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Estrogen is well known as the dominant 'female hormone.' Like testosterone, 'the male sex hormone,' both are produced from cholesterol. Estrogen is one of two main sex hormones that women produce, the other one being progesterone. Estrogen is responsible for female physical characteristics and is involved in reproduction. In the same way, testosterone kick starts a boy to become a man; estrogen is also responsible for the changes a girl goes through during puberty.

What is not so widely regarded is that estrogen is essential for both men's and women's health. Estrogen protects your heart, your brain, and your skin. It also facilitates many of the benefits of testosterone on the body.

There are three primary forms of estrogen, all of which have different effects on the body. The two main active estrogens in 'nonpregnant humans' are estrone (E1) and estradiol (E2). The third bioactive estrogen, estriol (E3), is only active when a woman is pregnant, so it has no real effect on anyone else. In terms of HRT, the most crucial estrogen hormone is estradiol for both men and women.

  1. Estrone (E1): Created mainly from body fat, but also a little bit in the ovaries and placenta, this estrogen is relatively 'weak' and estrone can be converted into estradiol, and serves mainly as a precursor or metabolic intermediate of estradiol. 
  2. Estradiol (E2): E2 is produced primarily in the ovaries and testes from testosterone. Small amounts come from the adrenal glands and some other tissues. Most importantly, estradiol is produced via aromatase conversion from visceral fat (note this is one of the essential hormones during TRT or HRT in both men and women.
  3. Estriol (E3): This is estrogen is only associated with pregnancy. It is primarily made in the placenta from about five weeks after conception. 

Where Does Estrogen Come From?

Men produce estradiol in two ways. The first is via testosterone, which is good. The other is through fat, which is bad. Estradiol from fat can drop your testosterone levels. That is why many obese men suffer from low T. In this case, it is not the estradiol causing the problems; it is the fat.

What Does Estrogen Do?


  • Puberty and sexual development: Estrogen is responsible for the development of the female reproductive system, the vagina, the uterus, pubic hair, underarm hair, and the development of breasts

  • Menstrual cycle:  Estrogen is the hormone that controls the monthly cycle in women, Every month, estrogen builds in the uterus, preparing for the possibility of pregnancy. If insemination does not occur, estrogen facilitates the shedding of the uterus' lining, also known as a period.

  • Your bones: Bone development and bone mass are down to estrogen. When a woman enters menopause, her estrogen production decreases along with bone strength and density. This bone weakening is why you see an increased risk of fracture and broken bones in older women. Also, as a man gets older, his testosterone and estrogen levels decrease, having a similar weakening impact on the bones.

  • Your heart:  As men and women age, estrogen levels fall, increasing the risk of heart problems. Estrogen actively protects the heart against cardiovascular disease by keeping blood vessels healthy and flexible, controlling cholesterol, and reducing inflammation, a major cause of heart disease. 

  • Your mood: Estrogen affects almost the entire body, including areas of the brain which control your mood. It increases serotonin and endorphin levels, your brains happy chemicals.' As estrogen levels, these 'happy chemicals' also reduce either after childbirth, menopause, or the male 'andropause' leaving many feeling depressed and lacking in a zest for life.  

  • Your Skin: Estrogen has a profound influence on skin. As men and women age, estrogen levels decrease, leaving your skin more susceptible to environmental and natural aging. Estrogen protects your skin in many ways by increasing collagen, skin thickness, and helping your skin retain moisture.

  • Alzheimer's disease: Estrogen protects the brain from specific proteins that build up in the brain. Amyloid-β and tau proteins become concentrated in certain parts of the brain, causing damage or even killing some cells. Maintaining optimum estrogen levels in the body helps protect the brain from this damaging protein. Studies brandished around claiming that estrogen replacement for women over a certain age (who are well past menopause) causes dementia and memory loss. There lies the problem; it is the lack of estrogen long term after menopause that is the issue—those who start hormone therapy during perimenopause or just after menopause usually exhibit no cognitive deficit. Estrogen protects the brain for both women and men.

  • Your Sleep: Estrogen also promotes healthy sleep. It contributes to you having better quality sleep with less waking up during the night ,it may also help you fall asleep faster. Estrogen helps the body use serotonin and other neurochemicals that assist sleep.


    Estrogen Benefits: Protects against heart disease, stroke, osteoporosis, Alzheimer’s disease and memory disorders, vaginal atrophy, urinary incontinence, UTI’s, macular degeneration, colon cancer, cataracts. Prevents menopausal hot flashes, temperature dysregulation, and mood disorders.

Estrogen In Men

There is much debate about estrogen and men's health. The standard (incorrect) assumption is that estrogen will turn you into 'less of a man' and cause you to develop man boobs (gynecomastia). The truth is that gynecomastia is triggered by a decrease in the amount of testosterone compared with estrogen. Conditions that block the effects of testosterone, reduce testosterone, or increase estrogen (from fat) can cause this condition. So it is not usually the estrogen directly causing the 'man boobs'; it is the lack of testosterone. 

If you give testosterone to a man, his estrogen levels will increase; this is not a problem if these levels are balanced. Your hormone levels would have been highest in your twenties, with naturally high testosterone and estrogen, the perfect balance for your body. When you give testosterone, estrogen levels increase; if it wasn't a problem back then, why is it now? Historically bodybuilders and most doctors advocate using estrogen blockers to reduce estrogen levels to increase the effects of testosterone. Using blockers is a mistake, what most don't understand is that this does not help!

Do Not Block Estrogen!

Estrogen is essential for testosterone to become active with its many benefits. By blocking estrogen, you reduce the beneficial 'side effects' this hormone has, improved cardio health, stronger bones, better mood, and improved erectile function. Block your estrogen and shortly, you will discover what E.D. is like.

The conversion of testosterone into estrogen facilitates the positive effects of testosterone on the body. Aromatization also masculinizes neural pathways and sex-specific behaviors, so by blocking aromatization, you are blocking this critical pathway and its effects.

In Summary

  • Estrogen is essential for long term health
  • Through aromatization the positive benefits of testosterone are facilitated. However, aromatization from visceral fat is bad.
  • By blocking estrogen (aromatization) you have an increased risk of heart disease, osteoporosis, memory loss, Alzheimer's disease and a reduction in the positive effects of testosterone replacement therapy.


(1) Polo-Kantola P, Erkkola R, Helenius H, Irjala K, Polo O. When does estrogen replacement therapy improve sleep quality? Am J Obstet Gynecol. 1998 May;178(5):1002-9. doi: 10.1016/s0002-9378(98)70539-3. PMID: 9609575.

Disclaimer: Information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please feel free to contact us or consult your doctor.