Overview
- The DLC was announced on Tuesday, November 10, 2026, and will launch December 2 as a standalone $14.99 purchase or as part of The Outer Worlds 2 Premium Edition.
- The story begins with a distress call that leads your crew to a derelict ship whose infected occupants suffer a violent 'explosive cell death' and forces you to choose between rival Sub Rosa agents.
- Side Effects Guaranteed adds a new region called Elysium Valley on Eden and introduces new enemies, including vicious canids and oversized 'primal sprats'.
- The expansion raises the level cap from 30 to 36, adds more than 15 new perks, and introduces four new playable flaws such as Lethally Tolerant, which raises toxicity resistance but causes instant death on a Toxicity Crash.
- Quality-of-life and presentation additions include an Alternate Start to jump straight into the DLC, new weapons and outfits for companions, a Sub Rosa radio station with 20 songs, and cross-platform availability with the base game on Game Pass.