1300mgs/day. The teenage years represent a critical period for bone mineral accrual with rapid gains occurring until age 16. If one doesn’t maximize bone building during this period, equivalent increase cannot be made up for later in life making proper calcium intake of great importance. To make matters worse, as we age, the calcium content of bone begins to decline, increasing the likelihood of fractures. When this critical “breaking point” is reached, the condition is known as osteoporosis. If you are unable to consume 1300mgs/day through foods, which most teenagers don’t, you must supplement, especially during this phase of life through age 25. Also, supplement only 500mgs of calcium at a time because that’s about all the body can use effectively from one dose. Therefore, if your health professional tells you that you need to add 1000mgs/day of calcium in the form of a supplement, take calcium carbonate in 2 doses: one 500mgs tablet with a morning meal and another one with an evening meal.