23/08/2026
If you use oestrogen gel or spray for HRT, your pet could be exposed too.
Oestrogen can transfer from treated skin through close contact.
Published veterinary cases have linked repeated exposure to topical human HRT with hair loss, mammary enlargement, reproductive changes and abnormal hormone related behaviour in dogs and cats.
In some cases, the exposure was incredibly ordinary. A puppy being lifted into bed. Puppies being carried on an arm. A very cuddly cat spending more time in contact with its owner.
Once the exposure stopped, many of the animals improved.
This does not mean you need to stop HRT or stop cuddling your pets. I use oestrogen gel myself. It simply means being aware of where you apply it.
Wash your hands after application, let the area dry, prevent pets from licking treated skin, cover the area where appropriate, and follow the contact instructions for your particular HRT product.
Dogs and cats feature most often in the published evidence, but I also take care around Murray, my budgie, because we simply do not know enough about repeated exposure in other small pets.
If you use HRT and have pets, this is worth knowing and sharing.
I’ve broken down the research and case studies in more detail on Pet Matters. Link first comment.