You're right. I outsourced the ingredients.

[ Maybe he should start growing his own ingredients. It would take more time, but if he was planning to sell them, the time would be rewarded with money. ]

I'll need to get more ingredients. I'll try a different supplier.

[ And, as L pointed out, he can increase the potency. ]

I've made smaller potions before, and they've worked. This should have just been a step up.