“The one that puts you to sleep best is melatonin,” was a comment from “Mike” in response to Natural Sleep Aids, a video that features naturopathic physician Andrew Rubman, ND, a contributing medical editor for Health Insider discussing his go-to sleep aids—valerian and L-tryptophan.

But then “I.Popoff” responded, “I recall an interview in which Dr. Rubman expressed caution about regular use of melatonin because it is a hormone.” Indeed, he did, in a video interview titled Melatonin to Help You Sleep—Maybe Not.

We checked with Dr. Rubman, and he said that even though melatonin has a good record for efficacy and safety, he’s cautious because it is produced in the pineal gland, one of the master glands of the endocrine system—which is still being studied. That’s why he prefers valerian and L-tryptophan.

“I.Popoff” clearly took Dr. Rubman’s melatonin caution to heart—and to bed: “I took half a Schiff’s Melatonin Ultra an hour before bedtime nightly for several years…A few months ago, given Dr. Rubman’s caution, and other things I have read, I thought maybe I should get out of the habit, and I have done so without any problem. I still use it occasionally, maybe once or twice a week, when I am not feeling ready to sleep.”