How much protein should a very active 15 year old boy who has been weightlifting for 5-6 days a week for the last 8 months and is 5 foot 10 inches and weigh 125 pounds?

Take as much protein as you possibly can, take it in meals as well as supplements. The body only utilizes about 30-40g at a time usually in about an hour so always take a shake after a workout which has about 25-30g some even 37g. Then for meals eat egg whits about 24g, steak and other meats like chicken and turkey another 15-20g based on amount, and nuts, cottage cheese, and milk all Excellent sources of protein.