For optimal absorption, isotretinoin must be taken with high-fat, high-calorie meals.3 The FDA defines “high fat” as 50 percent of total caloric intake of the meal, while “high calorie” refers to 800 to 1,000 calories (150 from proteins, 250 from carbohydrates, 500-600 from fat).4 Clinical trials evaluating the efficacy and safety of isotretinoin are all performed under those conditions. In the real world, where many patients do not even eat three meals a day, let alone high-fat, high-calorie meals, absorption of isotretinoin may be much lower. Moreover, many dermatologists are not educating patients on the true dietary needs of patients on this medication.