'This is a legitimate business. These users are not perverted or unethical'

Netflix drama Orange is the New Black recently cast the sale of used underwear into the mainstream, with a storyline where the incarcerated women capitalised on men's fetishes with an illegal sales operation.

But the business is very real, and some women can earn up to $5,000 (£3,850) for a pair, the owner of a website has revealed to The Independent.

After the first episode featuring the business model hit Netflix in June last year, Google searches spiked, and did so again in recent weeks.

Those in the industry say that the once little-known market is becoming more crowded. Sofia Gray, one such website which looks similar to a high-street lingerie store, launched in 2015 and is among the online businesses trying to seize a monopoly on worn underwear sold to fulfill sexual fantasies.

The operations all look sleek, with professional websites promising a great service for both parties, including complaints procedures and FAQs.

Alex Matthews, co-founder of Sofia Gray, says that the website generally attracts sellers aged between 18 to 35, while the buyers – most of whom are men – are aged between 18 to 60. 

Why people choose to sell their underwear online is simple: money. Some may also find it arousing.

"It’s different for everyone,” Reddit user pantysellingfiend, who claimed to have sold their underwear online, said on a thread. "I've had men say they just wanted them so they can masturbate with them, others want to wear them, and I've had some men say they wanted to put them around their home so their friends would think that they slept with a lot of women."

The cash raked in can also vary, from tens of pounds to thousands. As with anything, the more personal the service the higher the cost. Cashing in is more complex than slipping on some underpants and shoving them in an envelope. Anything from the style of the pants to the woman’s occupation can play a part.

The most surprising experience of running Sofia Gray, says Matthews, was when a buyer paid $5,000 for a pair a seller wore for three weeks straight. And “veterans of the industry” can identify a fake, she warns. 

So, if sellers have a keen eye for “counterfeit” pants, are sellers putting themselves at risk by wearing pants for prolonged periods of time?

Dr Alyssa Dweck, a gynaecologist and assistant clinical professor at Mt. Sinai School of Medicine, told Cosmopolitan that repeatedly wearing the same underwear can increase the risk of yeast infections and bacterial vaginosis. Whether a woman wants to take the risk for $5,000 is up to them.

For many, it's all too tempting. A 21-year-old from Hampshire recently told the National Student Money Survey that she turned to selling her used underwear because her student loans, part-time job and overdraft were not stretching to cover her rent, bills and food.

But while the business is baffling for outsiders Matthews is keen to defend it. “This is a legitimate business," she stresses. "These users are not perverted or unethical. They are buyers and sellers of a product, which is by no means harming anyone."