Testosterone is a hormone that plays a big role in men's health. It helps with energy, muscle growth and even mood. But when it comes to prostate cancer, the relationship between testosterone and the disease is more complicated than it might seem.

How does naturally occurring testosterone relate to prostate cancer?

Testosterone itself is not likely to increase a person's risk of developing prostate cancer. As with many cancers, the exact cause isn't clear. But many prostate cancers are sensitive to testosterone, meaning that testosterone can help cancer cells grow and multiply.

For many years, people believed there was a one-to-one relationship between testosterone levels and cancer growth — the higher the testosterone levels, the greater the growth of prostate cancer. But newer research has shown that this isn't entirely true.

Scientists now think that testosterone levels promote prostate cancer growth but only up to a certain point. One theory that helps explain this is called the saturation model. It says that prostate cancer cells only need a certain amount of testosterone to grow. Once they reach that level, adding more testosterone doesn't make much difference. So while testosterone is important for cancer growth, it's not the sole driver of prostate cancer.

Does testosterone therapy cause or increase the risk of prostate cancer?

Current evidence does not support a link between testosterone replacement therapy and new development of prostate cancer. Many studies have looked at older men with low testosterone who were treated with testosterone therapy. These men did not have higher rates of prostate cancer than men who did not receive testosterone therapy.

What may happen in some cases is that prostate-specific antigen (PSA) levels go up after taking testosterone therapy. These higher PSA levels may lead to more prostate biopsies. And that may lead to increased detection of prostate cancer that otherwise might have gone unnoticed.

Testosterone therapy often comes in injections, pellets, patches or gels. It can improve the signs and symptoms of low testosterone. Low testosterone is a condition called hypogonadism. Symptoms often include fatigue, loss of muscle and bone density, weight gain and changes in sexual function. These symptoms can have a big impact on quality of life.

If you don't have low testosterone, taking testosterone isn't recommended. The main reason is because taking testosterone doesn't seem to do much. For example, the improvement in sexual function from testosterone therapy is linked more to bringing testosterone levels up to the standard range rather than to the treatment itself.

How does prostate cancer affect testosterone levels?

Prostate cancer alone doesn't usually affect testosterone levels. However, the treatments for prostate cancer often do. For example, androgen deprivation therapy, sometimes called hormone therapy, is a common treatment for advanced prostate cancer. It works by reducing testosterone in the body. This treatment can lead to symptoms of low testosterone.

Is testosterone therapy ever safe after prostate cancer treatment?

This is a challenging question. The answer depends on your situation. In any case, the benefits of testosterone therapy must outweigh the potential risk of cancer recurrence. For people who have been successfully treated for prostate cancer and have no signs of the disease coming back, testosterone therapy may be an option. Studies have shown that testosterone therapy doesn't seem to increase the risk of prostate cancer returning in these cases. However, it's important to monitor prostate health closely with regular PSA tests and checkups.

If you're thinking about testosterone therapy after prostate cancer treatment, talk with your healthcare team. Your care team can look at your medical history and help you decide what is right for you.

Are there ways to increase testosterone without taking testosterone therapy?

It is possible to increase your testosterone without supplementation. The two factors with the most evidence are exercise and weight loss.

• General exercise. Regular exercise at moderate intensity increases testosterone levels. It also increases endorphins and decreases cortisol. These hormone changes can enhance sexual function and improve mood.
• Resistance training. Lifting weights increases testosterone levels. It also increases muscle strength and endurance.
• Cardio exercises. Engaging in activities that involve constant movement increases your heart rate. This improves blood flow to your heart, increasing overall health. Cardio exercises also increase blood flow to the genital area, which can improve erectile function.
• Weight loss. Obesity is a strong risk factor for low testosterone. Studies show that losing excess weight can raise testosterone levels and improve erectile function.

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Oct. 29, 2025 See more In-depth