Have you noticed changes in your energy, motivation, strength, mood, or sex drive?
Perhaps you are exercising regularly but finding it harder to maintain muscle. Maybe your sleep has changed, your waistline is increasing, or you simply do not feel like yourself.
For some men, these changes may be associated with declining testosterone levels. For others, they may be related to sleep disorders, metabolic health, stress, medications, thyroid function, or other medical conditions.
Testosterone is an important hormone in men's health, influencing much more than sexual function. It contributes to muscle development, bone health, red blood cell production, reproductive function, and aspects of mood and energy.
At Rediscover Health, we believe understanding men's health starts with looking beyond a single symptom or laboratory result.
Let's explore what testosterone does, how low testosterone is identified, and what men should know about treatment options.
What Is Testosterone?
Testosterone is the primary androgen hormone in men. It is produced mainly by the testicles, with smaller amounts produced by the adrenal glands.
Its production is regulated through a communication system involving the hypothalamus, pituitary gland, and testicles, known as the hypothalamic-pituitary-gonadal axis.
Testosterone plays important roles in:
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Muscle mass and strength
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Bone density
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Sexual desire and erectile function
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Sperm production and fertility
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Red blood cell production
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Fat distribution and body composition
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Mood and aspects of cognitive function
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Development of male reproductive tissues
Testosterone levels naturally change throughout life. They are generally highest during young adulthood and tend to decline gradually with age.
However, not every man experiences clinically significant testosterone deficiency as he gets older.
What Is Low Testosterone?
Low testosterone, also called male hypogonadism or testosterone deficiency, occurs when the body does not produce adequate testosterone and the individual has compatible signs or symptoms.
A diagnosis requires more than simply identifying a number below a laboratory reference range.
Clinical guidelines generally recommend diagnosing testosterone deficiency when a man has compatible symptoms or signs and consistently low testosterone levels confirmed with repeat morning testing.
This distinction matters because some men have low laboratory values without symptoms, while others have symptoms caused by conditions unrelated to testosterone.
Common Signs and Symptoms of Low Testosterone
Symptoms can vary considerably from one man to another.
1. Changes in Sexual Health
Some of the more specific symptoms associated with testosterone deficiency include:
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Reduced sexual desire
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Fewer spontaneous or morning erections
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Erectile difficulties
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Reduced sexual activity
Erectile dysfunction can have many causes, including vascular disease, diabetes, medication effects, and psychological factors. It should not automatically be attributed to testosterone.
2. Changes in Energy and Motivation
Some men report:
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Persistent fatigue
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Reduced motivation
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Decreased stamina
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Difficulty maintaining their usual activity level
These symptoms are nonspecific. Sleep apnea, anemia, thyroid disorders, depression, and other medical conditions should also be considered.
3. Changes in Muscle and Body Composition
Testosterone contributes to muscle development and maintenance.
Low levels may be associated with:
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Reduced muscle mass
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Decreased strength
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Increased fat mass
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Changes in body composition
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Reduced exercise performance
Nutrition, resistance training, physical activity, aging, and metabolic health also influence these outcomes.
4. Mood and Cognitive Changes
Some men with testosterone deficiency report:
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Depressed mood
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Irritability
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Reduced sense of well-being
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Difficulty concentrating
These symptoms are not specific to low testosterone and deserve a broader evaluation.
5. Bone and Blood Health
More significant testosterone deficiency can contribute to reduced bone density and anemia.
In certain men, evaluation may include a bone density assessment or a complete blood count.
What Causes Testosterone to Decline?
There are several reasons testosterone levels may become low.
Age-Related Changes
Testosterone levels generally decline gradually as men age. However, age alone does not establish a diagnosis or automatically justify treatment.
Obesity and Metabolic Health
Obesity, insulin resistance, and type 2 diabetes are associated with lower testosterone levels.
Excess adipose tissue can influence hormone regulation, including the conversion of testosterone to estradiol through the enzyme aromatase.
In some men, weight reduction and improved metabolic health can help improve testosterone levels.
Sleep and Sleep Apnea
Testosterone production is influenced by sleep.
Insufficient sleep and untreated obstructive sleep apnea can contribute to hormonal and metabolic changes.
Men experiencing fatigue, snoring, disrupted sleep, or daytime sleepiness may benefit from evaluation for sleep disorders.
Chronic Illness and Medications
Certain medical conditions and medications can affect testosterone production.
Potential contributors include:
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Chronic systemic illness
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Pituitary or testicular disorders
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Opioid medications
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Long-term glucocorticoid use
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Certain cancer treatments
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Previous testicular injury or surgery
Identifying the underlying cause is an important part of treatment planning.
How Is Testosterone Properly Tested?
One of the most important parts of evaluating testosterone is getting the timing and interpretation right.
Testosterone levels fluctuate throughout the day and may be affected by illness, sleep, food intake, medications, and other factors.
1. Total Testosterone
Total testosterone measures the testosterone circulating in the blood, including testosterone bound to proteins and the small fraction that is unbound.
For men with suspected testosterone deficiency, guidelines recommend obtaining an early-morning total testosterone level, generally between 7 a.m. and 10 a.m.
A low result should be confirmed with a second morning measurement on a separate day.
Testing should generally be performed when the patient is not experiencing an acute illness.
2. Free Testosterone
Most circulating testosterone is bound to sex hormone-binding globulin (SHBG) or albumin.
Only a small percentage circulates freely.
Free testosterone can be helpful when:
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Total testosterone is near the lower end of the reference range.
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SHBG is suspected to be abnormal.
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Symptoms are present but total testosterone does not clearly explain them.
When indicated, free testosterone should be measured using a reliable method or calculated using appropriate measurements of total testosterone, SHBG, and albumin.
Direct analog free testosterone immunoassays are generally less reliable.
3. SHBG: Sex Hormone-Binding Globulin
SHBG is a protein that binds testosterone and influences how much testosterone is available in circulation.
SHBG can be affected by several factors, including:
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Obesity and insulin resistance
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Aging
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Thyroid function
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Liver disease
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Certain medications
Understanding SHBG can help clinicians interpret testosterone results more accurately.
4. LH and FSH
When low testosterone is confirmed, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) may help identify the underlying cause.
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High LH: May suggest that the testicles are not responding adequately to pituitary signaling (primary hypogonadism).
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Low or inappropriately normal LH: May suggest a problem involving the hypothalamus or pituitary gland (secondary hypogonadism).
This distinction can influence further testing and treatment decisions.
5. Additional Testing When Appropriate
Depending on the patient's history and initial results, a clinician may consider:
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Prolactin
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Thyroid-stimulating hormone (TSH)
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CBC and hematocrit
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Comprehensive metabolic panel
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Hemoglobin A1c
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Lipid panel
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Ferritin and iron studies
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Estradiol in selected clinical situations
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PSA and prostate evaluation when appropriate before treatment
Not every man needs every test. Laboratory evaluation should be guided by symptoms, medical history, examination, and clinical findings.
What Are the Treatment Options for Low Testosterone?
Treatment depends on the cause, severity of symptoms, laboratory findings, reproductive goals, and overall health.
1. Address Underlying Health Factors
For some men, addressing contributing conditions may improve testosterone levels and overall well-being.
This may include:
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Weight management when appropriate
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Resistance exercise
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Adequate protein and nutrient intake
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Improved sleep
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Evaluation and treatment of sleep apnea
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Management of diabetes and metabolic risk factors
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Reviewing medications that may affect testosterone
Lifestyle changes are not a substitute for testosterone therapy in every man, but they are an important part of comprehensive care.
2. Testosterone Replacement Therapy (TRT)
For men with confirmed testosterone deficiency and appropriate clinical indications, testosterone replacement therapy may be considered.
FDA-approved formulations include:
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Topical gels
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Transdermal patches
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Injectable testosterone
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Certain nasal formulations
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Buccal formulations
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Long-acting injectable preparations
The best option depends on the patient's health history, preferences, access, cost, and clinical needs.
Potential benefits in appropriately selected men may include improvements in sexual desire, correction of anemia associated with testosterone deficiency, increased lean body mass, and improvements in bone density.
Effects on fatigue, mood, physical function, and overall quality of life vary.
Testosterone therapy is not a guaranteed solution for weight loss, muscle building, anti-aging, or general wellness.
3. Fertility Considerations
This is a particularly important topic for younger men.
External testosterone therapy suppresses the signals that stimulate the testicles to produce testosterone and sperm.
As a result, TRT can significantly reduce sperm production and may cause infertility.
Men who desire future fertility should discuss this before beginning treatment.
Depending on the cause, a specialist may consider alternative approaches that preserve or stimulate endogenous testosterone production, such as certain medications used under appropriate clinical supervision.
4. Monitoring During Testosterone Therapy
Testosterone therapy requires ongoing medical monitoring.
Depending on the treatment and individual risk factors, monitoring may include:
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Testosterone levels
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CBC and hematocrit
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Blood pressure
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PSA and prostate health when appropriate
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Assessment of symptoms and treatment response
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Evaluation for adverse effects
Testosterone therapy can increase hematocrit, sometimes to an unsafe level. Monitoring is important to identify this complication.
Is Testosterone Therapy Safe?
Testosterone therapy can be appropriate for men with confirmed testosterone deficiency, but it is not risk-free.
Potential concerns include:
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Increased red blood cell production and elevated hematocrit
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Acne and oily skin
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Fluid retention
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Breast tenderness or enlargement
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Suppression of sperm production and fertility
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Worsening of certain sleep-related breathing disorders
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Potential changes in blood pressure
Testosterone therapy is not appropriate for every man. Certain conditions require avoidance or specialist evaluation, including some prostate or breast cancers, elevated hematocrit, and specific cardiovascular or sleep-related conditions.
What About Cardiovascular Risk?
The cardiovascular safety of testosterone therapy has been an important area of research.
The large TRAVERSE clinical trial found that testosterone replacement was noninferior to placebo for major adverse cardiovascular events in the studied population of men with hypogonadism and increased cardiovascular risk. However, certain adverse events occurred more frequently in the testosterone group, including atrial fibrillation, acute kidney injury, and pulmonary embolism.
In 2025, the FDA removed the boxed-warning language about increased major cardiovascular outcomes from testosterone product labeling following review of the available evidence, while requiring class-wide labeling changes addressing increased blood pressure.
This does not mean testosterone therapy is risk-free or appropriate for men without a confirmed medical indication.
The decision should always be individualized.
What About Testosterone and Estrogen?
Men produce estrogen too.
A portion of testosterone is converted into estradiol through aromatase, an enzyme found in various tissues, including adipose tissue.
Estradiol plays important roles in men, including:
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Bone health
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Sexual function
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Hormonal regulation
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Aspects of metabolic and reproductive physiology
Both excessively low and elevated estradiol levels can be clinically relevant in certain situations.
However, elevated estradiol should not automatically be treated with an estrogen-blocking medication. Treatment decisions should be based on symptoms, laboratory findings, and the underlying cause.
The Rediscover Health Approach to Men's Hormonal Health
At Rediscover Health, we believe men deserve a thoughtful and individualized approach to hormone health.
Rather than focusing on one laboratory number, we consider the broader clinical picture.
This may include:
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Symptoms and health history
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Testosterone and other relevant hormone testing
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Metabolic health
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Nutrition and physical activity
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Sleep quality
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Medication review
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Cardiovascular and prostate risk factors
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Fertility goals
Our goal is to help men understand what may be contributing to their symptoms and explore appropriate, evidence-based options.
You do not have to ignore changes in your health simply because you are getting older. But you also deserve more than a quick prescription based on one laboratory result.
Ready to Take a Closer Look at Your Health?
If you are experiencing changes in energy, strength, sexual health, mood, or body composition, a personalized clinical evaluation can help determine whether testosterone testing or another type of assessment may be appropriate.
https://altroapp.com/rediscoverhealth
Look Deeper. Restore Balance. Rediscover Health.
Frequently Asked Questions
What is considered a low testosterone level in men?
The American Urological Association uses a total testosterone level below 300 ng/dL as a reasonable cutoff to support the diagnosis, when accompanied by symptoms or signs and confirmed with repeat testing. Laboratory reference ranges and clinical interpretation also matter.
What time of day should testosterone be tested?
Testing is generally recommended in the early morning, usually between 7 a.m. and 10 a.m. A low result should be confirmed with a second morning test on a separate day.
Can low testosterone cause weight gain?
Low testosterone can be associated with changes in lean muscle mass and fat distribution. However, weight gain is multifactorial and may involve nutrition, sleep, activity, insulin resistance, medications, and other health conditions.
Does testosterone therapy improve energy?
Some men report improvements in energy or well-being, but results vary. Fatigue has many potential causes, and testosterone therapy should only be considered when deficiency is appropriately diagnosed.
Can testosterone therapy cause infertility?
Yes. External testosterone can suppress sperm production and significantly reduce fertility. Men who want to have children should discuss fertility-preserving options before starting therapy.
Do men need estrogen testing?
Not routinely. Estradiol testing may be useful in selected clinical situations, such as certain breast symptoms or when evaluating specific hormone-related concerns.
Articles:
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American Urological Association — Testosterone Deficiency Guideline
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Endocrine Society — Testosterone Therapy in Men With Hypogonadism
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TRAVERSE Trial — Cardiovascular Safety of Testosterone-Replacement Therapy, New England Journal of Medicine (2023).
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FDA — Testosterone Products: Drug Safety Communication and Labeling Updates (2025).
Medical Disclaimer: This article is for educational purposes only and is not intended to diagnose, treat, cure, or prevent disease. Testosterone therapy requires an appropriate clinical evaluation, confirmation of testosterone deficiency, and ongoing monitoring. Do not begin, stop, or change hormone treatment without guidance from a qualified healthcare professional.