Median lethal dose

In toxicology, the median lethal dose, LD₅₀ (abbreviation for "lethal dose, 50%"), LC₅₀ (lethal concentration, 50%) or LCt₅₀ is a toxic unit that measures the lethal dose of a given substance.^[1] The value of LD₅₀ for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD₅₀ figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD₅₀ is indicative of higher toxicity.

The term LD₅₀ is generally attributed to John William Trevan.^[2] The test was created by J. W. Trevan in 1927.^[3] The term semilethal dose is occasionally used in the same sense, in particular with translations of foreign language text, but can also refer to a sublethal dose. LD₅₀ is usually determined by tests on animals such as laboratory mice. In 2011, the U.S. Food and Drug Administration approved alternative methods to LD₅₀ for testing the cosmetic drug Botox without animal tests.^[4]^[5]

^ "Absolute lethal dose (LD100)". IUPAC Gold Book. International Union of Pure and Applied Chemistry. Archived from the original on 2019-07-01. Retrieved 2019-07-01.
^ "John William Trevan, 1887-1956". Biographical Memoirs of Fellows of the Royal Society. 3: 273–288. 1957. doi:10.1098/rsbm.1957.0019. ISSN 0080-4606. Archived from the original on 2020-03-28. Retrieved 2024-03-31.
^ "What is a LD50 and LC50?". OSH Answers Fact Sheets. Canadian Centre for Occupational Health and Safety. 5 October 2021. Archived from the original on 26 June 2015. Retrieved 15 July 2006.
^ "Allergan Receives FDA Approval for First-of-Its-Kind, Fully in vitro, Cell-Based Assay for BOTOX and BOTOX Cosmetic (onabotulinumtoxinA)". Allergan Web site. 24 June 2011. Archived from the original on 26 June 2011. Retrieved 2012-08-15.
^ Gaul GM (12 April 2008). "In U.S., Few Alternatives To Testing On Animals". Washington Post. Archived from the original on 2012-11-12. Retrieved 2011-06-26.

[1] "Absolute lethal dose (LD100)". IUPAC Gold Book. International Union of Pure and Applied Chemistry. Archived from the original on 2019-07-01. Retrieved 2019-07-01.

[Biographical_Memoirs_of_Fellows_of_the_Royal_Society_1957_pp._273–288-2] "John William Trevan, 1887-1956". Biographical Memoirs of Fellows of the Royal Society. 3: 273–288. 1957. doi:10.1098/rsbm.1957.0019. ISSN 0080-4606. Archived from the original on 2020-03-28. Retrieved 2024-03-31.

[3] "What is a LD50 and LC50?". OSH Answers Fact Sheets. Canadian Centre for Occupational Health and Safety. 5 October 2021. Archived from the original on 26 June 2015. Retrieved 15 July 2006.

[4] "Allergan Receives FDA Approval for First-of-Its-Kind, Fully in vitro, Cell-Based Assay for BOTOX and BOTOX Cosmetic (onabotulinumtoxinA)". Allergan Web site. 24 June 2011. Archived from the original on 26 June 2011. Retrieved 2012-08-15.

[5] Gaul GM (12 April 2008). "In U.S., Few Alternatives To Testing On Animals". Washington Post. Archived from the original on 2012-11-12. Retrieved 2011-06-26.

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