“Your storied past has fallen from memory because everyone thought you died. Your Karma is reset, you inflict +10% damage, and for every 100 points of Karma, you gain 10 Health. You are also immune to critical hits. This perk requires you to have good Karma.”— In-game description.
One cannot gain more than 100 additional Hit Points from this perk, due to positive Karma maxing out at 1000.
The bonus HP is applied as an effect, which is visible on the Pip Boy, not as actual modification of total health.
Bonus HP is not shown on the onscreen HUD in the lower left corner. With full health and 100 bonus HP, for example, the display will not change until more than 100 HP is lost. The actual current HP is visible on the Pip Boy's Status screen.
The bonus HP gained from this perk are calculated based on the player character's Karma at the moment the perk was acquired. A PC that reaches level 50 with 1000 Karma will immediately gain the maximum 100 additional HP.
Because the perk requires level 50, it cannot be taken unless all four Fallout: New Vegas story add-ons are installed or one is playing the Ultimate Edition.
Taking this perk causes the Karma loss message to appear.
The perk will not be lost due to subsequent changes in Karma. Once taken, it is permanent.
PCPlaystation 3Xbox 360 If at full normal health, eating additional food to heal up the bonus HP will actually subtract HP from the HP Healed from Food statistic. [verified]
PCPlaystation 3Xbox 360 Having any magnitude of this perk (or possibly any additional HP that causes the actual maximum to exceed the reported maximum in the Pip Boy, such as Buffout) will make the character lose the built-in fail safe that normally prevents one from wasting healing items when already at full HP even if not already healed up to the actual modified maximum. [verified]