Alex trained his newfound technique and started making pills.
On his first try, he made a pill that reached 8 veins just as he had hoped. However, after making subsequent pills, he ended up with a slight problem.
The problem wouldn't be much of a bother to him, but to others, it would definitely be a major problem.
The energy in the cauldron was no longer potent enough to make a 100% pill all the time. As long as Alex was careful when making the pills from the very start, he wouldn't have much of a problem in this regard.
Even when he made a pill that didn't have enough energy to reach 100%, he could simply add a single World Defying Mushroom into the cauldron, and he would have more than enough energy to reach what he wanted.
As for others, they would have no chance from the start since they didn't have any World Defying Mushroom.