What 'functional' actually does to the flavour brief
Functional beverages add bioactives — L-theanine, ashwagandha, lion's mane, electrolytes, magnesium, B-vitamins, caffeine, taurine, mushroom extracts, collagen, prebiotic fibre — that almost all introduce bitter, metallic, earthy or astringent off-notes the flavour system has to cover.
Generic citrus or berry profiles do not solve this; you need a masking architecture that targets the specific off-note signature of the active. Magnesium glycinate reads metallic and salty; ashwagandha is earthy-bitter; mushroom extracts are funky-umami; ionic minerals add a salty/electric back-tongue tail.
