Pfizer still owns Viagra’s patent—it expires in April 2020—but in 2013, Pfizer and pharmaceutical company Teva struck a deal allowing Teva to introduce its own version of Viagra in 2017. To keep pace, Pfizer put its own generic version of the classic blue pill on the market for a reduced price of $32.50 per pill. Prices of generic sildenafil have continued to drop since: Ro sells generic sildenafil at $6 per 60-milligram dose, while Hims offers a monthly plan of 10 20-milligram pills at $30. Both require that users connect with a physician online, or via an app, before getting a prescription.

Since the two companies launched, breezy coverage has celebrated their apparent focus on young men, as seen in carefully curated Instagram feeds and winking ads featuring eggplants. But some health and sexuality experts are concerned that the companies are overemphasizing the role of erections in sexual satisfaction, and noting that online care may be less effective than seeing a doctor in person.

Zachariah Reitano, Ro’s 27-year-old CEO and co-founder, pushes back on the perception that Ro is targeting a millennial customer base. “A vast majority of our members are over 40,” he says. Reitano experiences ED as a result of heart medication he takes. “There are younger people on the platform, but statistically, about 25 percent of men under 40 experience ED… It’s just not the majority of our members.”

He adds that young men experience ED for a variety of reasons, including alcohol, stress, smoking, and weight problems. “I don’t think it would be difficult for anyone to say, ‘Do I know a 30-year-old who is drinking too much, stressed, smoking, or overweight?’”

Andrew Dudum, the 30-year-old founder and CEO of Hims, says his brand’s marketing approach is a concerted effort to appeal to younger customers. “When people ask, ‘Why does this look like this is for men in their twenties and thirties and forties?’ I’ll just point them to the studies which say, ‘Because men suffer from this at an overwhelmingly shocking rate in those age ranges, and it’s really important to help these guys not feel like they’re the only ones because they’re not.’”

A 2013 study of 439 patients found that 1 in 4 seeking first-time medical help for new-onset ED were under 40, but it’s hard to capture accurate data about a condition many men are embarrassed to discuss. Evidence suggests that complaints of ED in younger men are on the rise, which experts say may be due to lifestyle issues like smoking and high blood pressure. “If you look at men over the age of 40, over half have some trouble with erections,” says Dr. Michael Eisenberg, an associate professor of urology at the Stanford University Medical Center. “If you look at men under 30, it depends on which studies you’re looking at, but it can be 10 percent or 20 percent.”

Erectile dysfunction, he adds, is often one piece of a larger health puzzle. Medications for depression, anxiety, pain, and high blood pressure can lead to ED, or the condition may be a sign of underlying problems like heart disease, high blood pressure, diabetes, high cholesterol, or obesity. Obesity, for example, appears to damage the inner lining of blood cells, which in turn can limit blood flow to the penis and hamper erections.

While sildenafil and related medications are considered relatively safe, they are not without side effects, including erections that last a very long time, low blood pressure, and interactions with other medications.

Jamin Brahmbhatt, an assistant professor of urology at the University of Central Florida College of Medicine, says ED meds shouldn’t be prescribed without a medical evaluation. “Issues in the bedroom may improve with these medications,” he says. “But what if there is another underlying problem like relationship issues, low testosterone, low thyroid, a heart blockage? These are all the things we screen for when a new patient [sees] us in the office.”

On the whole, Stanford’s Eisenberg is in favor of both companies’ approaches. “It takes a lot to get men to the doctor,” he says. “Here’s this whole segment of the population that’s really underrepresented and undercared for, and so by increasing access for them, I think that could do a lot.”