Advancing to Tier-3 was no different than advancing to the 1st or 2nd Tier. It was just a little bit more intense – especially with Superior Constitution in his possession.
Superior Constitution had already done miraculous things to alter his physique, strengthening it above the limit of a Tier-2 Awakened. His physical strength was already at Tier-3 even though he had yet to advance to the 3rd Tier. Breaking through to the next Tier would enhance his physical strength once again, therefore boosting his combat prowess drastically. Simultaneously, his body would be altered once again, not only by the advancement of his Tier but also due to the effect of Superior Constitution.
Michael had to absorb a tremendous amount of energy and more than a dozen Apex Nutrition Serums to supply enough nutrients and energy as the breakthrough to Tier-3 had been initiated. Superior Constitution sucked him dry to strengthen Michael alongside the advancements provided by the War Rune.