have a shikimic pathway. So while RoundUp might not affect in human cells in vitro it might have a direct impact on our biome kn situ (or any creature’s biome for that matter.) More so, if Roundup et ail interferes with our gut bacteria it could manifest itself in many different ways as we all have a different compliment of bacteria in our gut. This could make its impact difficult to access because it could be the same cause resulting in many different illnesses including sub-optimal or chronic health. That could also be why it might affect some people very little and some significantly. Until agencies do research on the effects of Round Up et ali on gut bacteria and in situ I think it is a good idea to avoid agricultural products raised with RoundUp or products that can have residual RoundUp on it.

  8. Any claim today that any pesticide is “safe” is false, per se, due to the gut flora issue.

    In the unlikely event that the fully formulated product (seldom) was tested on the human microbiome (nearly unheard of), we haven’t enough knowledge of gut flora to have any confidence in the results, and the testing would have been done in the context of standard diets, which are (to be charitable) a “high noise” environment for seeking any microbiome effects.

    The spectrum of microbes in the human gut is already known to include bacteria, eukaryotic parasites, fungi (e.g. yeasts), protozoans and viruses. We have so far only a primitive idea of what a healthy bacterial profile looks like, and hardly even guesses on the remainder.

    And then we have the unknown unknowns:
    How can we test for extinctions of things not even named yet?

    The context also means that retrospective epidemiology is almost impossible to decipher, due diets and personal environments awash in toxic food-like substances and myriad other actual toxins. What did what?

    So that leaves us running our little N=1s. On the pesticide issue, my bias is organic. Those who disagree can bet their lives, and their children’s lives, on other advice.

  9. Very much welcome open and open-minded discussion around primal lifestyle and sexuality. Also love this line: “Be true to who you are and what you want. Don’t hurt others. Be honest. Be safe.”

    When it comes to polyamory vs. monogamy, another important consideration is whether monogamy is “forever”…or just one relationship after another.

  10. Polyamory sounds like fun unless one is concerned about becoming pregnant. Complications due to child birth, historically, have often resulted in death for the woman and infants. Perhaps monogamy arose as a way to create a stronger, more resilient tribe. It is difficult to imagine the social impact of birth control, but this time-line provides interesting data:

    1. Looks like I can’t post a link. It was from and basically started with the year 3000 BC with the first condoms being used, made of fish bladders, animal intestines, and linen sheaths. If you google “history of birth control” you might find it. Then support Planned Parenthood.

  11. I have a close friend from West Africa who is just two generations out from polygamy in her family (i.e., her grandparents were polygamous). In her country, becoming Christian is synonymous with adopting monogamy, and her parents are Christian.

    Her grandparents gave her father all kinds of grief about his monogamy, and pressured him to take a second wife whenever there was any tension or trouble in his marriage – because they wanted more grandchildren, and also because they thought as a monogamous man he was “whipped” and under his wife’s thumb, and he should assert his independence by taking another.

    What’s fascinating is how poisonous polygamy was in her family, by my friend’s account. According to her, half the family (the one wife’s offspring) still believes the other wife poisoned the grandfather to death, because of disputes over the inheritance and the relative status of each wife’s offspring.

    Makes sense to me. Claims that this is “natural” – well, I wonder what exactly they mean by “natural.”

  12. There’s more than one Roundup. It comes in different formulations, with different additives in addition to glyphosate. I use the “plain” concentrate. I wear a Tyvek suit when I use Roundup and gloves, and I take a shower afterwards and was the Tyvek suit separately.

  13. I don’t buy this argument about the division of property being the motive for monogamy. Many monogamous couples have had 12 or more offspring. And many societies organize themselves so that only the oldest son inherits the property.

    Also, there are agricultural societies like the Na of China who are polyamorous. Marriage does not exist among the Na; the families are matrilineal; people live with their siblings, their mother, and her siblings; men visit women at night for sex. Relationships are fluid and constantly changing, but they can also last for decades. The farms are passed down to the entire next generation of brothers and sisters, who run the farms cooperatively. If a family lacks female members, it adopts a woman into the family. There are STDs and sometimes these STDs cause sterility, which limits population growth. See the wonderful book, A Society Without Husbands or Fathers.

    I think that before there was enforced monogamy, humans probably had better immunity to STDs. But after millenia of forced monogamy, we lost that immunity and became very susceptible to common viruses such as herpes.

    I believe that monogamy evolved from polygamy (that is, one man having multiple wives) because other men resented the shortage of wives. Marriage itself evolved as patriarchy evolved, and although it could be polygamous, it was virtually never polyandrous.

    There are some societies in Asia where polyandry–a woman having two husbands, usually brothers–is sometimes practiced, as in Ladakh and Nepal.

  14. I’m so excited to hear what Mark has to say about Sex at Dawn. I read it early in my own Primal journey, at a pivotal moment in my own relationships and life. I agree with the premise that agriculture changed the way we relate to each other in somewhat damaging ways. I like to think that our ancestors used sex somewhat like the dolphins — as a way to play and strengthen bonds. I practice polyamory — it is very hard work but ultimately so much more fulfilling than expecting one other person to be your everything. As Mark said, being honest and safe are the keywords to being in more than one intimate relationship.

    1. I know this is an old comment but I completely agree with what you said. I am also polyamorous and while it is definitely a lot of work, it’s very rewarding. All that work has also given me a massive boost in both my communication and introspection skills. Polyamory requires intense honesty to self and others– little white lies just fester in the poly world.

      Also, to the people here talking about how it sounds like fun but a committed relationship is more rewarding, poly relationships can be just as committed and just as emotionally involved. It’s just not at the cost of limiting yourself to having that with only one person at a time 🙂

  15. “Studies” showed that DDT was perfectly safe, you could bath in the stuff, until 20 years later – they went, oh, dam, it causes all manor of ills such as cancer and birth defects – sorry guys.

    1. Don’t tell that to Kenneth Mellanby. He turned out just fine after eating it for forty years.

  16. Let’s face it. All you have to do is read the news or even just know a few people to realize that polyamory is in existence (dare I say thriving?) in American and Christian communities. The only difference is that it is not practiced openly – it is usually a secret from the official partner and the community (until someone gets busted.) I am not in any way condoning it; just saying.

  17. I loved this. Now every time I look with longing at a piece of bread, warm and fragrant, I will now see the spraying of the wheat and, snap, don’t want that thanks!
    I will simply have the butter, that’s even better.

  18. Excuse me, but let’s get something straight here – Roundup and glyphosate are not pesticides – they are herbicides. This gigantic error alone brings all of the assertions and claims in this article into question. Yikes!

    1. I’m sure Mark knows the difference. In popular use “pesticide” seems to include herbicides under it’s usage umbrella, but not the other way around. Semantically, you are 100% correct of course

    2. Herbicides are a type of pesticide, as are fungicides and insecticides. Those are the three most commonly used types of pesticides in agriculture.

  19. Benefits of polygamy? lol Have fun with that antibiotic resistant strain of gonorrhea!

  20. I am very glad to see this non-hyped discussion of glyphosate. There are entirely too many exclamation points involved in material on both sides of this question! I personally have no trust that any large company is going to put safety above profit, so I trust none of the information that comes from Monsanto’s “testing”, since it is biased. The EPA has been underfunded for years now, which has made them less capable and more vulnerable to political and monetary pressures, and I do not trust them either.
    Thank you for clearly explaining the adjuvants – testing only the central ingredient is very misleading, and many trials do just that. In the meantime, I will continue trying to grow as many of my vegetables as possible in my own, unpoisoned back yard! And when I must buy, I will try to buy organic whenever possible.