The Super Soldier Serum is a chemical formula from Marvel Comics.
Created by the brilliant scientist Abraham Erskine, it grants the ones who inject themselves with amazing powers. However, the subject must then be subject to a special beam of energy known as the Vita Rays, or else he/she will suffer an horrible mutation.
Steve Rogers volunteered for a secret government project that revolved around injecting him with the Super Soldier Serum, which gave him superhuman strength and invulnerability, thus he became Captain America.
Johann Schmidt injected himself with the Super Soldier Serum. However, since he didn't expose himself to the Vita Rays, he mutated into the monstrous Red Skull.
The U.S. soldier, Isaiah Bradley, secretly took the serum and became a Super Soldier, and was later sent to confront Bucky Barnes in the Korean War. After the war, he was imprisoned for 30 years and members of HYDRA experimented on him, runing tests with his blood and cells. The samples of Isaiah's blood were later obtained by the CIA.
Bucky, in his Winter Soldier persona, was sent to retrieve packets of the Super Soldier Serum that were recreated by Howard Stark, the night he killed Howard and his wife, Maria Stark. HYDRA then used these packets to create more Winter Soldiers.
The Super Soldier Serum was used as part of the Centipede Project.
Emil Blonsky injected himself with the Super Soldier Serum to be a match for the Hulk. However, he tried to substitute the Vita Rays with the Hulk's gamma radiation-enhanced blood, which backfired when Emil mutated into the reptilian monstrosity known as the Abomination.
Many years later, it is revealed that a scientist called Wilfred Nagel was able to recreate the serum. Nagel was initially hired by HYDRA during the Winter Soldier program and later by the CIA to work with the samples obtained from Isaiah. Nagel managed to recreate a more subtle and optimised version of the serum's formula. However, a group called Flag Smashers led by Karli Morgenthau stole the 20 vials Nagel made. The Flag Smashers consumed 8 of the vials, acquiring Super Soldier powers, but 11 of the vials were later destroyed by Baron Zemo. The last serum was taken by the U.S. agent John Walker, who injected himself with it to become stronger as the new Captain America. After injecting himself, Walker became mentally unstable. As result, upon confronting the Flag Smashers, Walker brutally murdered one of them, Nico, to avenge the death of his partner at the hands of Karli.