Quick Guide to Testosterone

By |2018-10-01T13:17:51+00:00July 27th, 2015|Categories: Testosterone|Tags: , , , |9 Comments

Testosterone is a critical hormone for sperm production, secondary male characteristics such as facial hair, large muscles, deep voice and a healthy admiration for Chuck Norris. But did you know that testosterone is actually made by the testicle or that it can be transformed into estrogen?

Testosterone is a hormone that is produced by your testicles and is especially concentrated where sperm cells are being produced. This mega dose of Testosterone is absolutely vital for sperm production. Most testosterone is used directly by the balls the help the development of sperm. Each baby sperm cell has special “nurse” cells (called Sertoli cells) which feed and attend to them. These nurse cells make sure each tiny sperm has a healthy diet of testosterone which helps it mature into a finely crafted baby making machine.  All the leftover testosterone not needed by developing sperm will get absorbed into the blood and circulate around the body where it binds to androgen receptors and produces male characteristics such as facial and body hair, lower voice, larger muscles and the like.

If blood testosterone levels are low, the pituitary gland in the brain releases three hormones, Follicle Stimulating Hormone (FSH), Lutenizing Hormone (LH) and Gonadotropin-Releasing Hormone (GnRH). These hormones send a signal to leydig cells within the testicle to start producing more testosterone. Testosterone slowly absorbs into the blood stream, raising the blood testosterone levels. Sensors on the pituitary gland sense how much testosterone is in the blood and if the level gets too high, it will reduce the amount of FSH, LH and GnRH. Similarly to how a thermostat that shuts off the heat when a room gets too hot, the brain regulates testosterone production by sensing how much is present and works to keep testosterone in a healthy range. Because testosterone production relies on a feedback cycle, T levels vary throughout the day. They are typically highest early in the morning when you first wake up and lowest in the early to mid-afternoon.

When athletes take “steroids” or juice, they are injecting various forms of testosterone directly into the bloodstream to be taken up by muscles. The problem is that when there are large amounts of testosterone in the blood, the brain thinks that the body is making too much and stops producing FSH, LH and GnRH which in turns stops production of testosterone in the testicles. Additionally, the testicle isn’t able to absorb testosterone from the blood stream, so while there is plenty of T for cells in the body, testicular tissues are deprived and begin to atrophy which is why steroids can cause sterility and shrink testicles.

Some men don’t have enough testosterone in the blood stream. This is what is meant by “low T“. As the body ages, there is less need to produce sperm and therefore less need for testosterone (from evolution’s standpoint) so many men undergo what is known as andropause, a hormonal shift in the body that mirrors the female menopause. This drop in testosterone naturally begins in the early 40s and continues through the 80s. Typically, testosterone levels drop by 1% per year and at some point they can get low enough that they cause symptoms such as  difficulty concentrating, drop in libido or difficulty achieving erection, fatigue and a number of other symptoms. Low T is most commonly treated with testosterone supplementation. As noted above, exogenous testosterone can disrupt natural production and damage the testicle. For men who are interested in future family building, there are other low T treatment options that can help maintain or improve fertility.

Estrogen in Men

You may be surprised to hear that men actually need small amounts of estrogen. A very tiny amount of testosterone is converted into a form of estrogen called estrodial via an enzyme known as aromatase. Estrodial’s primary role is to keep the new baby sperm from dying before having an opportunity to search out an egg. As a secondary effect, estrogen helps the male brain with verbal recall, multi-tasking and other functions that women normally are wired better to perform. It also helps maintain bone density. But, a little goes a long way. Just as too much testosterone can wreak havoc on a woman’s reproductive system by causing PCOS and other problems, too much estrogen can cause major problems for guys.

  1. Man boobs.
  2. Lower sperm count
  3. Decreases testosterone production
  4. Binds to androgen receptors which prevents them from binding with testosterone.

The enzyme aromatase, which turns testosterone into estrogen, occurs primarily in two locations in the body. First, the nurse cells who care for the baby sperm turn a portion of the testosterone that they are storing up into estrogen to prevent the baby sperm cells from dying prematurely. The other cells that churn out aromatase are fat cells. In other words, that spare tire around the waist can be an estrogen machine, creating a vicious cycle where testosterone is turned into estrogen, estrogen leads to weight gain, and weight gain leads to more estrogen.

Finding a healthy Testosterone / Estrogen Ratio

For optimal fertility, men want a healthy balance with a little estrogen and a lot of naturally produced testosterone. Here are a few pointers on how to get there:

  1. Maintain a healthy weight – Fat plays a primary role in the production of estrogen. Too much fat = too much estrogen, lower levels of testosterone and decreased sperm count.
  2. Easy on sweets and alcohol – Elevated blood sugar levels have shown to dramatically impact testosterone. While too much alcohol can increase estrogen and decrease FSH, LH and Testosterone.
  3. Workout – Working out is one of the best natural boosters for testosterone. It also burns fat which reduces estrogen and reduces stress which improves sperm production. There are a few keys to a sperm healthy workout. Check out our page with workout tips.

Sara SDx

Sara SDx

Editor of Don't Cook your Balls, Co-Founder of TrakFertility.com, Health Coach and Men's Health Advocate. Passionate about sperm, men's health and helping people build their families.


  1. Phil Castellano June 13, 2018 at 1:59 am

    This article on the site about the quick guide for testosterone is very helpful in explaining the shallow and its deeper meaning. I will recommend your site!

  2. Lloyd S Kim January 5, 2018 at 11:57 pm

    I don’t have ED anymore, but I wonder if living in a group home with all men will decrease my potency. When stimulated by images of women I can get an erection. I could not before seeing sexy photos of women.

  3. […] FSH is equally important in men. It plays a critical role in sperm production. There is a complicated hormonal feedback system between the brain and the balls that enables the testicles to accomplish their two primary jobs of producing sperm and testosterone. The process starts in the brain where the hypothalamus (the part of your brain that regulates things like hunger, sleep and body temperature) releases a hormone called Gonadotropin-releasing Hormone (GnRH). GnRH flows down to the pituitary gland and stimulates the release of LH and FSH. FSH gets into the blood stream which takes it to the testicle. Once in the testicle, FSH stimulates germ cells to divide, which is the first step in spermatogenesis. FSH is also absorbed by testicular sertoli cells enabling them to “nurse” baby sperm and help them to develop properly. Normal sperm production requires a minimum level of FSH, LH and Testosterone. […]

  4. […] for fertility in men as they are in women. A hormonal imbalance can affect sperm production. (See our biology lesson on hormones to learn more) Doctors will often order a blood test looking at a number of hormones to determine if they are a […]

  5. […] Topic: Testosterone […]

  6. […] production (spermatogenesis) starts in the brain where the hypothalamus constantly monitors blood testosterone levels as an indicator of testicular activity. As blood testosterone levels droop, the hypothalamus […]

  7. Low T: Hypogonadism | Don't Cook your Balls August 16, 2017 at 4:55 pm

    […] blood stream, where it is put to use building muscles and growing your 5 o’clock shadow. (see our bio lesson on hormones for more details). When there is enough testosterone around, sertoli cells secrete inhibin, which […]

  8. Do Receipts Affect Male Fertility? July 12, 2016 at 1:18 am

    […] Testosterone is responsible for your manly attributes-the low voice, hairy chest, big muscles. It’s also crucial for your reproductive system- especially your sperm quality. When your testosterone production is impacted, your body’s sperm production grinds to a halt. This may be why a recent study found that men with high traces of BPA in their urine were found to have 23% lower sperm concentration, 13% decline in morphology, 7.5% decrease in sperm motility and a 10% increase in sperm damage. […]

  9. […] A Quick Guide to Testosterone […]

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