The user can obtain superpowers by taking special drugs. However, most of the time the powers are either temporary or single use effect, and the user must continue to take the drugs to maintain their strength.
Misfits Gang (MisFits); they had they're powers reversed when they took ecstasy
Owen Elliot/Sam Matthews
The NKVDemon (DC Comics) possesses enhanced strength and near-immunity to physical pain as a result of experimental steroid usage.
Venom (DC Comics) is a highly addictive super-steroid that greatly enhances the user's physical strength.
Donatello (Batman/Teenage Mutant Ninja Turtles II) has injected himself with a new strain of Venom created from the TMNT universe's mutagen.
Sentry (Marvel Comics) gained his powers from the Super Soldier Serum, but 1000X more powerful which gave him "the power of a million exploding suns".
Kobra-Venom (Young Justice), a deadly combination of Bane's Venom drug and the Project Blockbuster formula, is three times as potent as Venom and permanent, inducing extreme growth in muscle mass and hardened skin.
Wolf (Young Justice) is one of many subjects enhanced by Kobra-Venom.
Titan (Batman: Arkham Asylum), a far more potent version of the Venom steroid, only requires a small amount to trigger a transformation, but tends to drive the infected insane in the process.
A henchman of the Joker (Batman: Arkham Asylum) enhanced by the Titan formula.
5-U-93-R (Injustice: Gods Among Us) is a Kryptonian nanotech drug that increases the user's strength and durability to superhuman levels.
Elhaym "Elly" Van Houten (Xenogears) having enhanced herself with the 'Drive' that gives her Ether boost, but makes her go berserk.
Due to a remote-controlled device embedded in her chest, Jill Valentine (Resident Evil) was unwillingly infused with P30, a performance enhancer that enhanced her strength, speed, and agility to superhuman levels while rendering her a mindless slave to Wesker and his control.
Riley Finn (Buffy the Vampire Slayer) was secretly fed strength-enhancing drugs by the Initiative.
Guardians (Nikita) take a highly addictive series of drugs called Regimen to enhance their physical abilities.
NZT-48 (Limitless), drug that vastly increases the user's intelligence. However it is highly addictive, and withdrawal is fatal.
Chems (The Bourne Identity/The Bourne Legacy) are a specialized drug cocktail given to Treadstone assassins and members of Operation Outcome in order to boost their mental and physical abilities.
The Genetic Modification Formula (Heroes) is a chemical compound that can grant special powers to the ones who weren't born with them.
CPH4 (Lucy; 2014 film) is a drug that allows the user to slowly access 100% of the user's cerebral capacity
GH.325 (Agents of S.H.I.E.L.D.), created from the blood of a Kree corpse code-named G.H., promotes cellular growth to heal mortal wounds and even resurrect the recently deceased, but also has drastic effects on the psyche of any human who takes it.
The Centipede Serum (Agents of S.H.I.E.L.D.) is a superpower-granting formula created by mixing the Super-Soldier Serum, the Extremis virus, GH.325, metal from salvaged Chitauri technology, and a blood sample from Chan Ho Yin/Scorch, and then exposing the mixture to gamma radiation.