pre-workout
3 interactions related to pre-workout
citrulline + arginine
Citrulline and arginine are both precursors to nitric oxide, the molecule that relaxes blood vessels and improves blood flow to working muscle. Each has a different limitation, and taking them together addresses both at once.
caffeine + yohimbine
Caffeine and yohimbine are both stimulants that activate the sympathetic ('fight or flight') nervous system through different routes. Caffeine blocks adenosine receptors and raises catecholamine output; yohimbine blocks alpha-2 adrenergic receptors, increasing norepinephrine release. Taken together they add to each other's effects on heart rate, blood pressure, and anxiety. Yohimbine-containing products have been linked to emergency-department visits and hospitalizations for fast heart rate, high blood pressure, and severe anxiety.
caffeine + creatine
Daily high-dose caffeine taken throughout a creatine loading week may modestly blunt creatine's strength benefit, but ordinary pre-workout caffeine in someone already taking creatine daily is at worst neutral and often additive. There is no safety concern at normal intakes.