Testosterone is the hormone that fuels the sex drive. Everyone has some amount of testosterone in the body, but levels are normally much higher in men. In fact, this sex hormone is what makes a man, well, a man. It helps form the male sex organs and creates cells that make sperm. Testosterone triggers the growth of facial hair and masculine muscle features. The hormone also works with brain chemicals, such as serotonin, to control mood. Testosterone levels rise during puberty and normally drop as men get older. Around age 40, the body just stops making as much as it once did. Sometimes, certain diseases or medicines (such as anabolic steroids) can lower testosterone levels. Symptoms of low testosterone or low T that you might notice are: Reduced interest in having sex (decreased libido) Difficulty getting or keeping an erection (erectile dysfunction or impotence) Mood swings, such as feeling angry or depressed Breast growth Hair loss; for example, you might not be able to easily grow a beard Getting in the Mood — When You're Not in the Mood If you have low T, you may not want to have sex as often as you once did – or at all. It might not be easy to "get in the mood" when you're feeling down or if you’re worried you can't get an erection. ( Important: Impotence isn't always due to low T. Other health conditions can cause this problem.) So how do you keep the fire alive when you have low T? Try these five simple steps to boost intimacy without intercourse. Never stop touching your partner. Intimacy is about feeling loved and emotionally connected. Hold hands, offer a shoulder rub or lovingly brush the hair out of your partner's face. Be soft, gentle and affectionate. Touch is a powerful tool, and one that helps spark desire. Cuddle up and smooch. Couples that cuddle and caress are happier in their relationships over the long term, according to a study by The Kinsey Institute, which examines sexual behavior. Stir up some conversation. Sexual health experts say communication is one of the most intimate aspects of a relationship. Some conversation starters: Express appreciation for something your loved one did, reminisce about your first dates or say how much you liked it when your partner did this or that. Couples counseling may help improve intimacy and communication. To find a certified counselor in your area, visit The American Association of Sex Educators, Counselors and Therapists website. Take a walk together. All types of exercise boost feel-good chemicals in the body called endorphins. Being active also pumps up testosterone levels. Don't forget to hold hands during your stroll. Go on a date. Remember that first-date feeling? Scheduling a regular date night can help stir up those emotions. Some sex therapy experts even suggest scheduling a "sex date." Planning for lovemaking can help relieve tension and build passion. And remember, sex doesn't necessarily mean intercourse. Can Supplements Help? Some men may consider testosterone replacement therapy (TRT) to restore their sex drive. TRT might be helpful for some men with very low T, but they are not right for everyone, and the treatment comes with risks. Always talk to your doctor before trying any supplements that claim to cure low T. It might be dangerous to take testosterone if you have certain heart, kidney or liver conditions or a history of cancer.