What Is Testosterone?
Testosterone is a hormone primarily produced in the testicles, with smaller amounts made by the adrenal glands. While it is often described as a “male sex hormone,” testosterone plays a much broader role in men’s health than sexual function alone.
In adult men, testosterone helps support:
- Muscle mass and strength
- Bone density
- Red blood cell production
- Libido and sexual function
- Mood, motivation, and cognitive focus
- Fat distribution and metabolic health
Testosterone production is regulated by a tightly coordinated system involving the brain and endocrine glands, often referred to as the hypothalamic-pituitary-gonadal (HPG) axis. Signals from the brain tell the testicles when to produce testosterone, and feedback loops help keep levels within a healthy range.
Because testosterone interacts with many other systems in the body, changes in testosterone levels in men can sometimes reflect broader shifts in health, such as sleep quality, stress levels, inflammation, or metabolic function. This is one reason clinicians tend to view testosterone as part of a bigger picture rather than an isolated number.
How Much Testosterone Does a Man Have?
Testosterone levels are measured through a blood test and are typically reported as nanograms per deciliter (ng/dL). When people ask how much testosterone a man has, they are usually referring to this lab value.
Most clinical labs define normal testosterone levels in men using a reference range that often falls somewhere between 300 and 1,000 ng/dL. However, this range can vary depending on the lab, the testing method, and the population used to establish the reference values.
It is also important to understand that testosterone levels in men are not static. They naturally fluctuate (even day to day) based on several factors, including:
- Time of day: Testosterone is usually highest in the morning and lower later in the day
- Age: Average testosterone levels in males tend to peak in early adulthood and gradually decline over time
- Health status: Illness, stress, poor sleep, and metabolic conditions can all influence levels
- Medications and lifestyle factors: Certain medications, alcohol use, and training intensity can affect testosterone production
Because of this variability, a single testosterone measurement may not fully reflect what is typical for an individual. Clinicians often look at patterns over time, symptoms, and related lab markers to better understand what a given testosterone level means for that person.
In the next section, we will look more closely at average testosterone levels in males by age and how those ranges tend to shift across the lifespan.
Normal Testosterone Levels in Men by Age
Testosterone levels change naturally throughout a man’s life. Understanding what is considered typical at different ages can help provide context, but it is important to remember that age-based ranges are only one part of the picture. Symptoms, overall health, and lifestyle factors all matter when interpreting results.
Most laboratories define normal testosterone levels in men using population-based reference ranges. These ranges reflect where the majority of tested individuals fall, not necessarily what is optimal for every individual.
Average Testosterone Levels in Males by Age Chart
While exact numbers vary slightly by lab, research and clinical data generally show the following patterns for total testosterone levels measured in nanograms per deciliter (ng/dL):
- Age Range: Late teens (16-19)
- Average Testosterone Level (ng/dL): ~300-1,000
- Age Range: 20s
- Average Testosterone Level (ng/dL): ~600-900
- Age Range: 30s
- Average Testosterone Level (ng/dL): ~500-800
- Age Range: 40s
- Average Testosterone Level (ng/dL): ~450-700
- Age Range: 50s
- Average Testosterone Level (ng/dL): ~400-650
- Age Range: 60s and older
- Average Testosterone Level (ng/dL): ~300-600
These ranges reflect average testosterone levels in males, not strict cutoffs for health or well-being. Two men of the same age can have very different testosterone levels and feel equally healthy.
Why “Normal” Doesn’t Always Mean “Optimal”
A common source of frustration is being told testosterone levels are “normal” even when symptoms are present. This happens because lab reference ranges are broad and designed to capture most of the population, including men with underlying health conditions.
For example:
- A testosterone level near the lower end of normal may be appropriate for one man but associated with symptoms for another.
- Some men function well at levels that are lower or higher than average for their age.
- Testosterone levels must be interpreted alongside other markers such as sex hormone–binding globulin (SHBG), free testosterone, and overall health status.
This is why many clinicians focus less on whether testosterone levels in men fall within a single reference range and more on how those levels relate to symptoms, trends over time, and the broader hormonal environment.
What Is the “Optimal” Testosterone Range?
The idea of an “optimal” testosterone range can be confusing, especially because it is not a formal category on most lab reports. While labs provide reference ranges to define what is statistically normal across a large population, clinicians often think about optimal testosterone levels in a more individualized way.
In general, normal testosterone levels in men are based on where most test results fall, not on how people feel or function. An optimal range, by contrast, is typically discussed in the context of overall health, symptoms, and long-term well-being.
Normal vs. Optimal: What’s the Difference?
A lab reference range answers the question: Is this value statistically common in the general population?
An optimal range asks a different question: Is this level supporting how the body functions and how a person feels?
For example:
- A man may have testosterone levels in men that fall within the lower end of the normal range but still experience fatigue, low libido, or changes in body composition.
- Another man may feel well, recover easily from exercise, and have stable energy at a similar number.
This is why testosterone levels should not be interpreted in isolation. Context matters.
Factors Clinicians Consider When Assessing “Optimal” Levels
Rather than relying on a single cutoff, clinicians often look at several factors together, including:
- Symptoms: Energy, mood, sexual health, muscle strength, and recovery
- Trends over time: Whether testosterone levels are stable, rising, or declining
- Free testosterone: The portion of testosterone that is biologically active
- Sex hormone–binding globulin (SHBG): A protein that affects how much testosterone is available to tissues
- Overall health markers: Metabolic health, inflammation, sleep quality, and stress load
Because of these variables, there is no single optimal testosterone number that applies to every man. Two people with the same lab value can have very different clinical experiences.
Why Chasing a Number Can Be Misleading
Focusing only on raising testosterone levels can sometimes miss the underlying issue. Low or suboptimal testosterone may be a downstream effect of factors such as chronic stress, poor sleep, insulin resistance, or systemic inflammation. It’s important that both the hormone levels as well as the symptoms are taken into consideration.
Addressing these contributors can sometimes support healthier testosterone levels naturally, without targeting the hormone directly. This whole-body perspective is a core principle of functional and preventive medicine.
Why Testosterone Levels Decline
Testosterone levels tend to change over time, and some degree of decline is a normal part of aging. However, age alone does not tell the full story. Many men experience testosterone changes earlier or more noticeably because of lifestyle factors, underlying health conditions, or chronic stress on the body.
Understanding why testosterone levels in men decline can help shift the focus from quick fixes to addressing the factors that influence hormone balance over the long term.
Age-Related Changes
On average, testosterone levels peak in early adulthood and gradually decline starting in the late 20s to early 30s. Research suggests this decline often occurs at a rate of about 1 percent per year, though the pace varies widely from person to person.
This gradual change is considered part of normal physiology, but it does not automatically lead to symptoms. Many men maintain stable energy, strength, and sexual health well into later decades, especially when overall health is well supported.
Chronic Stress and the Stress Response
Long-term stress can have a meaningful impact on testosterone production. When the body is under ongoing stress, it prioritizes cortisol, a hormone involved in the fight-or-flight response. Elevated or dysregulated cortisol levels can interfere with the hormonal signals that support testosterone production.
Over time, this imbalance may contribute to lower testosterone levels, particularly when stress is combined with inadequate sleep or recovery.
Poor Sleep Quality
Sleep plays a critical role in hormone regulation. Testosterone is primarily produced during deep sleep, especially in the early morning hours. Consistently short or disrupted sleep can reduce testosterone production and alter normal daily hormone rhythms.
Men who sleep fewer than six hours per night or who experience frequent sleep interruptions often show lower average testosterone levels compared to those with consistent, restorative sleep.
Metabolic and Inflammatory Factors
Metabolic health is closely linked to testosterone levels. Conditions such as insulin resistance, excess body fat, and chronic inflammation can all influence how the body produces and uses testosterone.
Fat tissue can convert testosterone into estrogen, which may further lower available testosterone levels. Inflammatory signals in the body can also disrupt the hormonal pathways involved in testosterone regulation.
Lifestyle and Environmental Influences
Several everyday factors can affect testosterone levels in men, including:
- Excessive alcohol intake
- Overtraining without adequate recovery
- Certain medications
- Limited physical activity or prolonged sedentary behavior
These influences often interact with one another, making it important to look at overall patterns rather than a single cause.
Symptoms of Low Testosterone in Men
Low testosterone does not look the same in every man. Some men notice clear changes, while others have subtle symptoms that develop gradually over time. Because testosterone influences many systems in the body, symptoms can be wide-ranging and are not always specific to testosterone alone, which can make diagnosis more complex.
This overlap is important. Many of the symptoms associated with low testosterone can also be linked to stress, poor sleep, thyroid dysfunction, depression, metabolic issues, or chronic inflammation. That is why symptoms are best interpreted in context rather than used as a standalone diagnosis.
Common Physical Symptoms
Men with lower testosterone levels may notice changes such as:
- Low energy or persistent fatigue
- Decreased muscle mass or strength despite regular activity
- Increased body fat, particularly around the abdomen
- Reduced exercise tolerance or slower recovery
- Decreased bone density over time
These physical changes often happen gradually and may initially be attributed to aging or lifestyle factors.
Sexual Health Symptoms
Testosterone plays an important role in sexual health, though it is not the only factor involved. Possible symptoms include:
- Reduced libido or sexual interest
- Changes in erectile function
- Fewer spontaneous morning erections
It is worth noting that vascular health, stress, sleep quality, and medications can also strongly influence sexual function, sometimes independently of testosterone levels.
Mood and Cognitive Changes
Testosterone receptors are present in the brain, which helps explain why changes in levels can affect mental and emotional well-being. Some men report:
- Low motivation or reduced drive
- Depressed or irritable mood
- Difficulty concentrating or “brain fog”
- Reduced confidence or sense of well-being
These symptoms are not specific to testosterone deficiency, but they are commonly reported in men with lower testosterone levels.
Why Symptoms Matter as Much as the Number
A key reason testosterone evaluation can be challenging is that symptoms do not always match lab values perfectly. Some men with testosterone levels at the lower end of the normal range feel unwell, while others with similar numbers feel fine.
This is why clinicians often consider:
- The pattern and severity of symptoms
- Whether symptoms are new or progressive
- How testosterone levels compare to prior results
- Other hormones and health markers
Symptoms of High Testosterone In Men
High testosterone levels are discussed far less often than low testosterone, but they can also have clinical implications. In most cases, significantly elevated testosterone levels are uncommon without external factors, such as certain medications or supplements. Still, understanding potential symptoms helps provide a more complete picture of testosterone balance.
It is also important to distinguish between naturally higher testosterone within a healthy range and levels that are elevated beyond what the body can regulate comfortably.
Possible Physical Effects
When testosterone levels are higher than the body can balance, some men may experience:
- Acne or oily skin
- Increased sweating
- Changes in hair growth patterns
- Headaches or flushing in some cases
These symptoms can be influenced by genetics and skin sensitivity, so they are not specific to testosterone alone.
Mood and Sleep Changes
Testosterone interacts with neurotransmitters in the brain, which means higher levels can sometimes affect mood and sleep. Possible changes include:
- Increased irritability or agitation
- Difficulty sleeping or feeling “wired” at night
- Heightened restlessness
Again, these effects are not universal and can overlap with stress, caffeine intake, or overtraining.
Reproductive and Hormonal Considerations
Very high testosterone levels, particularly when driven by external sources, can interfere with the body’s natural hormone signaling. In some cases, this may affect sperm production or alter the balance of other hormones involved in reproductive health.
This highlights an important point: more testosterone is not always better. Hormone balance relies on coordination across multiple systems, and pushing levels too high can disrupt that balance.
How Testosterone Is Measured
Testosterone levels are measured with a blood test, but not all testosterone tests provide the same information. Understanding what is being measured, and how, can make lab results far easier to interpret.
Total Testosterone
Most standard lab tests measure total testosterone, which reflects the overall amount of testosterone circulating in the bloodstream. This includes testosterone that is:
- Bound to proteins in the blood
- Loosely bound and potentially available
- Freely available to tissues
Total testosterone is typically the first test ordered and is often what people mean when they ask about testosterone levels in men.
Free Testosterone
Only a small percentage of testosterone circulates freely in the blood. This is known as free testosterone, and it represents the portion that is biologically active and able to interact with cells.
In some cases, men can have total testosterone levels that fall within the normal range but relatively low free testosterone. This can happen when more testosterone is bound to proteins and unavailable to tissues, which may help explain symptoms despite “normal” results.
Sex Hormone–Binding Globulin (SHBG)
Sex hormone–binding globulin, or SHBG, is a protein that binds tightly to testosterone. Higher SHBG levels can reduce the amount of free testosterone available, even if total testosterone appears adequate.
SHBG levels can be influenced by:
- Age
- Thyroid function
- Liver health
- Metabolic status
- Certain medications
Because of this, SHBG is often measured alongside testosterone to provide a better context.
Timing and Testing Conditions Matter
Testosterone levels follow a daily rhythm. They are typically highest in the early morning and gradually decline throughout the day. For this reason, most clinicians recommend testing testosterone levels in men in the morning, usually before 10 a.m., when levels are more consistent.
Illness, poor sleep, intense exercise, and acute stress can also temporarily affect testosterone levels. If a result is borderline or unexpected, repeat testing may be recommended to confirm a true pattern rather than a one-time fluctuation.
Factors That Influence Testosterone Levels
Testosterone levels in men are shaped by far more than age alone. Daily habits, overall health, and long-term patterns all play a role in how much testosterone the body produces and how effectively it is used. Understanding these factors can help explain why testosterone levels vary so widely between individuals.
Sleep Quality and Duration
Sleep is one of the strongest regulators of testosterone. Most testosterone production occurs during deep sleep, particularly in the early morning hours. Consistently short sleep or fragmented sleep can interfere with this process.
Men who regularly get fewer than six hours of sleep per night often show lower average testosterone levels compared to those who sleep seven to eight hours consistently. Sleep disorders such as obstructive sleep apnea can also disrupt normal testosterone rhythms.
Stress and the Nervous System
Chronic stress places ongoing demands on the body’s stress-response system. When stress hormones such as cortisol remain elevated or poorly regulated, they can interfere with the hormonal signals that support testosterone production.
Over time, this imbalance may contribute to lower testosterone levels, especially when stress is paired with poor recovery, irregular sleep, or inadequate nutrition.
Body Composition and Metabolic Health
Metabolic health has a close relationship with testosterone. Higher levels of body fat, particularly visceral fat, are associated with lower testosterone levels in men. Fat tissue can convert testosterone into estrogen, which may further reduce available testosterone.
Insulin resistance and blood sugar dysregulation are also linked to changes in testosterone production, making metabolic health an important piece of the hormonal picture.
Physical Activity and Recovery
Regular movement and strength-based exercise are generally associated with healthier testosterone levels. However, excessive training without adequate recovery can have the opposite effect.
Overtraining, particularly when combined with calorie restriction or poor sleep, can place stress on the body that suppresses testosterone production rather than supporting it.
Alcohol, Medications, and Environmental Exposures
Certain external factors can influence testosterone levels over time, including:
- Frequent or heavy alcohol intake
- Long-term use of certain medications, such as opioids or glucocorticoids
- Exposure to environmental chemicals that affect hormone signaling
These influences tend to matter most when they are chronic rather than occasional.
Taken together, these factors help explain why two men of the same age can have very different testosterone levels and symptoms.
Supporting Healthy Testosterone Levels With a Personalized, Whole-Body Approach
Because testosterone is influenced by so many systems in the body, supporting healthy testosterone levels often requires looking beyond the hormone itself. Rather than focusing on quick fixes or chasing a specific number, clinicians typically prioritize understanding what may be affecting hormone balance over time.
From a functional and preventive medicine perspective, testosterone is closely connected to sleep, stress regulation, metabolic health, inflammation, and overall hormonal signaling. Addressing these areas together can be more effective and sustainable than targeting testosterone in isolation.
Why a Whole-Body Approach Matters
Testosterone levels in men are often shaped by patterns that develop over time. Factors such as chronic stress, poor sleep, blood sugar imbalance, or unresolved inflammation can quietly influence hormone production and availability.
A holistic approach may involve evaluating:
- Sleep quality and circadian rhythm
- Stress load and nervous system regulation
- Metabolic and cardiovascular health
- Body composition and muscle mass
- Nutrient status and digestive health
- Other hormones that interact with testosterone
By identifying and addressing these contributors, clinicians aim to support the body’s ability to regulate testosterone more effectively, rather than forcing levels in a single direction.
How Parsley Health Clinicians Approach Testosterone Concerns
At Parsley Health, clinicians take a personalized, root-cause approach to hormone health. When testosterone concerns come up, they look at how symptoms, lab results, lifestyle factors, and medical history fit together.
This often includes:
- Reviewing testosterone levels alongside related markers such as free testosterone and SHBG
- Interpreting labs in the context of symptoms and trends over time
- Assessing sleep, stress, nutrition, and metabolic health
- Looking for patterns that may be affecting hormone balance across systems
For men who already have lab results, Parsley Health clinicians can also help interpret existing tests and explain what the numbers may mean for them specifically in the context of overall health.
When Working With a Clinician Can Be Helpful
While not every fluctuation in testosterone requires medical care, working with a clinician may be especially helpful when:
- Symptoms persist despite lifestyle changes
- Testosterone levels are borderline or inconsistent
- Multiple symptoms overlap across energy, mood, metabolism, and sexual health
- Lab results feel confusing or incomplete
In these situations, having guidance from a clinician who takes the time to understand the full picture can help clarify next steps and avoid unnecessary or premature interventions.
Focusing on Long-Term Health, Not Just a Number
Ultimately, supporting healthy testosterone levels is about more than optimizing a lab value. It is about improving how the body functions as a whole and how a person feels day to day.
A personalized, clinician-guided approach can help men understand what their testosterone levels mean for them specifically and how those levels fit into long-term health and well-being.
Frequently Asked Questions About Testosterone Levels in Men
What is a normal testosterone level for a man?
Most laboratories define normal testosterone levels in men as falling somewhere between 300 and 1,000 ng/dL, though the exact range can vary by lab. This reference range reflects what is statistically common across a broad population, not necessarily what feels optimal for every individual.
A level within the normal range does not automatically mean testosterone is well balanced for a specific person. Symptoms, trends over time, and overall health all play an important role in interpretation.
What are average testosterone levels in males by age?
Average testosterone levels in males tend to peak in early adulthood and gradually decline with age. Men in their 20s and early 30s often have higher average levels than men in their 50s or 60s, but there is wide individual variation.
Two men of the same age can have very different testosterone levels and feel equally healthy. Age-based averages are helpful for context, but they are not diagnostic on their own.
How much testosterone does a man have compared to a woman?
Men generally have significantly higher testosterone levels than women. Adult men typically have testosterone levels that are about 10 to 20 times higher than those seen in adult women.
That said, testosterone is important for health in all genders, and balance matters more than absolute comparisons.
Is it normal for testosterone levels to decline with age?
Yes, some decline in testosterone levels with age is considered normal. On average, testosterone levels begin to decrease gradually starting in the late 20s or early 30s.
However, the degree of decline varies widely. Lifestyle factors, sleep, stress, metabolic health, and chronic illness can all influence how quickly testosterone levels change over time.
Can testosterone levels be too high?
Yes. While less common, testosterone levels that are significantly higher than the body can regulate comfortably may cause symptoms or disrupt hormonal balance. Very high levels are most often associated with external hormone use rather than natural production.
This is one reason clinicians focus on balance and context rather than assuming higher testosterone is always better.
What’s the difference between total and free testosterone?
Total testosterone measures all the testosterone circulating in the blood, including testosterone bound to proteins.
Free testosterone measures the small portion that is not bound and is biologically active. Some men have normal total testosterone levels but low free testosterone, which can help explain symptoms.
Clinicians often look at both values, along with binding proteins like SHBG, to better understand testosterone availability.
How often should testosterone levels be tested?
There is no universal schedule for testosterone testing. For men without symptoms, routine testing is not always necessary. When symptoms are present or results are borderline, clinicians may recommend repeat testing to confirm patterns over time.
Testing is typically done in the morning, when testosterone levels are most consistent.
Can lifestyle changes really affect testosterone levels?
Lifestyle factors such as sleep, stress, physical activity, and metabolic health are closely linked to testosterone production and regulation. While results vary from person to person, addressing these areas can support healthier hormone balance over time.
Because testosterone is influenced by many systems, improvements often come from addressing overall health rather than focusing on the hormone alone.
