Testosterone is the primary male sex hormone that serves many roles in the body. Along with regulating muscle mass, fat distribution, and red blood cell production, testosterone also helps regulate libido and male fertility.

All men naturally experience a decline in testosterone with age. After the age of 30, testosterone levels decrease by around 2% per year. If testosterone levels drop below healthy levels, it’s referred to as low testosterone, also commonly known as low T or medically as hypogonadism. Low T is a common condition that can come with many side effects including male infertility. Fortunately, low testosterone can be treated to promote fertility and manage other symptoms.

What is Testosterone?
Testosterone is the main male sex hormone, although women also produce testosterone in smaller amounts. This hormone is crucial in male sexual and reproductive health and development. Testosterone is a type of hormone called an androgen or steroid that’s primarily produced in the testes. It’s this hormone that’s responsible for the development of male sex organs prior to birth and secondary sex characteristics during puberty like increased penis size and facial hair. Throughout adulthood, testosterone plays a role in everything from muscle maintenance and fat distribution to sperm production and sex drive.

While testosterone levels naturally decline with age, low T can affect men of any age when hormone levels get too low. Potential symptoms of low testosterone can include:

  • Low libido
  • Erectile dysfunction
  • Reduced sperm count
  • Gynecomastia or breast development
  • Depression and irritability
  • Softened or shrunken testes
  • Loss of muscle mass

Low testosterone is a common issue. Scientists with the New England Research Institute analyzed data from the Boston Area Community Health Survey which tracked over 1,500 people and compiled information on testosterone, symptoms of hormone imbalance, and medications that can affect sex hormones. This study found that 24% of the men had low total testosterone levels and 11% had low free testosterone levels. While older men were more likely to have low T, about 1 in 4 men over the age of 30 in the study had low testosterone.

How Testosterone Affects Fertility
Men without sufficient testosterone can suffer from male infertility. This is because testosterone is essential for the development of mature sperm. A deficiency in testosterone can lead to low sperm count, or the concentration of sperm cells in semen, and low motility, or how well sperm cells can move. Low T can also cause low libido and sexual dysfunction which also impact fertility.

Testosterone Evaluation
Men who have symptoms of low testosterone may consider a testosterone evaluation to measure the level of testosterone in the blood. This lab test measures free testosterone and the amount of hormone bound to sex hormone binding globulin (SHBG) and the albumin hormone. Only free testosterone and testosterone bound to albumin is considered active and bioavailable.

Once testosterone is measured, a physician must determine if it’s within the normal range. Normal levels can range from 300 to 1000 ng/dL based on Endocrine Society Guidelines.

Treatment for Low Testosterone
There are many treatment options available for men with low testosterone including hormone therapy, medications, dietary changes, exercise programs, and other lifestyle changes. The best treatment option will depend on the individual based on a physician’s evaluation and diagnosis.

For men who want to preserve fertility, testosterone replacement therapy may not be ideal. When testosterone introduced into the bloodstream by a gel, patch, or injection, the brain interprets the increase in testosterone as evidence that the body has sufficient testosterone. The brain will stop sending signals to the testes to produce testosterone, effectively shutting down the body’s natural production of this sex hormone. When the testes stop making testosterone, sperm production goes down. Testosterone therapy is so effective at stopping natural testosterone production that it’s even been used as a male contraceptive — certainly the last thing any man wants while trying to conceive.

“I see couples coming in for fertility evaluations with concern for sperm production, and one of the first drugs on the man’s list is testosterone replacement,” states Dr. Parviz Kavoussi, a leading Austin based reproductive urologist.

This doesn’t mean men with low testosterone will not be able to conceive. Treating low T is still possible through a balanced diet high in protein, regular exercise to lose weight, reducing stress, and getting plenty of high-quality sleep. There is a strong link between restful sleep and testosterone levels. In one study, men with sleep apnea were about 50% more likely to have low T than men without a sleep disorder.

Aside from lifestyle and dietary changes, one medication that is safe and effective in treating low T is clomiphene citrate (clomid ), which can help improve sperm concentration and fertility.

Low testosterone can come with serious side effects but there are many ways to treat this common condition. If you suspect you have low T, it’s important to undergo an evaluation to seek appropriate treatment, especially if you are considering becoming a father and want to preserve your fertility.