Sex Is The Only Physical Characteristic That Relates To Allergen Production

Sex Is The Only Physical Characteristic That Relates To Allergen Production
Sex Is The Only Physical Characteristic That Relates To Allergen Production

While studies have demonstrated that hair length and color have no influence on Fel d1 production, there is one physical factor that does appear to correlate: sex of the cat.1-6 

The facts

Sex has been shown in some studies to correlate with Fel d1 production.


  • It has been shown that intact male cats generally produce higher levels of Fel d1 than sterilized/neutered male cats and female cats regardless of sterilization status.1, 6-9
  • However, each cat’s level of Fel d1 varies based on genetics, and an intact male cat could potentially produce less Fel d1 than a high-producing female or sterilized male cat.1,6,8-11
Find out more
  1. Kelly, S.M., Karsh, J., Marcelo, J., Boeckh, D., Stepner, N., Litt, D.,...Yang, W.H. (2018). Fel d1 and Fel d4 levels in cat fur, saliva and urine. Journal of Allergy and Clinical Immunology. doi: 10.1016/j.jaci.2018.07.033
  2. Bonnett, B., Messaoudi, K., Jacomet, F., Michaud, E. Fauquert, J.L., Caillaud, D., & Evrard, B. (2018). An update on molecular cat allergens: Fel d1 and what else? Chapter 1: Fel d1, the major cat allergen. Allergy, Asthma and Clinical Immunology, 14, 14. doi: 10.1186/s13223-018-0239-8 
  3. Butt, A., Rashid, D. & Lockey, R. (2012). Do hypoallergenic cats and dogs exist?  Annals of Allergy Asthma and Immunology, 108, 74-76.
  4. Nicholas, C., Wegienka, G. & Havstad, S. (2008). Influence of cat characteristics on Fel d 1 levels in homes. Annals of Allergy Asthma and Immunology, 101, 47-50
  5. Siebers, R., Healy, B., Holt, S., Peters, S., Crane, J. & Fitzharris, P. (2001). Fel d1 levels in domestic living rooms are not related to cat color or hair length. Journal of Allergy and Clinical Immunology, 108, 652-653. doi: 10.1067/mai.2001.118788
  6. Platts-Mills, T.A.E., Vervloet, D., Thomas, W.R., Aalberse, R.C. & Chapman, M.D. (1997). Indoor allergens and asthma: report of the Third International Workshop. Journal of Allergy and Clinical Immunology, 100, S2-S24. doi10.1016/S0091-6749(97)70292-6 
  7. Zielonka, T., Charpin, D., Berbis, P., Luciani, P., Cassanova, D. & Vervloet, D. (1994). Effects of castration and testosterone on Fel d 1 production by sebaceous glands of male cats: I. Immunological assessment. Clinical and Experimental Allergy, 24, 1169-1173
  8. Ramadour, M., Birbnaum, J., Magalon, C., Lanteaume, A., Charpin, D. & Vervloet, D. (1998). Cat sex differences in major allergen production (Fel d1). Journal of Allergy and Clinical Immunology, 10, 282-284.
  9. Jalil-Colome, J., de Andrade, A.D., Birnbaum, J., Casanova, D., Mege, J.-L., Lanteaume, A., Charpin, D., & Vervloet, D. (1996). Sex difference in Fel d1 allergen production. Journal of Allergy and Clinical Immunology98(1), 165-168.
  10. Morgenstern, J.P., Griffith, I.J., Brauer, A.W., Rogers, B.L., Bond, J.F., Chapman, M.D. & Kuo, M.C. (1991). Amino acid sequence of Fel dI, the major allergen of the domestic cat: protein sequence analysis and cDNA cloning. Proceedings of the National Academy of Sciences, 88, 9690-9694.
  11. Bastien, B., Gardner, C. & Satyaraj, E. (2019). Influence of phenotype on salivary Fel d1 in domestic shorthair cats. Accepted, Journal of Feline Medicine and Surgery.