Ephedra analogues (synephrine)

Tier 4 — risky / avoid · Cardiovascular risk

Case reports have linked bitter orange / synephrine products to heart attack, stroke, and arrhythmia, particularly when stacked with caffeine or other stimulants. Evidence for isolated low-dose synephrine is more mixed, but the parent compound ephedra was banned by the FDA in 2004 after 155 deaths and similar risks apply to stimulant-heavy pre-workouts. Especially dangerous when combined with caffeine or during intense exercise.

Dose: AVOID — especially combined with caffeine and exercise