Ingredient review

Ammonium Carbonate

INCI: AMMONIUM CARBONATE

Ammonium carbonate is a functional pH adjuster that can be irritating at high concentrations, but is generally safe in well-formulated products.

beautyskincarepH adjuster

In plain English

Ammonium carbonate is a salt that helps control the acidity (pH) of a product. It can release a small amount of ammonia gas, which gives it a sharp smell. In skincare, it's used in small amounts to keep formulas stable and effective, especially in products that need a slightly alkaline environment, like some hair treatments or cleansers. It's not a moisturizer or active treatment ingredient.

Quick decision guide

Useful, but context matters

Ammonium Carbonate can be useful, but watch for some irritation potential.

Plain-English read

Treat this as a practical screening step before you compare products that contain this ingredient.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Ammonium Carbonate.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.

Score terms in plain English

Irritation risk

moderate

Can bother some users, especially with frequent use, damaged skin, or strong companion ingredients.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

Ammonium carbonate is a white crystalline salt formed from ammonia and carbon dioxide. In cosmetics, it acts as a buffering agent, meaning it helps maintain a stable pH level in the product.

How it works

When added to a water-based formula, ammonium carbonate dissociates into ammonium and carbonate ions. These ions interact with other ingredients to keep the pH within a desired range, which is important for product stability and skin compatibility. It can also help adjust the texture or feel of a product.

Pros

Effective pH control

Ammonium carbonate reliably adjusts and buffers pH, helping products stay stable and perform as intended over time.

Low comedogenic risk

It is not known to clog pores, making it suitable for acne-prone skin when used in appropriate concentrations.

Cons and cautions

Potential irritation

At higher concentrations, ammonium carbonate can cause stinging, redness, or irritation, especially on sensitive or compromised skin.

Strong odor

The ingredient can release a noticeable ammonia smell, which some users find unpleasant, though it usually dissipates quickly.

Best for

  • People using well-formulated products with low concentrations
  • Those who tolerate standard pH adjusters without irritation

Use caution if

  • Individuals with very sensitive or reactive skin
  • Anyone with a known ammonia sensitivity or allergy

Usage tips

Look for ammonium carbonate near the end of the ingredient list to ensure it's used at a low concentration.
If you have sensitive skin, patch test a new product containing this ingredient before full-face application.

Safety summary

Ammonium carbonate is considered safe in cosmetics at low concentrations (typically under 2%). Higher concentrations can cause skin and eye irritation. It is not a known carcinogen or endocrine disruptor.

Research notes

Research on ammonium carbonate in cosmetics is limited, but it has a long history of safe use as a pH adjuster. Safety assessments by industry panels support its use at low levels.

Common label clues

Typical concentration
Typically used at 0.1–2% in leave-on products; higher in rinse-off products
Regulatory status
Approved for use in cosmetics by the FDA and EU CosIng database, with concentration limits to ensure safety.
Common uses
pH-adjusting formulations, Hair waving/straightening products, Facial cleansers
Environmental note
Ammonium carbonate is synthetically produced and biodegradable, but its production involves ammonia, which has environmental considerations.

Good to know

  • Ammonium carbonate is sometimes used in baking as a leavening agent (baker's ammonia).
  • It is not a preservative, but its pH-adjusting role can indirectly affect microbial stability.

Common questions

What is Ammonium Carbonate in beauty products?

Ammonium carbonate is a salt that helps control the acidity (pH) of a product. It can release a small amount of ammonia gas, which gives it a sharp smell. In skincare, it's used in small amounts to keep formulas stable and effective, especially in products that need a slightly alkaline environment, like some hair treatments or cleansers. It's not a moisturizer or active treatment ingredient.

What does Ammonium Carbonate do in a beauty product?

When added to a water-based formula, ammonium carbonate dissociates into ammonium and carbonate ions. These ions interact with other ingredients to keep the pH within a desired range, which is important for product stability and skin compatibility. It can also help adjust the texture or feel of a product.

Is Ammonium Carbonate safe for most people?

Ammonium carbonate is considered safe in cosmetics at low concentrations (typically under 2%). Higher concentrations can cause skin and eye irritation. It is not a known carcinogen or endocrine disruptor.

Who should be careful with Ammonium Carbonate?

Individuals with very sensitive or reactive skin Anyone with a known ammonia sensitivity or allergy

Research sources

CosIng - Ammonium CarbonateOpenFDA - Cosmetic Ingredient ReviewOpenPubChem - Ammonium CarbonateOpen

Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.