The Hormone Testosterone and Its Role in Men's Health
Testosterone levels vary by age, but the definition of "normal" is changing. In 2025, updated research and lab guidelines reflect what many clinicians already know. Men often experience symptoms of low testosterone even when their levels fall within the standard range. This guide breaks down the most recent age-based averages, what's considered optimal for long-term health, and when it may be time to take action.
Testosterone is a vital hormone for men. It supports strength, energy, sex drive, and overall health. During puberty, it's responsible for building muscle, producing facial and body hair, deepening the voice, and sexual desire. As they age, it helps to regulate weight, control cholesterol levels, and maintain energy and mood. Throughout life, hormone levels fluctuate, which leaves many men wondering: what are average testosterone levels by age?
As a teen, testosterone levels are at their highest level, with a decline beginning in the mid-thirties and continuing to drop about 1-2% each year. Studies show (1) that testosterone levels can depend on several factors, including health conditions, genetics, and lifestyle factors. So determining average testosterone by age is more nuanced than it might seem.
That said, average testosterone levels for healthy men can be used as a baseline.
What Are the Average Testosterone Levels by Age?
Testosterone levels are typically measured in nanograms per deciliter (ng/dL), and according to Mount Sinai (2), a healthy testosterone range is between 300 to 1,000 ng/dL. Teen boys can reach peak levels around age 19, often above 300 ng/dL, with those levels staying high until the thirties, when gradual decline begins.
Based on recent research, average testosterone levels by age are as follows:
| Age Range | Testosterone Level (ng/dL) |
|---|---|
| 20-24 | 409-558 |
| 25-29 | 413-575 |
| 30-34 | 359-498 |
| 35-39 | 352-478 |
| 40-44 | 350-473 |
| 45-49 | 340-465 |
| 50-54 | 330-450 |
| 55-59 | 320-440 |
| 60-64 | 300-420 |
| 65-69 | 290-410 |
| 70-74 | 280-400 |
| 75-79 | 270-390 |
| 80+ | 260-380 |
Source: Data adapted from recent findings in Reproductive Biology and Endocrinology (2024), AUA News (2023), and Urology Times (2023). Chart values reflect updated 2025 averages based on aggregated clinical reference ranges.
Understanding Testosterone Decline
In addition to age-related decline, research shows testosterone levels have dropped 20 percent in young men compared to past generations (5). A level under 300 ng/dL is generally considered low, but many men experience symptoms well above that threshold.
The fact is, labeling any hormone level as “normal†can be misleading. While studies offer useful benchmarks, your symptoms are often the best indicator of whether your hormones are truly optimal. Even if your testosterone levels appear normal on paper, two key factors can still cause symptoms:
- SHBG (sex hormone-binding globulin): This protein binds to testosterone, making it unavailable for your body to use. SHBG levels naturally increase with age, so even if your total testosterone stays steady, your free testosterone may decline. This drop in usable testosterone often explains symptoms like low energy or reduced libido, even when lab results appear normal.
- Receptor sensitivity: Even with enough free testosterone, your body's cells might not respond to it properly. Poor receptor sensitivity can limit how effectively your body uses testosterone, which can lead to symptoms like fatigue, low libido, and brain fog.
The Importance of Healthy Testosterone Levels
Optimal, not just normal, testosterone levels help regulate cholesterol, lipids, and glucose. They also support bone health, brain function, and memory. When levels decline, you can feel it in everyday life.
You may experience brain fog, rising cholesterol despite a healthy diet, low energy, or a fading sex drive. If you're dealing with these issues, a drop in testosterone may be the root cause of the issues you're experiencing, and it may be time to consider getting your hormone levels checked.
The Decline in Testosterone with Age
Since testosterone levels begin to decline in the mid-thirties, by the time you reach 70 years of age, there could be a decline of as much as 30%. (6) Of course, various factors can affect testosterone levels, but when they drop to below-normal levels, they can affect all areas of physical and mental health. According to a study (7), testosterone levels are more closely related to behavioral and health-related issues than aging.
How Low Testosterone Affects Health
Low testosterone symptoms vary widely and don't always match up with lab numbers. According to the American Urological Association (9), low testosterone is officially defined as below 300 ng/dL. But many men experience symptoms at much higher levels, depending on factors like receptor sensitivity, thyroid function, and free testosterone.
This is why relying solely on numbers can be misleading. Two men with the same level may feel completely different. Symptoms, not just test results, should guide diagnosis and treatment.
These symptoms can occur even if your testosterone levels fall within the "normal" lab range:
- Loss of muscle mass
- Trouble concentrating
- Weight gain
- Low energy
- Trouble sleeping
- Low sex drive
- Erectile dysfunction
- Bone loss
- Irritability
- Depression
- Hair loss
It's not unusual for men to experience these symptoms even at 400 ng/dL, 600 ng/dL, or higher—depending on their free testosterone, SHBG, thyroid function, and overall hormone balance.
What is the Best Time of Day to Take a Testosterone Test?
According to Ronald Swerdloff, MD, chief of endocrinology at Harbor UCLA Medical Center, to get the most accurate hormone reading, testosterone should be tested early in the morning for the most accurate results.
Since hormones can have patterns of secretion, afternoon testing can provide false information about low levels. Doctors often recommend testing two to three times over a few weeks for confirmation. That said, repeating tests may not provide much clarity if your symptoms clearly indicate a hormonal imbalance. Symptoms matter more than the numbers.
Are Levels Actually That Important?
Unfortunately, many medical professionals haven't had the necessary training to understand hormones and what it means to have optimal levels. While they may be aware of the need for hormone replacement, they focus on baseline test numbers that don't even come close to telling the whole story. They may rely too heavily on standard reference ranges and overlook how the patient actually feels.
Symptoms often reveal more than lab results. You might feel terrible with a "normal" testosterone level, while another man feels great at that same number.
According to medical research, it's well documented that the 'normal levels' the medical community has been trained to use don't provide optimal levels for most men. Despite this, they continue to focus on the numbers and the symptoms the patient is experiencing are ignored.
The symptoms of low testosterone can severely interfere with your quality of life in all areas. When you don't feel your best, it takes a toll on your enjoyment of life and relationships with the people you care about. What you may not understand is that it also significantly affects your health.
Although your medical practitioner may focus on the hormone levels test, only you know how you feel. You don't have to live with the negative symptoms of low testosterone. If your practitioner doesn't give you the support you need, it may be time to consult a specialist who can.
What is a Testosterone Level Test?
According to the Cleveland Clinic (10), a testosterone test measures the concentration of the hormone in your blood. Both free testosterone and total testosterone levels are important.
Testosterone exists in the body as bound testosterone, which is bound to sex hormone binding globulin (SHBG) or free testosterone, which isn't attached to anything. The body can utilize free testosterone more easily than bound testosterone. In a testosterone blood test, results may show: (11).
- Total testosterone test. Measures both free testosterone and bound testosterone. The test should be done between 8 a.m. and 10 a.m. for best results.
- Estradiol. This form of estrogen is vital for a healthy sex drive, erections and sexual function. Estradiol also offers protection to brain health and bones. If estradiol is out of balance, it reduces the effectiveness of TRT.
- DHEAs. DHEA sulfate is an adrenal hormone that kick-starts the production of other hormones like testosterone. DHEA supplements are often recommended as part of our programs.
- Free T3. T3 is an active thyroid hormone that controls metabolism, promotes fat burning, and, if deficient, can be one of the biggest threats to overall hormone health. If your clinic doesn't offer this test, move swiftly on.
- PSA. A Prostate-specific androgen test checks levels of PSA, which, if too high, may indicate a prostate issue. We always check PSA is within the normal range before starting any TRT.
Why Would You Need a Testosterone Level Test?
If you've struggled with symptoms of low testosterone or have health issues that could be related, your provider may suggest you have testosterone levels checked. They can include:
- Erectile dysfunction (ED)
- Weight gain around your middle
- Low energy levels
- Brain fog
- Developing breast tissue
- Loss of muscle mass
- Low sex drive
- Type 2 diabetes
So, what can you do if your testosterone levels are out of whack? You may want to consider testosterone replacement therapy to feel like yourself again and enjoy the benefits of optimal testosterone levels.
What Is Testosterone Replacement Therapy?
Testosterone Replacement Therapy (TRT) uses medications such as injections, gels, or creams to restore healthy testosterone levels. The goal is to help you regain energy, strength, mental clarity, and overall well-being.
Conclusion: Don't Fixate on the Numbers
Testosterone is vital for performance and vitality. It begins to decline by the mid-thirties, bringing symptoms that affect both physical and mental health.
You don't have to wait for your lab numbers to fall below a certain line. If you're experiencing symptoms, it may already be time to act.
Your symptoms are a mirror of your hormone health. Blood tests give a baseline, but how you feel should guide your treatment.
If you're ready to address the root cause of your symptoms, testosterone therapy could help you feel like yourself again.
So, if you have symptoms of low testosterone, help is available. Testosterone replacement therapy can reduce the unwanted effects of low testosterone and give you your life back.
Ready to stop guessing and start optimizing? Take the first step with a free testosterone assessment and see if TRT is right for you.
Get TRT Online
Optimize Your Hormones
Last updated April 2025 to reflect the latest clinical research and testosterone reference data.
References
Original Sources
- Feldman et al. (2002) - Changes in testosterone levels with aging (NIH)
- Mount Sinai - Testosterone test overview and normal results
- AUA Journals - Clinical reference for testosterone in men
- University of Michigan - Rethinking the 300 ng/dL cutoff
- PubMed - Longitudinal trends in testosterone
- Harvard Health - Testosterone, aging, and the mind
- Science Daily - Testosterone levels and mental health
- Healthline - Complications of low testosterone
- AUA Clinical Guidelines - Testosterone deficiency
- Cleveland Clinic - Testosterone test
- Cleveland Clinic - Male hypogonadism
Additional 2023-2025 Research
- Reproductive Biology and Endocrinology (2024). Age-related decline in free vs. total testosterone.
- AUA News (2023). What is a normal testosterone level for young men?
- Urology Times (2023). Testosterone levels show steady decrease among young US men.
- Annals of Internal Medicine (2024). Low testosterone levels linked to increased all-cause mortality.
- Harvard Health (2024). Low testosterone levels linked to shorter life span.
