With RPN Havoc being a non-aromatising and anti-estrogen substance what are its potential side effects.

The same you'd expect from most other PHs/Anabolic substances, don't fool yourself into thinking you're exempt from a proper PCT because a PH claims to be "safer" in terms of sides. It's still Epitiostanol, always err on the side of caution.
I AM NOT TAKING THOSE PEPTIDES I NEVER SUGGEST YOU TAKE THEM EITHER