Testosterone is more than just the primary male sex hormone (androgen) behind deep voices and facial hair. It’s a key player in shaping your body from the inside out, influencing everything from muscle growth and fat distribution to energy levels and metabolic health.
Testosterone is more than just the primary male sex hormone (androgen) behind deep voices and facial hair. It’s a key player in shaping your body from the inside out, influencing everything from muscle growth and fat distribution to energy levels and metabolic health.
When T levels drop due to age, stress, or medical conditions (like male hypogonadism), men can experience a shift in body composition, which often looks like more fat around the midsection, less muscle, and a slower metabolism.
We’ve explored the science behind testosterone’s impact on your physique, the role of testosterone replacement therapy (TRT), and what you can do to optimize your body composition safely and effectively.
Testosterone plays a central role in determining how your body builds muscle, stores fat, and burns energy.
Here are some of the ways it’s involved in shaping your physique.
Testosterone is an anabolic hormone, meaning it promotes muscle growth by triggering protein synthesis, the process your body uses to build muscle tissue after working out or lifting weights.
It activates key pathways involved in repairing and growing new muscle fibers. Men with higher testosterone levels typically have greater lean body mass.
Testosterone helps regulate where your body hangs onto fat.
There’s a link between higher levels of testosterone and less visceral fat. Visceral fat is the type of lipid that sits deep in your abdomen and surrounds your internal organs. Having more visceral fat storage is linked to a higher risk of metabolic disease, a group of conditions like high blood sugar, high blood pressure, abnormal cholesterol levels, and excess belly fat, that affect how your body processes energy.
On the other hand, when T levels are low, an enzyme found in your fatty tissues (called aromatase) can convert more testosterone into estrogen. This further promotes abdominal obesity and, ultimately, a vicious cycle of imbalanced hormones.
There’s a close link between metabolic syndrome and low testosterone in men. Low testosterone is associated with obesity, insulin resistance, and poor lipid profiles, meaning that the levels of fats in your blood (especially cholesterol and triglycerides) are not in a healthy range.
Men with metabolic syndrome or type 2 diabetes often have hypogonadism, and both conditions independently raise the risk of cardiovascular disease and all-cause mortality. It's important to understand that the relationship goes both ways: metabolic problems can reduce testosterone levels, and low testosterone can, in turn, make metabolic issues worse.
Research suggests testosterone replacement may improve insulin sensitivity, which is how efficiently your body can use glucose.
Testosterone also helps maintain bone mineral density in men, which indirectly supports better posture, prevents injuries, and even assists in strength training goals.
Strong bones are foundational for optimizing muscle mass and physical performance as you get older, and a healthy hormone balance is an important piece of the puzzle.
The American Urological Association defines low testosterone as a total testosterone level of less than 300 ng/dL. When testosterone levels dip lower than that for an extended period of time, you might notice changes in your body — even if you’re eating well and staying active.
Here’s what testosterone deficiency might look like:
More belly fat. Low testosterone is linked to increased fat storage, especially deep abdominal fat. Hanging onto fat in your midsection increases your risk for heart disease and insulin resistance.
Less lean skeletal muscle mass. Without enough testosterone, your body struggles to maintain and build muscle, even if you’re working out like you always have.
Reduced strength and stamina. Men with low T might feel weaker overall and notice a drop in their endurance during workouts or everyday physical tasks.
Unexplained weight gain. When T levels are low, your resting energy expenditure can also drop, making it easier to gain body weight and harder to achieve weight loss. On top of that, when you’re not feeling energized, you may find it harder to stay active.
Sexual dysfunction. Low testosterone may also cause low sex drive and changes in sexual function, including erectile dysfunction (ED).
In addition to these physical changes, some psychological changes can occur. These may include mood swings, depressed mood, difficulty sleeping, and trouble concentrating — all of which can affect your quality of life.
If your body is changing in ways that don’t match your habits, it could be time to have your baseline testosterone levels checked. Hims offers at-home testosterone testing, so you can get data-driven insights into your hormonal health without leaving home. A healthcare provider will assess your results to verify if you have low levels to discuss personalized testosterone treatment options.
Additionally, our BMI calculator might be a useful tool, though remember that BMI doesn’t take into account the differences between skeletal muscle and body fat.
If you have your testosterone checked and have clinically low levels and symptoms of low T, your healthcare provider may consider testosterone replacement therapy (TRT) as a treatment option. Testosterone replacement therapy uses synthetic versions of the steroid hormone to increase circulating testosterone levels, and it can be a great option to help restore appropriate testosterone levels.
TRT can help bring your energy, libido, and body composition back to normal levels for you. When combined with exercise and good nutrition, evidence shows TRT can help men rebuild muscle, reduce fat, and improve their overall physical performance.
As we covered earlier, healthy testosterone levels support protein synthesis and muscle repair, reduce abdominal fat storage, improve muscle mass and strength, and support better overall metabolic health.
TRT can be effective for addressing low testosterone levels and related symptoms, but it’s not a one-size-fits-all solution, and it won’t change your body overnight.
If you decide to pursue TRT, it’s important to take it under careful medical supervision to avoid potential side effects, like:
Elevated red blood cell count (called erythrocytosis)
Suppressed natural testosterone production
Reduced fertility or testicular shrinkage
Potential cardiovascular risks in some populations
Before starting TRT, your healthcare provider should run a thorough hormone panel, discuss your goals, and monitor your progress with regular blood samples. Blood tests should check your serum testosterone levels, including total testosterone and free testosterone. If you’re interested in at-home testosterone testing through Hims, schedule a consultation to get started.
Your healthcare provider can also discuss alternative options to TRT, especially if you’re concerned about fertility. Hims offers access to fertility-safe testosterone treatments like enclomiphene citrate, a compounded medication that supports your body’s natural testosterone production without compromising sperm count. Another option is enclomiphene + tadalafil, which improves testosterone and erectile function at the same time.
If you're eligible and committed to pairing TRT with strength training, clean nutrition, and regular check-ins, it can be an effective tool for reshaping your body and restoring vitality.
Here are some natural ways to support healthy testosterone production and make the most of TRT:
Whether you’re already a seasoned gym goer or you’re just getting started, resistance training is an essential way to support healthy testosterone levels. Research shows exercise increases testosterone, at least temporarily.
Aim for at least two to three sessions per week, focusing on compound movements that use multiple muscle groups, such as squats, bench presses, deadlifts, and rows. To help build muscle, use progressive overload, which means gradually increasing the weights you’re using over time.
While consistency and patience are key, rest is also crucial for your muscle recovery, repair, and growth.
Nutrition is also key for healthy hormone levels and testosterone production.
Getting adequate protein is crucial, but even more important is getting it from quality sources, like lean meats, fish, and legumes (beans, peas, lentils, and soy foods). But, note that there’s a link between excessive protein intake and reduced testosterone levels in men.
To determine your protein needs, try our protein calculator.
Include plenty of healthy fats, like olive oil, avocados, nuts, and seeds over saturated fats found in red meats, coconut oil, and ultra-processed baked goods.
Finally, fiber is your friend, so opt for complex carbs like whole grains, legumes, and vegetables to fuel workouts and support blood sugar management.
Micronutrients also matter, and you can get plenty of vitamins and minerals by eating a wide variety of healthy foods. Specifically, vitamin D, zinc, and magnesium are crucial for testosterone production and male fertility.
Consider having your vitamin D levels tested and supplementing if needed, especially if you're not getting enough from fortified foods or sun exposure.
While you’re at it, drink plenty of water to support your metabolism and physical function. Even being slightly dehydrated can significantly affect how you feel and perform.
Getting adequate rest is also important for your body to repair and rebuild. Plus, sleep is a natural testosterone booster. Experts recommend seven to nine hours of quality sleep each night.
Not likely. While TRT can help reduce fat mass and build muscle, visible abs still require consistent training and a diet that supports fat loss.
Most guys start to see improvements in energy and muscle strength within a few weeks, but noticeable changes in body composition may take several months, especially for hypogonadal men with very low T levels. Consistency with workouts and nutrition can help speed up the progress.
No. TRT is a medical treatment that helps bring low testosterone levels back to a healthy range. In contrast, steroid misuse means taking very high doses of testosterone or similar hormones with the goal to build muscle or improve athletic performance, without a medical reason.
Body mass index (BMI) doesn’t distinguish between muscle and adipose tissue (fat), so it may not reflect your true health if you're muscular. However, it can be a helpful general tool when viewed alongside waist circumference and body fat percentage. Check out our BMI calculator.
It’s possible, but it’s harder. Low testosterone slows muscle growth and makes fat loss more difficult, even with good habits.
Not always, but stopping TRT can cause testosterone levels to drop again and bring symptoms back. That’s why it’s important to work closely with a healthcare provider and talk through a long-term plan.
Testosterone plays a powerful role in shaping how your body stores fat, builds muscle, and manages metabolism, whether you’re a young man, middle-aged, or older man.
Whether you’re optimizing your natural levels or considering TRT under medical guidance, combining hormone support with smart training and nutrition habits is essential for lasting results.
Here are the key takeaways:
Testosterone promotes lean muscle growth and reduces abdominal fat. This is especially true in men with clinically low levels.
If appropriate, TRT can significantly improve body composition. Particularly when paired with strength training, quality nutrition, and regular follow-ups with your provider.
Healthy lifestyle habits can help. Things like sleep, diet, physical activity, and managing your stress also play a big role in naturally supporting healthy testosterone levels.
Still have questions? Check out our men’s sexual health resources. You can speak with a licensed healthcare provider by taking our free online assessment.
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