caffeine + ephedrine + yohimbine

This is a combination of three stimulant compounds—caffeine, ephedrine, and yohimbine—used primarily in dietary supplements marketed for weight loss and enhanced athletic performance. Each component acts as a central nervous system stimulant but through different mechanisms: - **Caffeine** is an adenosine receptor antagonist that increases alertness and metabolic rate. - **Ephedrine** is a sympathomimetic amine that stimulates the release of norepinephrine, increasing heart rate, blood pressure, and thermogenesis. - **Yohimbine** is an alpha-2 adrenergic receptor antagonist that promotes the release of norepinephrine and enhances lipolysis. The combination has been studied for its effects on metabolism, cardiovascular function, and fat loss. While caffeine plus ephedrine (the EC stack) has demonstrated moderate efficacy in promoting weight loss in obese individuals (about 1 kg/month more than placebo), adding yohimbine further increases sympathetic activity but may also increase cardiovascular risks such as elevated heart rate and blood pressure[3][7]. The use of these combinations can lead to significant adverse effects including increased cardiac load during exercise, agitation, insomnia, hypertension, arrhythmias, stroke or even death[3][6]. Due to safety concerns—especially with ephedrine—the sale of such combinations is banned or restricted in many countries.