Compare to the active ingredient of Nexium 24 HR. Don’t let frequent heartburn keep you from enjoying flavorful foods. Amazon Basic Care Esomeprazole Magnesium Delayed Release Capsules, 20 mg works around the clock to make sure frequent heartburn doesn’t make you miss out on your favorite foods. This product is clinically proven to treat frequent heartburn occurring 2 or more days per week, and is taken once every 24 hours for 14 days. Not intended for immediate relief of heartburn; this drug may take 1 to 4 days for full effect. This product is gluten free. The active ingredient is esomeprazole, 20 mg, an acid reducer.