What Ammonium Lactate 12% Lotion Does for Very Dry Skin

Straight answer

Ammonium lactate 12% is lactic acid partly neutralized with ammonium hydroxide, made into a lotion or cream that exfoliates and moisturizes very dry, scaly skin. In the US, the 12% lotion and cream are prescription generic drugs labeled for dry skin (xerosis) and ichthyosis vulgaris, applied twice daily. Over-the-counter lotions labeled with 12% lactic acid are also sold, but as cosmetic moisturizers rather than approved drugs.

Ammonium lactate lotion 12% has been a dermatologist standby for dry, rough skin for decades. It’s also one of the more confusing products on the pharmacy shelf, because a prescription version and over-the-counter lookalikes exist side by side. Here’s what it is, how it differs from plain lactic acid, how to use it, and what to watch for.

What ammonium lactate 12% is

According to the prescription label, ammonium lactate lotion 12% “specially formulates 12% lactic acid neutralized with ammonium hydroxide,” giving a lotion pH of 4.5 to 5.5 (DailyMed). Lactic acid on its own is quite acidic; partly neutralizing it makes it gentler to leave on large areas of skin twice a day. The base also contains familiar moisturizing ingredients such as glycerin and mineral oil.

MedlinePlus classifies ammonium lactate as an alpha hydroxy acid that works by increasing skin hydration, and lists both a lotion and a cream (MedlinePlus). In practice it does two jobs at once: it loosens the buildup of dead cells that makes skin scaly, and it pulls water into the outer layer. For more on the parent ingredient, see our guide to lactic acid lotion.

Prescription or over the counter?

Both exist, and they’re regulated differently.

The prescription version

Generic ammonium lactate lotion 12% and cream 12% carry “Rx only” labels and are indicated for the treatment of dry, scaly skin (xerosis) and ichthyosis vulgaris, plus temporary relief of the itching that comes with them (DailyMed lotion label; DailyMed cream label). They’re listed as prescription drugs in the FDA’s National Drug Code Directory, which covers all finished drugs, prescription and over the counter (FDA). Lac-Hydrin was the original brand name.

Over-the-counter 12% lotions

You’ll also find body lotions labeled with 12% lactic acid on drugstore shelves without a prescription, AmLactin being the best known. These are marketed as moisturizers. Under FDA rules, what a product is depends on its intended use: a moisturizer sold to improve the skin’s appearance is a cosmetic, which doesn’t need FDA approval before sale, while a product intended to treat a disease is a drug that does (FDA). That’s why an over-the-counter lotion can say it relieves rough, dry skin but can’t claim to treat ichthyosis.

The practical upshot: an over-the-counter 12% lotion and the prescription generic contain the same headline percentage, but they aren’t guaranteed to be identical formulas, and only the prescription product has gone through FDA review for its labeled uses. For everyday dry legs, many people do well with an over-the-counter version. For ichthyosis or severe, cracked dryness, ask a dermatologist.

	Prescription ammonium lactate 12%	Over-the-counter 12% lactic acid lotion
Regulatory status	Rx drug (generic), FDA-reviewed	Cosmetic moisturizer
Labeled uses	Xerosis and ichthyosis vulgaris, plus related itch	Dry, rough skin (cosmetic claims only)
pH	4.5 to 5.5 (per label)	Varies by product
Directions	Twice daily or as directed by a physician	Per package
Where to get it	Pharmacy, with a prescription	Drugstores and online

Sources: DailyMed, FDA NDC Directory, FDA.

What it’s used for

Xerosis (dry, scaly skin)

This is the main use. The shins, arms and feet of adults with persistently dry, rough skin are classic targets. Our guide to dry skin on legs covers the habits that help it work.

Ichthyosis vulgaris

Ichthyosis vulgaris is an inherited condition that causes white, gray or brown scales with curled edges, often on the fronts of the legs and backs of the arms, and it tends to worsen in winter (AAD). Ammonium lactate 12% is specifically labeled for it (DailyMed).

Aging, thin body skin

This isn’t a labeled use, but it’s an active area of interest. In a forearm study, 12% ammonium lactate reduced the skin thinning caused by a potent steroid cream in both the outer and deeper layers of skin (Lavker et al., 1992). That’s one reason it comes up in conversations about crepey skin.

What the evidence shows

• Versus 5% lactic acid: in a double-blind study of moderate to severe xerosis, 12% ammonium lactate was significantly more effective than 5% lactic acid lotion during three weeks of twice-daily use and in the three weeks after treatment stopped (Rogers et al., 1989).
• Versus 40% urea: in a small randomized comparison, a 40% urea cream improved roughness, cracks, thickness and dryness faster than 12% ammonium lactate at day 14 (Ademola et al., 2002). High-strength urea may be the faster option for thick, cracked skin, such as heels.
• On steroid-thinned skin: 12% ammonium lactate spared both the epidermis and dermis from much of the thinning caused by a potent topical steroid, without reducing the steroid’s effect (Lavker et al.).

These are mostly older, small studies, so the honest summary is: good, consistent evidence for dry, scaly skin; promising but limited evidence for anything beyond that.

How to use ammonium lactate lotion 12%

1. Shake the lotion before each use (DailyMed).
2. Apply to clean, dry skin and rub in thoroughly (Cleveland Clinic).
3. Use twice daily, or as your doctor directs, for the prescription product (DailyMed). Starting once a day for the first week is a reasonable way to gauge tolerance.
4. Avoid the eyes, mouth, nose and vaginal area (MedlinePlus). The prescription label advises caution on the face because of the potential for irritation (DailyMed).
5. Time it around shaving. Shave at a different time of day so the lotion goes on intact skin.
6. Wash your hands afterward, unless you’re treating your hands.

Side effects and precautions

Stinging and burning

The most common reactions are transient stinging and burning. In clinical trials of the lotion in people with xerosis, each occurred in about 1 in 30 patients, and redness in about 1 in 50; rates were higher, about 1 in 10, in people with ichthyosis (DailyMed). The label notes stinging is more likely on cracked, eroded or abraded skin, “for example, after shaving the legs.”

Sun sensitivity

The prescription label says sun exposure to treated skin should be minimized or avoided (DailyMed). That fits with FDA research showing AHAs increase sensitivity to UV, with the effect fading about a week after stopping (FDA). On legs and arms that see daylight, use sunscreen or cover up.

Other precautions

• Stop and contact your clinician for rash, hives or swelling of the face, lips, tongue or throat (Cleveland Clinic).
• The label states that the potential for post-inflammatory hypo- or hyperpigmentation has not been studied (DailyMed). If you’re prone to dark marks after irritation, go slowly.
• Tell your doctor if you’re pregnant, trying to conceive or breastfeeding (Cleveland Clinic).
• Safety and effectiveness have been demonstrated in infants and children, per the prescription label (DailyMed), but ask a pediatrician before using it on a child.

Frequently asked questions

Is ammonium lactate 12% available without a prescription?

The generic ammonium lactate lotion and cream 12% are prescription products (DailyMed). Body lotions labeled with 12% lactic acid are sold over the counter as cosmetic moisturizers (FDA).

What is the difference between ammonium lactate and lactic acid?

Ammonium lactate is lactic acid that has been partly neutralized with ammonium hydroxide to a pH of about 4.5 to 5.5, which makes it gentler for leave-on use (DailyMed).

How long does it take ammonium lactate to work?

In a double-blind study, dry skin improved significantly within three weeks of twice-daily use (Rogers et al.). Many people notice softer skin sooner.

Can I use ammonium lactate lotion 12% on my face?

The prescription label advises caution on the face because of irritation risk (DailyMed). Use facial products designed for that skin instead, unless your dermatologist says otherwise.

Can I use it on crepey skin?

It isn’t labeled for that, but 12% lactic acid has increased skin thickness in studies, and ammonium lactate limited steroid-related thinning (Lavker et al.). Pair it with daily sunscreen; see our guide to the best moisturizer ingredients for crepey skin.

Sources

1. U.S. National Library of Medicine. “Ammonium Lactate Lotion, 12% (prescription label).” DailyMed. dailymed.nlm.nih.gov
2. U.S. National Library of Medicine. “Ammonium Lactate Cream, 12% (prescription label).” DailyMed. dailymed.nlm.nih.gov
3. U.S. National Library of Medicine. “Ammonium Lactate Topical.” MedlinePlus Drug Information. medlineplus.gov
4. Cleveland Clinic. “Ammonium Lactate topical lotion.” Cleveland Clinic. my.clevelandclinic.org
5. U.S. Food and Drug Administration. “National Drug Code Directory.” FDA. fda.gov
6. U.S. Food and Drug Administration. “Is It a Cosmetic, a Drug, or Both? (Or Is It Soap?).” FDA. fda.gov
7. U.S. Food and Drug Administration. “Alpha Hydroxy Acids.” FDA. fda.gov
8. Rogers RS 3rd, Callen J, Wehr R, Krochmal L. “Comparative efficacy of 12% ammonium lactate lotion and 5% lactic acid lotion in the treatment of moderate to severe xerosis.” Journal of the American Academy of Dermatology, 1989. pubmed.ncbi.nlm.nih.gov
9. Ademola J, Frazier C, Kim SJ, et al. “Clinical evaluation of 40% urea and 12% ammonium lactate in the treatment of xerosis.” American Journal of Clinical Dermatology, 2002. pubmed.ncbi.nlm.nih.gov
10. Lavker RM, Kaidbey K, Leyden JJ. “Effects of topical ammonium lactate on cutaneous atrophy from a potent topical corticosteroid.” Journal of the American Academy of Dermatology, 1992. pubmed.ncbi.nlm.nih.gov
11. American Academy of Dermatology. “Ichthyosis vulgaris: Signs and symptoms.” AAD. aad.org

General information, not medical advice. For a spot that’s new, changing or bleeding, see a dermatologist.