Matt Mercer Blood Hunter Mutant question

[TheChangelingMC]

I've been looking at making a blood hunter and the order of the mutant seems quite cool, but there's no explanation of how the mutagens get made.

Do they get created freely or do you need alchemical supplies or what?

That seems a big drawback to the subclass if they're needed, since alchemist's supplies cost 50 gold, but they can't just appear from nowhere, can they?

[Brutalitops]

Its implied that you get access to the mutagens when you level up. You can flavor crafting the Mutagens but you do not need to buy an alchemists kit or be proficient in it but if you want to get an alchemist kit it would fit the theme but no you do not need to buy them as its implied the mutagens come from your own body which is why only you can drink one.

[Cwyll]

Just collect plants and creature body parts as you travel around, and using an alchemist or brewing kit would be good for game flavour.
In real game terms though, they just happen, so discuss with your GM to make sure they're happy.