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Caprylic acid is the common name for the eight-carbon saturated fatty acid known by the systematic name octanoic acid. Its compounds are found naturally in the milk of various mammals, and as a minor constituent of coconut oil and palm kernel oil.[3] It is an oily liquid that is minimally soluble in water with a slightly unpleasant rancid-like smell and taste.[1]

Caprylic acid
Skeletal formula
Ball-and-stick model
IUPAC name
octanoic acid
Other names
3D model (JSmol)
ECHA InfoCard 100.004.253
EC Number
  • 204-677-5
Molar mass 144.214 g·mol−1
Appearance Oily colorless liquid
Odor Faint, fruity-acid; irritating
Density 0.910 g/cm3[1]
Melting point 16.7 °C (62.1 °F; 289.8 K)[3]
Boiling point 239.7 °C (463.5 °F; 512.8 K)[1]
0.068 g/100 mL[1]
Solubility soluble in alcohol, chloroform, ether, CS2, petroleum ether, acetonitrile
log P 3.05
Vapor pressure 0.25 Pa
Acidity (pKa) 4.89[2]

1.055 (2.06–2.63 K)
1.53 (−191 °C)

-101.60·10−6 cm3/mol
297.9 J/K mol
-636 kJ/mol
NFPA 704 (fire diamond)
Flash point 130 °C (266 °F; 403 K)
440 °C (824 °F; 713 K)
Lethal dose or concentration (LD, LC):
10.08 g/kg (orally in rats)[1]
Related compounds
Related compounds
Heptanoic acid, Nonanoic acid
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

Two other acids are named after goats via the Latin word capra: caproic acid (C6) and capric acid (C10). Along with caprylic acid (C8) these total 15% in goat milk fat.


Caprylic acid is used commercially in the production of esters used in perfumery and also in the manufacture of dyes.

Caprylic acid is an antimicrobial pesticide used as a food contact surface sanitizer in commercial food handling establishments on dairy equipment, food processing equipment, breweries, wineries, and beverage processing plants. It is also used as disinfectant in health care facilities, schools/colleges, animal care/veterinary facilities, industrial facilities, office buildings, recreational facilities, retail and wholesale establishments, livestock premises, restaurants, and hotels/motels. In addition, caprylic acid is used as an algaecide, bactericide, fungicide, and herbicide in nurseries, greenhouses, garden centers, and interiorscapes on ornamentals. Products containing caprylic acid are formulated as soluble concentrate/liquids and ready-to-use liquids.[4]

For ghrelin to have a hunger-stimulating action on a hypothalamus, caprylic acid must be linked to a serine residue at the 3-position of ghrelin. To cause hunger, it must acylate an -OH group. Other fatty acids in the same position have similar effects on hunger.

Caprylic acid is currently being researched as a treatment for essential tremor.[5][6]

The acid chloride of caprylic acid is used in the synthesis of perfluorooctanoic acid.

Dietary usesEdit

Caprylic acid is taken as a dietary supplement. In the body, caprylic acid would be found as octanoate, or unprotonated caprylic acid.[7]

Some studies have shown that medium-chain triglycerides (MCTs) can help in the process of excess calorie burning, and thus weight loss;[8][9][10][11][12] however, a systematic review of the evidence concluded that the overall results are inconclusive.[13] Also, interest in MCTs has been shown by endurance athletes and the bodybuilding community, but MCTs are not beneficial to improved exercise performance.[12]

Caprylic acid has been studied as part of a ketogenic diet to treat children with intractable epilepsy.[5]


  1. ^ a b c d e Budavari, Susan, ed. (1996), The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (12th ed.), Merck, ISBN 0911910123
  2. ^ Lide, D. R. (Ed.) (1990). CRC Handbook of Chemistry and Physics (70th Edn.). Boca Raton (FL):CRC Press.CS1 maint: extra text: authors list (link)
  3. ^ a b Beare-Rogers, J.; Dieffenbacher, A.; Holm, J.V. (2001). "Lexicon of lipid nutrition (IUPAC Technical Report)". Pure and Applied Chemistry. 73 (4): 685–744. doi:10.1351/pac200173040685.
  4. ^ EPA - Antimicrobials Division. Docket Number; EPA-HQ-OPP-2008-0477 Caprylic (Octanoic) Acid.
  5. ^ a b Voller, Bernhard; Lines, Emily; McCrossin, Gayle; Tinaz, Sule; Lungu, Codrin; Grimes, George; Starling, Judith; Potti, Gopal; Buchwald, Peter (2016-02-29). "Dose-escalation study of octanoic acid in patients with essential tremor". Journal of Clinical Investigation. 126 (4): 1451–1457. doi:10.1172/JCI83621. ISSN 0021-9738. PMC 4811161. PMID 26927672.
  6. ^ Lowell, Soren Y.; Kelley, Richard T.; Monahan, Marika; Hosbach-Cannon, Carly Jo; Colton, Raymond H.; Mihaila, Dragos (2018-12-25). "The Effect of Octanoic Acid on Essential Voice Tremor: A Double-Blind, Placebo-Controlled Study: Effect of Octanoic Acid on EVT". The Laryngoscope. 129 (8): 1882–1890. doi:10.1002/lary.27695. PMC 6592780. PMID 30585335.
  7. ^ PubChem. "Octanoic acid". Retrieved 2019-05-15.
  8. ^ B. Martena; M. Pfeuffer; J. Schrezenmeir (2006). "Medium-chain triglycerides". International Dairy Journal. 16 (11): 1374–1382. doi:10.1016/j.idairyj.2006.06.015. PMC 2020023.
  9. ^ Takeuchi, H; Sekine, S; Kojima, K; Aoyama, T (2008). "The application of medium-chain fatty acids: edible oil with a suppressing effect on body fat accumulation". Asia Pacific Journal of Clinical Nutrition. 17 Suppl 1: 320–3. PMID 18296368.
  10. ^ St-Onge, MP; Jones, PJ (2002). "Physiological effects of medium-chain triglycerides: potential agents in the prevention of obesity". The Journal of Nutrition. 132 (3): 329–32. doi:10.1093/jn/132.3.329. PMID 11880549.
  11. ^ Papamandjaris, AA; MacDougall, DE; Jones, PJ (1998). "Medium chain fatty acid metabolism and energy expenditure: obesity treatment implications". Life Sciences. 62 (14): 1203–15. doi:10.1016/S0024-3205(97)01143-0. PMID 9570335.
  12. ^ a b Clegg, M. E. (2010). "Medium-chain triglycerides are advantageous in promoting weight loss although not beneficial to exercise performance". International Journal of Food Sciences and Nutrition. 61 (7): 653–679. doi:10.3109/09637481003702114. PMID 20367215.
  13. ^ Rego Costa AC, Rosado EL, Soares-Mota M (2012). "Influence of the dietary intake of medium chain triglycerides on body composition, energy expenditure and satiety: a systematic review". Nutr Hosp. 27 (1): 103–108. doi:10.1590/S0212-16112012000100011 (inactive 2019-09-20). PMID 22566308.

External linksEdit