A lot of what you hear about testosterone levels in men focuses on muscle, energy, and aging. That matters, but your testosterone has a direct and powerful impact on your sexual health too, from desire and erections to fertility and mood. Understanding how this hormone works helps you make sense of your body, your lab results, and your options if something feels off.
In this guide, you will learn what testosterone does, what “normal” looks like, how low or high levels can affect your sex life, and what you can realistically do about it.
Understand what testosterone actually does
Testosterone is the main male sex hormone. Your brain sends signals to your pituitary gland, which then tells your testes to make testosterone, keeping levels within a tight range through a feedback loop (Harvard Health Publishing).
You produce the most testosterone in your teens and early 20s. Levels peak around age 19, then slowly decline by about 1 to 2 percent each year after age 30 (Healthline). Many men still feel fine, but some start to notice changes.
Testosterone helps:
- Drive your sex desire (libido)
- Support erections and response to sexual stimulation
- Build and maintain muscle mass and bone density
- Support sperm production and fertility
- Influence mood, energy, and overall well‑being
As you get older, your testes can produce less testosterone, your pituitary signals may weaken, and your liver makes more sex hormone binding globulin, which reduces free, active testosterone in your blood (Harvard Health Publishing).
Know what “normal” testosterone levels look like
You often hear about “low T” but normal ranges are rarely explained clearly. For adult men, typical total testosterone levels are about 250 to 836 ng/dL (8.7 to 29 nmol/L) (Medichecks).
Different medical groups use slightly different cutoffs, but here are useful guideposts:
- The American Urology Association defines low testosterone as less than 300 ng/dL (Cleveland Clinic).
- Some experts consider levels below 250 ng/dL to be clearly low.
- Levels below about 12 nmol/L may be where you start to benefit from testosterone treatment, but only if you also have symptoms like low libido or erectile problems (Medichecks).
This is important: your number alone does not tell the full story. You can have a “low‑normal” level and feel terrible, or a slightly lower number and feel fine. Doctors look at both your symptoms and your blood results, ideally from two separate early‑morning tests, before they diagnose low testosterone.
Recognize how low testosterone affects your sexual health
Low testosterone, often called male hypogonadism, happens when your testes do not make enough of the hormone or your brain is not sending strong enough signals to tell them to produce it (Cleveland Clinic).
Sexual symptoms you may notice include:
- Lower sex drive than usual
- Fewer or weaker morning erections
- Difficulty getting or keeping an erection
- Reduced sexual satisfaction or less intense orgasms
- Fertility issues related to low sperm count or poor sperm quality
Non‑sexual symptoms often show up alongside these, such as fatigue, low mood, loss of muscle, increased belly fat, and thinner bones or osteoporosis (Harvard Health Publishing).
Low testosterone becomes more common with age. About 2 percent of men overall have it, but estimates rise to more than 8 percent in men aged 50 to 79, about 30 percent of overweight men, and 25 percent of men with type 2 diabetes (Cleveland Clinic; Urology Care Foundation).
Because symptoms like fatigue and low libido can also come from stress, depression, sleep problems, or relationship issues, working with a doctor is essential to understand what is actually going on.
If your sex drive feels different, do not assume it is “just aging” or “in your head.” It is worth checking your testosterone levels and reviewing your overall health.
See how lifestyle and health conditions influence your levels
Your genetics lay the foundation for testosterone production, and certain conditions like Klinefelter syndrome can cause low levels from birth (Healthy Male). But your day‑to‑day choices and medical history also matter a lot.
Factors that can drive testosterone levels in men down include:
- Being overweight or obese. Belly fat increases aromatase activity, an enzyme that converts testosterone into estrogen. For every 1‑point drop in your body mass index (BMI), testosterone may rise by roughly 1 point (U.S. Department of Veterans Affairs).
- Diabetes. Men with diabetes are more likely to have low testosterone, and low testosterone raises your chances of developing diabetes later (Healthy Male; U.S. Department of Veterans Affairs).
- Poor sleep. Most of your testosterone is produced during deep REM sleep. Restricting sleep to five hours a night for a week can cut daytime testosterone by 10 to 15 percent (U.S. Department of Veterans Affairs; Healthy Male).
- Long‑term stress. High cortisol over time can suppress testosterone production (Healthline).
- Medications. Opioid painkillers like morphine can drop levels within hours of starting treatment, especially at higher doses. The effect may last months or years but often improves after stopping the drug (U.S. Department of Veterans Affairs).
On the flip side, several habits support healthy testosterone and sexual function:
- Regular exercise, especially a mix of resistance training and aerobic workouts, raises testosterone in the short term and improves body composition (Healthline; U.S. Department of Veterans Affairs).
- A balanced diet with enough protein, healthy fats, and complex carbohydrates keeps hormone production stable. Very low‑fat diets or constant yo‑yo dieting can harm levels (Healthline).
- Healthy weight management improves hormone balance, reduces aromatase activity, and can lift testosterone significantly, especially if you start out heavier (Healthy Male).
- Adequate vitamin D may help if you are deficient, although research results are mixed. Up to 1 billion people worldwide do not get enough vitamin D (Healthline).
These same lifestyle changes not only support testosterone, they also directly improve sexual health by boosting cardiovascular fitness, confidence, and mood.
Understand testosterone therapy and sexual health benefits
If you have clear symptoms and repeatedly low blood tests, your doctor may discuss testosterone replacement therapy (TRT). This is an approved treatment when your testes, pituitary, or hypothalamus do not work properly or when you have delayed puberty or certain genetic conditions (Harvard Health Publishing; Urology Care Foundation).
TRT can be delivered in several ways:
- Skin patches or gels
- Injections
- Oral or cheek (buccal) preparations
- Nasal gels
- Pellets placed under the skin
No single method has been proven best for everyone (Urology Care Foundation).
When you truly have low testosterone levels, treatment can:
- Improve libido and sexual desire
- Support better erectile function
- Increase lean muscle mass and strength
- Improve bone density and reduce fracture risk
- Help with anemia and sometimes low mood (Harvard Health Publishing; Urology Care Foundation; Cleveland Clinic)
It is not a magic fix for everything. For example, TRT has not consistently improved memory, energy in men without clear deficiency, or blood sugar levels in diabetes (Urology Care Foundation).
You also need to weigh risks. TRT can:
- Increase red blood cell and platelet counts, which may raise clot risk (UCSF News)
- Worsen sleep apnea
- Aggravate benign prostate enlargement
- Stimulate growth of an existing prostate cancer, although it does not appear to cause new prostate cancers (Harvard Health Publishing)
Because of these issues, you should be monitored regularly if you start therapy, especially if you have heart disease risks or a history of prostate problems (Urology Care Foundation).
Look at testosterone, heart health, and safety
You may have seen headlines about testosterone therapy and heart risk. The reality is nuanced, and scientists are still working through conflicting data.
One UCSF study of nearly 700 older men found that those with testosterone levels in the top 25 percent, at or above 495 ng/dL, were 2.2 times more likely to have a heart attack or other heart event than men in the lowest 25 percent, at or below 308 ng/dL, over four years (UCSF News).
In another trial of frail men aged 65 and older with low levels, a testosterone gel study was stopped early when 10 men in the treatment group had cardiac events, compared with 1 in the placebo group. The gel raised their levels into the 500 to 1000 ng/dL range, raising safety questions (UCSF News).
At the same time, some studies suggest that very low testosterone is linked with higher heart disease mortality, although those studies are less rigorously monitored and low levels may simply reflect chronic illness (UCSF News).
Because the heart and testosterone connection is still unclear, large NIH‑sponsored trials involving more than 800 men are underway to clarify the long‑term risks and benefits (UCSF News).
For you, this means:
- Do not pursue very high “bodybuilder” testosterone levels for sexual performance.
- If you are on TRT, keep up with your doctor appointments and blood tests.
- Always factor in your age, heart health, and other medical conditions when deciding whether therapy makes sense.
Take practical steps to support sexual health and testosterone
You cannot control every factor that influences testosterone levels in men, but you have more power than you might think. Small, consistent changes often help your sex life and your hormone balance at the same time.
Here are realistic steps to consider:
-
Get tested if something feels off
If you notice a sustained drop in sex drive, fewer morning erections, or new erectile issues, talk to your doctor. Ask for early‑morning testosterone tests on two separate days, along with checks for diabetes, thyroid problems, and cholesterol. -
Prioritize sleep
Aim for 7 to 9 hours of quality sleep. Set a consistent bedtime, keep screens out of the bedroom when you can, and watch caffeine and alcohol at night. Your body produces most of its testosterone during deep REM sleep (U.S. Department of Veterans Affairs). -
Lift and move regularly
Combine resistance training like weight lifting with brisk walking, cycling, or other cardio. This mix helps maintain healthy testosterone levels, improves blood flow for erections, and supports weight management (Healthline; U.S. Department of Veterans Affairs). -
Aim for a healthy waistline, not a perfect body
Even modest fat loss can boost testosterone and improve sexual confidence. Focus on sustainable habits like portion awareness, more whole foods, and cutting back on sugary drinks, rather than extreme diets. -
Manage stress in daily, practical ways
Chronic stress drags down testosterone and libido. Short walks, breathing exercises, hobbies, or talking with someone you trust can help keep cortisol from staying high all the time (Healthline). -
Review medications with your doctor
If you are on opioids or other drugs that might affect hormones, ask whether there are alternatives or strategies to protect your testosterone (U.S. Department of Veterans Affairs). -
Keep an eye on vitamin D and general health
Consider having your vitamin D checked, especially if you do not get much sun. Also stay on top of blood pressure, blood sugar, and cholesterol, since a healthy heart and blood vessels are essential for firm, reliable erections.
Finally, remember that sexual health is not only about numbers on a lab report. Your relationships, mental health, body image, and communication with partners all shape your experience in bed.
If you start by understanding how testosterone levels in men influence desire, erections, and overall health, you will be better equipped to ask the right questions, push for the right tests, and choose treatments or lifestyle changes that support both your hormones and your sex life over the long term.
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