Detection of Nandrolone Decanoate and Its Metabolites in Equine Hair After Intramuscular Administration.
Abstract: This paper describes the detection of nandrolone decanoate and its metabolites in mane hair collected from horses that have been treated with nandrolone decanoate (Deca-Durabolin). The intramuscular administration study of nandrolone decanoate in three Thoroughbred castrated horses (each received 800 mg weekly for 3 consecutive weeks) was previously conducted to investigate its metabolism and detection time in plasma and urine for doping control purposes. In this work, segmental analysis of the post-administration hair has revealed that (i) nandrolone decanoate and its metabolites, nandrolone and 4-estrene-3,17-dione, could be detected in horse mane after intramuscular administration, and (ii) the spreading of these substances along the entire hair strand was observed, which suggested the involvement of sweat or sebum incorporation.
© 2025 John Wiley & Sons Ltd.
Publication Date: 2025-11-19 PubMed ID: 41261805DOI: 10.1002/dta.70001Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
Overview
- This study investigated whether nandrolone decanoate and its metabolites could be detected in the mane hair of horses after intramuscular injections, with implications for doping control in equine sports.
- The research demonstrated that the drug and its metabolites were present along the entire hair length, suggesting incorporation not only during hair formation but also potentially through sweat or sebum.
Study Background and Purpose
- Nandrolone decanoate is an anabolic steroid used in veterinary medicine and is subject to doping control in horse racing and other equine sports.
- The parent compound and its metabolites have previously been studied in plasma and urine to establish detection windows and doping control methods.
- This study aimed to extend detection capabilities by analyzing hair samples, which allow retrospective longitudinal monitoring due to hair’s growth over time.
- Specifically, the researchers wanted to see if the drug or metabolites could be found in the horse’s mane, and how these compounds were distributed along the hair shaft after administration.
Experimental Approach
- Three Thoroughbred geldings were administered nandrolone decanoate intramuscularly at a dose of 800 mg weekly for three weeks, mimicking doping scenarios.
- Hair samples were collected from the mane after administration to assess drug incorporation.
- Segmental hair analysis was performed, meaning the hair was divided into segments to analyze the distribution of substances over the period correlating with hair growth.
- Advanced chemical analysis techniques were used to identify and quantify nandrolone decanoate and its metabolites, primarily nandrolone and 4-estrene-3,17-dione, within the hair segments.
Key Findings
- Nandrolone decanoate and its metabolites were successfully detected in mane hair after treatment, confirming that these substances are incorporated into hair.
- The presence along the entire hair strand rather than being limited to segments corresponding exactly to the administration time suggested another incorporation pathway besides blood supply to the follicle.
- The study hypothesized that sweat and/or sebum contributed to drug incorporation onto the external hair surface, which then spreads along the hair shaft as it grows.
- This finding is important for doping control because it affects interpretation of hair segment analysis, indicating external contamination routes in addition to systemic incorporation.
Implications for Doping Control
- Hair analysis offers a non-invasive and retrospective method to monitor doping substances over weeks to months, complementing plasma and urine testing.
- However, understanding the incorporation routes is crucial to distinguish between actual drug intake and external contamination, ensuring accurate interpretation of positive findings.
- The discovery of sweat/sebum involvement calls for cautious interpretation and possibly additional washing or decontamination procedures during sample preparation.
- This study contributes foundational information for developing reliable horse hair testing protocols to detect nandrolone decanoate misuse in the equestrian industry.
Cite This Article
APA
So YM, Kwok WH, Yuen SMS, Wong COL, Wan TSM, Ho ENM.
(2025).
Detection of Nandrolone Decanoate and Its Metabolites in Equine Hair After Intramuscular Administration.
Drug Test Anal, 18(1), 149-158.
https://doi.org/10.1002/dta.70001 Publication
Researcher Affiliations
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong, China.
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong, China.
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong, China.
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong, China.
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong, China.
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong, China.
MeSH Terms
- Animals
- Horses / metabolism
- Injections, Intramuscular
- Nandrolone Decanoate
- Anabolic Agents / administration & dosage
- Anabolic Agents / analysis
- Anabolic Agents / metabolism
- Substance Abuse Detection / methods
- Substance Abuse Detection / veterinary
- Doping in Sports
- Nandrolone / analogs & derivatives
- Nandrolone / analysis
- Nandrolone / administration & dosage
- Nandrolone / metabolism
- Male
- Hair / chemistry
- Gas Chromatography-Mass Spectrometry / methods
References
This article includes 23 references
- International Federation of Horseracing Authorities (IFHA). Article 6 in the International Agreement on Breeding, Racing and Wagering (IABRW). https://www.ifhaonline.org/default.asp?section=IABRW&AREA=2#article6 (accessed on 24 March 2025).
- Fédération Equestre Internationale (FEI). Equine Prohibited Substances List. (2025) https://inside.fei.org/sites/default/files/2025%20Prohibited%20Substances%20List.pdf (accessed on 24 March 2025).
- Harries RL, De Paoli G, Hall S. A Review of the Analytical Techniques for the Detection of Anabolic–Androgenic Steroids Within Biological Matrices. WIREs Forensic Science 6 (2024): e1504.
- Gray B, Viljanto M, Bright J, Gray BP, Pearce C, Maynard S. Investigations Into the Feasibility of Routine Ultra‐High Performance Liquid Chromatography–Tandem Mass Spectrometry Analysis of Equine Hair Samples for Detecting the Misuse of Anabolic Steroids, Anabolic Steroid Esters and Related Compounds. Analytica Chimica Acta 787 (2013): 163–172.
- Gray B, Viljanto M, Menzies E, Vanhaecke L. Detection of Prohibited Substances in Equine Hair by Ultra‐High Performance Liquid Chromatography‐Triple Quadrupole Mass Spectrometry—Application to Doping Control Samples. Drug Testing and Analysis 10 (2018): 1050–1060.
- Kwok KY, Choi TLS, Kwok WH, Wong JKY, Wan TSM. Detection of Anabolic and Androgenic Steroids and/or Their Esters in Horse Hair Using Ultra‐High Performance Liquid Chromatography–High Resolution Mass Spectrometry. Journal of Chromatography A 1493 (2017): 76–86.
- Choi TLS, Kwok KY, Kwok WH, Tsoi YYK, Wong JKY, Wan TSM. Detection of Seventy‐Two Anabolic and Androgenic Steroids and/or Their Esters in Horse Hair Using Ultra‐High Performance Liquid Chromatography‐High Resolution Mass Spectrometry in Multiplexed Targeted MS2 Mode and Gas Chromatography‐Tandem Mass Spectrometry. Journal of Chromatography A 1566 (2018): 51–63.
- So YM, Kwok WH, Ching CCW, Wong COL, Wan TSM, Ho ENM. Detection of Over 110 Anabolic–Androgenic Steroids, Corticosteroids and/or Their Esters in Horse Hair Using Ultra‐High‐ Performance Liquid Chromatography–High‐Resolution Mass Spectrometry and Gas Chromatography–Tandem Mass Spectrometry After Solid‐Supported Liquid Extraction. Drug Testing and Analysis 17 (2025): 1303–1322.
- Henderson GL. Mechanisms of Drug Incorporation Into Hair. Forensic Science International 63 (1993): 19–29.
- Anielski P, Thieme D, Schlupp A, Grosse J, Ellendorff F, Mueller RK. Detection of Testosterone, Nandrolone and Precursors in Horse Hair. Analytical and Bioanalytical Chemistry 383 (2005): 903–908.
- Anielski P. Hair Analysis of Anabolic Steroids in Connection With Doping Control—Results From Horse Samples. Journal of Mass Spectrometry 43 (2008): 1001–1008.
- Boyer S, Garcia P, Popot MA, Steiner V, Lesieur M. Detection of Testosterone Propionate Administration in Horse Hair Samples. Journal of Chromatography B 852 (2007): 684–688.
- Viljanto M, Love C, White D. Detection of Methandienone and Its Metabolites in Equine Urine, Plasma and Hair Following a Multidose Oral Administration. Drug Testing and Analysis 16 (2024): 1203–1218.
- So YM, Kong FKW, Kwok WH. Detection of Nonsteroidal and Steroidal Selective Androgen Receptor Modulators in Equine Hair After Oral Administrations. Drug Testing and Analysis 17 (2025): 655–662.
- So YM, Kwok WH, Tang CWY. Metabolic Studies of Nandrolone Decanoate in Castrated Horses After Intramuscular Administration. Drug Testing and Analysis 17, no. 11 (2025): 2107–2120.
- Musshoff F, Madea B. Analytical Pitfalls in Hair Testing. Analytical and Bioanalytical Chemistry 388, no. 7 (2007): 1475–1494.
- Gray B, Bailly-Chouriberry L, Kwok WH, Yamada S, Yamada M, Moeller B. Association of Official Racing Chemists Guidelines for Drug Testing in Animal Hair for Doping Control. Drug Testing and Analysis 17 (2025): 198–204.
- Dunnett M. The Diagnostic Potential of Equine Hair: A Comparative Review of Hair Analysis for Assessing Nutritional Status, Environmental Poisoning, and Drug Use and Abuse. in Advances in Equine Nutrition III, eds. J. D. Pagan and R. J. Geor (Nottingham University Press, 2005), 85–106.
- Preinbergs JK, Ström JO, Theodorsson E, Ingberg E. Segmental Hair Analysis as a Retrospective Testosterone Diary: Possibilities and Pitfalls. Scientific Reports 13 (2023): 16015.
- Cao Y, Qu H, Xiong C, Liu C, Zheng L. A Novel Method for Non-Destructive Determination of Hair Photo-Induced Damage Based on Multispectral Imaging Technology. Scientific Reports 7 (2017): 45544.
- Otten W, Heimbürge S, Tuchscherer A, Kanitz E. The Age of Hair Matters—The Incorporation of Cortisol by External Contamination Is Enhanced in Distal Hair Segments of Pigs and Cattle. Animal 16 (2022): 100495.
- Association of the Official Racing Chemists. “Guidelines for the Minimum Criteria for Identification by Chromatography and Mass Spectrometry,” https://www.aorc‐online.org/documents/aorc‐ms‐criteria‐ilacg7/ (accessed on 24 March 2025).
- Rygaard K, Linnet K, Johansen SS. A Systematic Review of Metabolite-To-Drug Ratios of Pharmaceuticals in Hair for Forensic Investigations. Metabolites 11 (2021): 686.
Citations
This article has been cited 0 times.Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
