What Is Ammonium Phosphate?
Ammonium phosphate, also known as ammonium dihydrogenorthophosphate, is a salt that forms when ammonia reacts with phosphoric acid. It looks like a white crystalline powder that dissolves easily in water. Because it can gently adjust acidity, chemists first used it in farming and food processing. Over time formulators noticed the same acid-balancing skill could help stabilize personal care products, so it found its way into cosmetics.
Making ammonium phosphate starts with mining phosphate rock, which is treated with sulfuric acid to get phosphoric acid. The acid is then combined with ammonia gas under controlled conditions, producing solid crystals that are filtered, dried and milled to the fine powder used in manufacturing.
Today you will spot ammonium phosphate in a range of rinse-off oral care items such as toothpastes, mouthwashes and breath sprays. Its ability to keep pH steady also makes it useful in some facial masks, exfoliating gels and leave-on lotions where stable acidity helps other ingredients perform at their best.
Ammonium Phosphate’s Cosmetic Benefits/Uses
In formulas this ingredient plays two key roles that support product performance and user experience:
- Buffering: It helps keep the product’s pH within a skin-friendly range, which protects delicate active ingredients and reduces the chance of irritation from sudden pH shifts.
- Oral care: In dental products it supports enamel health by maintaining a balanced environment in the mouth and can aid in neutralizing acids that lead to tooth sensitivity or decay.
Who Can Use Ammonium Phosphate
Because ammonium phosphate is primarily a pH stabilizer rather than an active treatment, it is generally well tolerated by normal, dry, oily and combination skin. People with very sensitive or compromised skin should still keep an eye on how their skin feels, since any buffer can cause discomfort if used in a formula with an extreme pH.
The ingredient is mineral based and made without animal derivatives, so it aligns with vegan and vegetarian preferences.
No specific warnings link ammonium phosphate to pregnancy or breastfeeding concerns. That said this is not medical advice and anyone who is pregnant or nursing should run the product past a healthcare professional just to be safe.
Ammonium phosphate does not increase photosensitivity, so it will not make skin more prone to sunburn. It is also odorless, colorless in solution and non staining, which keeps it user friendly for daily oral care or skincare routines.
Potential Side Effects/Adverse Reactions
Responses to topical or oral use of ammonium phosphate vary from person to person. The issues listed below are only potential outcomes and are unlikely for most users when the ingredient is used at appropriate levels in a well formulated product.
- Mild skin irritation such as itching or burning, especially on already inflamed skin
- Redness or a transient stinging sensation after application
- Eye irritation if the product accidentally gets into the eyes
- Allergic contact dermatitis in rare cases
- Oral or gum sensitivity when used in dental products formulated with an imbalanced pH
If any discomfort or unexpected reaction occurs discontinue use immediately and seek advice from a medical professional.
Comedogenic Rating
Rating: 0/5
Ammonium phosphate is a small, fully water-soluble mineral salt with no oily or waxy components, so it does not sit on the skin surface or block pores. It is normally used at very low levels, often in rinse-off products, further reducing any chance of buildup. For these reasons it earns a solid 0, meaning it is non-comedogenic and generally suitable for people prone to acne or breakouts.
The only situation that could indirectly trigger blemishes is if the overall formula has a very high or very low pH and stresses the skin barrier, but that would be due to the product as a whole, not this ingredient itself.
Summary
Ammonium phosphate acts mainly as a pH buffer and a supporting oral care agent. By releasing or accepting hydrogen ions it keeps formulas in a skin-friendly pH range, which protects both the product and the user from irritation. In toothpastes and mouthwashes it helps neutralize acids in the mouth, creating an environment that is less favorable to enamel erosion.
While it is valued by chemists for its reliability, the ingredient is not a headline-grabbing star in beauty marketing and remains a quiet workhorse found mostly in functional roles.
Safety profiles show it to be low risk for most skin types and it holds a non-comedogenic rating. Still, every person’s skin is unique, so it is smart to patch test any new product that contains ammonium phosphate or any other unfamiliar ingredient.