Testosterone is a key hormone in both males and females, though it plays a more prominent role in male sexual and reproductive function. When levels of this hormone drop below a healthy threshold, it can result in various physical, emotional, and metabolic symptoms.

Low testosterone—also called testosterone deficiency—can affect energy levels, mood, libido, bone health, and more. The good news is, it’s often treatable, especially when detected early.

In this article, we explore the signs of low testosterone in both men and women, its causes, how it’s diagnosed, and treatment options—including natural ways to support healthy levels.

What Is Low Testosterone?

Testosterone is produced mainly in the testicles in males and the ovaries in females, though a smaller amount is also released by the adrenal glands. It plays an essential role in:

  • Muscle and bone development

  • Facial and body hair growth

  • Sex drive and sperm production

  • Mood regulation and cognitive function

  • Fat distribution and metabolism

The American Urological Association defines low testosterone in males as having blood levels below 300 nanograms per deciliter (ng/dL).

Common Symptoms of Low Testosterone

Low testosterone can present differently in different individuals. Below are some of the most commonly reported symptoms.

1. Reduced Muscle Mass

One of testosterone’s roles is to help build and maintain muscle tissue. Low levels may result in decreased muscle size and tone, although muscle strength may not decline at the same rate.

2. Weakened Bones

Testosterone contributes to bone density. Deficiency may lead to lower bone mass, making bones more fragile and increasing the risk of fractures.

3. Lower Libido

Testosterone has a direct impact on sexual desire. A significant drop in libido—especially when sudden—may be a sign of declining testosterone levels.

4. Erectile Dysfunction

Although not the only cause, testosterone is involved in producing nitric oxide, a molecule that triggers erections. Low testosterone can contribute to difficulty achieving or maintaining erections.

5. Decreased Semen Volume

Testosterone plays a role in the production of semen. Men with low levels may notice reduced ejaculation volume, which can also affect fertility.

6. Increased Body Fat

Low testosterone may lead to fat accumulation, particularly around the abdomen. In some cases, men may develop gynecomastia, or enlargement of breast tissue.

7. Hair Loss

Testosterone affects hair growth. A drop in hormone levels can contribute to hair thinning or balding, beyond what’s expected from aging alone.

8. Mood Changes

Mood swings, irritability, depression, and decreased motivation may be linked to testosterone deficiency. Some men report feeling mentally sluggish or less confident.

9. Fatigue

Persistent tiredness or low energy—despite adequate sleep and nutrition—can be a sign of hormone imbalance.

10. Testicle Shrinkage

Men with low testosterone may observe a reduction in testicular size not related to temperature changes.

Symptoms of Low Testosterone in Women

While females produce lower amounts of testosterone, it still plays an important role in:

  • Regulating mood

  • Supporting bone density

  • Maintaining muscle strength

  • Influencing sex drive

Common signs of low testosterone in women include:

  • Fatigue

  • Decreased libido

  • Irregular periods

  • Thinning hair

  • Mood changes

  • Reduced muscle mass

  • Increased body fat

  • Anemia or low red blood cell count

Women who have undergone ovary removal or who are postmenopausal are more likely to experience testosterone deficiency.

Causes of Low Testosterone

Low testosterone levels can result from a variety of factors. These include:

In Males:

  • Aging – Testosterone levels typically decline after age 30

  • Injury to the testicles

  • Chronic diseases – Including type 2 diabetes or kidney disease

  • Hormonal disorders – Such as pituitary gland dysfunction

  • Chemotherapy or radiation therapy

  • Use of certain medications – Especially opioids or corticosteroids

  • Genetic conditions – Like Klinefelter syndrome

In Females:

  • Ovary removal or menopause

  • Adrenal insufficiency

  • Estrogen replacement therapy – May suppress natural testosterone production

  • Autoimmune or pituitary disorders

When to See a Doctor

If you notice any of the following symptoms, it may be time to speak to your healthcare provider:

  • Ongoing fatigue

  • Decreased interest in sex

  • Difficulty achieving erections

  • Mood changes

  • Unexplained weight gain or loss of muscle

  • Irregular periods (in women)

  • Infertility concerns

Routine blood work or a hormonal panel may detect testosterone deficiency even before symptoms arise.

How Is Low Testosterone Diagnosed?

Diagnosis typically involves:

  1. Physical exam

  2. Medical history review

  3. Blood test, ideally conducted in the morning when testosterone levels are highest

A result showing total testosterone levels under 300 ng/dL in males is generally considered low.

Additional tests may include:

  • Luteinizing hormone (LH)

  • Prolactin levels

  • Thyroid panel

  • Bone density scan

  • MRI of the pituitary gland if needed

Treatment Options

The primary treatment for testosterone deficiency is Testosterone Replacement Therapy (TRT). It can be administered in several ways:

  • Skin patches

  • Gels applied to the skin

  • Oral tablets or dissolvable pills

  • Intramuscular injections

  • Subcutaneous pellets implanted under the skin

Treatment choice depends on lifestyle, preference, and symptom severity. Most individuals start noticing improvements within a few weeks to a few months of starting therapy.

Can You Increase Testosterone Naturally?

Yes. While not a substitute for medical treatment in severe cases, the following lifestyle habits may help naturally support testosterone levels:

  • Exercise regularly, especially strength training and high-intensity interval workouts

  • Lose excess body fat, especially around the belly

  • Improve sleep hygiene, aiming for 7–8 hours of quality rest

  • Eat a balanced diet, including healthy fats, zinc, vitamin D, and protein

  • Reduce alcohol and avoid drug use

  • Manage stress levels through mindfulness, yoga, or therapy

  • Avoid environmental toxins like BPA and chemicals in plastics

Frequently Asked Questions (FAQ)

Q: What are the risks of untreated low testosterone?

Left untreated, low testosterone can lead to decreased bone density, reduced muscle mass, sexual dysfunction, infertility, and mood disorders.

Q: Can low testosterone cause diabetes?

Yes. Low testosterone can worsen insulin resistance, increasing the risk of type 2 diabetes and metabolic syndrome.

Q: Should I see a urologist or endocrinologist?

Both may be appropriate. A urologist focuses on male reproductive issues, while an endocrinologist treats hormone-related disorders. Your primary care doctor can refer you to the right specialist.

Q: Can TRT improve fertility?

Not directly. In fact, testosterone therapy may suppress sperm production. Men trying to conceive may require different medications, such as hCG or clomiphene.

Q: Is low testosterone genetic?

Yes, genetic conditions like Klinefelter syndrome and variations in the SHBG (sex hormone-binding globulin) gene may affect testosterone levels.

Summary

Low testosterone is a common condition that affects physical, emotional, and sexual health—especially as people age. While symptoms vary, the condition is both diagnosable and manageable.

If you're experiencing symptoms of low testosterone, don't ignore them. Early medical evaluation, along with healthy lifestyle changes or hormone therapy, can help restore hormonal balance and improve quality of life.