Allantoin (CAS 97-59-6) — Citrus Top Note Fragrance Ingredient

ByThe Good Scents
neutral

Allantoin

CAS 97-59-6

Origin
synthetic
Note
IFRA
Generally safe
Data as of: Mar 2026

What Is Allantoin?

Allantoin is a synthetic compound commonly found in skincare and pharmaceutical products. It’s known for its soothing and moisturizing properties, often used in lotions, creams, and wound treatments. While odorless itself, it’s valued in perfumery for its ability to modify other ingredients’ effects without contributing its own scent.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ Non-toxic and non-irritating
✓ Widely used in cosmetics and pharmaceuticals
CAS
97-59-6
Formula
C4H6N4O3
MW
158.12
Odor Family
neutral
Allantoin 2D structure
Allantoin
C4H6N4O3
Layer 1 · Enthusiast

What Does Allantoin Smell Like?

Allantoin is completely odorless, making it unique among fragrance ingredients. It serves as a neutral carrier or modifier rather than contributing its own olfactory profile. In formulations, it behaves like a blank canvas, allowing other notes to shine without interference. Its dry-down is similarly neutral, leaving no trace of scent evolution over time.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Clean Reserve Skin(Clean, 2017)

Used for its skin-soothing properties in this minimalist fragrance, enhancing wearability without affecting the delicate musky-amber accord.

Glossier You(Glossier, 2017)

Incorporated for its compatibility with skin chemistry, helping the musk and iris notes blend seamlessly with natural body scent.

Layer 2

2D Molecular Structure

Allantoin

SMILES: NC(=O)NC1NC(=O)NC1=O

Chemistry, Properties & Perfumer Guide

The Chemistry

Allantoin is a diureide of glyoxylic acid with the formula C4H6N4O3. It’s typically synthesized from uric acid via oxidation. The molecule features both urea and hydantoin moieties, giving it unique hydrogen-bonding capabilities. This structure is responsible for its excellent water retention properties. While naturally occurring in some plants, commercial allantoin is almost exclusively produced synthetically for consistency and purity.

Physical & Chemical Properties

Melting Point239 °C
Molecular Weight158.12 g/mol
SolubilitySoluble in alcohol, methanol, pyridine
AppearanceColorless crystals from aqueous methanol

Perfumer Guide

Note Position
Neutral
Volatility
N/A
Blending
Excellent
ApplicationTypical %RangeNotes
Skincare Fragrances0.5-2%Up to 5%Adds skin benefits without scent interference
Functional Fragrances1-3%Up to 8%Enhances product performance while maintaining fragrance integrity

Classic Accords

+ Galaxolide = Enhanced musk diffusion + Ethyl Maltol = Smoother gourmand bases

Tip: Use as a neutral carrier for delicate top notes that need stabilization without alteration.

Alternatives & Comparisons

1
Panthenol CAS 81-13-0

When additional moisturizing properties are desired, though it may slightly affect fragrance longevity.

2
Bisabolol CAS 515-69-5

For formulations requiring anti-inflammatory benefits with minimal scent contribution.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. IFRA, REACH, EU Cosmetics Regulation standards update periodically. Consult current IFRA Standards Library before formulating. Not legal or regulatory advice.

IFRA Status

No IFRA restrictions. Generally recognized as safe for all applications.

RIFM Assessment

RIFM has evaluated allantoin as safe for current use levels in fragrances.

Sustainability

Synthetic production from urea and glyoxylic acid is energy-efficient with minimal waste. The process avoids agricultural inputs, making it consistent year-round without seasonal variations. Packaging typically uses recycled materials due to pharmaceutical-grade standards.

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References

  1. PubChem Compound Summary for CID 204 (Allantoin) PubChem
  2. Cosmetic Ingredient Review Expert Panel (2006). Final report on the safety assessment of allantoin. PMID 16835129

Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Mar 2026.

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Ingredient Data Sheet

CAS 97-59-6

Physical Properties

Molecular Weight158.12 g/mol🔬 PubChem
LogP (Octanol-Water)-2.2🔬 PubChem
Boiling Point258 °C🔬 EPA CompTox
Vapor Pressure0 mmHg @ 25°C📊 OPERA
Flash Point232 °C🔬 EPA CompTox
log Kp (skin permeability)-5.227💻 Calculated
SMILESC1(C(=O)NC(=O)N1)NC(=O)N🔬 PubChem

Volatility & Performance

Fragrance NoteHeart💻 Calculated
Data Sources & Attribution
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.

Physicochemical Properties

DTXSID: DTXSID3020043

Physical Properties

Molecular Weight 158.117 g/mol🔬 EPA CompTox
Density 1.71 g/cm^3🔬 EPA CTX
Boiling Point 298.813 °C📊 OPERA
Melting Point 236.125 °C🔬 EPA CTX
Flash Point 232.05 °C🔬 EPA CTX
Refractive Index 1.616 Dimensionless📊 OPERA
Molar Volume 95.701 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) -2.26 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) -2.064 Log10 unitless📊 OPERA
LogD (pH 7.4) -2.916 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 9.38 Log10 unitless📊 OPERA
Water Solubility 0.028 mol/L🔬 EPA CTX
Henry's Law Constant 0 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 0 mmHg📊 OPERA
Surface Tension 82.625 dyn/cm📊 OPERA

Molecular Descriptors

Topological Polar Surface Area 113.32 Ų💻 Computed
H-Bond Donors 4 count💻 Computed
H-Bond Acceptors 3 count💻 Computed
Rotatable Bonds 1 count💻 Computed
Aromatic Rings 0 count💻 Computed
Molar Refractivity 33.422 cm^3/mol📊 OPERA
Polarizability 13.25 Å^3📊 OPERA

Data Sources:

🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.

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