Low testosterone means you don’t make enough of the hormone testosterone. It’s treatable with testosterone replacement therapy. Low testosterone (male hypogonadism) is a condition in which your testicles don’t produce enough testosterone. Mark Hay is a Brooklyn-based reporter who writes frequently about health, medicine, and sex for publications like Men’s Health, Men’s Journal, VICE, Aeon, Slate, and more. Sometimes low-T is caused by medical conditions, such as genetic diseases or past chemotherapy or radiation therapy. If you’re taking hormone replacement therapy, you’ll need regular follow-up visits with a healthcare provider. If you have symptoms of low testosterone, talk to a healthcare provider. This may include medicine to help you produce testosterone or long-term testosterone therapy. If you have signs and symptoms of low testosterone, a healthcare provider will give you a physical exam. Most males with symptoms of low testosterone don’t have a problem with their pituitary glands or testicles. This is known as hypogonadotropic hypogonadism because there are low levels of hormones. There are also many ways you can naturally boost testosterone levels, but those should be done in conjunction with TRT. If you are experiencing any symptoms as described above, you should definitely get your hormone levels checked. Too much estrogen in a male body is not a good thing; it can cause erectile dysfunction, or low libido." Although testosterone may make prostate cancer grow, it is not clear that testosterone treatment actually causes cancer. Affected women may experience low libido, reduced bone strength, poor concentration or depression. All of this reduces the active (free) form of testosterone in the body. Among women, perhaps the most common cause of a high testosterone level is polycystic ovary syndrome (PCOS). Low testosterone alone -- with no other health problems -- accounts for a small minority of those with erectile dysfunction. Doctors have found that Parkinson's disease patients treated with dopamine-stimulating drugs have increased sexual desire. Sexual desire involves your brain, and the brain's chemical messaging system is intimately linked to sexual desire. There is no set timeline, but if you take testosterone long enough then your body also basically forgets how to produce its own as well, becoming dependent on this external source of ample hormones. Some of it just reaffirms the fact that testosterone may not be as key to libido as many of us believe it is. "In cases where men who have low T don’t have improved low libido symptoms from testosterone treatments, it means the problem is not testosterone," stresses Bajic. If your body produces exceptionally little testosterone, you'll definitely have issues with your sex drive, which will improve once you start taking T. So it's often far harder to treat sex drive issues than banner ads for testosterone treatments often seem to suggest. If, say, you believe sex outside of marriage is a dire sin and you’ll be damned to hell if you pursue it, your raging hormones may not matter all that much. "Dopamine, serotonin, and oxytocin all play a role in libido, too," explains Justin Houman, M.D., a urologist in Los Angeles who specializes in men’s sexual and reproductive health.