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
3D model (Jmol) Interactive image
Interactive image
ChEBI CHEBI:15676 YesY
ChEMBL ChEMBL593429 YesY
ChemSpider 199 YesY
ECHA InfoCard 100.002.358
EC Number 202-592-8
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).
N verify (what is YesYN ?)
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. Allantoin is a major metabolic intermediate in most organisms including animals, plants and bacteria and is produced as a degradation product of purine nucleobases by urate oxidase (or uricase) from uric acid.[3][4][5]


Allantoin was first isolated in 1800 by the Italian physician Michele Francesco Buniva (1761–1834) and the French chemist Louis Nicolas Vauquelin, who mistakenly believed it to be present in the amniotic fluid.[6] In 1821, the French chemist Jean Louis Lassaigne found it in the fluid of the allantois; he called it "l'acide allantoique".[7] In 1837, the German chemists Friedrich Wöhler and Justus Liebig synthesized it from uric acid and renamed it "allantoïn".[8]


Named after the allantois (an amniote embryonic excretory organ in which it concentrates during development in most mammals except humans and other higher apes), 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.[9] In humans and other 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.[10]

Allantoin has been shown to improve insulin resistance when administered to rats and increased lifespan when administered to the nematode worm Caenorhabditis elegans.[11][12]


In bacteria, purines and their derivatives (such as allantoin) are used as secondary sources of nitrogen under nutrient-limiting conditions. Their degradation yields ammonia, which can then be utilized.[13] For instance, Bacillus subtilis is able to utilize allantoin as its sole nitrogen source.[14]

Mutants in the B. subtilis pucI gene were unable to grow on allantoin, indicating that it encodes an allantoin transporter.[15]

In Streptomyces coelicolor, allantoinase (EC and allantoicase (EC are essential for allantoin metabolism. In this species the catabolism of allantoin, and the subsequent release of ammonium, inhibits antibiotic production (Streptomyces species synthesize about half of all known antibiotics of microbial origin).[16]


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.[17]

Cosmetics and toiletries

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.

An 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.[18]

A study published in 2009 reported the treatment of pruritus in mild-to-moderate atopic dermatitis with a topical non-steroidal agent containing allantoin.[19]


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.[20]

Biomarker of oxidative stress

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.[21][22]

See also


  3. Pizzichini, Maria; Pandolfi, Maria Luisa; Arezzini, Laura; Terzuoli, Lucia; Fe′, Linda; Bontemps, Francois; Van den Berghe, Georges; Marinello, Enrico (1996-08-09). "Labelling of uric acid and allantoin in different purine organs and urine of the rat". Life Sciences. 59 (11): 893–899. doi:10.1016/0024-3205(96)00387-6.
  4. Xi, H.; Schneider, B. L.; Reitzer, L. (2000-10-01). "Purine catabolism in Escherichia coli and function of xanthine dehydrogenase in purine salvage". Journal of Bacteriology. 182 (19): 5332–5341. ISSN 0021-9193. PMC 110974Freely accessible. PMID 10986234.
  5. Johnson, Richard J.; Sautin, Yuri Y.; Oliver, William J.; Roncal, Carlos; Mu, Wei; Gabriela Sanchez-Lozada, L.; Rodriguez-Iturbe, Bernardo; Nakagawa, Takahiko; Benner, Steven A. (2009-01-01). "Lessons from comparative physiology: could uric acid represent a physiologic alarm signal gone awry in western society?". Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology. 179 (1): 67–76. doi:10.1007/s00360-008-0291-7. ISSN 1432-136X. PMC 2684327Freely accessible. PMID 18649082.
  6. See:
    • Buniva and Vauquelin (1800) "Sur l'eau de l'amnios de femme et de vache" (On the amniotic fluid of women and cows), Annales de chimie, 33 : 269-282.
    • See also: Leopold Gmelin with Henry Watts, trans., Hand-book of Chemistry (London, England: The Cavendish Society, 1856), vol. 10, p. 260.
  7. Lassaigne (1821) "Nouvelles recherches sur la composition les eaux de l'allantoïde et de l'amnios de la vache" (New investigations into the composition of the allantoic and amniotic fluids of the cow), Annales de chimie et de physique, 2nd series, 17 : 295-305. On pp. 300 ff, Lassaigne names and characterizes "l'acide allantoique" (allantoic acid).
  8. See:
    • Liebig and Wöhler (1837) "Ueber die Natur der Harnsäure" (On the nature of uric acid), Annalen der Physik und Chemie, 41 (8) : 561-569. Allantoin is named on p. 563. From p. 563: "Sie sind Allantoïssäure, oder dieselbe Substance, die man in der Allantoïsflussigkeit der Kühe gefunden hat; wir werden sie von nun an Allantoïn nennen." (They [i.e., the crystals previously isolated] are allantois acid, or the same substance that one found in the allantois fluid of cows; we will call it "allantoin" from now on.)
    • Reprinted in: F. Wöhler and J. Liebig (1838) "Untersuchungen über die Natur der Harnsäure" (Investigations into the nature of uric acid), Annalen der Pharmacie, 26 : 241-340.
  9. 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.
  10. 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 1136261Freely accessible. PMID 7492331.
  11. Ko, W.C., Liu, I.M., Chung, H.H., and Cheng, J.T. (2008). "Activation of I(2)-imidazoline receptors may ameliorate insulin resistance in fructose-rich chow-fed rats". Neuroscience Letters: 90–93.
  12. Shaun Calvert, Robi Tacutu, Samim Sharifi, Rute Teixeira, Pratul Ghosh and João Pedro de Magalhães (2016). "A network pharmacology approach reveals new candidate caloric restriction mimetics in C. elegans". Ageing Cell. 15 (2): 256–266. doi:10.1111/acel.12432.
  13. Ma, Pikyee; Patching, Simon G.; Ivanova, Ekaterina; Baldwin, Jocelyn M.; Sharples, David; Baldwin, Stephen A.; Henderson, Peter J. F. (2016-05-01). "Allantoin transport protein, PucI, from Bacillus subtilis: evolutionary relationships, amplified expression, activity and specificity". Microbiology (Reading, England). 162 (5): 823–836. doi:10.1099/mic.0.000266. ISSN 1465-2080. PMC 4851255Freely accessible. PMID 26967546.
  14. Goelzer, Anne; Bekkal Brikci, Fadia; Martin-Verstraete, Isabelle; Noirot, Philippe; Bessières, Philippe; Aymerich, Stéphane; Fromion, Vincent (2008-02-26). "Reconstruction and analysis of the genetic and metabolic regulatory networks of the central metabolism of Bacillus subtilis". BMC systems biology. 2: 20. doi:10.1186/1752-0509-2-20. ISSN 1752-0509. PMC 2311275Freely accessible. PMID 18302748.
  15. Schultz, A. C.; Nygaard, P.; Saxild, H. H. (2001-06-01). "Functional analysis of 14 genes that constitute the purine catabolic pathway in Bacillus subtilis and evidence for a novel regulon controlled by the PucR transcription activator". Journal of Bacteriology. 183 (11): 3293–3302. doi:10.1128/JB.183.11.3293-3302.2001. ISSN 0021-9193. PMC 99626Freely accessible. PMID 11344136.
  16. Navone, Laura; Casati, Paula; Licona-Cassani, Cuauhtémoc; Marcellin, Esteban; Nielsen, Lars K.; Rodriguez, Eduardo; Gramajo, Hugo (2013-11-29). "Allantoin catabolism influences the production of antibiotics in Streptomyces coelicolor". Applied Microbiology and Biotechnology. 98 (1): 351–360. doi:10.1007/s00253-013-5372-1. ISSN 0175-7598.
  17. Patent Lens search
  18. 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.
  19. 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.
  20. 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.
  21. 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.
  22. 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.

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