What Is Allantoin Powder (CAS 97-59-6)?
Allantoin is an organic compound with the molecular formula C4H6N4O3 and a molecular weight of 158.12 g/mol. It occurs naturally in comfrey and in the urine of most mammals, and it is produced synthetically for commercial supply so that purity and volume stay consistent. Pure allantoin is a white, odourless, tasteless crystalline powder that is non-toxic, non-irritating and non-allergenic at the concentrations normally used in cosmetics.
Key Properties and Specifications
| Property | Detail |
|---|---|
| CAS number | 97-59-6 |
| Molecular formula | C4H6N4O3 |
| Molecular weight | 158.12 g/mol |
| Appearance | White crystalline powder, odourless |
| Melting point | 226 - 240 °C with decomposition |
| Solubility | Soluble in hot water and hot alcohol, slightly soluble in cold water |
| pH of saturated solution | About 5.5 |
| Stability | Stable at pH 4 - 9 and in dry air |
The compound is only slightly soluble in cold water, so it dissolves most easily when added to the heated water phase of a formulation. Its saturated solution is mildly acidic and it remains stable across the pH 4 to 9 window that most skin-care emulsions occupy.
Skin Care, Cosmetic and Anti-Irritant Applications
Allantoin is a versatile skin-care active. As a humectant it attracts and holds moisture, helping creams, lotions and body butters keep skin hydrated and resist dryness and flaking. It supports the healing of minor wounds, burns, abrasions and inflammation by encouraging cell renewal, which is why it appears in ointments and therapeutic skin products. It also works as an anti-irritant that calms sensitive skin, so formulators use it in after-shave care, baby skin care and products for irritated or reactive skin. A mild keratolytic effect softens the stratum corneum and helps remove dead cells, which suits exfoliating products and treatments for thickened cuticles. Mild anti-inflammatory and antioxidant activity further reduces redness and shields skin from free-radical damage, supporting anti-ageing claims.
Pharmaceutical, Oral Care and Wound-Healing Uses
In pharmaceuticals, allantoin is used in topical preparations for wound healing, in dermatological products for dry and irritated skin, and in oral care products for its soothing effect on gums and mucosa. Pharmaceutical grades must meet stricter purity specifications and are handled under the applicable pharmacopoeia monograph, so the grade selected must match the intended route of use. Cosmetic grade material is intended for external use in finished formulations only.
Formulation Guidance and Use Levels
Typical cosmetic use level: 0.1 percent to 1.0 percent of the formulation
Common practical range: 0.2 percent to 0.5 percent for leave-on and rinse-off products
Compatibility: emulsifiers, humectants, preservatives, gelling agents and most common cosmetic raw materials
Processing: dissolve in the heated water phase before emulsification, then verify the final pH stays within the stable range
Beyond its activity, allantoin contributes to product stability and helps extend shelf life by maintaining the pH and physical integrity of an emulsion at the recommended concentration.
Quality Control, Storage and Regulatory Notes
Buyers should verify the assay, typically 98 percent to 100 percent on a dry basis, together with loss on drying, heavy metal content and residual impurities. Assay methods follow the relevant pharmacopoeia or cosmetic raw material monograph, and colour and clarity of the solution are checked visually or by spectrophotometry. Always require a certificate of analysis and confirm that the grade matches the application, because cosmetic and pharmaceutical purity requirements differ. Allantoin is recognised as safe for cosmetic use at commercial concentrations and is permitted in cosmetics in the EU and the United States, but finished products still need a safety assessment before marketing. Store the powder in sealed containers in a cool, dry place protected from direct sunlight and moisture, and close containers after each use to prevent caking and contamination.
Frequently Asked Questions
Q: What is allantoin used for in skincare?
Allantoin is used as a moisturiser, a skin-healing promoter, an anti-irritant and a mild exfoliant in creams, lotions, ointments and baby care products.
Q: Is allantoin safe for sensitive skin?
Yes. Allantoin is known for its low irritation potential and is frequently included in products formulated for sensitive skin, babies and irritated or damaged skin.
Q: What is the CAS number of allantoin?
The CAS registry number of allantoin is 97-59-6, and its molecular formula is C4H6N4O3 with a molecular weight of 158.12 g/mol.
Q: What concentration of allantoin is used in cosmetics?
Typical use levels are 0.1 percent to 1.0 percent, with 0.2 percent to 0.5 percent being common for most leave-on and rinse-off cosmetic products.
Q: Is allantoin natural or synthetic?
Allantoin occurs naturally in plants such as comfrey and in animal metabolism, but commercial powder is usually produced synthetically for consistent purity and supply. Both routes give a chemically identical molecule.
Q: Does allantoin dissolve easily in water?
It is soluble in hot water and only slightly soluble in cold water, so it should be dissolved in the warmed water phase with adequate agitation before emulsification.