Draft foal suckling.

Why in the heck use pregnant mare’s urine to relieve menopausal symptoms?

Jane Allin tells us the history of Premarin—the hormone replacement therapy drug for the treatment of menopausal symptoms—in timeline format. It is riveting reading and explains a lot.

Did you know that the first estrogen replacement product marketed in the US ― called Emmenin ― was made from the urine of pregnant women? The year was 1933. It was costly so the search continued looking for a cheaper alternative.


Menopause “Discovered”

1686: Fourteen “witches” are executed at Salem – thirteen of them are menopausal women.

1821: A French physician named de Gardanne coins the term “menopause” a century prior to the isolation of the hormone estrogen and publishes a book “De la ménopause, ou de l’âge critique des femmes”. Thus begins the search for the “cure”.

1872: Menopausal women are considered mentally deranged and are classified by Lawson Tait, an influential physician and surgeon of London, as having incurable dementia. In his opinion relief can be achieved by the use of “an occasional purgative” and “removal from home at frequent intervals” – the asylum!

1890: Merck suggests that menopausal symptoms can be treated with wine, cannabis, opium, and a product made out of powered ovaries, among others.

1899: An idea was emerging that sex hormones might be involved in menopause. A Parisian woman medicates herself with liquids derived from pigs’ ovaries with positive effects.

1929: Estrogen is isolated and identified by Edward Doisy at Washington University in St. Louis.

Premarin® –The “Cure”?

1930: Water soluble estrogens are discovered in pregnant mares’ urine by a German doctor, Bernhard Zondek. Other researchers reveal that decomposed and hydrolyzed pregnant mare’s urine contain estradiol.

1933: The first estrogen replacement product marketed in the US is developed – Emmenin, a product made from the urine of pregnant women. However, it is costly and the search continues for a cheap alternative.

1942: Wyeth’s predecessor Ayerst receives approval for the patent of Premarin, formulated from the urine of pregnant mares, and is approved by the FDA to market. Initial approval was based on a “replacement” therapy to “replace” a woman’s depleted estrogen levels.

1943: Wyeth merges with Ayerst, McKenna and Harrison, Ltd. Of Canada. With this came Premarin®, the world’s first conjugated estrogen medicine.

The Journal of Clinical Endocrinology publishes four independent studies of Premarin® use in five US cities praising its ease of use and effective relief of symptoms.

1965: The growth in use of estrogen replacement therapy (ERT) and the HRT concept is supported by a book written by Dr. Robert Wilson titled “Feminine Forever”. Unbeknownst to the general public, he is a consultant for Wyeth.

1972: The FDA publishes a Federal Register notice indicating that estrogen products including Premarin® are effective in treating menopausal symptoms. At the same time, the FDA provides for submission and approval of abbreviated new drug applications (ANDAs) for generic conjugated estrogens.

1973: The belief that estrogen was beneficial for the heart in women led to a trial in which men took Premarin® for the prevention of heart attacks and strokes. The trial was abruptly halted since the men receiving the treatments had increased incidences of heart attacks and blood clots. Instead of a wakeup call to the deleterious side effects, they simply attributed this to dosage issues and continued to praise the drug for its use in relieving menopausal symptoms in women.

1975: The New England Journal of Medicine publishes two articles that indicate a four to fourteen times increased risk of endometrial cancer with post-menopausal use of ERT.

1976: Ayerst sends a “Dear Doctor” letter to every physician in the country regarding the use of Premarin®. The FDA reprimands the letter maintaining it is misleading and minimizes the risk of the association of CEEs and uterine cancer. In turn, the FDA issues a drug bulletin underscoring the increased risk of uterine cancer with prolonged use of estrogen products.

The New England Journal of Medicine publishes the first report of a link between estrogen use and breast cancer.

1977: Ayerst Laboratories Premarin® is definitively linked to uterine cancer. Ayerst responds by adding a warning to the label but Hill and Knowlton, a public relations firm, simply attribute the cancer risk a “public relations” issue.

Premarin® becomes the fifth most frequently prescribed drug in the US with more than 30 million prescriptions written.

1980s: Several smaller companies offer a generic form of Premarin®.

1982: Cancer research journals report that CEE menopausal hormones are a major factor in the development of cancer indications.

1989: A Swedish study indicates that women on a regimen of estrogen or estrogen-progestin had a slightly increased risk of breast cancer when on estrogen yet when on the combined drug therapy their risk more than doubled (New England Journal of medicine).

1990s: Premarin® becomes the most frequently dispensed drug in the US.

1991: The Women’s Health Initiative (WHI) is launched. The clinical trials were designed to test the effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, and breast and colorectal cancer.

1995: Prempro® is the first estrogen-progestin HRT drug approved by the FDA

NAERIC (North American Equine Ranching Council) is established. It is an organization engaged in the collection of pregnant mares urine (PMU) that reportedly is dedicated to the progressive science-based horse management techniques to ensure the highest possible care standards are utilized in the equine ranching industry.

NAERIC is heavily funded by Wyeth and supports horse slaughter.

1997: Premarin® becomes Wyeth-Ayerst’s first brand to reach $1 billion in sales.

The FDA rejects an application for a generic version of the drug Premarin®. Both the FDA and Wyeth-Ayerst want the public to believe it was in their best interest to protect and safeguard the public. In reality it was motivated by scores of lobbyists, fraught with conflicts of interest, and epitomized by questionable surreptitious political manipulation.

Data from 51 epidemiological studies is published in The Lancet (a UK medical journal) further implicating an increased risk of breast cancer with post-menopausal estrogen use.

1998: The first major placebo controlled trial of HRT indicates no benefit to women who have had heart attacks, in fact, increasing their risk and advises them to withdraw.

READ MORE: 2001-2009 | 2010 | 2011 | 2012 | 2013

RELATED READING: Menopause, as Brought to You by Big Pharma, New York Times, By NATASHA SINGER and DUFF WILSON; Dec. 12, 2009


:: Premarin Horses Fact Sheet >>
:: Dear Physician Letter >>
:: Dear Pfizer Letter >>
:: Alternatives >>


We are so grateful to Jane for the incredible body of work she keeps producing on this issue, and the high calibre of her research and writing. She does it on a volunteer basis, motivated entirely by her love for horses.

5 thoughts on “Why in the heck use pregnant mare’s urine to relieve menopausal symptoms?”

  1. It should be well noted that NAERIC, the international organization of Mare Pee Collectors, is a Partner of the pro-slaughter coalition, the Horse ‘Welfare’ Alliance of Canada.

    I strongly urge horse lovers to read the list of partners in horse torture and slaughter. It likely includes your own provincial Horse Council and breed association.

    The Saskatchewan SPCA is there, as they are the only SPCA known to send rescued equines to slaughter instead of to adopters.

    There is a movement to demand Horse Councils and breed registries withdrew membership from HWAC and create a foundation to fund horse rescue. This has strongly been suggested by the Canadian Horse Defense Coalition. Their letters to this effect have been ignored by these agencies.

    The Horse ‘Welfare’ Alliance of Canada and its director Bill Des Barres routinely submit dis-information about horse slaughter to equine magazines and organizations, claiming slaughter is for the good of horses. The Partners listed here all profit from horse slaughter. You can see that in the centre of the page are listed Bouvry, slaughter plant owners, the CFIA (who DON’T inspect horse meat as they are mandated to do) and J. Woods, possibly the most prolific kill buyer in the country.

    Tell your breed registry and Horse Council you want their support of slaughter to end. Support Bill C-571 to end horse slaughter. More info at http://www.defendhorsescanada.org


  2. In 1982, I went through a sudden onset menopause. I started on Estradiol and did well for two years and then started an extended bleeding. I called over 50 local Gynecologists and every one of them wanted to perform a hysterectomy. I then went to the local bookstore. There were 19 books which were written for lay persons which advised that estrogen should be taken with progesterone. I learned that teaching hospitals were prescribing progesterone, made an appointment, was examined and taken off all estrogen for three weeks. Then I was put on Premarin and Provera understanding that it was simply estrogen and progesterone.

    I took these drugs for several years and then I began to suspect that all was not well. I was convinced that the drugs were affecting my liver. About that time I learned that I was taking several horse estrogens which are foreign to humans and that the Provera was progesterone-like not progesterone. I had to fight my Gyn to go back to the plant based estradiol and to move to Prometrium which is actually progesterone. I insisted on this as a result of extensive research which indicated that estradiol from plants was identical to human estrogen.

    There is no excuse in 2014 for any Gyn to put a woman or keep a woman on Premarin. It is dangerous for the woman much less the mares. This information must be circulated not only to women but to the Gynecologists. Many don’t have a clue. They do not read their journals, they honor the AMA, and they listen to the pharmaceutical reps who are selling a product. And most of all they put the women and the mares in dire danger.

    Liked by 1 person

  3. Our system of health care pushes dangerous, ineffective, or unnecessary drugs a lot. The more effective and less dangerous alternatives are often dismissed by ‘modern’ medicine as quackery. I think the real quacks are the ones prescribing these drugs that often have bad side effects. Adding cruelty to the way they’re made only adds to the reasons not to be doing it this way.


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