Ammonium Lactate

Ammonium lactate is the ammonium salt of lactic acid, one of the alpha-hydroxy acids that occur naturally in the body and in fermented foods. Buffering the acid with ammonia raises its pH to a level that is gentler on the skin while preserving its activity. The result is a compound that acts both as a humectant, drawing and holding water in the outer skin, and as a keratolytic that loosens and helps shed excess scale ^[1].

Its main use is the treatment of dry, thickened, or scaly skin. It is applied for ordinary dry skin (xerosis) and for scaling disorders such as ichthyosis vulgaris and keratosis pilaris, where it softens rough patches and smooths the skin surface ^[1][3]. Preparations are available without a prescription at lower strength and by prescription at higher strength, typically as lotions or creams ^[3].

Controlled studies support its effectiveness. In moderate to severe dry skin, ammonium lactate lotion reduced scaling and roughness more effectively than plain lactic acid lotion of similar strength, and its benefit persisted for weeks after treatment stopped ^[1]. It also outperformed a plain emollient lotion in relieving dryness ^[2]. When compared with high-strength urea cream, another common keratolytic moisturizer, urea acted somewhat faster on the roughest skin, while both improved the condition ^[3].

Research into how lactic acid works has shown that it does more than simply hydrate. Laboratory and human studies found that lactic acid, especially its L-isomer, stimulates skin cells to make more ceramides, the lipids that form the skin's water-retaining barrier, thereby strengthening that barrier and making the skin more resistant to drying out ^[4]. This helps explain why the improvement from ammonium lactate can outlast the period of application ^[1][4].

Ammonium lactate is generally well tolerated but can cause temporary stinging or burning, particularly on cracked skin or soon after shaving, and like other alpha-hydroxy acids it can make the skin more sensitive to sunlight ^[1]. It is meant for external use and should be kept away from the eyes and mucous membranes. The lower-strength form is regulated as an over-the-counter product and the higher-strength form as a prescription medicine; the underlying lactate is also recognized as a food additive.

Ammonium lactate is available over the counter and by prescription and is generally safe for external use. The most common effects are stinging, burning, redness and irritation, which are more likely on broken, cracked or freshly shaved skin. As an alpha hydroxy acid it can increase sensitivity to sunlight, so sunscreen is advised on treated areas. It is meant for the body and should be kept away from the eyes, lips and the inside of the nose.

Ammonium lactate grew out of long-standing observations that alpha-hydroxy acids, and lactic acid in particular, could soften and smooth thickened, scaly skin. To make the naturally acidic lactic acid gentler and better tolerated, it was partly neutralized with ammonia to form its ammonium salt, buffered close to skin-friendly pH. The higher-strength 12 percent formulation was developed and marketed as Lac-Hydrin as a prescription treatment for dry and ichthyotic skin, and lower-strength versions such as AmLactin later became widely available over the counter. It has been a documented dermatological staple since the 1980s, studied head-to-head against agents such as urea for the treatment of xerosis.

Ammonium lactate has earned a solid reputation as an affordable, effective everyday treatment for rough, dry, and scaly skin, and it is a frequent recommendation for conditions such as xerosis, ichthyosis vulgaris, and keratosis pilaris. Dermatologists value it because it does more than sit on the surface; by prompting the skin to make its own barrier lipids, its benefit can outlast the application. Users appreciate the visible smoothing of bumpy or flaky skin, though it is honest to note that the acid can sting on cracked or freshly shaved skin and may increase sensitivity to sun. On balance it is considered a dependable, well-studied member of the moisturizer and keratolytic toolkit.