ECA. Here's why.Originally Posted by Urban Monk;
The main idea is to initiate and prolong thermogenesis. Ephedrine (a sympathetic nervous system stimulator) triggers the release of noradrenaline/norepinephrine, the body's primary endogenous thermogenic hormone. However, the release of norepinephrine is inhibited by prostaglandins (inflammatory hormone-like substances derived from arachidonic-acid/cyclooxygenase metabolism) and adenosine. Without adequate norepinephrine production, thermogenesis will be compromised. Now comes caffeine. A central nervous system stimulant, caffeine inhibits adenosine and phosphodiesterase (PDE), leading to and prolonged thermogenesis. And aspirin? Caffeine takes care of adenosine and PDE, but the prostaglandin channel is still open. So, aspirin contributes centrally to the ECA stack by inhibiting prostaglandin production, thus supporting and prolonged thermogenesis. As an aside, aspirin may also deplete hepatic (liver) levels. So aspirin users may consider taking liver-supporting supplements.
Net, the synergistic action of ECA ensures significant norepinephrine receptor-stimulation activity, and therefore, effective thermogenesis. So, prefer ECA to EC.