The declining energy, mood, physical performance, and sexual health of men as they age brings about new health concerns. Testosterone is considered one of the most important (but most often misunderstood) factors contributing to these changes. This essential hormone influences almost all of the systems of the male body, and an age-related gradual loss of it can have broad-ranging sides effects.

Here, we will be substance and attempt to deconstruct what testosterone does, rates of change, the symptoms of low testosterone, and when it becomes a health problem. With or without a birthday in your 40s, or 70s, it is important to realize that testosterone decline is a factor that contributes to living a healthy and vibrant life.

Testosterone is a hormone primarily produced in the testicles, regulated by the hypothalamic-pituitary–gonadal (HPG) axis — a complex system involving the brain and reproductive organs. While it’s most known for its role in sexual function and male development, testosterone plays a far more expansive role.

‍

According to Cheng et al. (2024), testosterone affects:

‍

- Spermatogenesis (sperm production)

- Sexual function and libido

- Bone mineral density

- Muscle mass and strength

- Red blood cell production

- Fat metabolism and insulin sensitivity

- Mood and cognitive function

- Cardiovascular health

Testosterone levels peak in early adulthood and begin a gradual decline after the age of 30–35. This decline is part of a natural aging process, but it can impact health and well-being if levels fall too far or too quickly.

Rojas-Zambrano et al. (2025) highlight testosterone’s effect not just on physical strength but also on mood regulation, immune function, and even brain health. This multifaceted hormone acts like a central switchboard for male vitality.

Unlike the hormonal shifts women experience in menopause, testosterone levels in men decline slowly — about 0.4% per year for total testosterone and 1.3% per year for free testosterone after age 40 (Cheng et al., 2024). By the time a man reaches 70, his levels may be 30–50% lower than they were in early adulthood.

‍

This decline occurs due to:

‍

- Reduced Leydig cell function in the testes

- Diminished hormone signaling from the brain

- Mitochondrial damage due to oxidative stress

- Chronic inflammation, common with age

‍

But age is not the only factor. Solan (2023) notes that lifestyle and environmental influences can exacerbate testosterone loss. These include:

‍

- Obesity (especially abdominal fat)

- Lack of physical activity

- Chronic stress

- Sleep apnea and poor sleep

- Diabetes and metabolic syndrome

- Excessive alcohol or opioid use

- The decline is therefore not just inevitable — it can be influenced and, in some cases, slowed or mitigated.

‍

Many men with age-related testosterone decline will not experience noticeable symptoms. However, for others, the decline can lead to a condition known as late-onset hypogonadism, where testosterone falls below the threshold necessary for healthy function.

‍

Common symptoms include:

‍

- Persistent fatigue and lack of motivation

- Reduced libido and erectile difficulties

- Depressed mood, irritability, or emotional flatness

- Increased body fat, particularly around the waist

- Decreased muscle mass and strength

- Thinning bones (osteopenia or osteoporosis)

- Impaired memory, focus, or mental clarity

‍

These symptoms can emerge gradually and are often mistakenly attributed to stress, depression, or simply “getting older.”

‍

Rojas-Zambrano et al. (2025) and Rodrigues dos Santos & Bhasin (2021) note that testosterone therapy in men with these symptoms can lead to improvements in mood, sexual function, muscle mass, and cognitive performance. But identifying who truly needs therapy begins with proper evaluation.

‍

Not all testosterone decline is abnormal. Some men age without any symptoms or health impact despite lower hormone levels. Others develop clinical hypogonadism, where testosterone falls below 300 ng/dL in the presence of symptoms.

‍

This distinction is critical. According to Liverman & Blazer (2004), the rise in testosterone prescriptions has often outpaced scientific evidence — driven in part by aggressive marketing of testosterone as a cure-all for male aging.

‍

Diagnosis of testosterone deficiency requires:

‍

- Blood tests showing low total or free testosterone

- Symptoms consistent with androgen deficiency

- Clinical judgment ruling out other causes

‍

Barone et al. (2022) stress that many older men remain undiagnosed because symptoms of testosterone deficiency can overlap with conditions like depression, thyroid dysfunction, and aging-related frailty.

‍

Testing and Diagnosis: When Should You Talk to Your Doctor?

‍

If you're experiencing symptoms such as low libido, fatigue, muscle loss, or mood changes, it’s worth speaking with a healthcare provider. Testosterone testing involves a simple blood draw, ideally done between 7–10 a.m., when levels are highest.

‍

Your provider may test:

‍

- Total testosterone

- Free testosterone

- Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) (to evaluate pituitary function)

- Sex hormone-binding globulin (SHBG)

‍

If initial results are low, the test is often repeated to confirm the finding. A comprehensive health evaluation will also help rule out other contributing factors.

‍

For men with confirmed low testosterone and relevant symptoms, Testosterone Replacement Therapy (TRT) may be an option. TRT can be delivered through:

‍

- Injections (weekly or biweekly)

- Topical gels or patches

- Nasal sprays

- Pellets implanted under the skin

- Potential benefits of TRT include:

- Increased libido and sexual satisfaction

- More energy and improved mood

- Greater muscle strength and lean mass

- Better bone density

- Enhanced cognitive function

‍

However, TRT is not without risks. Cheng et al. (2024) and Rodrigues dos Santos & Bhasin (2021) caution that long-term therapy may lead to:

‍

- Enlarged prostate or risk of prostate cancer progression

- Elevated red blood cell counts (increasing clotting risk)

- Worsening of sleep apnea

- Fluid retention or acne

- Cardiovascular events (though data is mixed)

- Men undergoing TRT require ongoing monitoring of hormone levels, blood counts, and prostate health.

Alternatives to TRT: Natural Ways to Support Testosterone

‍

Not every man with mildly low testosterone needs TRT. In many cases, lifestyle changes can significantly improve levels and reduce symptoms — especially when low testosterone is linked to obesity or stress.

‍

Evidence-based strategies to boost testosterone naturally:

‍

- Lose excess body fat, particularly belly fat

- Engage in strength training and regular physical activity

- Improve sleep hygiene, aiming for 7–9 hours per night

- Reduce stress through relaxation techniques or therapy

- Limit alcohol, especially binge drinking

- Avoid opioids and anabolic steroids

- Correct nutrient deficiencies, particularly zinc, magnesium, and vitamin D

- These interventions not only support testosterone but improve overall metabolic, cardiovascular, and psychological health.

- The Bigger Picture: Testosterone and Whole-Body Health

- Emerging research shows that testosterone may be more than just a reproductive hormone. It could be a marker for overall health.

‍

Rastrelli et al. (2021) found that low testosterone levels predicted worse outcomes in men hospitalized with COVID-19 pneumonia. This aligns with broader evidence linking low testosterone with increased risk for:

‍

- Type 2 diabetes

- Cardiovascular disease

- Osteoporosis

- Cognitive decline and dementia

- Increased all-cause mortality

‍

In other words, testosterone may act as a signal of biological aging, not just sexual health. Monitoring and managing testosterone could help reduce risk for chronic disease in aging men.

‍

Conclusion

Testosterone decline is a natural part of aging, but it doesn’t have to define your quality of life. By understanding the signs of low testosterone and taking proactive steps, men can maintain strength, drive, and health well into later life.

‍

Key Takeaways:

- Testosterone affects much more than sex drive — it’s central to muscle, mood, bone, and brain health.

- Levels begin declining in your 30s and continue gradually throughout life.

- Symptoms like fatigue, low libido, and reduced strength may signal a testosterone deficiency.

- Diagnosis requires blood testing and medical evaluation, not guesswork.

- Treatment options range from lifestyle changes to medically supervised TRT, depending on the severity of symptoms and lab results.