The Cult Of Biologique Recherche’s P50 Is Weirder Than You Think

Sometime during the past several years, in between the burst of the dot-com bubble and becoming Russia's weapon of choice for meddling in foreign elections, the internet turned a skin-care product formulated over four decades ago into a very modern craze. Thanks to the effusive digital praise of the countless beauty editors, influencers, celebrities, and industry experts who swear by it, Biologique Recherche's P50 is now about as recognizable a name as it gets in the world of prestige beauty. It has been called "Jesus in a bottle," "life-changing," and "The Best Beauty Product in the World." It smells like vinegar and the quart of milk you pushed to the back of the fridge and forgot about for three months. Its fans will still tell you it is the single best thing they have ever put on their face.

For the sake of transparency, let me say this: I am one of those fans. I didn't mean for this to happen. I have sensitive skin and a disturbingly acute sense of smell, which are two qualities you'd think would be enough to turn me off a product that is considered one of the most intense chemical exfoliants on the market and also reeks. And yet. I tried splashing it on one night before bed, pressing a few drops into my face with my fingertips, just to say I did. I woke up to smoother, clearer skin and nonexistent pores, after just one use, and have been hooked ever since.

But while I am a fan, I am also a skeptic. Yeah, this French garbage water works — but how? Why is phenol, one of the original formula's star ingredients, so controversial? And why does the bottle — the computerized font, the lack of adequate description, the pure mystery — make it look like something you shouldn't touch unless you have lab goggles, rubber gloves, and some kind of safety certification?

The legend of P50 starts in an unexpected place: with a love story. Before there was Biologique Recherche, there was Yvan and Josette Allouche — a biologist and physiotherapist, respectively. "My father was totally in love with my mother, all his life," Dr. Philippe Allouche, Biologique Recherche's co-owner and head of creation, and Yvan and Josette's son, tells me. "He prepared products for her and for the patients at the clinics she ran in and around Paris." Yvan came up with the formulation; Josette, a proponent of integrative medicine, came up with the application technique. "For her," Dr. Allouche says, "the epidermis was the interface to connect to the rest of the body."

P50 was not made to be beautiful, or glamorous, or to not smell like it's been pickled. It was made to work. "My father understood that skin had to be respected, and he wanted to create something to rebuild the epidermis," Dr. Allouche says. "He thought it would be better to have a gradual, soft exfoliation with acids that could also enrich the natural moisturizing factor in our skin." True, exfoliating is something that the skin does naturally, as its own organic process, but it slows down with age. The Allouches wanted to create something to help speed it up, while reinforcing the strength of the epidermis and the skin's natural protective functions.

And so, in 1970, the first iteration of P50 came to be. "My parents started giving it to their friends in France and abroad," Dr. Allouche recalls. "During the 1973 oil crisis, a Saudi Arabian princess who was a friend of my mother’s suggested putting a pipeline between the two countries. 'On one side, I send you the oil,' she told my mother. 'On the other side, you send me P50.'" Later, they presented the concoction to the press in France. "They would say, 'You know, it smells.' We would say, 'Who cares what it smells like? Look what you have inside.' We were drawing attention to the ingredients, which was unusual at the time."

So what's in it, really? The original version Yvan created, now known as P50 1970, has one thing you won't find in what Dr. Allouche calls the "new generation" of the product... or anywhere else in skin care, for that matter: phenol. Also known as phenolic acid, it is a mildly acidic compound with antiseptic properties that is also not great for you. The European Union forbids it for use in cosmetics, as does Canada; it also works nicely as a component in industrial-strength paint strippers and embalming fluid. You can understand why this is an unpopular ingredient — it's hard to want to use something on your face once you find out that it's also used to help preserve corpses.

Dr. Allouche created the four new versions of P50 himself, with the first reformulation launching in 2000, both as a response to consumers who would rather rot than put phenol on their skin and to cater to a range of different skin types. He chalks those variations up to environmental changes that weren't of as much concern in 1970: pollution, lower-quality food supply, and the growing hole in the ozone layer. There's P50W, for the most sensitive complexions; P50V, which is ideal for skin in need of plumping and toning; and P50PIGM 400, which is the best for serious brightening and dark spot-diminishing. And then there is P50, the closest you'll get to the original formulation without the phenol.

Lotion P50 is essentially a modernized gentler version of the 1970 potion, a smart, smelly blend of proven clarifying ingredients like lactic acid, gluconolactone, salicylic acid, and sulfur, with a few less-expected additions, like horseradish, onion, and thyme extracts. "It’s basically an alpha-hydroxy acid blend with niacin, which has excellent anti-inflammatory and anti-acne properties on the skin," says dermatologist Ava Shamban, MD. "There are a number of high-quality botanicals, too."

Nearly a half-century since its invention, P50 is just as popular as ever — with a following that proselytizes the stuff so insistently, it gives true meaning to the term "cult favorite." But the past few years especially have seen something that Biologique Recherche didn't have to contend with back in the '70s: imitators. Most of the liquid exfoliators, alpha-hydroxy acid-infused toners, and skin-perfecting solutions that have started to flood the market are more or less "inspired" by their face-tingling, pore-shrinking, gag reflex-triggering predecessor. In a highly criticized move, Glossier even called out the steep price and scent of P50 during the Instagram marketing efforts for its $24 take on the classic.

About that price: Good luck finding it, because part of P50's appeal is that it's a spa-professional product only sold by licensed retailers. The brand recommends having a trained esthetician "prescribe" it for you in person, but if you like things quick and dirty (and using potent exfoliating acids at your own risk), you can order online from Shop Rescue Spa and similar spas with e-commerce. A 1.7 oz bottle of straight-up P50 will run you $28; the biggest 8.5 oz size is $101.

The ultimate question, of course, is whether or not it's worth your money. I, and the rest of the P50-loving world, say yes. If you can spare the price, and choose the right formula (go see that esthetician, if you have to!), it will make a huge difference, and you will wonder how you ever lived without it. I do, as I pat it into my skin every night, and then climb in bed and turn out the lights and dream of salt and vinegar chips.