New York: For older men who are facing lower sexual drive, erectile dysfunction and sperm production, undergoing testosterone therapy can prove to be beneficial, new research says. Testosterone is a key male sex hormone involved in maintaining the sex urge. Testosterone levels decline as men age and some men develop low testosterone levels and symptoms of sexual dysfunction. "Our findings indicate low testosterone is one cause contributing to reduced libido and erectile dysfunction in older men," said lead author Glenn R. Cunningham from Baylor College of Medicine in the US. "Men experiencing these symptoms should be evaluated for testosterone deficiency," Cunningham added. The findings showed that men treated with testosterone therapy displayed consistent improvement in libido. Further, older men with symptoms of androgen deficiency showed improvement in their testosterone levels as well as more interest in sexual activity. Androgen deficiency occurs when a man has consistently low levels of testosterone and resulting symptoms such as sexual dysfunction. The study, published in The Journal of Clinical Endocrinology & Metabolism, was designed to investigate the effectiveness of testosterone therapy. For the research, the team examined the effect of testosterone therapy on sexual function in a group of 470 men who were at least 65 years old and had low testosterone levels. "For symptomatic older men with low testosterone levels, testosterone therapy led to consistent improvement in most types of sexual activity," Cunningham concluded.