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.

If you enjoy Beer & Wine Journal, please consider supporting us by purchasing my book — “Home Brew Recipe Bible,” by Chris Colby (2016, Page Street Publishing). It is available from Amazon and Barnes & Noble. You can also find the nearest independent bookstore that sells it on Indiebound

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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.

  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

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