From Leaguepedia | League of Legends Esports Wiki
Every second while in combat, you will generate stacks of Grasp of the Undying. After 4 seconds, your next basic attack on a champion will:
- Deal bonus magic damage equal to 4% of your max health (reduced to 2.4% for ranged users)
- Heal you for 2% of your max health (reduced to 1.2% for ranged users)
- Permanently increase your health by 5 (3 for ranged users)
The empowered attack is primed for 6 seconds, refreshing whenever you deal or receive damage.
Ranged penalties in healing, damage, and health gain decreased.
Taking advantage of Grasp of the Undying is way easier if you're ranged, so we wanted to make sure it was less impactful on ranged champions. However, it seems like we went too far; even champions like Gnar and Urgot don't perform well with it.
RANGED HEALING AND DAMAGE REDUCTION : [50%] ⇒ 40%
RANGED PERMANENT HEALTH PER PROC :  ⇒ 3
NOODLE SLURP Every 4 seconds in combat, your next basic attack on a champion will: Deal bonus magic damage equal to 4% of your max health, heal you for 2% of your max health, and permanently increase your health by 5
NO CHOPSTICKS Ranged champions’ damage and healing are halved and they gain 2 permanent health instead