Is low testosterone genetic?

Low testosterone (medically known as male hypogonadism and colloquially called low T) is a relatively common men’s health issue, particularly among older men.

On average, testosterone levels tend to go down gradually with age. The decline is estimated at around 1 percent per year starting in midlife — though this varies widely between individuals. So, is low testosterone genetic, or are there factors within your control?

Like many health problems, there isn’t always a single cause of low testosterone — multiple factors are often at play. Genetics can influence how sensitive your tissues are to testosterone and may affect your overall risk of developing low T.

We’ll explore the genetic factors that affect testosterone production and what this means for treatment and prevention.

Your testosterone levels have a big impact on your overall health in many ways, including supporting your intimate, mental, and physical health.

The Role of Hormones in Testosterone Production

A series of hormones collectively called the hypothalamic-pituitary-gonadal (HPG) axis regulates testosterone production. Here’s a simplified overview:

• Your hypothalamus (an area in the front of your brain) releases gonadotropin-releasing hormone (GnRH) in pulses. This release is partly regulated by feedback from testosterone levels in your blood.

• GnRH stimulates your anterior pituitary gland (a pea-sized gland at the base of your brain) to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

• LH acts on cells in the testes to produce testosterone.

• FSH tells other cells in your testes to aid with sperm production.

Type of Male Hypogonadism

There are a few types of male hypogonadism. They’re classified based on the location of the underlying problem:

• Primary hypogonadism. This is when low testosterone is due to an issue with your testes.

• Secondary hypogonadism. Low testosterone can be due to the pituitary gland not releasing enough LH and FSH (often called hypogonadotropic hypogonadism). In clinical practice, hypothalamic causes are often grouped with this category.

• Tertiary hypogonadism. This is when low testosterone is primarily caused by problems with your hypothalamus. It’s sometimes included under secondary hypogonadism.

So, how is low testosterone genetic? Genetic factors can contribute to problems with testosterone levels at any of these stages.

Inherited Conditions That Affect Testosterone

A number of genetic conditions can cause low testosterone. For example:

• Kallmann syndrome. Kallmann syndrome is a genetic condition that leads to a lack of GnRH (and testosterone by extension) and a delay or lack of puberty.

• Klinefelter syndrome. Klinefelter syndrome happens in roughly 1 in 500 to 1,000 males, though many cases may go undiagnosed. It’s when you’re born with an extra chromosome, resulting in a biological XXY instead of the typical XY for males. People with Klinefelter syndrome often have low testosterone levels.

• Androgen insensitivity syndrome. Androgens are male hormones. Androgen insensitivity syndrome is where your body produces testosterone, but your receptors don’t fully respond to it. People with complete androgen insensitivity syndrome may appear female.

• Isolated congenital hypogonadotropic hypogonadism (ICHH). ICHH is a genetic disorder present from birth where cells in the hypothalamus don’t produce enough GnRH. It’s estimated to occur in one in 5,000 to 10,000 people.

Genetics and Age-Related Low Testosterone

Testosterone levels generally decline with age. Two factors can contribute to this decline:

• First, it’s normal for the HPG axis to become less efficient as you get older.

• Second, conditions linked to low testosterone, such as diabetes, tend to become more common with age.

Researchers are still investigating how much genetic factors vs. lifestyle habits play a role in age-related testosterone decline. Recent studies suggest that non-genetic factors (like body weight and chronic conditions) account for much of the variation.

In a 2025 study, researchers looked at trends in bioavailable testosterone levels with age among 6,354 men in the U.K. Biobank. The U.K. Biobank is one of the most comprehensive bio-databases — many studies have used data from this database to look for trends.

The researchers found that non-genetic factors (such as BMI, and chronic diseases) were strongly associated with a decline in bioavailable testosterone. Meanwhile, genetics had a minimal contribution.

Heritability is the proportion of the variation in a trait or disease in a population that can be explained by genetic differences between individuals. So, is low testosterone hereditary? If so, how much of it is about genetics?

Although research has come a long way in understanding the human genome, there’s still a lot we don’t know.

Some conditions are relatively simple to understand. For instance, Huntington’s disease is caused by a faulty copy of the Huntington (HTT) gene. But most conditions, like low testosterone, are more complex because they involve many different genes and environmental factors.

Twin and family studies suggest that genetics account for roughly 40 to 70 percent of the variation in testosterone levels, with the remaining 30 to 60 percent explained by environmental and lifestyle factors. That doesn’t mean your testosterone is “fixed,” but it does mean genes matter.

Twin Studies on Genetic Low Testosterone

Twin studies are one of the best ways to separate genetic effects from environmental ones, since identical twins have the same genes. Any differences between twins must be from environmental factors.

An older but relatively large twin study from 2008 examined testosterone and other blood markers among 274 pairs of brothers and estimated that genetic factors accounted for about 65 percent of the variation in serum testosterone levels.

How is testosterone genetic? In recent years, large-scale, genome-wide association studies (GWAS) have found dozens of genes related to testosterone regulation.

Some of the most studied genes include:

• Hormone-binding globulin (SHBG) gene. Hormone-binding globulin (SHBG) is a protein that binds testosterone in the blood. Only a small fraction of unbound testosterone (or loosely bound) is biologically active, so variations in SHBG can affect how much usable testosterone is available. Twin and family studies suggest that SHBG levels themselves are highly heritable, with genetics explaining a large share of the variation.

• Androgen receptor (AR) gene. This gene determines how easily your cells respond to testosterone. The AR gene is located on the X chromosome.

• LH and FSH pathway genes. Variations in these genes can alter LH and FSH production. These hormones influence testosterone and sperm production, respectively.

• Aromatase (CYP19A1). This gene helps convert testosterone into estrogen. Differences in this gene can change the balance of male and female hormones — although both are always present to some degree in the male body.

Genetics can definitely contribute to the development of low testosterone. But environmental or lifestyle factors also play a role.

Here are some of the biggest environmental influences:

• Weight and body fat. Obesity is a top risk factor for low testosterone. A combination of genetic and lifestyle habits can contribute to carrying excess body weight.

• Diabetes and other underlying conditions. Diabetes, liver disease, kidney disease, and other conditions affecting overall health can contribute to low testosterone. A mix of genetics and environmental factors plays a role in developing these diseases.

• Sleep and stress. Poor sleep can lead to higher cortisol (the stress hormone) and decreased testosterone. Chronic stress has a similar effect on your body.

• Exercise and physical activity. Strength training and intense workouts can modestly boost testosterone, at least temporarily. Extreme or prolonged overtraining may have the opposite effect.

• Medications. Some medications, such as androgen blockers for prostate cancer, can cause low testosterone.

• Advanced age. Low testosterone generally becomes more common with age. Some risk factors, like obesity and type 2 diabetes, are also more common with age.

• Diet and nutrition. Your body needs essential nutrients for testosterone production, including healthy fats, cholesterol, and nutrients like zinc, vitamin D, and magnesium.

Low testosterone is diagnosed when early-morning testosterone levels are consistently on blood tests or a man has symptoms of hypogonadism. Many labs list a normal total testosterone range of about 300 to 1,000 nanograms per deciliter (ng/dL), but reference ranges can vary.

Signs of Low Testosterone

Signs and symptoms of low testosterone can include:

• Fatigue and loss of energy

• Depression or irritability

• Loss of muscle mass and strength

• Increased body fat

• Decreased bone density

• Difficulty concentrating

• Increased risk of osteoporosis

• Poor red blood cell production

• ED

• Low drive (low libido)

Since these symptoms can have many causes, it’s important not to self-diagnose low T based on symptoms alone.

Is High Testosterone Good?

A common misconception is that more testosterone is always better. But everybody’s tissue sensitivity to testosterone is different. Some guys might not have any symptoms of low testosterone at the bottom of the normal range, while others might.

It’s worth noting that very high levels of testosterone — especially from anabolic steroid use — can increase the risk of side effects, like acne, male pattern hair loss (androgenetic alopecia), fertility problems, and other health issues.

Low testosterone can have many causes, and not all are genetic. If you’re experiencing symptoms like fatigue, low libido, or mood changes, it’s worth talking to a healthcare provider.

After going over your medical history and symptoms, your provider can order a blood test to measure your total testosterone and free testosterone. Depending on the results, they might check for underlying issues, like:

• Thyroid problems

• Obesity

• Diabetes

• Medication side effects

You can connect with a healthcare professional through our telehealth platform to avoid the need to see a doctor in person. We also offer at-home testing kits where you take a sample yourself at home and send it away for analysis. Many people find this more convenient than going to a laboratory themselves.

Depending on your symptoms and health history, your provider may still recommend in-person exams or additional testing.

Low Testosterone Treatment

If your testosterone levels come back low, your healthcare provider might recommend lifestyle changes, like eating more nutritious foods, working on better sleep, and regular exercise.

If lifestyle adjustments aren’t effective, or if an underlying medical condition is contributing to low T, your provider may discuss testosterone treatment, such as testosterone replacement therapy (TRT). But this depends on the underlying cause and your fertility goals.

There’s a genetic component to testosterone deficiency. But there can be many potential causes of low testosterone — and sometimes, multiple factors are at play.

Genetics can potentially contribute to low T in multiple ways. For example:

• Specific genetic markers might make you more sensitive to environmental factors that suppress testosterone.

• Certain genetic markers may increase your risk of diseases associated with low testosterone, like diabetes.

• Genetics can lead to congenital conditions that greatly impact testosterone levels, like Kallmann or Klinefelter syndrome.

You can’t change your DNA, but you can change your lifestyle habits to help support your natural testosterone levels and well-being.