In 2018, quality sleep is a luxury.

Sleep boasts its own national week-long holiday; executives like Arianna Huffington have built entire brands around the concept; and the mattress startup Casper launched a quarterly print magazine, Woolly, which covers sleep and relaxation. For lifestyle publishers, stories like  Bustle’s “15 Beauty Products To Help You Sleep Better” are driving traffic.

When sleep is luxury and skin care is wellness, there’s money to be made for brands in related markets. So as beauty brands increasingly move into the larger wellness space, they’re rushing to capitalize on the trend, launching products marketed as beauty sleep manifestors. That means overnight masks, night creams, silk pillowcases (for their supposedly “wrinkle-fighting” properties) and essential oils by brands including Charlotte Tilbury, Slip, Erno Laszlo and This Works have popped up at retailers like Sephora, Net-a-Porter and more.

The timing makes sense: An estimated 75 percent of America’s workforce is suffering from chronic sleep deprivation, and the worldwide sleep aid market is expected to reach roughly $31 billion by 2025, according to a new study from Persistence Market Research. That could be because the category is no longer relegated to unsexy items like earplugs and herbal sleeping pills like melatonin.

While some of these products, like night creams, are by no means novel, many renditions are now being marketed as deep sleep instigators and repositioned as wellness proponents, evidence be damned.

“We’re seeing a generation of workday zombies, coasting on poor quality sleep,” said Melisse Gelula, the co-founder and chief content officer of Well+Good. “Sleep, and the lack of it, has become a huge wellness category, like food and fitness,” she said, noting that it’s a major traffic driver for the site.

But whether or not there’s any truth to the claims being made with these products can only be determined on a case-by-case basis, said Irena James, the vice president of product development at YG Laboratories, one of the biggest private label skin-care and cosmetics manufacturers.

“Some companies might be quick to reposition their products as suitable for nighttime simply so they can jump on the trend bandwagon,” she said.

But there can also be some legitimate science behind them, said James, pointing to last year’s Nobel Peace Prize in Physiology or Medicine, which was awarded to a trio that discovered how our cells operate differently during the day versus at night. “Our skin performs distinctly different functions during the day and night, and different ingredients can be beneficial or detrimental depending on when they are applied on the skin.”

Some companies really do spend significant R&D time and resources to carefully design their products along those lines, she argued, helping to activate cellular turnover, restoration and DNA-repair.

But it’s not always easy to gauge what kind of science and research goes into these sleep-centric products.

The skin-care brand de Mamiel recently rolled out its Sleep Series, a line of five essential oil rollerballs ($57 to $65) meant to be rubbed on the skin and inhaled to induce and maintain a deeper sleep. The items sold out within a few hours of launch, reported the brand. When asked what kind of testing went into the product, founder Annee de Mamiel offered only “countless hours in a clinic and lab.” Still, she said, no one should expect the items to be a quick fix: “They need to be included in your daily routine to see true, long-lasting results.”

Lars Fredriksson, the founder of Verso skin care, said its Night Cream — which retails for $100 on sites like Net-a-Porter — went through 12 weeks of clinical testing, followed by formulation and irritation tests. The retinol-enhanced formula is said to increase collagen production and have a “calming and reparative effect on the skin.”

Jules Miller was more explicit about the process that went into testing her brand The Nue Co’s Night Drops ($75), a liquid sleep tincture said to help customers drift off when consumed with another liquid. Developed in the buzzy supplement company’s lab in Cambridge, she said they are extensively tested for safety, consistency, taste and results. Once approved, the brand sends product samples out to their “testing committee,” a group of VIP customers and industry experts.

“They have a month to test the products and tell us what they love and what they’d change,” she said. “We may make some tweaks based on their feedback, and only then do we finalize the formula.”

Since launching earlier this year, they’ve been a best seller, said Miller, pointing to more potential in the category.

The Hungarian skin-care brand Omorovicza’s Midnight Radiance Mask, meant to be worn overnight, is in the brand’s top 10 best-selling products, and it’s its second best-selling mask, reports Omorovicza. Net-a-Porter has also seen immense traction in the category, according to its beauty director Newby Hands, who predicts it will get even bigger in the coming months.

“Everyone I know finds it hard to fall asleep, or wakes up constantly throughout the night,” explained Miller of her initial inspiration for the sleep tincture. “You’re at your best after a good night’s sleep; aside from your productivity being higher, you’re also more creative.”