What Is Ammonium Sulfate?
Ammonium sulfate is an inorganic salt made by combining sulfuric acid with ammonia, creating white to slightly off-white crystals that dissolve easily in water. Although it has long been used in agriculture as a fertilizer, manufacturers noticed its reliable thickening qualities and began adapting it for personal care. Today most cosmetic-grade ammonium sulfate is produced through a controlled reaction of purified ammonia gas with sulfuric acid, then filtered, dried and milled to a uniform particle size suitable for skincare and haircare labs.
You are most likely to encounter this ingredient in products that need a stable yet light consistency such as facial cleansers, shampoos, liquid soaps, exfoliating washes and certain sheet mask serums. Its ability to fine-tune thickness without a greasy feel makes it handy in both rinse-off and leave-on formulas.
Ammonium Sulfate’s Cosmetic Benefits/Uses
At the lab bench ammonium sulfate is valued for one key job: viscosity controlling. By adjusting how easily a formula flows, it helps chemists strike the right balance between a watery drip and a stiff gel. The result is a product that feels comfortable in the hand, spreads smoothly across skin or hair and stays homogenous on the shelf, reducing the chance of separation over time.
Who Can Use Ammonium Sulfate
Because ammonium sulfate is an inert mineral salt with no oily or occlusive feel, it suits most skin types including oily, combination, normal and even dry skin when paired with other hydrating ingredients. Sensitive or compromised skin can usually tolerate it as well, although open cuts or raw patches may experience a brief stinging sensation due to its salt content.
The compound is made through a fully synthetic process using ammonia and sulfuric acid, so it contains no animal by-products. That makes it acceptable for vegans and vegetarians as long as the finished product is not animal tested, which must be confirmed brand by brand.
Current cosmetic safety assessments consider ammonium sulfate safe for use during pregnancy and while breastfeeding. Still, this is not medical advice and anyone who is pregnant or nursing should review all personal care products with a qualified health professional before use, just to be cautious.
Ammonium sulfate does not increase photosensitivity, so it will not make skin more prone to sunburn. It also has no known interactions with common active ingredients like retinoids or vitamin C, allowing it to sit comfortably in multi-step routines.
Potential Side Effects/Adverse Reactions
Reactions to topical ammonium sulfate differ from person to person. The issues listed below are only potential outcomes and are unlikely for most users when the ingredient is formulated at appropriate levels.
- Mild skin irritation or redness, particularly on already inflamed areas
- Transient stinging if applied to broken skin
- Eye irritation if the product accidentally gets into the eyes
- Rare allergic contact dermatitis in individuals with specific sensitivities
If you notice any discomfort or persistent reaction while using a product that contains ammonium sulfate stop using it immediately and consult a healthcare professional.
Comedogenic Rating
Rating: 0 out of 5. Ammonium sulfate is a highly water-soluble mineral salt that leaves no oily film on skin and rinses away cleanly, so it does not block pores or trap sebum. Its job is simply to tweak thickness, not to coat the skin, which is why it earns the lowest score on the clog-pore scale.
Suitable for acne-prone or breakout-prone users.
Because it is usually added at low levels and often found in rinse-off formulas, the chance of pore blockage is even lower than its rating suggests.
Summary
Ammonium sulfate is mainly used to control viscosity, keeping cleansers, shampoos and lightweight serums at the right flow so they feel good and stay stable on the shelf. It does this by interacting with water in the formula and slightly tightening the liquid structure, giving chemists a simple way to fine-tune texture without adding oils or gums.
While not the trendiest ingredient around, it remains a quiet workhorse in labs because it is inexpensive, dependable and easy to formulate. Safety reviews find it low risk for skin and eye contact when used at cosmetic levels, yet it is still smart to patch test any new product to make sure it agrees with your own skin.