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For the trait, see Chem Resistant (trait).
Chem Resistant
Chem Resistant FO3.pngChem Resistant FO4.png
Fallout 3, Fallout: New Vegas
RequirementsLevel 16, Medicine 60
Effects50% less addiction chance
base id00099827
Fallout 4
RequirementsEndurance 4
Level 1 and 22
EffectsReduce chances of addiction
base id0004a0d5 (level 1) 00065e0c (level 2)

Chem Resistant is a perk in Fallout 3, Fallout: New Vegas, and Fallout 4.


Fallout 3 and Fallout: New Vegas

Having the Chem Resistant perk means you're 50% less likely to develop an addiction to any chem, like psycho and jet or alcoholic drinks like whiskey and vodka.

Fallout 4

The Chem Resistant perk reduces the likelihood that you'll get addicted to chems. At the highest rank, it grants total immunity to addiction.

Fallout 4 loading screen hints

The first rank of this perk reduces the chances of being addicted to anything by 50%. The second rank negates all chances of become addicted.


  • This perk is rendered useless if the player opts for Logan's Loophole trait in Old World Blues.
  • Due to the usage monitor effect, you will still have a 100% chance to become addicted after using a chem a certain number of times.