If you have low T, testosterone therapy can work wonders. How do you know if testosterone therapy is right for you? The answers to these frequently asked questions about testosterone therapy will boost your IQ on low T. How common is low T? An estimated 5 million men have low T. What causes low T? Testosterone goes down naturally as you get older. You hit your peak at about age 17. By age 30, a gradual decline starts. Other conditions that can make your testosterone go down are: Alcoholism Cancer treatment Diseases of or injury to your testicles Genetic diseases Hormone disorders Liver or kidney disease Stress How do you know if you have low T? Signs and symptoms of low T include decreased interest in sex, erectile dysfunction (ED), brain fog, depression, loss of muscle, increased fat, decreased body hair, thinning bones, and high cholesterol. The only way to know if these signs and symptoms are due to low T is with a blood test to check your testosterone level. If you have low T, do you always need to be treated? If your low T is caused by a health condition, you may need to treat that condition. If only aging causes your low T, you may not need treatment. You and your health care provider will need to decide, based on your testosterone level and your signs and symptoms. What are the benefits of low T treatment? If you have signs or symptoms of low T, and your blood test shows low T, treatment can: Boost energy Boost mood Clear your mind Decrease fat Improve sexual performance Increase muscle Strengthen bones Are there any dangers of low T treatment? Testosterone can make some types of cancer grow. If you have prostate or male breast cancer, you may not be able to have testosterone therapy. Also, testosterone therapy may worsen the following conditions: Enlarged prostate Heart, kidney, or liver disease Polycythemia (too many red blood cells) Sleep apnea What are the treatment options and the side effects? Testosterone is not available in pill form. Talk with your health care provider about the following options: Injections.You'll get a shot every two to three weeks. The injection site may feel sore. Patches. You'll probably use a patch each day. The patches might irritate your skin. Gels. You'll probably apply gel daily on your skin. You will need to make sure women and children do not come into contact with the gel. Side effects from any type of testosterone therapy may include acne and breast enlargement. What happens during treatment? Your health care provider will do blood tests every so often to check your testosterone level and make sure your red blood cell counts are normal. He or she will also keep an eye on your prostate, by doing prostate specific antigen (PSA) blood tests and digital rectal exams. Key Takeaways Low T is common, especially in older men. If you have low T symptoms and low T results on blood tests, your health care provider may suggest treatment. You and your health care provider should weigh the risks and benefits of treatment. You and your health care provider will need to discuss the options for treatment, side effects of treatment, and testing during treatment.