A plot device used by Marvel Comics
. The first mention of the super soldier formula appeared in Captain America Comics #1
A chemical formula/process first perfected by Dr. Emil Erskine, the super soldier formula caused its subjects to gain the ultimate in human potential. The formula caused increased muscle mass along with heightened reflexes and balance. The formula helped neutralize the toxins and lactic acid in the recipient allowing him or her to exercise for extended period of time without tiring.
The super soldier formula was part of an on-going program in the 1940's by the U.S. government called Project: Rebirth. The program went through a number of trials before the formula was tested. The intial subjects, a trio of black soldiers, seemed to be a success until it was discovered that the formula would become unstable in a person's system, causing them to become enraged and paranoid. This oversight lead to the deaths of two of the subjects and the third suffering decreased intelligence and increased muscle mass.
Dr. Erskine determined that exposure to an unknown type of radiation which he devised and called "vita rays" would stop the harmful effects of the formula. Erskine and the U.S. army recruited a young man named Steve Rogers, a slight frail young man too small for active duty, but who wished to help fight the Axis powers, to be their first test subject. Rogers was injected with the serum and exposed to the vita rays. The formula did as it was designed, but Erskine was killed moments later by a Nazi agent. Rogers quickly defeated the spy, but too late to save Erskine, who died with the secret of the formula. Rogers became a rallying point when the U.S. government created a costumed identity for him as Captain America.
Unbeknownst to the U.S. government, an officer assigned to Project:Rebirth disagreed with the project's choice of test subjects and recruited and administered the formula to his own test subject. The formula worked, but the test subject, a private named Clinton McIntyre, was not subjected to the vita rays and soon became unhinged. He was taken into custody, but later escaped and fought Captain America in the guise of Protocide believing him to be a usurper to his rightful role.
Attempts have been made over the years to duplicate the formula. Different versions have been created with varying results. One version was produced by agents of Nazi Germany which was used to create Master Man, a Nazi agent capable of trading blows with the super-humanly strong Submariner. Another version was used by the British hero Union Jack.
The U.S. government has continued to try and recreate Erskine's original success over the years as well, producing Nuke and G.I.Maxx in the process. An admirer of Captain America discovered a copy of Erskine's notes years later and was successful to a point in the process, but the notes did not include the information on the vita rays. The result was that this admirer and his companion while in the guise of Captain America and Bucky, became increasingly unstable. Eventually, they were put into suspended animation. When they were awakened, they again went berserk and though the admirer was killed in battle with the original Captain America, the young man who was using the identity of Bucky eventually recovered and became the hero Nomad.
Another attempt to recreate the formula was the result of the experiments of Dr. Ted Sallis. Sallis was working on a plant-based formula, but an explosion in his lab in Florida, caused the formula to mix with the swamp elements to transform Sallis into the inhuman, Man-Thing, a being composed of the material of the swamp, similar to DC Comics' Swamp Thing.