I had hair loss from taking the supplement creatine since it raises dht. i'm on propecia (finasteride) now so would it be safe on hair to take creatine again?

Wouldn't risk it: Supplemental creatine is generally marketed as a way to increase length of workouts & thereby cause faster muscle build-up. However, there is no proof that it works & in your case seems to have instigated a medical problem (alopecia). It stands to reason that you risk more hair loss if you restart. Propecia, (finasteride) to my knowledge, doesn't interfere with creatine, so there's still potential for hair loss