The detection of capsaicin and dihydrocapsaicin in horse serum following long-term local administration.
Authors: Zak A, Siwinska N, Slowikowska M, Borowicz H, Szpot P, Zawadzki M, Niedzwiedz A
Journal: BMC veterinary research
Summary
# Editorial Summary Capsaicin and dihydrocapsaicin, alkaloid compounds with proven analgesic properties, work by desensitising nerve endings when applied topically—yet both are prohibited substances under FEI competition rules, necessitating reliable detection protocols. Researchers administered a commercially available capsaicin gel to horses according to manufacturer recommendations over an extended period, then analysed serum and plasma samples using chromatography to establish how long these compounds remain detectable in circulation and which sample type provides the most reliable evidence for doping control. The study demonstrated that both capsaicin and dihydrocapsaicin could be detected in equine serum following long-term local application, establishing specific detection windows that differ between the two alkaloids and confirming serum as the superior matrix for regulatory testing. These findings have direct implications for competition authorities and testing laboratories tasked with enforcing anti-doping regulations, as they now have evidence-based guidance on sampling methodology and detection timeframes when investigating suspected topical analgesic use in performance horses. For practitioners, understanding these detection parameters is essential, particularly when advising clients on withdrawal periods and compliance with competition rules, especially given that many commercial pain-relief products containing capsaicin are marketed for equine use without explicit warning of their prohibited status.
Read the full abstract on PubMed
Practical Takeaways
- •Topical capsaicin products are prohibited in competition horses under FEI rules; even when used as directed, systemic absorption occurs and can be detected in testing
- •If using capsaicin-containing products for therapeutic purposes, allow sufficient clearance time before competitions or understand doping test implications
- •Serum sampling is the preferred diagnostic material for detecting capsaicin residues in anti-doping compliance testing
Key Findings
- •Capsaicin and dihydrocapsaicin were detected in horse serum following long-term local application of commercial gel formulation
- •Serum proved superior to plasma for detection of capsaicin as a doping substance
- •These alkaloids are banned substances under FEI Prohibited Substances List for competition horses