NEW YORK (NYTIMES) - "If I drink this stuff, will I turn into a beautiful supermodel?" reads an Instagram comment on a post from Kin Euphorics, a line of "mood-boosting" beverages co-founded by Bella Hadid.

Probably not, but Kin Euphorics makes some brazen claims about its products. Sparkling drinks in pretty cans will "conjure cosmic energy" and "welcome inner peace", reads the company's website. Its beverages contain mushrooms, amino acids and nootropics, substances said to aid in cognitive function and creativity.

One flavour, Lightwave, purports to help "transcend stress" and "open a portal to peace" vis-a-vis reishi mushrooms and L-theanine, an amino acid.

Kin Euphorics is part of a flourishing "functional beverage" category, often branded with gradient, pastel colours, 1970s nostalgia logos and no alcohol.

Poppi, Ruby, Superfrau, Dune Glow Remedy, Droplet, Brighter, Evexia Kafe, Sunwink and De Soi assert that their seltzers, juices and tonics can heal you from the inside out with prebiotics, mushrooms, apple cider vinegar, collagen, ginger, antioxidants, amino acids, nootropics and adaptogens, which is not an accepted scientific term, despite rampant use in the wellness and beverage industries.

Some of these ingredients are long-time home remedies and supplements recommended by doctors; others, such as adaptogens, are more dubious in their claims and may amount to little more than marketing.

In any case, the drinks are selling. What can they actually do for you?

Purported benefits include a balanced gut, a relaxed mind and brighter skin - similar to the promises supplements and topical skincare products have always made. The caveat: These drinks are not regulated by the United States Food and Drug Administration and none of the effects has been backed up by regulatory or trade commissions.

Beverage and Beauty Converge

"When I go to beauty retailer Sephora, it's all of these products offering me moisture and anti-ageing benefits, and it's the same things you see going down these beverage aisles," said Ms Andrea Hernandez, a food and beverage forecaster and the founder of Snaxshot, a newsletter about trendy seltzers, canned wines, dips, cereals and more. "These drinks are literally labelling 'beauty' as a function." And people will pay up for anything perceived as a shortcut to beauty or better health.

Sales of functional beverages increased by almost 16 per cent from November 2020 to November 2021, according to Spins, a data firm. It is one of the fastest-growing, non-alcoholic drink categories in the US. Brands such as Poppi and Ruby are sold at mainstream supermarkets including Whole Foods.

In early January, singer Katy Perry introduced De Soi, her sparkling aperitif made with "mind-mellowing" adaptogens. Barcode, developed for National Basketball Association (NBA) players, fancies itself a better-for-you Gatorade; and Ghia, aperitifs and spritzes with nervines (herbs that are purported to boost energy and alleviate stress), became an influencer favourite on Instagram.

Droplet sells a three-can sampler of its sparkling adaptogen drinks - Pretty Balanced, Pretty Happy and Pretty Bright - for US$20 (S$27).

Every aspect of these drinks - how they look, what they are named, the use of Goop-y ingredients and the prospect of being a better version of your current self - is designed for consumers of "clean" beauty, gluten-free and vegan diets, and boutique fitness. And most of them are not cheap.

Many of the ingredients in functional beverages have shown up in skincare too.

Superfrau contains lactic acid, an alpha hydroxy acid found in moisturisers and serums. Ruby is infused with polyphenols, the naturally occurring compounds in berries and plants with antioxidant properties that are often used in skincare.

"We could sit in a Sephora and Ulta and do really well," said Ms Allison Ellsworth, a co-founder and the chief brand officer of Poppi, a sparkling beverage infused with apple cider vinegar. Poppi sold close to US$35 million of its seltzers and colas in 2021, up from US$3 million the year before, Ms Ellsworth said.

Do the drinks deliver on the promises?

Experts do not know whether ingestible skincare ingredients can actually improve your skin.

Overall, they say the research to support these claims and potential benefits is flimsy at best (and non-existent, in many instances). It is an evolution of a largely unregulated supplement and ingestible craze.

Ms Marisa Plescia, a cosmetic chemist at Bell International Laboratories and a research scientist at NakedPoppy, an online beauty store, said that although apple cider vinegar may have benefits when applied topically to the skin - it contains acetic acid and exfoliates and helps balance skin pH levels - "there is little to no information on these benefits if drunk".

For Dr Ranella Hirsch, a dermatologist, the issue with ingesting skincare ingredients comes down to an inability to target specific concerns.

"Every dermatologist on planet Earth went nuts and said, 'Collagen drinking is bull,'" she said of the backlash after collagen's drink and supplement boom of the past few years. But this is not exactly true either. "The issue they have - which is not a wrong point - is you can't drink collagen and say, 'Okay, please go to the skin of my jawline,'" she pointed out.

Dr Emeran Mayer, a gastroenterologist, neuroscientist and the founding director of the University of California, Los Angeles' Brain Gut Microbiome Research Programme, believes there is little to no "hard-core science" to support the many claims of functional beverages, but he does think there's "something there".

"If I see that some things have survived thousands of years in a healing condition - ayurveda or Chinese medicine - then I almost take this as surrogate evidence in the absence of true scientific evidence," he said. "Why would people continue to do this for thousands of years?"

Even if it is hard to substantiate most of these claims, experts agree on one thing: The gut, brain and skin are intimately connected, and what affects one almost always affects the other. Even if your adaptogenic seltzer does not plump or hydrate the way a pricey moisturiser does, a balanced gut could make your skin appear clearer and brighter.

Do not underestimate a potential placebo effect.

"If you're taking 20 minutes to have a drink and think about your stress level, that in and of itself will probably make you less stressed," Dr Hirsch said.

And if you are less stressed, your skin and gut are less likely to act up.

"Drink it if you like the taste and enjoy it," Dr Hirsch said. "Just don't expect much, and if it happens, it's gravy."