Vitamin C is an antioxidant that aids in the formation of collagen and serotonin. It helps strengthen your immune system, boosts energy levels, and reduces Asthma symptoms. Our bodies cannot make vitamin C, so dietary and/or supplemental intake is necessary. While it is essential for the body, Vitamin C toxicity can occur which causes diarrhea, kidney stones, or elevated iron stores. Your body only absorbs 250 mg of vitamin C. If a higher amount is ingested, it will be excreted from the body since it is a water soluble vitamin.