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Skeletal formula of allantoin
Heap of white powder on a watch glass
Ball-and-stick model of the allantoin molecule
IUPAC name
(2,5-Dioxo-4-imidazolidinyl) urea
Other names
97-59-6 YesY
ChEBI CHEBI:15676 YesY
ChEMBL ChEMBL593429 YesY
ChemSpider 199 YesY
EC Number 202-592-8
Jmol interactive 3D Image
KEGG D00121 YesY
PubChem 204
RTECS number YT1600000
UNII 344S277G0Z YesY
Molar mass 158.12 g·mol−1
Appearance colourless crystalline powder
Odor odorless
Density 1.45 g/cm3
Melting point 230 °C (446 °F; 503 K) (decomposes)
Boiling point 478 °C (892 °F; 751 K)
0.57 g/100 mL (25 °C)
4.0 g/100 mL (75 °C)
Solubility soluble in alcohol, pyridine, NaOH
insoluble in ethyl ether
log P -3.14
Acidity (pKa) 8.48
Safety data sheet Allantoin MSDS
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
> 5000 mg/kg (oral, rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Allantoin is a chemical compound with formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide.[1][2] It is a diureide of glyoxylic acid.[citation needed]

In biology[edit]

Named after the allantois (an amniote embryonic excretory organ in which it concentrates during development in most mammals except humans and higher apes[vague]), it is a product of oxidation of uric acid by purine catabolism. After birth, it is the predominant means by which nitrogenous waste is excreted in the urine of these animals.[3] In humans and higher apes, the metabolic pathway for conversion of uric acid to allantoin is not present, so the former is excreted. Recombinant rasburicase is sometimes used as a drug to catalyze this metabolic conversion in patients. In fish, allantoin is broken down further (into ammonia) before excretion.[4] Allantoin is a major metabolic intermediate in many other organisms including plants and bacteria.


Allantoin is present in botanical extracts of the comfrey plant and in the urine of most mammals. Chemically synthesized bulk allantoin, which is chemically equivalent to natural allantoin, is safe, non-toxic, compatible with cosmetic raw materials and meets CTFA and JSCI requirements. Over 10,000 patents reference allantoin.[5]

Cosmetics and toiletries[edit]

Manufacturers cite several beneficial effects for allantoin as an active ingredient in over-the-counter cosmetics, including: a moisturizing and keratolytic effect, increasing the water content of the extracellular matrix and enhancing the desquamation of upper layers of dead skin cells, increasing the smoothness of the skin; promoting cell proliferation and wound healing; and a soothing, anti-irritant, and skin protectant effect by forming complexes with irritant and sensitizing agents.

A animal study in 2010 found that based on the results from histological analyses, a soft lotion with 5% allantoin ameliorates the wound healing process, by modulating the inflammatory response. The study also suggests that quantitative analysis lends support to the idea that allantoin also promotes fibroblast proliferation and synthesis of the extracellular matrix. [6]

A study published in 2009 reported the treatment of pruritus in mild-to-moderate atopic dermatitis with a topical non-steroidal agent containing allantoin.[7]


It is frequently present in toothpaste, mouthwash, and other oral hygiene products, in shampoos, lipsticks, anti-acne products, sun care products, and clarifying lotions, various cosmetic lotions and creams, and other cosmetic and pharmaceutical products.[8]

Biomarker of oxidative stress[edit]

Since uric acid is the end product of the purine metabolism in humans, only non-enzymatic processes with reactive oxygen species will give rise to allantoin, which is thus a suitable biomarker to measure oxidative stress in chronic illnesses and senescence.[9][10]

See also[edit]


  1. ^
  2. ^
  3. ^ Young E. G., Wentworth H. P., Hawkins W. W. (1944). "The absorption and excretion of allantoin in mammals". J. Pharmacol. Experi. Therapeutics 81 (1): 1–9. 
  4. ^ Fujiwara, S; Noguchi T (1995). "Degradation of purines: only ureidoglycollate lyase out of four allantoin-degrading enzymes is present in mammals". The Biochemical Journal 312 (Pt 1): 315–8. PMC 1136261. PMID 7492331. 
  5. ^ Patent Lens search
  6. ^ Araújo LU, Grabe-Guimarães A, Mosqueira VC, Carneiro CM, Silva-Barcellos NM. (2012-10-22). "Profile of wound healing process induced by allantoin". Acta Cir Bras 25 (5): 460–6. doi:10.1590/S0102-86502010000500014. PMID 20877959. 
  7. ^ Veraldi, S; De Micheli, P; Schianchi, R; Lunardon, L (2009). "Treatment of pruritus in mild-to-moderate atopic dermatitis with a topical non-steroidal agent". Journal of drugs in dermatology : JDD 8 (6): 537–9. PMID 19537379. 
  8. ^ Thornfeldt, C (2005). "Cosmeceuticals containing herbs: fact, fiction, and future". Dermatologic Surgery 31 (7 Pt 2): 873–80. doi:10.1111/j.1524-4725.2005.31734. PMID 16029681. 
  9. ^ Kand'ár R, Záková P. (2008). "Allantoin as a marker of oxidative stress in human erythrocytes". Clinical chemistry and laboratory medicine : CCLM / FESCC 46 (9): 1270–4. doi:10.1515/CCLM.2008.244. PMID 18636793. 
  10. ^ Zitnanová I, Korytár P, Aruoma OI, Sustrová M, Garaiová I, Muchová J, Kalnovicová T, Pueschel S, Duracková Z (2004). "Uric acid and allantoin levels in Down syndrome: Antioxidant and oxidative stress mechanisms?". Clinica chimica acta; international journal of clinical chemistry 341 (1–2): 139–46. doi:10.1016/j.cccn.2003.11.020. PMID 14967170. 

External links[edit]