Hill'S Prescription Diet Y/D Thyroid Care Dry Cat Food Is Specially Formulated By Hillã¢ÂS Nutritionists And Veterinarians To Manage Your Catã¢ÂS Overactive Thyroid The Only Clinically Proven Nutrition To Decrease Thyroid Hormone Production In 3 Weeks When Fed As The Sole Source Of Nutrition. For Best Results, Consistent And Exclusive Long Term Feeding Of This Product Is Critical For Efficacy Of The Product Benefits Controlled Phosphorus And Reduced Sodium With Omega-3 Fatty Acids From Fish Oil To Support Kidney And Heart Health High Levels Of L-Carnitine To Maintain Lean Muscle Mass And Supports A Healthy Body Condition Omega-6 Fatty Acids For Visible Improvements In Skin & Coat Health Prescription Diet Y/D Is Clinically Proven To Improve Thyroid Health In 3 Weeks For Cats When Fed As The Sole Source Of Nutrition. Itã¢ÂS Made In The Usa With Global Ingredients You Can Trust, And Was Developed By Hillã¢ÂS Nutritionists And Veterinarians. This Food Is Also Formulated To Promote A Urinary Environment That Reduces The Risk Of Developing Struvite And Calcium Oxalate Crystals. Please Consult Your Veterinarian For Further Information On How Prescription Diet Foods Can Help Your Cat Continue To Enjoy A Happy And Active Life