Dark Seals potions passive should work for Singed Insanity Potion (his R)

Dark Seal +25% increased healing from Health Potion Health and Refillable Potion

So Singed is the mad chemist and his ulti is called Insanity potion and it gives him Health regen increased among oither things, can't this part be increased by 25% as well?

I mean, it's a potion after all