Biologique Recherche Lotion P50 is said to be for all skin types except sensitive, but this liquid exfoliant is surprisingly likely to sensitize anyone’s skin. The adage “no pain, no gain” shouldn’t have to apply to skin care (we mention this because lots of online reviews mention that this product stings and burns upon application). This is one cult favorite beauty product whose positive reputation baffles us.
Housed in a translucent bottle with an opaque white cap, Lotion P50 has a watery liquid texture that’s similar to a toner or essence. You can apply it the same way you would those products: daily, with either your fingers or a cotton pad.
Biologique Recherche does not reveal the percentage of acids in this exfoliant, something many brands do because this is important to know before buying a leave-on exfoliant. It’s alleged to contain 12.8% AHAs (mostly lactic acid), plus the polyhydroxy acid (PHA) gluconolactone. AHA ingredient malic acid likely provides some exfoliation, too, and BHA (salicylic acid) is present in an amount we suspect is between 0.5-1%.
The acid blend is impressive, and the pH of 2.9 permits all of them to exfoliate; however, this pH level, while effective, is on the low side (although not unacceptably so). AHA, BHA, and PHA ingredients work beautifully when formulated between pH 3 and 4. A pH of 2.9 might not seem like much difference from a pH of 3, but it definitely tips the scales toward irritating skin—it’s a delicate balance.
Just as for Lotion P50V, we’re concerned about the amount of vinegar Lotion P50 contains. Low amounts of vinegar are used in cosmetics as a solvent or to adjust pH, but its acetic acid content can irritate skin. The amount of vinegar Lotion P50V contains also lends a telltale odor.
Vinegar isn’t the only problem ingredient in Lotion P50. It also contains thyme oil and sulfur, both proven skin irritants, as well as a plant extract (Rumex acetosa leaf) whose high tannin content can constrict skin, causing further irritation. As with most plant extracts, both Rumex acetosa and thyme oil contain antioxidants, too.
Horseradish root is also included, but two-thirds of this root is composed of a volatile compound known as allylisothiocyanate. Also known as mustard oil, this compound can trigger immediate and prolonged inflammation, adding up to a formula whose negatives far outweigh the positives.
We’re aware that this exfoliant and the other P50 Lotions have a cult following. Many people love these products, and they’ve been highly requested by our readers. That’s why we want to take this opportunity to tell you our conclusions aren’t based on personal opinion or our own experience but instead on what the research on these ingredients has shown to be true, for better and for worse.
Some of the ingredients in Lotion P50 are great for skin, no question, but since there are leave-on AHA and BHA exfoliants from several other brands (including those rated four stars) that deliver all of the benefits without irritating, drying ingredients, why expose your skin to unnecessary troublemakers?
Simply put, the considerable irritation Lotion P50 is capable of triggering—even if you don’t see or feel it taking place (see More Info for details)—makes this exfoliant unworthy of its cult status. Effective exfoliation can be done gently, and the results can surpass what many have experienced from Lotion P50.
Note: This product is also sold in a 1.7 ounce size for $28 or an 8.1 ounce size for $101.
- pH-correct formula exfoliates skin.
- Good mix of AHAs, BHA, and PHA.
- Fragrance free (but the ingredients give this an acrid aroma).
- Contains a plant whose high tannin content constricts and dehydrate skin.
- Thyme oil and sulfur are antibacterial, but also potent irritants.
- Myrrh is a skin irritant.
References for information on vinegar/acetic acid:
The Journal of Clinical and Aesthetic Dermatology, June 2015, page 50
mBio, March-April 2014, ePublication
Encyclopedia of Toxicology, 3rd Edition, pages 33-36
References for information on sulfur:
Journal of Clinical and Aesthetic Dermatology, May 2012, pages 32-40
CMAJ, April 2011, pages E430–E435
Journal of the American Academy of Dermatology, March 1988, pages 553-558
References for information on horseradish:
Pain, September 2017, pages 1,723-1,732
Rural Sustainability Research, August 2012, pages 1-10
References for information on tannins in Rumex acetosa leaf:
BMC Complementary and Alternative Medicine, September 2015, ePublication
Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics, 2nd Edition, John Wiley & Sons, 1996
Irritating Ingredients: We cannot stress this enough: Sensitizing, harsh, abrasive, and/or fragrant ingredients are bad for all skin types. Daily application of skincare products that contain these irritating ingredients is a major way we unwittingly do our skin a disservice!
Irritating ingredients are a problem because they can lead to visible problems, such as redness, rough skin, dull skin, dryness, increased oil production, and clogged pores, and they contribute to making signs of aging worse.
Switching to non-irritating, gentle skincare products can make all the difference in the world. Non-irritating products are those packed with beneficial ingredients that also replenish and soothe skin, without any volatile ingredients, such as those present in fragrance ingredients, whether natural or synthetic.
A surprising fact: Research has demonstrated that you do not need to see or feel the effects of irritants on your skin for your skin to be suffering, and visible damage may not become apparent for a long time. Don’t get lulled into thinking that if you don’t see or feel signs of irritation, everything is OK.
Generally, it’s best to eliminate, or minimize as much as possible, your exposure to ingredients that are known to irritate skin. There are many completely non-irritating products that contain effective ingredients, so there’s no reason to put your skin at risk with products that include ingredients research has shown can be a problem.
References for this information:
Journal of Dermatological Sciences, January 2015, pages 28–36
International Journal of Cosmetic Science, August 2014, pages 379–385
Clinical Dermatology, May-June 2012, pages 257–262
Aging, March 2012, pages 166–175
Chemical Immunology and Allergy, March 2012, pages 77–80
Skin Pharmacology and Physiology, June 2008, pages 124–135
Food and Chemical Toxicology, February 2008, pages 446–475
American Journal of Clinical Dermatology, 2003, pages 789–798
The P50, P50V and P50W balancing exfoliators are the unique fruit of 30 years of reflection and experience. P50 balancing exfoliators speed up the epidermis' natural exfoliating process and the reconstruction of the epidermal shield. The fortified epidermis can then fulfill its protective functions completely, enhancing skin's self-regeneration potential. Lotion P50, our most famous and coveted product, is the keystone to Biologique Recherche skin care treatment. It is applied in the morning and in the evening. It gently exfoliates the skin, regulates excessive sebum secretion, moisturizes and helps maintain the epidermis' acid pH.
Biologique Recherche is a skin care line created by French husband and wife team Yvan and Josette Allouche, who are respectively a biologist and a physiotherapist. As the story goes, Yvan prepared skin care solutions for Josette’s patients, and the formulations soon became a word-of-mouth hit. In 1970, the pair started selling the products to dermatologists and estheticians, and a developed enough of a following that today the products are available in 70 countries.
The star product for Biologique Recherche is its P50 Lotion, which is an exfoliating solution. Nearly 50 years after its creation, it remains a top seller and has spun off variations for different skin types and concerns. While these products get exfoliation right – they feature proven AHA and PHA ingredients usually formulated at the ideal pH for exfoliation – they also include ingredients like vinegar, sulfur, and phenol which are harsh and damaging to skin.
Biologique Recherche range extends beyond their coveted leave-on exfoliants to also include cleansers, moisturizers, and serums, many containing pretty hefty price tags for relatively lackluster formulas. Nevertheless, this brand’s air of French exclusivity, limited availability, and devoted following of the P50 Lotion and spinoffs are enough to keep this brand at the forefront among beauty junkies around the world.
For more information on the brand, visit www.biologique-recherche.us.
About the Experts
The Beautypedia team consists of skin care and makeup experts personally trained by the original Cosmetics Cop and best-selling beauty author, Paula Begoun. We’re fascinated by skin care and makeup products and thrilled when they meet or exceed our expectations, but we’re also disappointed when they fail to perform as claimed, are wildly overpriced, or contain ingredients scientific research has proven can hurt skin.
Our mission has always been to help you find the best products for your skin, no matter your budget or preferences. Beautypedia’s thorough and insightful reviews cut through the hype and provide reliable recommendations for all ages, skin types, and skin tones.