What kind of dermaroller should I buy?

[xy53]

1247
What kind of dermaroller should I buy to use before applying Rogaine? I have read that applying Rogaine on a scalp after I used a dermaroller can be dangerous for the heart. Does anyone know true true this is? I would imagine the Rogaine works better because the scalp absorbs it better after the tiny wholes have been punched into the scalp.
Thanks for your suggestions.

 

[Wolf Pack]

1.5 mm on Amazon.

 

[steveo1218]

+1 a 1.5 is what's recommended and what I use - don't be a wimp with it you have to push down real hard to get in to penetrate - hmm lol