Lac-Hydrin Five is a product we no longer recommend because its pH is too high for exfoliation to occur (despite containing 5% lactic acid) and the preservative system is Kathon CG, which is contraindicated for use in leave-on products (Sources: Contact Dermatitis, November 2001, pages 257–264; European Journal of Dermatology, March 1999, pages 144–160; and The Journal of Dermatology, December 2005, pages 951–955).
Lactic acid buffered with ammonium hydroxide makes Lac-Hydrin five a moisturizer unlike any other. It is dermatologically tested, and guaranteed to soften and smooth even the body's roughest, driest skin- yet it's gentle enough to use on the face. Lac-hydrin is a formulation of 12% lactic acid neutralized with ammonium hydroxide, as ammonium lactate, with a ph of 4.4-5.4.
Water, Lactic Acid, Ammonium Hydroxide, Glycerin, Petrolatum, Squalane, Steareth-2, Poe-21-Stearyl Ether, Propylene Glycol, Dioctanoate, Cetyl Alcohol, Dimethicone, Cetyl Palmitate, Magnesium Aluminum Silicate, Diazolidinyl Urea, Methylchloroisothiazolinone, Methylisothiazolinone
Lac-Hydrin products were the original AHA products, long before most consumers knew what AHAs were. They have been available in drugstores for years, and much of what we know about how AHAs perform is a result of these formulations. Lac-Hydrin Five (5% lactic acid) and Lac-Hydrin 12 (12% lactic acid, available only by prescription) are indicated for use primarily on persons with dry, itchy skin. The lactic acid is not positioned as an exfoliant, and the pH of both products (pH 4.1 for the 5% version and pH 4.5–5.5 for the prescription version) bears this out. Lactic acid has research proving it is a valuable water-binding agent for skin, and preventing moisture loss by protecting the skin's barrier helps quell itchy skin (Sources: The British Journal of Dermatology, December 1999, pages 1027–1032; and The Skin Sourcebook, Alan Boyd, M.D., Lowell House Anodyne, 1998). Users are cautioned to not apply lactic acid lotions on abraded or cracked skin because stinging will result. In instances where skin is very dry and cracked, it is advised to apply an emollient product (such as Vaseline or Aquaphor Ointment) until the skin is healed, and then you may begin using a lactic acid moisturizer. If you're looking to gain the benefit of exfoliation from an AHA product, consider the options from Neutrogena or Alpha Hydrox before these products.
For more information about Lac-Hydrin, call Bristol-Meyers Squibb Company at (800) 332-2056 or visit www.drugstore.com.