Pretty sure lunar effect is a real, scientifically confirmed thing, just known by a different name. Perhaps not the full moon specifically, but we do oscillate according to the moon phase. It’s called circalunar cycles. The name might sound familiar to circadian cycles because they both derive from the same word structure, ie circa-dia (“around a day”) and circa-lunar (“around a month”)

At minimum, I’m quite surprised that Wikipedia lists this as a pseudoscience, because my impression has generally been that circadian researchers acknowledge circalunar cycles as a given