WWW- The elusive search for a woman’s version of Viagra may be one step closer to a climax.

A National Institutes of Health panel has green-lighted a large clinical trial for a herbal remedy called Zestra that promises better and more orgasms for women. The study will involve 200 women diagnosed with various forms of sexual disorders, including reduced libido and difficulty becoming aroused or achieving orgasm, researchers said.

Recruitment for the trial will begin this fall at 16 research sites around the country, including New York-Presbyterian Hospital in Manhattan. The study should be completed by next summer, with results published toward the end of 2006.

Zestra, already on the market as a “female arousal fluid,” is applied topically on the genital area. It is not a drug, so it doesn’t require approval from the U.S. Food and Drug Administration. But researchers hope the new study will show whether the herbal remedy really works.

A preliminary trial in 2003 involving only 20 women suggested Zestra showed promise in treating female sexual dysfunction, said Susan Kellogg-Spadt, director of sexual medicine at the Pelvic & Sexual Health Institute at the Graduate Hospital in Philadelphia.

“We’re going [to] look at the entire gamut of female sexual dysfunctions,” Kellogg-Spadt said of the upcoming trial.

Until recently, scientists thought female sexual dysfunction was caused mostly by poor blood flow to the genitals, which is the main reason for impotence in men.

But in June, a landmark study by researchers at Yale and the Albert Einstein College of Medicine in the Bronx found that nearly half the women enrolled had dulled nerves in the so-called pleasure pathways, including the clitoris.

That research may explain why drug makers have had such a difficult time developing a female version of Viagra.