For a 7-month-old baby weighing 21 pounds, the recommended dose of LaxAday is usually between 0.2 to 1 gram per kilogram per day, with a maximum of 17 grams per day. This means you can give up to 9 grams per day for your baby. The powder should be diluted in 100mL of liquid and given once a day. It may take 1 to 3 days for the product to take effect. If the issue persists, it is important to consult a pediatrician.