Andrew Huberman· PhD
Now, this is probably also a good opportunity to say that if you heard that the ovulatory/menstrual cycle is 28 days long, that's true in some cases, but that's not always true. It's, on average, 28 days long. There are some females for which the ovulatory cycle will be shorter-- it can be as short as 21 days-- and other females for which it will be 35 days long.