UFC Fighter Paige VanZant -- I Fight Better ... With PMS

Pre-menstruation = obliteration.

That's according to UFC hottie Paige VanZant who tells TMZ Sports there's a certain time of the month she's even more dangerous in the octagon than usual.

The 20-year-old prodigy was out in NYC and says fighters wanna be angry and aggressive when they get in the ring ... so why not harness the power of Mother Nature??

Check out the clip ... Paige also tells us one of her "musts" when it comes to dating ... and let's put it this way -- you better know how to use your hands.