DENVER—Clomiphene citrate may enable subfertile men who are overweight or obese to increase testosterone levels and possibly improve semen parameters, according to a new study presented at the 66th Annual Meeting of the American Society for Reproductive Medicine.

“We have found that testosterone levels, both total and bioavailable, significantly increased when the patients were followed-up at one month, three months, and five months,” said investigator  David Shin, MD, Assistant Professor of Urology at Hackensack University Medical Center in Hackensack, N.J.  “The study showed that an increase in endogenous testosterone levels did not cause an elevation in PSA levels, so implying that it is safe.”

Body mass index (BMI) has been shown to be negatively correlated with total testosterone (TT) and bioavailable testosterone (BT) in infertile men. As a result, men with a high BMI who present for fertility evaluation often are found to have low TT and BT levels, which may impair fertility. Clomiphene citrate is a selective estrogen receptor modulator that is used in the empiric treatment of subfertile men to increase testosterone levels.

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Dr. Shin and his colleagues conducted a retrospective observational study in which they analyzed the efficacy of clomiphene citrate for treatment of subfertile men who were overweight (BMI 25-29.9 kg/m2) or obese (BMI greater than 30 kg/m2).  The researchers included in their analysis 20 men (mean age 32.9 years) with hypogonadism (TT below 350 ng/dL). Eight were overweight and 12 were obese. They were treated with clomiphene citrate 50 mg three times a week for at least five months.

Investigators recorded TT, BT, and PSA levels at baseline and at one, three, and five months after treatment began. The researchers also documented follow-up semen analysis or pregnancy status when known.

One month after the start of treatment, average TT levels in the overweight group increased from 306 ng/dL at baseline to 663 ng/dL and average BT levels rose from 187 to 486 ng/dL. Among obese men, average TT levels increased from 237 to 577 ng/dL and average BT levels increased from 155 to 371 ng/dL.

“These findings suggest that with higher testosterone levels in these men with high BMIs that it could potentially improve semen parameters, which include sperm count and motility, and possibly lead to improved pregnancy rates,” Dr. Shin told Renal & Urology News. “This is the first study to really look at this specific population of men with higher BMIs.”

TT and BT levels remained significantly elevated for the duration of therapy. PSA levels did not increase significantly after three months of therapy. Four patients demonstrated improved sperm concentration and motility at six months after the end of therapy; five subjects achieved pregnancy.

“We typically didn’t see any major side effects,” Dr. Shin said. “Some guys have headaches for the first week or so, but it is a very well tolerated medication overall. I always tell my patients that it is an off-label use. It is not FDA approved for this particular indication.  Despite this, many men are willing to take clomiphene citrate to potentially increase their sperm counts.”