Average Testosterone Levels By Age

Average testosterone levels by age follow a clear pattern. Levels climb through puberty, peak in the late teens and early 20s, and then drift down slowly in most men from their 30s or 40s. For healthy, non-obese men aged 19 to 39, a reference range harmonized across four large US and European studies runs from 264 to 916 ng/dL (9.2 to 31.8 nmol/L). Low levels become more common with each decade: in one long-running US study, about one in eight men in their 50s and about half of men in their 80s had low total testosterone.

Age is only part of the story. Weight, sleep, illness, alcohol and some medicines can move testosterone more than birthdays do, and the spread between men of the same age is wide. This guide gives the adult data by decade, the normal ranges in both ng/dL and nmol/L, how to get tested properly, the signs of low testosterone, and what actually helps.

What Testosterone Does

Testosterone is a steroid hormone. In men, most of it is made by the testes, in response to signals from the pituitary gland. Women make much smaller amounts in the ovaries and adrenal glands.

In men, testosterone drives the changes of puberty: a deeper voice, facial and body hair, and larger muscles. Through adult life it helps maintain muscle mass and strength, bone density, sex drive, erections, sperm production and red blood cell production. It also affects mood, energy and where the body stores fat.

Both too little and too much cause problems. Low testosterone can lead to low libido, erection problems, fatigue, low mood, loss of muscle and weaker bones. Unusually high levels in men almost always come from taking testosterone or other anabolic steroids, and they bring their own problems, including acne, a raised red blood cell count, shrinking testes and reduced sperm production.

Average Testosterone Levels By Age

The chart above comes from a 2014 study in PLoS One that built an age model of total testosterone in men from published data. Its title sums up the main finding: increasing variance but no decline after age 40. Average levels peaked in the late teens or early 20s, and from middle age on, men grew more and more different from each other.

Other large studies do show a slow fall in the average man, and a steady rise in the share of men with low levels. Much of that fall appears to be tied to weight gain and illness rather than age alone, which is why two men of the same age can have very different results. The table below brings together the best-known adult data by decade.

Testosterone Levels by Age in Men (20s to 80s)

All figures are total testosterone. “Low” in the Baltimore study meant below 325 ng/dL (11.3 nmol/L). Using the free testosterone index instead, which measures testosterone relative to its binding protein SHBG, the shares were higher: 9%, 34%, 68% and 91% for men in their 50s, 60s, 70s and 80s.

Two things stand out. First, there is no official “average” for each decade: most labs use one adult range for all men. Second, free testosterone falls faster than total testosterone, because SHBG (sex hormone-binding globulin) rises with age and holds on to more of it. For the free side of the picture, see our guide to the free testosterone range.

Normal Testosterone Ranges for Adults

Reference ranges vary between labs and test methods, so compare any result with the range printed on your own report. These are the figures most often used:

How Testosterone Changes Through Life

Before puberty: Before birth, testosterone from the fetal testes drives the development of the male reproductive organs. Baby boys have a short surge in the first months after birth, and then levels stay very low in both boys and girls until puberty.

Puberty to early adulthood: Levels rise sharply in boys during puberty. This brings a deeper voice, body and facial hair, growth of the penis and testes, broader shoulders and gains in muscle and bone. Adult levels are usually reached by the late teens.

The 30s and 40s onward: In many men, average levels start to drift down slowly at some point in the 30s or 40s. The figure often quoted is about 1% a year. In the Massachusetts Male Aging Study, which followed men aged 40 to 70, total testosterone fell about 1.6% a year and free testosterone 2-3% a year. Other cohorts, such as the European Male Ageing Study, found a smaller average fall in total testosterone and linked obesity and chronic illness to lower levels.

Later life: Low levels become more common in the 60s, 70s and 80s, but many healthy older men stay in the normal range. A low result in an older man is still worth investigating rather than putting down to age.

Testosterone Levels in Women

Women produce testosterone in the ovaries and adrenal glands, at a small fraction of men’s levels. A typical lab range for adult women is about 8 to 60 ng/dL (0.3 to 2.1 nmol/L).

In women, testosterone falls gradually from the 20s onward. Natural menopause itself causes little sudden change, but surgical removal of the ovaries lowers testosterone noticeably. Many standard testosterone tests are less accurate at the low levels found in women, so a result near the bottom of the range should be read with care.

ng/dL vs nmol/L: How to Read Your Result

US labs usually report total testosterone in nanograms per deciliter (ng/dL). Labs in the UK, Europe, Canada and Australia usually use nanomoles per liter (nmol/L). To convert:

• ng/dL to nmol/L: divide by 28.84 (or multiply by 0.0347)
• nmol/L to ng/dL: multiply by 28.84

Free testosterone is reported in other units again, such as pg/mL, ng/dL or pmol/L, so always check the unit before comparing a result with any range.

When and How to Get Tested

Testosterone follows a daily rhythm. It is highest in the early morning and lower by the afternoon, and the swing is larger in younger men. An afternoon result can look low when the morning level is normal.

Guidelines from the American Urological Association and the Endocrine Society agree on the basics:

• Test in the early morning, usually between about 7 and 10 a.m.
• Fast beforehand if you can. A meal, especially a sugary one, can lower testosterone for a few hours.
• Repeat a low result. One low reading is not a diagnosis. Both guidelines call for at least two low morning measurements on separate days.
• Pick a normal day. Avoid testing during or just after an illness, or after a night of poor sleep.
• Ask about free testosterone and SHBG if your total is borderline or you have a condition that changes SHBG, such as obesity, diabetes, thyroid or liver disease, or older age.
• Check LH if testosterone is low. Luteinizing hormone shows whether the problem is in the testes or in the signals from the pituitary.

Men already on testosterone therapy are tested on a schedule set by their prescriber, and the right timing depends on the type of testosterone used.

Signs and Symptoms of Low Testosterone

Low testosterone (hypogonadism) means consistently low blood levels together with symptoms. The most specific symptoms are sexual ones. In the European Male Ageing Study, poor morning erections, low sex drive and erectile dysfunction were the three symptoms most closely tied to low testosterone.

Sexual symptoms include:

• Lower sex drive
• Fewer morning or spontaneous erections
• Erectile dysfunction (ED)
• Lower sperm count and reduced fertility

Other symptoms include:

• Tiredness and low energy
• Low mood and poor concentration
• Changes in sleep
• Loss of muscle size and strength
• More body fat, especially around the waist
• Weaker bones and, over time, a higher risk of fractures
• Breast tissue growth (gynecomastia)
• Less body and facial hair, which happens slowly over years
• Hot flushes, with very low levels

Many of these symptoms have other causes, such as poor sleep, depression or thyroid problems. That is why a blood test is needed before anything is put down to testosterone.

What Causes Low Testosterone?

Doctors split the causes into two groups. Primary hypogonadism is a problem in the testes themselves, for example from Klinefelter syndrome (a genetic condition), injury, mumps affecting the testes, chemotherapy or radiation. Secondary hypogonadism is a problem with the signals from the pituitary gland or hypothalamus. Common causes include pituitary disorders, high prolactin, obesity, type 2 diabetes, opioid use, and anabolic steroid use that has shut down natural production.

Treatment for Low Testosterone

Testosterone replacement therapy (TRT) is a prescription treatment for men with symptoms and confirmed low levels. It comes as injections, gels, patches, pellets and other forms. A doctor should look for the cause first, then check blood tests before and during treatment.

Age alone is not a reason to start. In 2015 the FDA stated that testosterone products are approved for low testosterone caused by specific medical conditions, such as disorders of the testes, pituitary or hypothalamus, and that their benefits and safety for low testosterone due to ageing alone have not been established.

On safety, the best data comes from TRAVERSE, a large randomized trial published in 2023. It enrolled men aged 45 to 80 with low testosterone and existing heart disease or a high risk of it. Testosterone gel did not increase major heart events compared with placebo, but atrial fibrillation, acute kidney injury and blood clots in the lungs were more common. High-grade prostate cancer was rare in both groups.

TRT also lowers sperm production and can cause infertility, so men who want children need a different plan. It raises the red blood cell count, which needs regular monitoring. Our guide to the pros and cons of TRT covers the trade-offs in detail.

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How to Support Healthy Testosterone Levels

Lifestyle changes will not fix low testosterone caused by a disorder of the testes or pituitary. But for many men, especially those carrying extra weight, they make a real difference.

1. Lose Excess Weight and Eat Well

Obesity is one of the most common causes of low testosterone in men. Fat tissue converts testosterone to estrogen, and excess weight lowers SHBG and dampens the signals from the pituitary. A 2013 meta-analysis found that weight loss raised testosterone in men with obesity, and the more weight they lost, the bigger the rise.

A balanced diet with enough protein, fruit, vegetables, whole grains and healthy fats supports weight control and steady blood sugar. That matters, because type 2 diabetes is strongly linked to low testosterone. Very low-fat diets may lower testosterone slightly: a 2021 meta-analysis of diet trials found men’s levels were modestly lower on low-fat diets. For what to cut back on, see our list of foods that can lower testosterone.

Zinc matters too, because a true zinc deficiency lowers testosterone. Oysters, red meat, shellfish and pumpkin seeds are rich sources. Extra zinc does not appear to raise testosterone in men who are not deficient.

Heavy drinking lowers testosterone, and so do opioid painkillers. If you take regular medication, ask your doctor whether it could be a factor.

2. Exercise Regularly

Resistance training raises testosterone for a short time after a session, and levels return to baseline within an hour or two. Over months, regular training has only a small effect on resting levels in men whose testosterone is already normal. Its main benefit comes from building muscle, losing fat and improving insulin sensitivity, all of which support healthy levels.

More is not always better. Very high training loads combined with too little food can push testosterone down, as seen in some endurance athletes and in military training studies. Recovery matters as much as effort.

3. Get Enough Sleep

Testosterone rises during sleep, so short sleep lowers it. In a 2011 study in JAMA, healthy young men who slept five hours a night for one week had 10-15% lower daytime testosterone. Adults are generally advised to get at least seven hours a night.

Untreated sleep apnea is also linked to low testosterone. Loud snoring, gasping at night and daytime sleepiness are worth raising with a doctor.

4. Correct a Vitamin D Deficiency

Vitamin D and testosterone are linked in observational studies, but supplement trials are mixed. In a year-long trial of overweight men in a weight-loss program, those given about 3,300 IU of vitamin D3 a day saw their total testosterone rise, while the placebo group did not. A later trial in men whose testosterone was already normal found no effect.

The practical point: if a blood test shows you are low in vitamin D, correcting it is worthwhile for your bones and general health, and it may help testosterone. Taking it when your vitamin D is already fine is unlikely to raise testosterone.

5. Manage Stress

Cortisol, the main stress hormone, and testosterone tend to move in opposite directions. Long periods of high cortisol, whether from chronic stress, severe illness or steroid medicines such as prednisone, suppress testosterone production. Chronic stress also tends to worsen sleep, eating habits and weight, which adds to the effect.

Regular exercise, enough sleep and steady routines all help. If stress, low mood or anxiety are constant, talk to a doctor. Depression shares many symptoms with low testosterone, and the two are easy to confuse.