The Side Effects Guaranteed DLC for The Outer Worlds 2 will be the first of two expansions and costs $14.99. The plot begins with the investigation of a distress signal coming from an abandoned ship. For an unknown reason, a virus causing “explosive cell death” has spread among its crew. To avoid an agonizing death, the infected placed themselves in stasis. The player's main objective will be to find a cure, and clues can be discovered in a new location, the Elysium Valley on the planet Eden. Along the way, players will have to face agents of the Sub Rosa faction, who have plans of their own.
The expansion will increase the maximum character level to 36 and add new gear for each companion. Players will also be able to choose from more than 15 new perks and four flaws. Among the latter is Excessive Shrinkage, which reduces the protagonist's size. Another addition will be the Sub Rosa radio station featuring 20 music tracks. It will allow players to find out what faction representatives think about their actions.
The developers promise “several hours of new content,” although they do not reveal the exact length of the expansion.
Side Effects Guaranteed will be released on December 2, 2026, on PC, PS5, and Xbox Series X/S.