From peel-off face masks to skin-care pills, the beauty industry is saturated with products that claim to cure acne and other blemishes. But, according to thousands of shoppers, at least one product on the market is the real deal.

Biologique Recherche's P50 exfoliators are beloved by many, from novice beauty fans to spa professionals. The French skin-balancing line has even been hailed by some as "life-changing" and a "miracle product," despite the product's strong, vinegar-like smell.

These reviews aren't all that surprising. P50 exfoliators are said to moisturize, regulate oil, and prevent ingrown hairs, among other capabilities. However, getting your hands on the product isn't all that simple. Biologique Recherche cosmetics are only sold through authorized retailers, and can be pretty pricey.

Here's what you need to know about the products.

P50 exfoliators are said to be balancing and moisturizing.
Biologique Recherche

P50 exfoliators were first created almost 50 years ago with a controversial ingredient called Phenol

A physiotherapist named Josette Allouche created the products alongside her husband, a biologist named Yvan, in 1970, according to the Biologique Recherche website. Josette formulated the exfoliators while Yvan created an application technique.

Together, the Allouches focused on the skin's epidermis, and worked to create a product that would quicken its natural exfoliating process while strengthening its protective barrier. To do so, the couple used a controversial ingredient called phenol in its first batches.

According to Refinery29, the acid is used in both industrial-strength paint strippers and embalming fluid, and typically isn't safe for people. Canada and the European Union have even banned the ingredient from all beauty products.

The "P50 1970" exfoliator is currently sold by Shop Rescue Spa.
Shop Rescue Spa/Biologique Recherche
However, the phenol-based product is still produced and can be purchased in the US through retailers such as Shop Rescue Spa.

But there's good news for people who wish to avoid phenol.

Dr. Philippe Allouche, the couple's son, now works as Biologique Recherche's co-owner and head of creation. He's since reformulated the exfoliator into four new versions, all of which are said to work as well as the original, but without the controversial ingredient.

The product claims to work by tackling problems found on the epidermis

On Biologique Recherche's website, the brand says that its current P50 exfoliators work similarly to the original product.

"P50 balancing exfoliators speed up the epidermis' natural exfoliating process and the reconstruction of the epidermal shield," the Biologique Recherche website reads.

P50 lotion is said to work for skin conditions ranging from acne to rosacea.
Biologique Recherche

According to the brand's website, "the fortified epidermis can then fulfill its protective functions completely, enhancing skin's self-regeneration potential."

Biologique Recherche recommends applying the exfoliators twice a day, once in the morning and again in the evening. By doing so, the product is said to "gently exfoliate the skin, regulate excessive sebum secretion, moisturize, and help maintain the epidermis' acid pH."

Speaking to INSIDER, Dr. Philippe Allouche said that the exfoliators also work to reduce whiteheads, blackheads, and symptoms of rosacea

"The formulas are effective due to their unique combination of hydroxyl acids," Dr. Allouche told INSIDER. "The formulas offer exfoliating ingredients like lactic acid and cider vinegar, which removes dead cells and impurities to promote an even skin tone."

Dr. Allouche also said salicylic acid plays a major role in making P50 effective for acne.

"Salicylic Acid makes the product great for combating acne and keeping skin clear of blemishes," Dr. Allouche said. "P50 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."

P50 is difficult to purchase, but that doesn't stop tons of customers from raving about it

You won't find P50 exfoliators in Sephora, Ulta, or any other popular beauty store. Instead, Biologique Recherche sells its products exclusively through authorized retailers, such as the online beauty store Shop Rescue Spa, where bottles of P50 products range in price from $28 to $106.

Regardless, the exfoliators have a rating of 4.7 out of five stars on product review website Influenster from 182 customer reviews.

"Every single amazing review you've heard about this product is 100% true and then some," wrote Influenster user Madeline D. "This product is the single best toner I have ever used."

"The hype is real! This is truly a miracle in a bottle," wrote Influenster reviewer Dani E.

Celebrities in particular favor the P50 exfoliator line

Speaking to Popsugar, Jennifer Aniston's facialist and a brand ambassador for Biologique Recherche, Toska Husted, said she uses the P50 Pigment 400 exfoliator to reverse sun damage on the actress.

Ozark actress Julia Garner also referred to the original P50 exfoliator as a product she can't live without in a December 2018 issue of Vanity fair.

As far as professional makeup artists go, YouTuber Jackie Aina said on Twitter that P50 products are among her favorites.

Twitter users have equally praised P50 products

While some have recommended the line to their followers, others have said that they've bonded with strangers over the products' strong, yet memorable, smell.

Dr. Allouche believes P50 is so popular because it can fight a variety of skin conditions

"Biologique Recherche Lotion P50 does not belong to an existing product category because it serves several purposes, which is why I think it has gained such a loyal cult following," Dr. Allouche told INSIDER.

"Lotion P50 has always been a product of its time, and it will continue to be," Dr. Allouche said. "I always say, if someone loves this product, they love it for the rest of their life."

You can find out more about Biologique Recherche on its website, and its products on Shop Rescue Spa.