The reward for completing the Citadel: Medical Supplies is either increased Medi-gel capacity or enhanced Medi-gel depending on which doctor is stationed on Normandy.
The increased capacity is self-explanatory. However, I do not understand what "enhancement" has been given to the enhanced Medi-gel. Is it simply that the amount of health restored through the use Medi-gel has been increased? What exactly puts the "enhanced" in "enhanced Medi-gel"?