Why do men need estrogen? At what level should they keep it?

Estrogen (oestrogen) is commonly referred to as E2. But to be more precise, it's made up of Estrone (E1), Estradiol (E2), and Estriol (E3); that said, don't be surprised when the nurse writes down "estradiol" before completing blood tests in the lab even though you asked to check out estrogen - since estradiol forms 95% of estrogen, examining E1 & E3 levels (excluding rare medical conditions) is unnecessary and costly.

The primary way estrogen is produced in the male body is through aromatization via aromatase. Aromatase is an enzyme that is essential to complete estrogen biosynthesis. It is responsible for converting androgens (i.a., testosterone/androstendione) into estrogens.

The male body is highly susceptible to estrogen activity, just as women are sensitive to testosterone - even slight changes, disproportionate to the ratio of testosterone to estrogen, may trigger a cascade of adverse effects. Nevertheless, the claim that "estrogen is a female hormone" is a half-witted oversimplification. Estrogen in males plays a critical role on multiple levels. It modulates libido, erectile functions and spermatogenesis. Estrogen also promotes GH (growth hormone) and IGF-1 (insulin-like growth factor) release and has neuroprotective properties. Finally, it plays an important role in regulating insulin activity.  Contradictory to most of the popular claims, you should under no circumstances attempt to "kill" your estrogen.

Both increased and decreased estrogen levels induces many adverse effects, e.g., lowered libido, oily skin, acne, lethargy, or even loss of appetite (read more about high and low estrogen symptoms: https://www.patreon.com/posts/how-to-recognise-24732637 ).

The perfect estrogen level

The perfect estrogen level is when you feel flawless - happy, have a great libido, long-lasting and firm erections, and masculine thoughts. Also, of course, when you don't observe any physical symptoms of high/low estrogen.

That said, remember the human organism isn't a computer. If you notice a slightly elevated estrogen after completing a blood test but experience no symptoms - feel great - you don't need to take any action. These are "just" numbers. Additionally, bear in mind that estrogen may also become slightly elevated along with high testosterone levels. It's expected and beneficial.

Bro-science aside. From a mathematically accurate point of view:

- If you are not on gear, you should keep your estrogen within regular labolatory reference range, not higher than 50pg/ml.

A stressful lifestyle, improper diet, low physical activity, and dysfunctions of, e.g., pituitary/thyroid gland, will usually lead to increased estrogen levels. If you start to experience adverse effects typical for estrogen, complete full blood tests, and once regular measures don't bring the desired results, visit an endocrinologist to find the root cause instead of masking it. Still, lifestyle changes (resistance training 3x per week, a well-composed diet and supplementation, and limiting exposure to phytoestrogens) are usually enough to regulate this hormone.

- If you're on gear, you should keep your estrogen slightly elevated, about 50-80pg/ml depending on your testosterone dose.

Read about aromatase inhibitors: Aromatase Inhibitors (AI) - The difference between AI and SERM's / Which AI to choose?