Transformation: Henry Jekyll possessed the ability to physically alter his physical body to embody the essence of his dual personality Edward Hyde. Initially, Jekyll required a serum in order to instigate the change. As time went on however, the changes began to take affect involuntarily. Severe stress, or sometimes even mild agitation, was enough to prompt the change. With effort, Jekyll could occasionally suppress the transformation into Hyde, but this was seldom and always with great difficulty.
Transformation: Edward Hyde possessed the ability to physically alter his body back into its original form, that of Henry Jekyll. This ability was usually involuntary, as Edward preferred being the dominant persona between the two.
Enhanced Senses: Edward Hyde possessed heightened olfactory senses and could perceive scents that were normally imperceptible to a normal human being.
Enhanced Vision: Edward Hyde's vision was acute enough that he could see in the dark, and could also detect heat patterns. He was one of the few people that could actually "see" Invisible Man, Hawley Griffin, though he only saw him as a thermal pattern.
Superhuman Strength: Edward Hyde possessed superhuman strength. Though the limits of his strength has never been measured, he could tear the limbs off of opponent as if he were snapping a twig. The pressure from Hyde's oversized jaw was powerful enough to bite through solid bone.