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ECA stands for Ephedrine, Caffeine and Aspirin; these compounds were found to be synergistic for fat loss, and isolating ephedrine from the Ephedra Sinicus plant and putting it into ECA appears to be quite an effective method of fat loss and neural stimulation.

Our evidence-based analysis on eca features 20 unique references to scientific papers.

Research analysis led by and reviewed by the Examine team.
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Research Breakdown on ECA

Three doses of:

  • Ephedrine in 24mg (72mg total)

  • Caffeine in 200mg (600mg total)

  • Aspirin in 81mg (Baby Aspirin) once daily

The ECA stack is usually taken in 6-8 week cycles. Dosages should start off small, before reaching 3 doses a day.


  1. ^ Astrup A, et al. The effect and safety of an ephedrine/caffeine compound compared to ephedrine, caffeine and placebo in obese subjects on an energy restricted diet. A double blind trial. Int J Obes Relat Metab Disord. (1992)
  2. ^ Toubro S, et al. Safety and efficacy of long-term treatment with ephedrine, caffeine and an ephedrine/caffeine mixture. Int J Obes Relat Metab Disord. (1993)
  3. ^ Astrup A, et al. Thermogenic synergism between ephedrine and caffeine in healthy volunteers: a double-blind, placebo-controlled study. Metabolism. (1991)
  4. ^ Haller CA, Jacob P 3rd, Benowitz NL. Enhanced stimulant and metabolic effects of combined ephedrine and caffeine. Clin Pharmacol Ther. (2004)
  5. Loose I, Winkel M. Clinical, double-blind, placebo-controlled study investigating the combination of acetylsalicylic acid and pseudoephedrine for the symptomatic treatment of nasal congestion associated with common cold. Arzneimittelforschung. (2004)
  6. Schachtel BP, et al. Demonstration of the analgesic efficacy and dose-response of acetylsalicylic acid with pseudoephedrine. J Clin Pharmacol. (2010)
  7. Daly PA, et al. Ephedrine, caffeine and aspirin: safety and efficacy for treatment of human obesity. Int J Obes Relat Metab Disord. (1993)
  8. Horton TJ, Geissler CA. Aspirin potentiates the effect of ephedrine on the thermogenic response to a meal in obese but not lean women. Int J Obes. (1991)
  9. Horton TJ, Geissler CA. Post-prandial thermogenesis with ephedrine, caffeine and aspirin in lean, pre-disposed obese and obese women. Int J Obes Relat Metab Disord. (1996)
  10. Agonist-Directed Desensitization of the β2-Adrenergic Receptor.
  11. Kenakin TP. Cellular assays as portals to seven-transmembrane receptor-based drug discovery. Nat Rev Drug Discov. (2009)
  12. Fang Y. Label-Free Receptor Assays. Drug Discov Today Technol. (2011)
  13. Fang Y, Ferrie AM. Label-free optical biosensor for ligand-directed functional selectivity acting on beta(2) adrenoceptor in living cells. FEBS Lett. (2008)
  14. Receptor internalization and ERK1/2 phosphorylation are dependent on the agonist exposure time.
  15. The desensitization and resensitization patterns of quiescent A431 cells induced by epinephrine is sensitive to stimulation duration and several inhibitors.
  16. January B, et al. beta2-adrenergic receptor desensitization, internalization, and phosphorylation in response to full and partial agonists. J Biol Chem. (1997)
  17. Characterization of β2-Adrenergic Receptor Dephosphorylation: Comparison with the Rate of Resensitization.
  18. Sears MR. Adverse effects of beta-agonists. J Allergy Clin Immunol. (2002)
  19. Nelson HS. Is there a problem with inhaled long-acting beta-adrenergic agonists. J Allergy Clin Immunol. (2006)
  20. Astrup A, et al. Enhanced thermogenic responsiveness during chronic ephedrine treatment in man. Am J Clin Nutr. (1985)