The components of Senilife work synergistically and have a specific neuroprotective action to protect your pet from brain aging and improve the behavior signs that are often seen in senior pets. Directions - Place entire capsule into pet's mouth or place contents onto animal's food. The small is for dogs under 50 pounds and the large is for dogs over 50 pounds. Dosage: Small - Up to 30 lbs.1 capsule, 31-50 lbs.2 capsules, Over 50 lbs.3 capsules, Large - 51-99 lbs.1 capsule, Over 100 lbs.2 capsules.