The Ultimate Guide to Male Hormones & Men’s Health

Mel introduces Stanford urologist Dr. Michael Eisenberg, who leads Stanford’s Male Reproductive Medicine and Surgery Program and the International Azoospermia Center. She says she and her husband, Chris, had discussed testosterone for two years and asks whether he should take it. Eisenberg frames reproductive health as more than sex or fertility: hormone and sexual changes can be windows into future overall health. He says the conversation will cover hormonal, sexual, and reproductive testing, treatment options, and the agency men have to improve quality of life and possibly longevity. Mel positions the episode for men and for partners who notice that someone they love is unusually tired, withdrawn, or unlike himself.

Eisenberg explains that testosterone rises during puberty, peaks around ages 20 to 30, and then generally falls about 1% per year. The normal range is broad—roughly 300 to 900 nanograms per deciliter—so “normal” varies among men. Population data suggest low testosterone occurs in about 10% to 20% of men in their 40s or 50s, about 20% in the 60s, 30% in the 70s, and 50% in the 80s. Age, metabolic health, and body fat also affect levels. He says symptoms such as low energy, low sex drive, depressed mood, poor sleep, poor concentration, erectile dysfunction, anemia, or unexplained low bone density warrant discussion with a doctor.

Eisenberg emphasizes that low energy, low libido, mood changes, sleep problems, and concentration difficulties are not specific to testosterone, but they deserve evaluation when they persist or bother the man or his partner. Mel relates this to Chris’s earlier depression, low energy, shutdown behavior, and reduced sex drive, while noting that these signs could point to something deeper without proving the cause. Eisenberg welcomes partners who attend appointments, calling treatment a “team sport” and saying an engaged spouse or partner can improve the likelihood of treatment success. He says men may first seek care only after years of silently compensating for symptoms.

Eisenberg says men with symptoms or risk factors—including loss of a testicle, chemotherapy, anemia, or low bone mineral density—may reasonably be screened, often beginning around ages 40 or 50, or earlier when risk factors exist. Testing is a blood draw, preferably around 9 or 10 in the morning because testosterone follows a daily rhythm; Eisenberg generally prefers a fasted sample but is not rigid about it. A single low result should usually be repeated. Testosterone treatment is considered when two tests confirm low levels and the man has relevant symptoms. Most testosterone—90% or more—is produced in the testicles, with the adrenal glands contributing a small fraction.

For men who truly have low testosterone, Eisenberg says treatment can improve energy, vitality, libido, erectile function, penile health, bone mineral density, anemia, lean body mass, strength, and sometimes metabolic health. Studies of prediabetic men found those receiving testosterone had a lower risk of developing diabetes. Patients also report improved mood, cognitive capacity, sleep, work focus, and motivation, although Eisenberg distinguishes these responses from claims that testosterone benefits everyone. Mel asks about Chris having one testicle after hernia-related surgery. Eisenberg says one testicle can often compensate by enlarging and producing enough hormone, but not always, so the individual’s levels and symptoms must be checked.

Poor sleep blunts the brain-to-testicle hormonal feedback loop and suppresses the normal morning rise in testosterone; seven to nine hours is ideal, while four or five hours, shift work, and disrupted circadian rhythms can lower levels. Sleep apnea is linked in both directions with low testosterone. Excess body fat increases conversion of testosterone into estradiol in fatty tissue and can worsen metabolic regulation; weight loss through diet, exercise, GLP-1 medications, or bariatric surgery can raise testosterone. Chronic stress elevates cortisol and shifts the body toward immediate survival rather than reproduction and longevity. Depression can both lower testosterone and be worsened by it, while some antidepressants also reduce hormone and sexual function. Heavy alcohol use blunts testosterone production, though reducing consumption can allow recovery.

Mel asks about Chris’s concern that injectable testosterone means decades of oil-based injections and uncertain long-term effects. Eisenberg confirms injections are oil-based, usually given every two weeks, though some men use weekly or twice-weekly dosing to reduce peaks and valleys. Other options include longer-acting injections, daily gels, pellets under the skin, and oral tablets. Testosterone has been used for decades, but it is not automatically appropriate. Exogenous testosterone tells the brain there is enough hormone, suppressing the signals that stimulate the testicles; sperm production falls reliably, probably about 90% of the time, because sperm require testosterone levels inside the testicle far higher than levels in the bloodstream.

Eisenberg lists possible side effects of testosterone as oily skin, acne, hair loss, breast growth from conversion to estrogen, increased red blood cell counts, and clotting risk. He says the large TRAVERSE trial, involving about 5,000 men given testosterone or placebo, did not find the previously feared increases in prostate cancer, heart attacks, or strokes; he expects FDA prescribing warnings to be updated. However, men with normal testosterone should generally not take it: evidence suggests it is unlikely to improve their symptoms or sexual performance. Military studies found testosterone increased lean body mass but did not improve performance or recovery compared with placebo. Treatment should therefore be supervised by a knowledgeable physician rather than a clinic that simply upsells prescriptions.

Men whose testicles cannot produce testosterone—for example, after losing both testicles or because of certain congenital conditions—usually need lifelong replacement. For men with symptoms and low readings caused by potentially reversible conditions, Eisenberg recommends a monitored trial. Doctors check whether the level reaches a therapeutic range, adjust formulations for convenience, and assess whether energy, mood, sexual function, or other symptoms improve. If there is no meaningful benefit after roughly six months to a year, treatment can be stopped. Weight loss and improved health may restore the body’s own production, allowing some men to taper off. Mel asks partners to raise the issue compassionately by connecting testing to overall health, longevity, and being present for one another.

Eisenberg defines erectile dysfunction as a recurrent or consistent inability to achieve or maintain an erection sufficient for sexual activity. He cites the Massachusetts Male Aging Study: trouble affects about 40% of men in their 40s, 50% in their 50s, 60% in their 60s, and 70% in their 70s, while roughly 15% to 20% of men in their 20s and 30s experience it. An erection depends on blood entering and remaining in erectile tissue after stimulation triggers nitric oxide and cyclic GMP. Smoking, diabetes, high cholesterol, high blood pressure, medication, prostate surgery, and sometimes bicycle saddles can impair that blood flow. Eisenberg’s message is that what is good for the heart is generally good for the penis.

Men with erectile dysfunction may feel inadequate, less masculine, guilty, depressed, or responsible for relationship problems, and may withdraw from intimacy. Eisenberg tells partners that ED is common and treatable, saying, “As long as you have a penis, we can always make it hard,” though treatment may require increasingly aggressive options. First-line therapy is usually a phosphodiesterase-5 inhibitor. Sildenafil or Viagra is taken about an hour before sex, preferably away from food, and may cause headache, flushing, backache, indigestion, nasal congestion, or cramps. Tadalafil or Cialis lasts longer—roughly 16 to 18 hours versus six to eight for sildenafil—and can be taken daily. Possible cardiovascular benefits are observational, not proven in the strongest trial design.

Eisenberg says Viagra, Levitra or vardenafil, and Cialis or tadalafil work through the same general mechanism, though they differ in speed, duration, and side effects. These drugs do not create a permanent erection or force unwanted sex; they help a man respond when he is stimulated. If pills fail, medication can be placed in the urethra as a gel or small pellet five to ten minutes before sex. It works 60% to 80% of the time but may cause tingling or a low-grade burn. Penile injections directly dilate the erectile bodies and work about 90% of the time. Eisenberg acknowledges the psychological barrier of injecting the penis but describes it as highly effective.

Eisenberg cites a study of about 30,000 men followed for roughly 20 years in which men reporting 20 or more ejaculations per month had about a 20% lower risk of prostate cancer than men reporting fewer. The association did not depend on whether ejaculation occurred through sex or masturbation, though he does not prescribe 20 ejaculations as a requirement. Other studies associate sex once or twice weekly with longer life than sex less than once monthly, possibly reflecting both sexual activity and relationship quality. Scandinavian registry data, as Eisenberg presents it, found that men without a partner had a 60% higher mortality risk, men without children also had a 60% higher risk, and men with neither had about a threefold higher risk.

Eisenberg says sperm counts have declined globally across Western and Eastern countries and every continent, with evidence suggesting the decline may have accelerated over the past 20 years. He also notes falling testosterone levels, altered puberty timing, and higher testicular cancer risk. Fertility problems involve a male factor in about half of cases: roughly 30% are attributable only to the man and 20% involve both partners. Yet men are often never evaluated before couples move to IVF, leaving correctable hormonal, anatomical, medication, lifestyle, or general-health issues undiscovered. Because sperm production takes two to three months, earlier evaluation matters. Home testing is making private, immediate initial assessment more accessible.

Pelvic-floor muscles help control erections, ejaculation, orgasm, urination, and bowel movements. Spasms can contribute to pelvic or scrotal pain, while exercises after prostate surgery can help restore urinary control. With age, an enlarging prostate can narrow the urethra, making the bladder work harder and causing slower emptying, urgency, or nighttime urination. Waking once nightly can be normal, but waking two, three, or four times—or taking a long time to urinate—should be evaluated, especially because sleep apnea can increase nighttime urine production. Doctors may check urine for infection or inflammation, assess the prostate, and order PSA, which helps estimate prostate size and screens for prostate cancer. Prostate cancer is usually asymptomatic and detected through screening.

Eisenberg’s central recommendation is to take an honest inventory of health and recognize that men have agency to improve it. Annual medical visits can establish blood pressure, cholesterol, blood sugar, hormone, sexual-function, and reproductive baselines, while exercise, healthy weight, better sleep, stress reduction, and moderated alcohol use may address several problems at once. Low testosterone, erectile dysfunction, reduced sperm counts, or urinary symptoms should not be dismissed as shameful or inevitable aging; they may signal broader health issues and have multiple treatments. Mel closes by stressing that Dr. Eisenberg’s message is not simply about sex: medical evaluation can help men feel better, remain connected to partners, and preserve quality of life and longevity.