Generating billions of dollars in sales since they hit the market in 1998, Viagra, Cialis, and other erectile dysfunction drugs have been a boon to many men. But there’s a “paucity of treatment options for women” who struggle to become aroused or to climax, said Padma-Nathan, who joined Manna Molecular Science in December, as chief medical officer.

Now Dr. Harin Padma-Nathan, a Los Angeles urologist and specialist in sexual disorders, is working with a Worcester biotechnology startup on a naturally derived product that he hopes could do the same for women. Its source: cannabis.

He oversaw clinical trials of Viagra and Cialis, the blockbuster pills that revived the sex lives of millions of men.


“The prevalence of sexual dysfunction is high in both genders, and this causes distress in both genders,” he said.

So the 62-year-old former assistant professor of urology at the University of Southern California is working on a cannabis-infused gel that women would apply to themselves before intercourse.

Sound crazy? There is research indicating that marijuana users have more frequent sex. A 2017 study of more than 28,000 women and nearly 23,000 men published in the Journal of Sexual Medicine reported that a “positive association between marijuana use and sexual frequency is seen in men and women across all demographic groups,” although it said more research was needed.

Meanwhile, executives at Manna — which makes cannabis-infused transdermal patches for people who complain of pain, anxiety, and sleeplessness — said some female customers have told them the product, especially when worn on the pelvis, reduces discomfort that can occur during intercourse.

That prompted Manna’s CEO, Nial DeMena, to approach Padma-Nathan at a conference on cannabinoids in medicine that the latter organized in Los Angeles last May. DeMena asked whether there was reason to believe cannabis might improve women’s sex lives.


“He said, ‘Actually, there’s pretty good evidence,’ ” DeMena recalled Wednesday, after a tour of Manna’s laboratory at Mansfield Bio-Incubator.

The LA encounter led Manna, which began selling its skin patches over the counter in 2016, to recruit Padma-Nathan.

“We never would have made a [sexual health] product unless Harin was somebody driving that,” DeMena said.

Unlike Viagra, Cialis, and other erectile dysfunction medicines, cannabinoids are a potential “sexual enhancement,” not a drug, Padma-Nathan says. Manna doesn’t plan to test the gel on patients in clinical trials or seek approval by the Food and Drug Administration, typically a long and difficult process.

“This is not a treatment for a severe medical issue,” Padma-Nathan said. “We want to be conservative in what we promise.”

Nonetheless, Manna executives say they are applying more scientific rigor to their gel than other companies that market health-related cannabis products.

Manna recently began performing tests on vaginal tissue removed from rats at Pelvipharm, a contract research organization in France that specializes in studies of sexual disorders. Pfizer and Eli Lilly and Co. used the same consulting company when testing Viagra and Cialis on animals, Padma-Nathan said.

For Manna’s tests, Padma-Nathan wants to see whether the tissue relaxes when bathed in cannabidiol, or CBD, an active ingredient in cannabis that binds to receptors lacing the surface of cells. If it does, it may indicate that human tissue from that part of the body will respond the same way, fostering arousal.

“The evidence is that in lower doses, cannabis enhances sexual function, and at extremely high doses, it may have a detrimental effect,” he said.


The startup also plans to study whether tetrahydrocannabinol, or THC, the ingredient that makes marijuana users high, can also improve sexual performance, DeMena said. Ultimately, the gel might contain both ingredients.

Dr. Martin Miner, a clinical professor of urology and family medicine at Brown University who specializes in male and female sexual health, knows Padma-Nathan and called him a “very brilliant researcher.”

Miner said some studies do indicate that THC can intensify sex by acting on the central nervous system. A gel inserted in the vagina might increase blood flow, as some over-the-counter botanical topical products already do, he said. But poor blood flow is not the main cause of sexual dysfunction in women.

“The most common sexual dysfunction in women is desire” — or lack of it, to be more precise, Miner said. “And there’s so many reasons for that.”

The FDA in 2015 approved the only drug to treat low sexual desire in pre-menopausal women, Addyi. It’s nowhere near as successful as drugs for erectile dysfunction.

Although the tests on the rodent tissue have just begun and are expected to take about three months, DeMena said he hopes the gel makes it to the market this summer — impossibly fast if this were an FDA-approved drug. A bottle of the gel would probably cost about $20 to $30 and could deliver as many as 10 doses.

Unlike other products on the market that deliver cannabis extracts in, say, coconut oil, said Manna executives, their gel wouldn’t cause latex condoms to disintegrate — a big problem with oil-based products if couples want to avoid pregnancy and sexually transmitted diseases.


Manna has 15 employees and began with over $1 million in investments from various sources, including a private equity firm that specializes in cannabis-related ventures, DeMena said. The skin patches generated more than $1 million in revenue last year. So far, the patches are Manna’s only product on the market.

Even if a cannabis-infused gel does improve sex, Padma-Nathan doubts anything will work as reliably for women as erectile dysfunction drugs do for men. Men and women, he said, are just wired differently.

“Men are more simplistic than women,” he said. “Our sexual response cycle is linear, starting with desire, arousal, and orgasm. Women are more complex.”

Jonathan Saltzman

can be reached at jsaltzman@globe.com.