EPISODE · Sep 16, 2026 · 11 MIN
Does Soy cause manboobs?! Gynecomastia, Testosterone, Estrogen
from Nutrition Made Simple! · host Nutrition Made Simple!
Does soy cause gynecomastia aka manboobs? Do the phytoestrogens in soy lower testosterone or cause breasts on men? A look at reported cases of soy-related gynecomastia, testosterone and estrogen levels. Gynecomastia tied to foods other than soyDoes eating soy cause manboobs?Gynecomastia can be caused by hormones. can soy also cause gynecomastia aka breasts on men?Soy contains phytoestrogens. estrogen after the female hormone. chemical structure similar to estrogenthe manboobs story took off after a case of gynecomastia in a man drinking a lot of soy milkscientists dispute the cause of gynecomastia: “not necessarily due to the phytoestrogens” in soy. it probably was related to the soy drink, when he stopped it his gynecomastia resolved. lets say it was the phytoestrogens, how common is gynecomastia tied to soy consumption? only a couple cases tying gynecomastia to soy.8y old boy with gynecomastia eating a lot of processed soy foods. soy nuggets, soy crumbles, soy chili. most reputable sources: soy is healthyBillions of people eating soy. tied to processed soy products not soy itselfif soy caused gynecomastia Japanese men would have breasts?maybe western men cant handle the phytoestrogens? Asian men dont have breasts. randomized trial: soy with or without phytoestrogens, “no changes in breast tissue”maybe only adults can handle phytoestrogens? study: children drinking soy formula vs no soy. none of the boys developed gynecomastia; "soy protein formula in early life does not seem to produce estrogen-like hormonal effects”ok so maybe eating soy doesn’t give me manboobs, but maybe it lowers my testosterone?Rats fed phytoestrogens have lower testosterone. amount of phytoestrogen that lowered testosterone was v. high compared to normal human consumptiondoes soy and phytoestrogen lower testosterone in humans?study found “No significant effect of soy protein or isoflavone (that’s the phytoestrogens) on Testosterone level”“neither soy protein nor isoflavones affect reproductive hormone concentrations in men”They looked at soy foods like tofu and soy milk, soy grits, soy flour as well as phytoestrogen supplementsoverview:“neither isoflavone supplements nor soy itself affect testosterone levels. no evidence that isoflavone affects estrogen levels in men”“isoflavones do not exert feminizing effects on men”“men can feel confident that making soy a part of their diet will not compromise their virility or reproductive health”so soy contains phytoestrogens which look like estrogen but the physiological role is differentin clinical trials phytoestrogens have no effect on many biological processes known to be affected by estrogen. in some cases they even do the opposite of estrogenit’s funny that people associate soy with gynecomastia because other foods are linked to a lot more casesgynecomastia reported in young boys in Puerto rico, meat samples with higher estrogen levels suspected outbreak in Italy with gynecomastia in very young girls and boys, poultry and beef suspected to be the cause.manboobs are a very common issue in our society but they’re not coming from soy. soy is health-promoting. edamame, tempeh, tofu. Some soymilk is ok tooif you're allergic or can't have soy, that’s ok, soy is not essential, you can have a healthy diet without soywe focused on gynecomastia today but we have a lot more soy material in the works. more detail on soy-based imitation meatsConnect with me:Facebook: https://www.facebook.com/DrGilCarvalho/Twitter: https://twitter.com/NutritionMadeS3Animations: Even Topland @toplandmediaReferences:https://www.sciencedirect.com/science/article/pii/S1530891X20433038https://www.endocrinepractice.org/article/S1530-891X(20)43301-4/fulltexthttps://www.degruyter.com/document/doi/10.1515/jpem-2020-0397/htmlhttps://academic.oup.com/jcem/article/102/2/425/2972 Learn more about your ad choices. Visit megaphone.fm/adchoices
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Does Soy cause manboobs?! Gynecomastia, Testosterone, Estrogen
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