VETIQ Serene Calming PLUS have been especially formulated for dogs over 20kg and is formulated with natural ingredients for hyperactive or nervous dogs. VETIQ Serene-UM Calming PLUS can help calm and pacify your pet without the need for tranquilisers in a totally natural way and as it is not a sedative, it does not cause drowsiness. Starts working 6-8 hours but for maximum effect allow 24-36 hours