Obsidian Entertainment announced on November 10 that Side Effects Guaranteed, the first story expansion for The Outer Worlds 2, arrives on December 2, 2026. It costs $14.99 on PC, PlayStation 5 and Xbox Series X|S, and it is included in the Premium Edition and the Premium Edition Upgrade. The Outer Worlds 2 is a first- or third-person action RPG, out since October 29, 2025. This expansion raises its level cap from 30 to 36.
Obsidian’s add-ons have a long habit of being where its writers try the stranger idea. Fallout: New Vegas had Dead Money and Old World Blues. The first Outer Worlds had Peril on Gorgon in September 2020 and Murder on Eridanos in March 2021, each a single mystery in a single new place. Side Effects Guaranteed follows that shape, and it is the first dose of two. Part two is due in spring 2027, and Obsidian says choices made here carry into it.
The premise, as Mikey Dowling, Obsidian’s director of communications, laid it out on Xbox Wire, starts with a distress signal. It leads the Incognito’s crew to a derelict ship whose own crew sits frozen in suspended animation, contaminated with a condition that will liquefy them without a cure. A video from the ship’s captain points toward Sub Rosa, a criminal organization. Gordon Hazen, a leading Sub Rosa agent who favours diplomacy, sends you to Elysium Valley, a settlement of former Protectorate subjects on Eden. Algernon Lankester, another agent, would rather exploit the settlers. That is where I stop.
What Side Effects Guaranteed adds to a build
The title's joke lands hardest on the character sheet. There are 15 new perks, three of them reachable only above the old cap, and four new flaws, including Lethally Tolerant and Must Have Been the Wind. Flaws are the series' bargain: the game notices a weakness in how you play, and accepting it buys a perk point. An expansion that hands out new side effects is at least honest about its dosage.
Dowling's PlayStation Blog post names five new weapons, including the Immobilizer, which holds targets in the air, and the 1/6 Resolver, whose every sixth bullet hits harder. There are new armor sets and companion outfits, new enemies such as primal sprats (very large sprats), and a Sub Rosa radio station with 20 songs. A free update on the same day lets every player respec at any time.
New players can start at the expansion from the main menu, with a premade level 27 character. That is a kind offer to anyone who stopped halfway through Arcadia.
Side Effects Guaranteed is on Steam for wishlisting now. The second dose follows in spring.
