Ammonium lactate softens, hydrates, and gently exfoliates skin by working as both a humectant that pulls moisture into the outer skin layer and a mild chemical exfoliant that loosens the bonds between dead skin cells. It is the neutralized form of lactic acid, an alpha-hydroxy acid (AHA), and is most commonly found in over-the-counter and prescription lotions at a 12% concentration. Dermatologists reach for it to treat persistent dryness, rough bumpy patches, inherited scaling disorders, and even to protect skin from thinning caused by steroid creams.
How Ammonium Lactate Works on Your Skin
Lactic acid is one of the mildest AHAs and occurs naturally in the skin as part of what is sometimes called the “natural moisturizing factor.” When it is combined with ammonium hydroxide, you get ammonium lactate, a salt that is less acidic and therefore less stinging than straight lactic acid while still delivering the same active ingredient once it contacts the skin. The compound does two things at once. First, it acts as a humectant, drawing water from the deeper layers of your skin and from the environment into the outermost layer, the stratum corneum. Second, at concentrations around 12%, it works as a keratolytic, meaning it loosens the protein glue that holds dead cells together on the surface. The result is smoother, more supple skin that sheds its rough outer layer more efficiently.
Beyond simple moisturizing, lactic acid triggers a deeper biological response. Research on keratinocytes has shown that the L-isomer of lactic acid stimulates the production of ceramides, the waxy lipid molecules that form the mortar between your skin cells and keep the barrier intact. When ceramide levels rise, the skin loses less water through evaporation and becomes more resistant to environmental irritants. In barrier-function tests, L-lactic acid and the mixed D,L form produced measurable improvements, while the D-isomer alone did not, suggesting the specific molecular shape matters for this ceramide-boosting effect.1PubMed. Effect of lactic acid isomers on keratinocyte ceramide synthesis, stratum corneum lipid levels and stratum corneum barrier function
Treating Severe Dryness and Ichthyosis
The most common prescription use of ammonium lactate is for moderate to severe xerosis, the clinical term for abnormally dry, flaky skin. In a double-blind comparison, 12% ammonium lactate lotion proved significantly more effective than 5% lactic acid lotion at reducing xerosis severity over three weeks of twice-daily use. The improvement even persisted during a three-week washout period after treatment stopped, suggesting it had genuinely changed the skin’s condition rather than just sitting on the surface.2PubMed. Comparative efficacy of 12% ammonium lactate lotion and 5% lactic acid lotion in the treatment of moderate to severe xerosis
For people with ichthyosis, a group of inherited conditions that cause thick, dry, fish-scale-like skin, ammonium lactate has been a meaningful treatment option. A clinical trial testing 12% lactate lotion against both its vehicle (the lotion minus the active ingredient) and a petrolatum-based cream found the active lotion significantly outperformed both comparators. Several forms of the disease responded, including ichthyosis vulgaris, lamellar ichthyosis, X-linked ichthyosis, Netherton syndrome, and epidermolytic hyperkeratosis.3Journal of the American Academy of Dermatology. Therapeutic activity of lactate 12% lotion in the treatment of ichthyosis: Active versus vehicle and active versus a petrolatum cream That breadth is worth noting because ichthyosis is not one disease, and treatments that help one type do not always help another.
A separate clinical evaluation in patients with dry skin from both atopic (eczema-prone) and non-atopic backgrounds found that 12% ammonium lactate emulsion produced significant increases in skin hydration, surface lipids, extensibility, and firmness, along with improvements in barrier function and surface texture.4Acta Dermato-Venereologica. Clinical and non-invasive evaluation of 12% ammonium lactate emulsion for the treatment of dry skin in atopic and non-atopic subjects The fact that it worked in both groups is helpful because eczema-prone skin is often more reactive, and many moisturizers that work well on “normal” dry skin can irritate atopic skin.
Keratosis Pilaris and Rough, Bumpy Patches
If you have keratosis pilaris (KP), those small, sandpaper-like bumps that cluster on upper arms, thighs, and sometimes cheeks, you have probably already encountered ammonium lactate on recommendation lists. KP happens when excess keratin plugs individual hair follicles, and because ammonium lactate breaks down keratin buildup, it is a logical fit. In a case series of patients with both severe xerosis and KP, treatment with 12% ammonium lactate lotion over three months led to noticeable improvements in skin texture, hydration, and a reduction in itching, scaling, and roughness.5INDIAN JOURNAL OF APPLIED RESEARCH. CLINICAL OUTCOMES OF AMMONIUM LACTATE 12% IN PATIENTS WITH SEVERE XEROSIS & KERATOSIS PILARIS: A CASE SERIES
KP is notoriously stubborn, though. In the cases that responded best, ammonium lactate was paired with other treatments like chemical peels and microneedling rather than used alone. That tracks with what dermatologists generally advise: ammonium lactate can smooth and soften the bumps, but KP tends to recur once you stop treatment, and more severe cases often need a multi-pronged approach. Using it consistently as a daily body lotion is the simplest strategy and works well for milder KP, but if you are not seeing results after a couple of months of daily use, the issue may be that the plugs are too deep for a topical exfoliant at this concentration to fully clear.
Effects on Skin Thickness and Signs of Aging
One of the less-discussed benefits of ammonium lactate is what it does beneath the surface. A study examining skin biopsies found that 12% ammonium lactate increased epidermal thickness and boosted the amount of glycosaminoglycans in the dermis, the deeper layer below the epidermis.6PubMed. Effects of topical ammonium lactate on cutaneous atrophy from a potent topical corticosteroid Glycosaminoglycans are molecules that hold water in the dermis and give skin its plump, resilient feel. If those names sound familiar from anti-aging marketing, it is because hyaluronic acid is the most famous glycosaminoglycan, and the mechanism here is similar: more of these molecules in the dermis means firmer, better-hydrated skin from the inside.
Research on topical lactic acid at 12% concentration found it increased both epidermal and dermal firmness and thickness, and clinicians noted smoother skin and visible improvement in lines and wrinkles. At 5%, the dermal changes were not detected, but surface-level improvements in smoothness and fine lines still appeared.7PubMed. Epidermal and dermal effects of topical lactic acid This distinction matters if you are choosing between a lower-strength over-the-counter product and a prescription-strength 12% formulation. The lower concentration can still improve texture and brightness, but the structural, collagen-adjacent benefits in the dermis seem to kick in at the higher dose.
Ammonium lactate is not typically marketed as an anti-aging product the way retinoids or vitamin C serums are, and it is not a substitute for those ingredients if your primary concern is photoaging. But if you already use it for dryness or KP, the mild wrinkle-smoothing and skin-thickening effects are a practical bonus you get without adding another product to your routine.
Protecting Skin from Steroid-Induced Thinning
Topical corticosteroids are among the most widely prescribed skin medications, used for everything from eczema to psoriasis. One of their best-known downsides is cutaneous atrophy: with prolonged use, the skin thins, becomes fragile, and develops visible blood vessels. Ammonium lactate can help counteract that process. The same biopsy study mentioned earlier found that when 12% ammonium lactate was applied alongside a potent topical corticosteroid, it significantly reduced atrophy in both the epidermis and dermis, without interfering with the steroid’s anti-inflammatory effect.6PubMed. Effects of topical ammonium lactate on cutaneous atrophy from a potent topical corticosteroid
This pairing has been studied specifically in psoriasis management. In a randomized, double-blind trial, patients with plaque psoriasis first used a combination of 12% ammonium lactate lotion and halobetasol propionate ointment (a very potent steroid) for two weeks. About three-quarters of patients were rated clear or almost clear after that initial phase. Then, during a maintenance phase, patients who continued applying ammonium lactate daily with weekend-only steroid applications sustained their improvement significantly longer than those on placebo, and without developing steroid-related side effects like skin thinning.8PubMed Central. A Randomized, Double-blind, Placebo-controlled Study to Evaluate the Safety and Efficacy of Ammonium Lactate Lotion 12% and Halobetasol Propionate Ointment 0.05% in the Treatment and Maintenance of Psoriasis The logic is straightforward: the ammonium lactate preserves dermal ground substance and epidermal thickness while the steroid does the heavy anti-inflammatory lifting on the weekends.9Psoriasis Forum. Compatibility of Ammonium Lactate 12% with Halobetasol Propionate 0.05% and Hydrocortisone Valerate 0.2%
If your doctor has you on a long-term topical steroid regimen, asking about adding ammonium lactate as a companion product is a reasonable conversation to have, especially for areas prone to thinning like the inner arms, neck, or groin folds.
How It Compares to Urea and Glycolic Acid
Two ingredients often discussed alongside ammonium lactate are urea and glycolic acid. All three are used to treat dry, scaly skin, but they are not interchangeable.
Urea, particularly at high concentrations like 40%, tends to work faster and more aggressively. A head-to-head trial comparing 40% urea cream to 12% ammonium lactate lotion found that by day 14, the urea cream was superior in reducing roughness, fissures, thickness of scale, and overall dryness.10PubMed. Clinical evaluation of 40% urea and 12% ammonium lactate in the treatment of xerosis That does not mean urea is always the better choice: 40% urea is a thick cream that can sting and has a characteristic odor many people dislike, and it is typically reserved for very rough, calloused, or cracked areas like heels and elbows. At lower concentrations around 5%, urea and ammonium lactate perform more similarly. A study testing 5% ammonium lactate against 5% urea and combinations of both found no significant differences in hydration improvement among the treatments that included urea or the combination formulas.11Karger. Do urea/ammonium lactate combinations achieve better skin protection and hydration than either component alone?
Glycolic acid is the other major AHA people encounter in skincare. It is a smaller molecule than lactic acid and penetrates the skin more readily, which makes it a stronger exfoliant at the same concentration but also more likely to cause irritation. A comparative study of different AHAs found that with long-term use, L-lactic acid and glycolic acid produced similar improvements in hydration and fine lines, but L-lactic acid caused fewer complaints from users. When concentrations were pushed higher, the gap in irritation widened further, with glycolic acid and D-lactic acid provoking noticeably more stinging than the L-form.12PubMed. Comparative effectiveness of alpha-hydroxy acids on skin properties Because ammonium lactate is derived from lactic acid (primarily the L-isomer in most commercial formulations), this gentler profile is one of its practical advantages. If your skin does not tolerate glycolic acid products well, ammonium lactate may deliver comparable results with less discomfort.
Using It on Your Feet
Dry, cracked heels and the thick callused skin on the soles of your feet are among the most satisfying targets for ammonium lactate because the keratolytic action is exactly what that stubborn tissue needs. A systematic review of moisturizers for foot dryness identified a trial in which 12% ammonium lactate was significantly superior to no treatment in reducing overall dryness severity scores on the feet after eight weeks of use.13PubMed Central. Moisturisers for the treatment of foot xerosis: a systematic review Foot skin is much thicker than skin elsewhere on the body, so the exfoliant effect of ammonium lactate at 12% is less likely to cause irritation there and more likely to make a visible difference. A common approach is to apply a generous layer at bedtime and cover with cotton socks to prevent it from rubbing off on your sheets and to keep the product in contact with the skin longer.
Side Effects and Practical Considerations
The most common side effect is stinging or mild burning, especially when you first start using it or when you apply it to freshly shaved skin, broken skin, or areas that are already inflamed. This usually fades within a few minutes and tends to lessen over a week or two as the skin adjusts. If the stinging is persistent or intense, try applying the lotion to completely dry skin rather than slightly damp skin after a shower, or reduce the frequency to once daily until your skin acclimates.
Because ammonium lactate is an AHA, it can make your skin more sensitive to the sun. All AHAs thin the dead-cell layer that provides some passive UV protection, which means the living cells beneath are more exposed. Using sunscreen on treated areas that see daylight is a smart habit. This is less of a concern on the legs, which are often covered, and not an issue at all on the feet, but it matters if you are using ammonium lactate on your forearms, chest, or face (though most formulations are intended for body use, not facial skin, where the concentration tends to be too high for comfort).
You should avoid using ammonium lactate on open wounds, actively oozing eczema, or deeply cracked skin with visible raw tissue. The acid component will cause significant pain on broken skin and could potentially slow healing in those spots. Let acute inflammation or open fissures heal first, then introduce ammonium lactate once the surface has closed.
Who Should and Should Not Use It
Ammonium lactate is broadly well-tolerated across skin types. It is available over the counter in some formulations (usually labeled as “lactic acid lotion” or by brand names like AmLactin) and by prescription at 12%. People who tend to benefit most include those with chronically dry skin on the body, KP, mild to moderate ichthyosis, rough or calloused feet, and anyone on long-term topical steroids who wants to preserve skin thickness.
It is generally not recommended for children under two years old, and pregnant or nursing individuals should check with a healthcare provider because formal safety data in those groups is limited. People with very sensitive or rosacea-prone facial skin should be cautious about applying body-strength formulations to the face, as the 12% concentration is typically too strong for that purpose. Lower-concentration lactic acid products designed specifically for facial use exist and are a better fit for that area.
One common misconception is that because ammonium lactate contains the word “acid,” it must be harsh. In reality, the ammonium salt form has a higher pH than pure lactic acid, making it gentler while still active. Another misconception is that it works instantly. While you may feel smoother skin within a day or two, the deeper structural improvements in ceramide levels, epidermal thickness, and barrier function develop over weeks of consistent use. If you give up after a few applications because the rough patches have not vanished, you are quitting before the most meaningful changes have had time to build.
What Ammonium Lactate Does Not Do
It is worth setting boundaries on expectations. Ammonium lactate is not a treatment for acne, hyperpigmentation, or deep wrinkles. While its exfoliant action can mildly improve skin tone and texture, it does not have the potency or the mechanism to replace retinoids for photoaging or benzoyl peroxide for breakouts. It is not an anti-itch medication, even though it can reduce the itch that comes specifically from dry, cracked skin. If your itching is from an allergic reaction, hives, or a fungal infection, ammonium lactate will not address the underlying cause and may irritate the area further.
It also does not treat the inflammation of eczema or psoriasis directly. As the steroid-pairing research shows, it plays a supportive role, keeping skin hydrated and protecting against atrophy, while the corticosteroid handles the inflammatory disease. Expecting ammonium lactate alone to control an eczema flare will leave you disappointed. Its strength is in maintenance and in managing the dry, scaling component of these conditions, not the red, swollen, actively inflamed phase.