For atherosclerosis, researchers have sometimes started therapy using very high amounts, such as 5 grams twice per day with meals, lowering the amount to 500 mg three times per day after a few months. Before taking such high amounts, people should consult a doctor. For osteoarthritis, a typical level is 400 mg three times per day. Oral chondroitin sulfate is rapidly absorbed in humans when it is dissolved in water prior to ingestion. Approximately 12% of chondroitin sulfate taken by mouth becomes available to the joint tissues from the blood.