The Facts About Testosterone

Testosterone is the primary sex hormone in people who are assigned male at birth. It is produced in the gonads—the testicles—though small amounts are produced by the adrenal glands.

In men, the hormone is responsible for lower voices, facial and pubic hair, and larger muscles. It contributes to the further development of the penis and testicles during puberty. Testosterone is also largely responsible for spermatogenesis, which is another name for the creation of sperm, and is vital to a man's ability to reproduce. Testosterone levels that are too high or too low can affect a person's libido, energy levels, muscle mass, bone density, mood and perhaps even cognition.

While testosterone production naturally declines in men by about 1 percent per year after age 30, testosterone replacement therapy (TRT) can help alleviate the effects of this decline.

Testosterone is a natural, critical component of having a healthy body, particularly for people assigned male at birth and for those transitioning to male. For people assigned male at birth, keeping optimal testosterone levels can ensure they face less dramatic and less negative bodily changes as they age. And for those who are transitioning, it can help with gender dysphoria and fat distribution.

Maintaining healthy testosterone levels has numerous physical health benefits:

• Fat is reduced and muscle mass is increased.
• Bone density is kept optimal.
• The risk of cardiovascular issues is reduced.
• Red blood cell production is optimized.
• Sex drive is improved.
• Erectile function is healthier.

The more researchers study testosterone's effects on the body, the more the medical community learns about how critical it is for also maintaining a healthy mental state. Testosterone was once thought of as simply a hormone that functions in a mechanical way to give certain bodies their "maleness." Studies today show it is vital to other aspects of health, including:

• Warding off depression
• Improving cognition
• Enhancing mood and lessening irritability
• Minimizing issues with anxiety
• Holding stress at bay
• Improving happiness or general well-being

Even though it is the primary sex hormone in men, naturally produced testosterone is not exclusive to people assigned male at birth, or even for those who transition to male later in life. Women naturally produce low levels of testosterone, just as men naturally produce low levels of estrogen, long considered the "female hormone."

Testosterone is an androgen, another name for a hormone that promotes male sexual characteristics. When women's bodies produce testosterone, they turn it into a form of estrogen, the primary sex hormone in females. Men's bodies also produce estrogen. It is a key component in the production of sperm.

Healthy general nutrition is essential to maintaining optimal testosterone levels naturally. Generally speaking, the more you stick to natural, whole foods that are less processed and contain fewer additives, the better your body is going to function.

It's important to gain an understanding of how inflammation functions in the body. To minimize inflammation, avoid excessive amounts of inflammatory foods such as sugar, high-fructose corn syrup, refined carbohydrates like white bread, trans fats and alcohol.

Here are a few specific foods and supplements that studies suggest may help keep testosterone at ideal levels:

• Egg yolks
• Fatty fish
• Shellfish
• Leafy greens
• Legumes and beans
• Beef
• Almond milk
• Pomegranate juice
• Vitamin D supplements

Overall fitness in general, and exercise in particular, are known to contribute to optimal testosterone levels. Indeed, obesity has long been linked to lower testosterone levels. Simply dropping a few pounds may help you produce more testosterone.

Both endurance training (cardio) and resistance training (weights) boost testosterone levels. Weight training specifically appears to have a more profound, longer-lasting impact on testosterone production. Resistance training for as little as three days per week for four weeks was shown to increase testosterone levels right after the workout and over longer periods of time, according to one study.

Another type of exercise, high-intensity interval training (HIIT), appeared to boost testosterone levels more than simply running at a moderate pace for 45 minutes. One example of HIIT is to run for 90 seconds at high speed, followed by 90 seconds of rest. The exercise is then repeated.

One type of exercise to avoid to maintain the best testosterone levels possible is endurance exercise, such as continually cycling or running for hours at a time. Endurance training may actually reduce testosterone in the body.

Testosterone levels have a direct and dramatic influence on a man's sperm production and fertility. In recent decades, overall testosterone levels have dropped among American men. The drop is likely caused by a number of factors, including poor diet, lack of exercise, increased obesity and environmental factors.

Testosterone is produced in the testes, and signaling from testosterone, along with signals from other hormones, is a critical step in telling the testes to begin the process of spermatogenesis, or creating sperm.

Men who take exogenous testosterone—types from outside the body, such as injections or cream—stop producing the hormone naturally in their testicles. This, in turn, has a dramatic, negative impact on their ability to produce sperm.

Testosterone levels in men appear to have a direct impact on their ability to enjoy a healthy, normal sexual response. This impact includes their overall libido, the ability to get and maintain erections, and the ability to ejaculate.

It's true that sexual function is a coordinated symphony of bodily functions, including electrochemical, blood flow, the nervous system, emotions and mental imagery. But testosterone is believed to be the primary conductor of sexual function in areas such as libido and the release of crucial enzymes, like nitric oxide synthase (NOS), that are needed for erections.

Numerous studies indicate that men with hypogonadism (low testosterone, or low-T) who receive testosterone replacement therapy show a marked improvement in both erectile function and sex drive.

Men's testosterone levels vary a great deal over their lifetimes. Testosterone arrives in the womb at around six weeks, beginning the process of sexual differentiation.

During puberty, testosterone production skyrockets. It begins declining naturally around age 30, at a rate of about 1 percent per year. Approximately 40 percent of men older than age 45 have hypogonadism. But age isn't the only cause. Here are some other causes of low testosterone:

• Obesity
• Alcoholism
• Pituitary gland problems
• High levels of iron
• Certain medications
• Hypothyroidism
• Sleep apnea
• Tumors

Aging is the most well-known and predictable cause of reduced testosterone production in men. Beginning around age 30, men's testosterone levels begin to decline by about 1 percent per year and continue along that trajectory for life.

But men can make a number of lifestyle choices to help reduce the effects of lower testosterone production. Research has revealed some ways to avoid the worst effects of the age-related dropoff in testosterone:

• Maintain a healthy weight.
• Get a good night's sleep.
• Exercise regularly, especially resistance training.
• Avoid excessive alcohol consumption.
• Eat a healthy diet.
• Avoid stress and anxiety.

Just as fluctuations in women's hormones can affect their mood during their menstrual cycle, so too can men be affected by testosterone levels periodically rising and falling. Researchers have developed a theory called "irritable male syndrome," reflecting the resulting behavioral changes that can occur.

At different points in the month, during different seasons and even at different hours of the day, your body experiences variations in how much testosterone is being produced. It can result in mood swings, inexplicable anger, frustration, anxiety and hypersensitivity.

Some common times when this phenomenon might occur include when the seasons change to colder weather—cold's stress on the body affects testosterone production—and later in the day, since testosterone production peaks in the morning.

When a transgender person who was assigned female at birth decides to transition, their medical team put thems on testosterone therapy. They are prescribed regular doses of testosterone to be administered by injection or topically. It's the same way people who are assigned male at birth administer the hormone when they go on TRT, but the dosages may vary.

The hormone is intended to produce certain changes in the transitioning person to help reduce their gender dysphoria, the feeling of discomfort that might occur because their gender identity differs from their sex assigned at birth. TRT should:

• Lower their voice
• Produce facial hair growth
• Make their muscles more robust
• Alter the body fat-to-muscle ratio
• Change the fat distribution in their bodies
• Make their face more angular and male as facial fat changes

Another common effect is their clitoris begins to grow larger—generally not nearly as large as a typical penis—and their sex drive may be significantly stronger.

What does testosterone do to a man?

Testosterone doesn't so much do anything to a man as it determines he has masculine traits. The hormone is responsible for giving men their facial and body hair, larger muscles, deeper voice and a strong libido. It's vital to the production of sperm in their testicles. If a man experiences hypogonadism (low-T), TRT can restore his energy, help with weight loss, help with erectile dysfunction (ED), restore sex drive, and reduce testosterone-reduction-related depression and anxiety.

Does masturbation reduce testosterone?

No. Currently, there is a great deal of confusion on some social media channels regarding the supposed connection between abstaining from masturbation, or even ejaculating, and testosterone levels. But no scientific evidence backs up these claims. Even the primary paper frequently cited by advocates of "semen retention" was famously retracted. While all men experience a "refractory period" after ejaculating, during which the body needs time to recover before being able to get another erection, this has nothing to do with a supposed drop in testosterone levels.

What happens when a man has high testosterone?

A testosterone balance must be maintained to avoid the effects of high testosterone. Typically, most men should have between 300 nanograms per milliliter and 1,200 ng/mL of total testosterone in their blood. The symptoms of this amount being higher include:

• Acne
• Blood pressure problems resulting in dizziness, headaches, fatigue and nausea
• Erectile dysfunction
• Reduced libido
• Newly developing male pattern baldness
• Excessive mood swings, including irritability, anxiety and depression

Men may also experience chest pain, heart attacks, difficulty breathing or prostate issues, including benign prostatic hyperplasia (BPH), or enlarged prostate. There is also some evidence that chronic high testosterone may be correlated with a higher incidence of prostate cancer.