IPAs Are Not Giving You Man Boobs

Lupulin - yellow gold

Lupulin – yellow gold

There’s no evidence that IPAs are giving you man boobs. A provocatively titled article claiming the exact opposite made the rounds on social media a few days ago, but there is no evidence to back up this claim. Here are the facts.

As with any plant, hops contain a wide variety of chemical compounds. One of these compounds — 8-prenylnaringenin (8-PN) — is a phytoestrogen. A phytoestrogen is a plant compound (hence the prefix “phyto”) that binds to estrogen receptors. Specifically, 8-PN has been shown to bind tightly to estrogen receptors in rat uterus. Hops also contain isoxanthohumol, which can be converted to 8-PN in the intestines.

8-PN is a potent phytoestrogen, one of the strongest detected to date, but it’s concentration in beer varies from undetectable to very low levels. (One study found 20 micrograms per liter as the highest concentration.) In the few papers that have been published on the topic, none show a direct link between beer consumption and male breast development (or female breast development). One study claimed that 8-PN levels in beer might reach a level that could result in human biological activity, but two others claimed this was unlikely.

Phytoestrogens in hops may have some effects on humans. It’s been suggested that female workers at hop plants may develop irregularities in their menstrual cycles, but this hasn’t been proven. It’s too early to tell, but the fact that 8-PN is a potent phytoestrogen may have consequences for people who are directly exposed to lots of hops. It could even have some effects on heavy consumers of very hoppy beers, but this is not likely and has yet to be shown.

An explicit link between IPAs (or other beers) and male breast development has never been documented. The same goes for hops from beer consumption and impotence, another claim made in the article. Heavy beer consumption may lead to males having more adipose around their chests because beer contains a fair amount of Calories. However, actual male breast development (gynecomastia) is different from simply being fat. Gynecomastia involves hormone-induced changes in breast tissue, usually leading to a layer of firm tissue developing behind the areola. More adipose tissue forming beneath the skin across the whole breast, as in weight gain, is not by itself gynecomastia. Likewise, high sustained levels of alcohol consumption can cause impotence. There’s no evidence that hops are the culprit.

That whole idea that IPAs give you man boobs rests on the idea that 8-PN is a phytoestrogen (which it is), but completely ignores that fact that the dosage required to cause problems in humans is unknown. And, there are more likely reasons for “man boobs” (fat) than a hop compound that can’t even be detected in many beers. In addition, lots of plants contain phytoestrogens and the amount we consume of these plants far outweighs the relatively tiny amounts of hop compounds in beer. (In a homebrewed IPA, you are talking about a few ounces of hops in 5 gallons (19 L) of liquid, and most of the plant material is left behind in the kettle.) 

The presence of 8-PN in hops is interesting, and deserving of further study, but the idea that drinking IPA gives you man boobs is completely unfounded. The current evidence is scarce, but levels of 8-PN in beer appear to be too low to cause a problem.

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  1. Big Dick Ben says

    Basically all you said was Nuh-uhh. And considering the hundreds of other sources of phytoestrogens then yes infact the super high levels in crappy hoppey beer will be enought to tip the scales and have a hormonal effect.

    • Chris Colby says

      Sorry, you’re just believing what you want in spite of the facts. The original story was not a peer-reviewed science paper. It was just someone saying, “Hops have phytoestrogens, therefore they cause man-boobs.” Unfortunately, the author didn’t have any actual evidence to support her claim.
      Hops indeed have phytoestrogens, but so do a lot of things. In order to cause gynecomastia, you would need a dosage of phytoestrogens high enough to cause gynecomastia. Nowhere did the author show that she understood this or give any evidence that the level in beer exceeded this level. And, a search of the actual medical literature shows that not a single case of man boobs brought about by IPA consumption has ever been reported.
      Peaches contain cyanide, yet peaches don’t ever kill anyone. Why? Dosage. The amount of cyanide is tiny. Likewise, there’s no evidence that hop phytoestrogens survive in beer at a concentration that has any health consequences.

      • Gregory Jones says

        I don’t have a source for this, but I read somewhere that phyto estrogens have a weaker effect in the human body than endogenous estrogens. So perhaps it’s simply the fact that people imbibe far too much alcohol and that is what in turn suppresses the testosterone.

    • Obviously, Ben has a small dick.

  2. Chris, do you have a peer reviewed article disproving the claim that hops reduces male sexual drive? This belief is actually several hundred years old. Supposedly it was used by women to discourage unwanted attention from men at a time when simply saying “no” was much less effective than it is today. This doesn’t make it true at all, many old folk remedies are not actually effective at all. I’m just curious as I haven’t seen peer reviewed data either way.

  3. Well… you talk about how little 8-PN there is in beer, but not the massive isoxanthohumol content… “intestinal conversion of IX upon moderate beer consumption can lead to 8-PN exposure values that might fall within the range of human biological activity.” http://www.ncbi.nlm.nih.gov/pubmed/16772450

    • Chris Colby says

      This is interesting.

    • If you happen to read the full abstract, you’ll notice that they only tested female participants. Beyond this, they found that individual differences in intestinal biota were likely the mediator for their results, which means only women (again, theor point had nothing to do with men) who were high-producers of the biota in question were affected by the proestrogen.

  4. Watch the short videos below on how phytoestrogens preferentially bind to either alpha or beta receptors in breast tissue. Activation of alpha receptors triggers a proliferative effect – potentially leading to breast augmentation or cancer, whereas activation of the beta receptors has an opposing effect.

    While soy phytoestrogens bind to the beta receptors, hop phytoestrogens bind mainly to the alpha receptors – the reason why they cause gynecomastia/man boobs.

    More recent research has revealed that even low concentrations of 8-PN in beer demonstrated a problematic estrogenic effect, since intestinal microbes were able to convert another phytoestrogen (isoxanthohumol – or IX) into 8-PN at a much higher rate than such conversion taking place in the liver, giving a more than 10-fold higher estrogenic effect than the 8-PN concentration present in beer would achieve directly.

  5. Gary Gray says

    Hmmmmmm a beer and wine journal poopooing the estrogenic aspect of hop based beer. Imagine that. Men need to avoid everything estrogenic and bad for testosterone synthesis. A little here and a little there in addition to the cortisol inducing stresses from life and diet have men in a testosterone deficiency which is increasing year after year. For men over 40 especially, who are seeking to enhance their T production and usability need to do all they can to avoid estrogenic foods and chemicals. But if you don’t care if your testicles shrink, drink up.

  6. Big Dick Ben; you a big IPA guy?

  7. Namey Name says

    “Men need to avoid everything estrogenic and bad for testosterone synthesis. ”


  8. Phytoestrogens might serve to increase testosterone due to innate feedback loops in the body. Phytoestrogens often attach to estrogen receptor sites in the body and effectively block more potent forms of estrogen. Men really need to worry about XENOestrogens, the kind found in BPA and plastics. Xenoestrogens will attach to the estrogen receptor site and are much more potent than human estrogen (estradiol). Most phytoestrogens are less potent than human estrogen. You can use dietary phytoestrogens to LOWER your levels of estrogen as a man. Craft Beer also contains robust levels of B vitamins and selenium, nutrients crucial to men’s health. Hops also potently inhibit the aromatase enzyme, which converts a male’s testosterone into estrogen. Anectdotally, living in San Diego, IPA capital of the world, i know many men who drink several IPA’s daily, and most are lean and strong with other interests like rock climbing and working out. The only people i see with “man boobs” tend to be the kind of men who eat processed crap foods laden with chemicals, lack fiber in their diets and are sedentary. many of them choose soda over beer. Men who drink soda over beer have man boobs.


    • David Peoples says

      I live in San Diego. I watched an ex ballast point brewer drop 30LB switching from craft to bud light. I work in the industry and watch the many, many people get fat off drinking craft beer that triples the carb count of their select beverage. The bloated, full, fat feeling from drinking heavy IPAs is real, regardless of if it comes from the hops, the calories, or the carb count. Yes, I have friends in the industry that were rail skinny in high school, gained a little muscle mass, and continue to drink heavy craft beer into their mid thirties with zero consequences due to their genetics and exercise regiment. This IS NOT the norm. Most men and women get super unhealthy getting buzzed on high calorie content a few times a week. It contributes to obesity and type 2 diabetes. I see it every day where I work. Brewery workers get fat. Reps get fat. There are always exceptions, but let’s not kid ourselves into being delusional.

      • David Peoples says

        Also, the bearded tattood mechanic shirt brewer thing seems pretty funny when you realize they are pumping plant estrogen into beer. People get so passionate about an art form that is the equivalent of being a pastry chef, Once you ad in the carb/ alcohol count. Once you see what craft beer does to the majority ( 70> percent of booze is consumed by 10 percent of drinkers) there is nothing masculine about IPAs at all.

      • Craft Beer is not the demon at work. Its the extreme excess of simple carbohydrates and sedentary life style. It comes down to DISCIPLINE!!!

  9. Nice Sources Guys says

    Why not, you know, cite the scientific sources for the damn article? All this bull from both sides just making unverifiable claims and not citing any peer-reviewed journals, it’s like you need a degree in biochemistry to do any fact checking.

  10. Most studies on this topic have only tested the effects of hops-proestrogens on women, and most of those found that only those with high levels of a certain intestinal bacteria were affected by hops. From what I’ve seen, there really isn’t much evidence to say hops cause moobs, and you don’t need to disprove what hasn’t been proven in the first place. There are plenty of articles on ncbi so feel free to browse using the terms “hops” and “phyloestrogen”.

  11. Bunch of hoagwash . Hops are not a good thing for men when they were introduced in German beer making in the 1500’s women took over beer making and they noticed the sedative effect of hops by just harvesting them. Furthermore barley has high prolactin content which again is wonderful for pregnant women. To the guy that mentioned San Diego etc. Wait few years and check these guys at 50 then you can talk. There is plenty of reeearch done on the subject and it is not because it is Phytoestrogen that it is good!!

  12. Ok, just read an article of Judith S. Gavaler, Ph.D. Don’t speculate, learn.


    Thank you.

  13. I find it interesting that all of these comments and the article are written by people who have zero medical degrees and are not nutritionists or scientists. You wouldn’t go to a an engineer for medical advice. Why would I go to any of these people for medical advice?

  14. This is all well and good, but when I stop drinking ipa’s for about a month or beer in general, my gyno gets significantly smaller. As soon as I start up again BAAM that little lump comes right back with a little pain to boot.

  15. https://pubs.niaaa.nih.gov/publications/arh22-3/220.pdf

    Studies using subjects who produced no estrogen themselves (i.e.,
    rats whose ovaries had been removed and postmenopausal women) demonstrated that phytoestrogens in alcoholic beverage congeners exerted estrogenlike effects in both animals and
    humans. Those effects were observed even at moderate drinking levels.

  16. Shut it down the goyim know

    • HAHAHAHAHA!!! Indeed! Anglin from the daily stormer was talking about avoiding beer because of this, and a search led me here. Then I see your (((comment))); classic!

  17. Rob Borghese says

    I found 2 studies published on NIH webpage indicating levels of phytoestrogens in hops. 1st: https://pubs.niaaa.nih.gov/publications/arh22-3/220.pdf
    The 2nd used not only rats but also post menopausal women as test subjects: https://pubs.niaaa.nih.gov/publications/arh22-3/220.pdf. This one showed that indeed alcohol increased estrogen markers. This one did however indicate that among beer, wine and bourbon, beer showed the lowest increases. Just my guess, but if you want to drink it comes down to a choice of what has less of an estrogen increasing effect. Based on this one study seems beer is as good a choice as any, maybe vodka is better, and since the phytoestrogens are highest in hops, perhaps IPAs are not the best choice for those of us wanting to avoid estrogen.

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  20. So, I know I’m way late to the game here, but I found this article because I was trying to figure out why Hazy IPA’s make me feel so ridiculously drunk so fast and if its related to my pituitary tumor. I’ve come to the conclusion that its because the polysaccharide beta glucan, which hasn’t been filtered out in hazy beers, increases prolactin. And prolactin also causes man boobs and ED. In case anyone thinks this might be thier issue, I’ve summarized what I learned here: https://www.reddit.com/r/Prolactinoma/comments/s8sjne/hazy_ipa_makes_me_crazy_now_i_know_why/
    I’m not a scientist or researcher, so apologies, I didn’t site my work, but I used all academic journals.

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