ECA is three inexpensive, long-established oral drugs — ephedrine, caffeine and aspirin — used together for fat loss. Added to a reduced-calorie diet, fat falls faster and muscle is better preserved, and that does not fade over months of use. Cholesterol readings improve alongside the fat loss. Sleep, tremor, heart rate and blood pressure all move in the wrong direction, most sharply in the first weeks. (Full Review)

Protocol

Standard regimen

Ephedrine 20 mg + caffeine 200 mg

Three times daily with meals; the 1:10 ratio gave the largest thermic effect

Adding the third agent

Aspirin 81 mg once daily

Contemporary practice adds aspirin 81 mg; the two-agent regimen without aspirin is a co-equal alternative

Best time of day

Waking, midday, early afternoon

Trials dosed pre-meal; final dose at least 8 hours before intended sleep

Time to effect

Fat loss

From week 8

Weight separated from placebo from week 8 in the largest trial; 8–12 weeks is the minimum useful assessment period

Thermic and appetite effects

1–2 hours

Thermic and appetite effects appear within 1–2 hours of the first dose

Cycling for efficacy

Persists to 50 weeks

The thermogenic effect persisted through 50 weeks of continuous use, so cycling is not required

Benefits

High: Accelerated fat loss on a reduced-calorie diet; preservation of lean mass during weight loss; improved blood lipid profile during weight loss; reduced risk of a first cardiovascular event

Low: Increased 24-hour energy expenditure and fat oxidation; improved time to exhaustion in high-intensity exercise; appetite suppression; reduced long-term colorectal cancer incidence; increased subjective energy and alertness

Speculative: Brown-fat thermogenesis as a contributor to fat loss

Contraindications

Coronary artery disease, prior myocardial infarction, or unstable angina

Uncontrolled hypertension (systolic ≥160 or diastolic ≥100 mmHg)

Atrial fibrillation or other fast heart rhythm; structural heart disease (hypertrophic cardiomyopathy)

Prior ischemic or hemorrhagic stroke, or known cerebral aneurysm

Overactive thyroid, or pheochromocytoma

Closed-angle glaucoma; benign prostatic hyperplasia with >100 mL urine left after voiding

Peptic ulcer disease, prior gastrointestinal bleed, or untreated Helicobacter pylori

Aspirin allergy, or aspirin-exacerbated respiratory disease

Chronic kidney disease (eGFR <45 mL/min/1.73 m²), or prior ephedrine-associated stone disease

Liver impairment, Child-Pugh Class B or C

Pregnancy, attempted conception, and breastfeeding

Age under 18

Monoamine oxidase inhibitors within 14 days, or linezolid

Panic disorder, bipolar disorder, or any psychotic illness

Body weight under 50 kg if aspirin is 75–100 mg

Athletes under World Anti-Doping Agency rules (ephedrine prohibited in competition above 10 µg/mL urine)

Anticoagulants and antiplatelet drugs (warfarin, apixaban, rivaroxaban, clopidogrel) with aspirin

Key Interactions

Other sympathomimetics and stimulants (pseudoephedrine, phenylephrine, amphetamine, methylphenidate, atomoxetine, modafinil)

Non-selective beta-blockers (propranolol, nadolol)

Other non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac)

Serotonin-acting antidepressants (sertraline, fluoxetine, venlafaxine, duloxetine)

Methotrexate and valproate

CYP1A2 inhibitors (fluvoxamine, ciprofloxacin, cimetidine, oral contraceptives)

Theophylline and aminophylline

Halogenated inhalational anesthetics (halothane, isoflurane) and digoxin

Over-the-counter products (decongestants, caffeine- or NSAID-containing analgesics, antacids and alkalinizing agents)

Stimulant and thermogenic supplements (synephrine, yohimbine, higenamine, guarana, green tea extract, theacrine, methylhexanamine)

Supplements with additive antiplatelet effects (fish oil, Ginkgo biloba, high-dose vitamin E, garlic extract, nattokinase, curcumin)

Other interventions (sauna, hot yoga, heat training; blood donation, endoscopy)

Risk & Side Effects

High: Insomnia and disrupted sleep; tremor, nervousness and agitation; palpitations and sustained heart-rate elevation; acute rise in systolic blood pressure; transient rise in blood glucose and insulin after dosing; dry mouth and heartburn; major bleeding and upper gastrointestinal injury

Medium: Caffeine-withdrawal headache and fatigue on stopping

Low: Stroke, heart attack, seizure and sudden death; excess all-cause and cancer mortality in healthy older adults; kidney stones from ephedrine deposition; blunted muscle adaptation to resistance training

Speculative: Loss of brown-fat responsiveness with continued use

Monitoring

Marker	Target	Why
Seated blood pressure	105–120 / 65–80 mmHg	Detects the blood-pressure-raising effect
Resting heart rate	50–70 bpm	Tracks the most persistent circulatory effect
Thyroid-stimulating hormone (TSH)	0.5–2.0 mIU/L	Excludes overactive thyroid, which multiplies stimulant risk
Hemoglobin and ferritin	Hemoglobin 13.5–15.0 g/dL (women 12.5–14.5); ferritin 50–150 ng/mL	Makes slow aspirin-related bleeding visible before anemia appears
High-sensitivity C-reactive protein (hs-CRP)	<1.0 mg/L	Interprets ferritin and tracks background inflammation
Fasting glucose	75–90 mg/dL	Ephedrine raises glucose acutely; sustained use with fat loss lowers it
Fasting insulin	2–5 µIU/mL	Separates the post-dose insulin rise from the fat-loss fall
Glycated hemoglobin (HbA1c)	4.9–5.4%	Distinguishes a transient post-dose glucose rise from real change
Serum potassium	4.0–4.5 mmol/L	β2 stimulation drives potassium into cells; low potassium provokes arrhythmia
Estimated glomerular filtration rate (eGFR) and creatinine	eGFR >90 mL/min/1.73 m²	Aspirin and thermogenic fluid losses both stress the kidney
Lipid panel: LDL and HDL cholesterol, triglycerides	LDL <100 mg/dL; HDL >55 mg/dL; triglycerides <80 mg/dL	Trials reported LDL falling and HDL rising alongside the fat loss
Body composition by dual-energy X-ray absorptiometry (DEXA)	No established target — track change from own baseline; the trial pattern is fat mass down, lean mass held	Distinguishes the specific claim from ordinary weight loss

Cadence: Blood pressure and resting heart rate daily for two weeks, then weekly; blood count with ferritin and a basic metabolic panel at 6 weeks; a full panel adding lipids, fasting insulin, HbA1c and kidney function at 3 months, then every 6 months; body composition every 12 weeks.

Qualitative Assessment

Sleep onset latency and number of night wakings
Resting hand tremor at rest and with arms outstretched
Appetite and time from a meal to first hunger
Perceived exertion at a fixed training load
Heat tolerance and sweating at rest
Irritability, anxiety and mood stability
Awareness of palpitations or skipped beats
Dyspepsia (upper abdominal discomfort), heartburn, or dark stools

ECA for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment