Most Helpful Girl
Er. False ones...?
Obviously do some research first, but hormones/vitmains might help...but it would encourage hair to grow everywhere.
Failing that, you could use an eyebrow pencil to make them darker which would make them look thicker? I know it's make up and ew girly, but girls to it to give their eyebrows shape and definition. If you have dark hair anyway, it might be worth a thought?