Models Swear By This French Skincare Product For Tight Skin — Here’s How It Works

“What’s that scent?” my husband says, turning his nose away from my attempt to give him a peck on the lips. “Your face smells like a chemical plant…”

I’m wearing my essential nightly skincare step, Biologique RechercheSM P50 1970 Lotion ($67 for 5.1 oz), and it’s worth missing an evening cuddle session for.

The French-made, acid-based toner beloved by industry pros, models, and people everywhere. And yes, it smells absolutely awful. Users describe it as everything from vinegar mixed with peanut butter to blue cheese and even breast milk. To make matters worse, it also slightly stings when applied to the skin, and it’s not readily available in the U.S. You can only purchase it at spas, and many require you to log in with a password before you can even find out the price.

After all that’s said and done, I must clarify that P50 is absolutely magical and worth it (beauty is pain, right?). It’s perhaps my favorite exfoliator ever, and I credit it for keeping my skin visible pore-and-pimple free. My devotion to this smelly, tingling, hard-to-find formula is one of many. Seriously, just google it — the reviews are raves! 

To understand why P50 (as fans call it) became the skincare staple it is and how it works, I interviewed the brains behind it and one of the top estheticians who uses it.

First Of All, What Is Biologique Recherche P50 1970 Lotion?

Biologique Recherche Lotion P50 1970 does not belong to an existing product category because it serves several purposes,” explains Dr. Philippe Allouche, the co-owner and head of creation at Biologique Recherche. “It’s truly a do-all skincare product. It combines cleanser with a soft exfoliator and a toner, while helping regulate sebum secretion and balancing the skin’s pH for healthy, glowing skin.”

A list of all of the wonderful benefits of P50 on the skin include: exfoliating, purifying, cleansing, and regenerating. “It’s formulated with exfoliating ingredients like lactic acid and cider vinegar, which removes dead cells and impurities to promote an even skin tone,” Dr. Allouche says. “Ingredients like salicylic acid make the product great for combating acne and keeping skin clear of blemishes. It also contains ingredients (like vitamin B3) that improves the strength of the epidermis, balance the surface pH of the skin, all while enhancing epidermal renewal.”

Basically, the clear lotion cleans your skin in a pretty aggressive way thanks to a medley of acids, which remove dead skin cells. And because it both exfoliated and hydrates, it has a balancing effect. Even though the name calls it a lotion, it is more like toner and used in that same step of your routine.

“To me, P50 is like a ‘facial in a bottle,’” enthuses Danuta Mieloch, an esthetician and the founder of Rescue Spa in NYC and Philadelphia. “Think of it as a probiotic balancing magic lotion that does it all on any type of skin. It allows all of the products that follow for better penetration and builds healthy skin.”

For me, P50 was always something I avoided as most acids, peels, and harsh toners irritate my sensitive skin. But after receiving a facial incorporating P50 at Rescue Spa, I was shocked by how clear and bright my skin appeared (even in a magnifying mirror). Mainly, it helps make my pores appear invisible, since it decongests them. It also reduces my cystic acne breakouts, lightens the sun spots dusting my cheeks, and minimize the appearance of fine lines of my forehead thanks to its ability to turn over skin cells. Since I had no “bad” reaction or sensitivity, I purchased a bottle and became a dedicated, twice-a-day user. I never looked back.

In fact, when I don’t use it religiously, I notice an immediate difference. Mainly, I am plagued by clogged pores again— blackheads, tiny whiteheads, and other micro-bumps. And my complexion seems duller, overall. After about two days of consistent use, my skin returns to feeling smooth and looking radiant. Note to the wise: it definitely does prep your skin for what’s next, so choose your serum wisely and make sure it has the right actives for your skin type.

[Editor’s note: If you have sensitive skin or concerns about trying this product, make sure to ask your dermatologist.]

How Does Biologique Recherche P50 1970 Lotion Actually Work?

It’s P50’s unique formula —  a combination of hydroxy acids in different percentages — that makes the product so effective. There are currently different variations of P50 now (with 1970 being the original) that address everything from hyperpigmentation to maturing skin; so talk to a specialist when shopping about which one is right for your skin type.

Let’s take a closer look at the ingredients in the original formula and dissect how they work. There are two camps, one being the exfoliating, moisturizing and reconditioning active ingredient group. These are phenol, salicylic acid, lactic acid, cider vinegar, sulfur, and glycerin. The other half are aimed at purification and sebum regulation; they include vitamine PP, magnesium chloride, and bardane extracts.

Phenol is the most talked-about ingredient of the bunch, as it is unique to the 1970 version and one of the most effective components of the secret sauce. That said, it’s also controversial, because it’s banned from being included in cosmetics in Europe (but still allowed in the US). Phenol can cause chemical irritation and acute burns, but not in the amount used in P50. So if you’re concerned, try the phenol-free version of P50.

Dr. Allouche explains the science behind it as well as four other of the star actives:

Phenol is an exfoliating ingredient. It improves the appearance of the skin by removing superficial layer of the skin and promoting new cell growth. It also promotes glycosaminoglycan synthesis and protein production, improving skin elasticity.

Lactic acid is another exfoliating ingredient, as it helps to eliminate dead skin cells while indirectly stimulating the synthesis of dermis proteins. Lactic acid is also a component of NMF (Natural Moisturizing Factor), meaning it has hydrating properties.

Niacinamide (vitamin pp or B3) helps stimulate barrier function by increasing ceramide and keratin synthesis. It’s a useful ingredient to treat acne because it has anti-inflammatory and bactericidal properties. It also helps diminish sebum production, which keeps pores clear.

Magnesium chloride is a soothing ingredient that diminish the expression of certain inflammatory mediators. It is also useful in skin repair, as it increases proliferation and migration of keratinocytes.

Burdock extract is a great ingredient to fight acne because of its antibacterial and anti-inflammatory properties.”

Why Does Biologique Recherche P50 1970 Lotion Smell So Potent?

Due to this concoction of acids, P50 gets its unusual scent. “Lotion P50’s smell is due to particularly fragrant ingredients, like vinegar and onion extract,” explains Dr. Allouche. “We formulate our products with pure and raw marine, botanical and biological ingredients, and never with fragrances. Because of this, several of our products — including Lotion P50 — have strong and distinctive smells due to the high concentrations of active ingredients.”

He also points out that nothing is added to “mask” the smell. Other companies will add the delightful scent of rose or coconut to make their products more enticing. Not P50. It’s all about efficiency for the chemists behind the brand. “ This is because we know perfumes don’t add anything to the performance of the product but can have some sensitizing side effects to skin,” Dr. Allouche notes.

How Should You Apply Biologique Recherche P50 1970 Lotion?

When I first tried P50, my esthetician at Rescue Spa told me to apply it by pressing it with a cotton pad into my skin (never swipe it around!). If it burned too much at first, I could add water to the cotton pad to dilute the formula. Within a week, I was able to tolerate P50 and ditched the extra H2O. Now I honestly crave that tingly feeling, because it lets me know it’s working.

“You can start using once a day and as your tolerance builds you can graduate to twice a day,” Mieloch advises. “It’s a bit like a workout — you have to be consistent to see results. Our skin constantly regenerates and builds new skin, and P50 helps to assist in the natural regeneration and remove the unwanted and unnecessary buildup. Think of it as a probiotic for the skin, it helps balance the pH level. ”

Speaking of balance, P50 also gives me feedback on the state of my skin. For instance, if I’ve just gotten of the plane or woken up after a night of drinking, my skin will feel a bit more sensitive when I apply the product. This is P50 working extra hard to bring my skin back to equilibrium.

“It increases the circulation,” Mieloch notes on P50’s ability to react the skin’s state. “You feel immediate firming and tightening of the pores. The tingling sensation creates a pleasant ‘this works’ effect. It has a cumulative result if you use it on a regular basis. You are known for that Biologique Recherche glow. Your skin stays healthier, more youthful, and balanced.”

Where Can You Buy Biologique Recherche P50 1970 Lotion?

As mentioned, you can’t just walk into Sephora or Ulta to buy this product. Instead, it’s exclusively distributed via the brand’s exclusive day spa, medispa, and hotel spa partners. (So it’s a good excuse to go to the spa!)

“Biologique Recherche isn’t more widely available because we choose to limit our presence,” Dr. Allouche shares. “Our goal is to ensure our spa partners maintain the highest level of service for our clients. We want to make sure that the line is dispensed by people who have been thoroughly trained, and know which products to prescribe during treatments, as we have over 100 products for the face alone.”

Other Biologique Recherche products I use in tandem with P50 are Masque VIP 02 ($146) for deep hydration; the Placenta Serum ($68), which is another stinky formula that helps keep skin clear and youthful looking; and Emulsion Originelle ($128), a plumping daily moisturizer.

“Anyone at any age will benefit from P50, “ Mieloch sums up. “It’s great for acne because of its antibacterial and anti-inflammatory active ingredients, and it’s a great anti-aging weapon to keep in your skincare arsenal since it helps strengthen the skin. Magic it is!”