Ammonium lactate (AL) is a compound created by neutralizing lactic acid, an alpha-hydroxy acid, with ammonium hydroxide. It is widely used in dermatology for its effects on skin texture and moisture. Despite its use in treating skin conditions that can sometimes accompany fungal infections, ammonium lactate is not classified as a direct antifungal medication. It does not possess the specific biological mechanisms required to kill or inhibit the growth of fungus, which is the definition of a fungicidal or fungistatic agent.
Primary Dermatological Action
Ammonium lactate functions as both a keratolytic agent and a powerful humectant. As an alpha-hydroxy acid, it interacts with the outermost layer of the skin, the stratum corneum. The keratolytic action decreases the cohesion between corneocytes (dead skin cells), loosening the bonds holding thickened skin together and promoting accelerated exfoliation.
The result is a smoother skin surface and a reduction in the excessive scaling often observed in chronic skin conditions. Simultaneously, ammonium lactate functions as a humectant by drawing water into the stratum corneum. This moisturizing effect increases the water-binding capacity of the skin, enhancing hydration and improving flexibility and barrier function. These combined actions make a 12% concentration of ammonium lactate a standard treatment for conditions characterized by severe dryness and scaling, such as xerosis and ichthyosis vulgaris.
Adjunctive Role in Managing Fungal Conditions
Ammonium lactate is associated with fungal treatment because it manages the physical symptoms accompanying certain mycoses. Fungal infections, such as tinea pedis (athlete’s foot), frequently result in hyperkeratosis, a significant thickening of the skin’s keratin layer. This thick, scaly skin acts as a physical barrier that prevents topical antifungal medications from reaching the fungal organisms below.
Using ammonium lactate as an adjunctive therapy helps to break down and thin this dense, hyperkeratotic layer. By promoting exfoliation, the medication prepares the skin, allowing prescribed antifungal agents to penetrate the epidermis more deeply and effectively. This indirect action increases the therapeutic concentration of the antifungal drug at the site of the infection, improving the overall success rate of the treatment regimen. This benefit is why it is often recommended alongside a dedicated antifungal drug.
Key Differences from Direct Antifungal Medications
The distinction between ammonium lactate and a direct antifungal drug lies in their molecular targets and mechanisms of action. True antifungal medications interfere with specific biological pathways unique to fungal cells. For instance, the azole class of antifungals, such as clotrimazole, works by inhibiting the enzyme lanosterol 14-α-demethylase. This inhibition disrupts the production of ergosterol, essential for maintaining the fungal cell membrane.
Allylamine antifungals, like terbinafine, operate via a different, yet targeted, enzymatic pathway. They inhibit squalene epoxidase, which leads to a toxic buildup of squalene within the fungal cell and a depletion of ergosterol. This dual effect destabilizes the cell membrane and ultimately kills the fungus. Ammonium lactate, in contrast, engages in a physical and chemical interaction with human skin cells to promote hydration and exfoliation. It lacks the enzyme-targeting capabilities necessary to be considered fungicidal or fungistatic.