Great question, thank you! Melatonin is a hormone that is naturally made by a gland in the body called the “pineal gland” (which helps us sleep). You can also buy melatonin “over-the-counter”, without a prescription, in the form of a dietary supplement. Unfortunately, there isn’t much research that has looked at whether melatonin supplements interfere with birth control pills. What we do know is that dietary supplements are not regulated by the Federal Food and Drug Administration (FDA) so it’s hard to know how much of an active ingredient (of melatonin) is in each tablet. This means, when you take a dietary supplement (of any kind) you don’t really know how much of the active ingredient you are getting—you may be taking too little or too much. The bottom line? Anytime you’re thinking about taking a dietary supplement, talk to your health care provider first to make sure it doesn’t interact with any of the medicines you are currently taking.