Mystical creatures like him used the same magic herbs to create their magic pills, but for them to be effective on them, they had to be at least level 6 and magic crystals had to be used during their making.
Also the effect wasn't so great but it was enough to make a huge difference during a fight.
The grade and number of the magic crystals added to the magic pill depended on the level of the Mystical creature, and for example when he would get the first level 6 magic pill he needed to repair his Mystical core, before swallowing it he would have to add 2 grade 5 magic crystals in it.
His mother who was a mage had taught him how to do this, and even though it was a process that took longer than if it was a mage who added these magic crystals during the making process, at least he didn't need anyone to do it and so his identity could remain secret.