Testosterone

What Is Testosterone?

Testosterone is a hormone — a chemical messenger that travels through your bloodstream telling different parts of your body what to do. While it is often called the "male hormone," both men and women produce testosterone. Men just make a lot more of it.

In men, testosterone is primarily made in the testicles. In women, smaller amounts are produced by the ovaries and adrenal glands. This hormone plays a role in everything from muscle mass and bone density to mood, energy levels, and sex drive. It is one of the most important hormones for overall health and well-being in both sexes.

What Does It Measure?

A testosterone blood test measures the total amount of testosterone circulating in your blood. Most testosterone in the bloodstream is bound to proteins (mainly sex hormone-binding globulin, or SHBG, and albumin), while a small percentage floats freely. A "total testosterone" test captures all of it — both bound and free.

Your doctor uses this test to evaluate whether your body is producing an appropriate amount of testosterone for your age and sex. It is a key piece of the puzzle when investigating symptoms like fatigue, low libido, mood changes, or fertility issues.

Normal Ranges

| Group | Range | Unit | |---|---|---| | Adult men (19–39 years) | 264 – 916 ng/dL | ng/dL | | Adult men (40–59 years) | 200 – 870 ng/dL | ng/dL | | Adult men (60+ years) | 170 – 750 ng/dL | ng/dL | | Adult women (19–49 years) | 8 – 48 ng/dL | ng/dL | | Adult women (50+ years) | 5 – 32 ng/dL | ng/dL | | Children (prepubertal) | Less than 20 ng/dL | ng/dL |

Testosterone levels in men naturally decline by about 1–2 percent per year after age 30. Levels also fluctuate throughout the day, peaking in the early morning and dipping in the evening, which is why doctors typically draw blood in the morning for the most accurate reading.

What Does a High Level Mean?

Elevated testosterone can mean different things depending on your sex:

In men:

• Anabolic steroid use: The most common cause of very high testosterone in men is the use of testosterone supplements or anabolic steroids.
• Tumors: Rarely, tumors of the testicles or adrenal glands can produce excess testosterone.
• Congenital adrenal hyperplasia: A genetic condition that causes the adrenal glands to overproduce certain hormones.

In women:

• Polycystic Ovary Syndrome (PCOS): This is the most common cause of elevated testosterone in women, often accompanied by irregular periods, acne, and excess hair growth.
• Adrenal disorders: Conditions affecting the adrenal glands can raise testosterone levels.
• Ovarian tumors: Rarely, certain ovarian tumors can produce excess testosterone.

Symptoms of high testosterone in women may include acne, deepening of the voice, increased body hair, thinning scalp hair, and irregular menstrual periods. In men, symptoms are less common but can include aggressive behavior, acne, and in some cases, shrinking of the testicles if external testosterone is being used.

Your doctor may recommend additional hormone testing, imaging studies, or a referral to an endocrinologist.

What Does a Low Level Mean?

Low testosterone (sometimes called "low T") is increasingly common and can affect quality of life significantly:

In men:

• Hypogonadism: The testicles do not produce enough testosterone, either due to a problem with the testicles themselves (primary) or with the pituitary gland that signals them (secondary).
• Aging: Gradual decline is normal, but some men drop below healthy levels.
• Chronic illness: Conditions like type 2 diabetes, obesity, liver disease, and kidney disease can lower testosterone.
• Medications: Opioid pain medications, certain antidepressants, and corticosteroids can suppress testosterone production.

In women:

• Adrenal insufficiency: The adrenal glands are not producing enough hormones.
• Surgical removal of ovaries: This causes a sharp drop in testosterone.
• Pituitary gland disorders: Problems with the pituitary can reduce hormone production across the board.

Common symptoms of low testosterone include fatigue, decreased sex drive, difficulty concentrating ("brain fog"), depressed mood, loss of muscle mass, increased body fat, and reduced bone density.

If your levels are low, your doctor may repeat the test, check other hormones (like LH, FSH, and prolactin), and discuss potential treatment options.

When Should You Get Tested?

Consider talking to your doctor about a testosterone test if you experience:

• Persistent fatigue that does not improve with rest
• Low sex drive or erectile dysfunction
• Unexplained loss of muscle mass or strength
• Mood changes, irritability, or depression
• Difficulty concentrating or memory problems
• In women: irregular periods, unexplained acne, or excess hair growth
• Fertility difficulties in either sex
• If you are monitoring hormone replacement therapy

How to Improve Your Levels

If your testosterone is on the lower side, these lifestyle changes may help support healthy levels:

• Prioritize sleep: Aim for 7–9 hours of quality sleep per night. Most testosterone is produced during sleep, so poor sleep directly impacts your levels.
• Exercise regularly: Resistance training (weight lifting) and high-intensity interval training (HIIT) have been shown to boost testosterone. Aim for 3–4 sessions per week.
• Maintain a healthy weight: Excess body fat, especially around the midsection, is strongly linked to lower testosterone. Losing even 10–15 percent of body weight can significantly improve levels.
• Manage stress: Chronic stress elevates cortisol, which suppresses testosterone production. Meditation, deep breathing, and regular physical activity can help.
• Eat a balanced diet: Include plenty of protein, healthy fats (like olive oil, avocados, and nuts), and zinc-rich foods (like oysters, beef, and pumpkin seeds). Vitamin D is also important — get sunlight or consider a supplement.
• Limit alcohol: Heavy drinking can significantly reduce testosterone production.

Frequently Asked Questions

Q: Is it normal for testosterone to decrease with age?

Yes, it is completely normal. Testosterone levels peak in the late teens to early twenties and then gradually decline by about 1–2 percent per year starting around age 30. This natural decline does not necessarily require treatment unless levels drop below a healthy range and you are experiencing symptoms.

Q: Why does my doctor want to test in the morning?

Testosterone levels follow a daily rhythm called a circadian pattern. Levels are highest in the early morning (around 7–9 AM) and lowest in the late afternoon and evening. Testing in the morning gives the most consistent and accurate baseline measurement.

Q: Can low testosterone cause weight gain?

Yes, low testosterone can contribute to increased body fat, particularly around the abdomen. Testosterone helps regulate fat distribution and metabolism. At the same time, excess body fat can further lower testosterone, creating a frustrating cycle. Exercise and dietary changes can help break this pattern.

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This content is for educational purposes only and is not medical advice. Always consult your healthcare provider about your lab results.