Integrity is Health. To upgrade the size of your Health Bar (Max Integrity): 1. Pick up Resin to fill slots towards Max Integrity Upgrade (3 slots next to Integrity). 2. Pick up Silphium (Health Item) when your health is 100% full to fill a slot. 3. Pick up Spoiled Resin and Malignant Resin. 4. Use Max Integrity Fabricator 5. Equip Parasites with Max Integrity perks.