a glass in a pleasant setting with milk being poured into it

Dairy Products are Full of Estrogens (and other hormones)

Dairy products are very common in the Western diet. People grow up eating milk and cheese regularly, and this continues throughout adulthood. In fact, the average American adult consumed 627 pounds of dairy products in 2015, which includes milk, cheese, and butter 1. That’s a lot of dairy. Dairy products are widely considered to be quite healthy, especially milk. But is it?



Milk contains a cocktail of various hormones that can affect the body, and estrogen is only one of them. This is especially true in countries that have largely “industrialized” their farms, like the US. In such places, it’s common practice to regularly inject dairy cows with growth hormones and similar compounds to improve their milk production. It doesn’t help that the cows are kept pregnant as much as possible (over 300 days a year) for the purpose of maximizing milk production 2, since the longer a cow is pregnant, the more estrogen and other hormones are present in its milk. Aside from that, milk contains over 60 hormones, some of which are:

  •  progesterone (from pregnenolone)
  •  testosterone
  •  androstenedione
  •  5α-androstene-3β17β-dione
  •  5α-androstanedione
  •  5α-androstan-3β-ol-17-one
  •  insulin
  •  insulin like growth factors 1 and 2 (IGF-1 and IGF-2)
  •  dehydroepiandrosterone sulphate acyl ester
  •  5-Alpha P (DHT precursor)

And plenty more. Fortunately, most of these are broken down by liver enzymes and have no effect on the body. Unfortunately, not all them are, at least not completely. Milk consumption has been found to correlate strongly with estrogen-sensitive cancers like breast, ovarian, and uterine cancers in 40 countries 3 4. It also seems to increase the risk of prostate cancer 5.


A nice cow.
A Friesian dairy cow.

Additionally, consuming milk from pregnant cows has been found to adversely affect testosterone levels in men 6. It also seemed to affect women’s menstrual cycles. Milk is also likely to contribute to acne 7, especially for people who consumed large amounts of it during their developmental years 8.

Even milk from more organic farmers that don’t inject their cows with these things still contains a variety of hormones. It really isn’t surprising, considering that milk is produced for baby mammals to help them grow, that it may have undesirable effects on grown mammals.

For the sake of balance, it’s worth noting that milk does have a number of positive effects, thanks mainly to its high levels of many important nutrients, like calcium and protein. And there are conflicting results from many studies on its effects on the body. However, many of the studies that returned milk-positive results were funded by pro-dairy organizations, so it’s worthwhile to consider the conflict of interest involved.


Before considering any drastic changes to your diet, it’s best to first do a “trial run” to see if there are any significant improvements for you. Not everyone’s digestive systems work exactly the same, as genetics and preexisting dietary habits play a massive role. Consider removing all dairy products from your diet for two weeks or so, and see if you notice any improvement in any areas you feel they may have been affecting you negatively in. At the end, you might eat a large amount of dairy products for a day and then stop again for roughly a week, to see if anything flares back up. This is a quick and dirty method, but it should reveal for you any particularly acute effects it may have on your body. If you have the means, consider getting blood tests done at different points during that trial for more comprehensive results.

But if you’re not as worried about acne or your testosterone levels or testosterone/estrogen balance and are more concerned about the potential effects of cancer, then that trial probably won’t help you much. If you’re set on dropping dairy or at least minimizing your consumption of it and the damage it may do, there are many options.


Most of the estrogens and other hormones are contained in the milkfat, so switching to a lower-fat variant may help in that regard as they contain far less exogenous hormones 9.


You might try and locate a dairy farmer who does not use artificial means to keep their cows pregnant as much as possible, as hormone content of milk (especially estrogen) increases drastically as the pregnancy goes on. Also on this note, you could try and find a source of milk that does not come from pregnant cows at all.


To get the nutritional benefits of dairy products without the hormones, you could switch to eating kefir products. They are far healthier in many regards 10 while still containing many of the important nutrients found in milk, like calcium, magnesium, iron, and potassium, among others. It is also a great source of probiotics as are most fermented foods.


(Header image credit to Pezibear at Pixabay)


  1. https://www.ers.usda.gov/webdocs/DataFiles/Dairy_Data__17975//milksandu_1_.xlsx
  2. http://www.holsteinusa.com/holstein_breed/holstein101.html?tab=2#TabbedPanels1
  3. Ganmaa D, Sato A. “The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers.” Med Hypotheses. 2005;65(6):1028-37. Epub 2005 Aug 24.
  4. Hassan M, Aysa R “Hormones in Dairy Foods and Their Impact on Public Health – A Narrative Review Article” Iran J Public Health. 2015 Jun; 44(6): 742–758.
  5. http://www.pcrm.org/health/health-topics/milk-consumption-and-prostate-cancer
  6. Maruyama K, Oshima T, Ohyama K. “Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows. Pediatr Int. 2010 Feb;52(1):33-8. doi: 10.1111/j.1442-200X.2009.02890.x. Epub 2009 May 22.
  7. Adebemowo, C. et al “Milk consumption and acne in teenaged boys” Journal of the American Academy of Dermatology May 2008Volume 58, Issue 5, Pages 787–793
  8. Melnik B “Milk consumption: aggravating factor of acne and promoter of chronic diseases of Western societies.” J Dtsch Dermatol Ges. 2009 Apr;7(4):364-70. doi: 10.1111/j.1610-0387.2009.07019.x. Epub 2008 Feb 20.
  9. Henderson KM1, Camberis M, Simmons MH, Starrs WJ, Hardie AH. “Application of enzymeimmunoassay to measure oestrone sulphate concentrations in cow’s milk during pregnancy.” J Steroid Biochem Mol Biol. 1994 Aug;50(3-4):189-96.
  10. Ahmed Z1, Wang Y, Ahmad A, Khan ST, Nisa M, Ahmad H, Afreen A. “Kefir and health: a contemporary perspective.” Crit Rev Food Sci Nutr. 2013;53(5):422-34. doi: 10.1080/10408398.2010.540360.

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