In general, it is not recommended to put a regular collar over Seresto. The flea and tick collar should be worn snugly but not too tight on your pet’s neck, and lay flat against the side of their neck for optimal effectiveness. The collar may shift if there is an additional collar or harnesses underneath, which will make it less effective. Putting a regular collar over the Seresto could cause chafing, irritation or even prevent the active ingredients from spreading along the animal’s coat.
If you must use an additional collar with Seresto, there are specially designed collars available that can be used safely alongside the Seresto flea and tick collar. Some are even designed to fit closely around it or cover Seresto completely so that no further irritation occurs. These collars have been tested and registered with ITC (International Toxicity Chart), so they won’t interfere with Seresto’s effectiveness at all.