Pre-Workout Supplements: Hidden Stimulants and Heart Risks
Pre-workout supplements sit in a legal gray zone that has repeatedly proven dangerous. Manufacturers introduce new stimulant compounds — usually chemical cousins of banned drugs — that are technically legal when first sold but carry unknown or already-documented heart risks. The FDA bans one compound; the industry swaps in another. The cycle repeats.
The History of Banned Stimulants in Pre-Workouts
The FDA banned ephedra in 2004 after it was linked to more than 100 deaths and thousands of adverse-event reports. DMAA (1,3-dimethylamylamine) replaced it and was associated with multiple cardiac deaths and strokes; the FDA began issuing warning letters in 2012 and declared DMAA an unsafe food additive in 2013. DMHA (octodrine, 2-aminoisoheptane) then emerged as a DMAA analog and has been the subject of further FDA warning letters. Each compound appeared on shelves, caused harm, and faced regulatory action only after years of lag.
Ingredients, dose, and safety signal
Independent testing has repeatedly shown that workout supplements contain undeclared stimulants. Cohen and colleagues have analysed pre-workout and weight-loss products multiple times and consistently found banned or unapproved compounds — including BMPEA, oxilofrine, DMAA, DMBA, and DMHA — that are not listed on the label. The FDA Center for Food Safety and Applied Nutrition adverse-event reporting system (CAERS) has accumulated thousands of reports related to weight-loss and energy supplements over the last decade, including reports of cardiac arrest, myocardial infarction, stroke, and death.
What Is Safe in Pre-Workouts
The pre-workout ingredients with established safety profiles and real performance evidence are caffeine (about 3–6 mg per kg of body weight), beta-alanine (3.2–6.4 g per day, with harmless tingling as a side effect), citrulline (6–8 g per day for "pump" and endurance), and creatine monohydrate (3–5 g per day). These four cover the legitimate ergogenic effects without novel stimulants. Anyone with high blood pressure, a history of arrhythmia, or a family history of sudden cardiac death should avoid stimulant pre-workouts entirely. Disclosed-dose products are far safer than "proprietary blends" that hide individual ingredient amounts.
Sources
- Cohen PA, Travis JC, Keizers PHJ, Deuster P, Venhuis BJ. "Four experimental stimulants found in sports and weight loss supplements: 2-amino-6-methylheptane (octodrine), 1,4-dimethylamylamine (1,4-DMAA), 1,3-dimethylamylamine (1,3-DMAA) and 1,3-dimethylbutylamine (1,3-DMBA)." Clinical Toxicology, 2018;56(6):421–426. PMID: 29115866. DOI: 10.1080/15563650.2017.1398343.
- Cohen PA, Travis JC, Vanhee C, Ohana D, Venhuis BJ. "Nine prohibited stimulants found in sports and weight loss supplements: deterenol, phenpromethamine (Vonedrine), oxilofrine, octodrine, beta-methylphenylethylamine (BMPEA), 1,3-dimethylamylamine (1,3-DMAA), 1,4-dimethylamylamine (1,4-DMAA), 1,3-dimethylbutylamine (1,3-DMBA) and higenamine." Clinical Toxicology, 2021;59(11):975–981. PMID: 33755516. DOI: 10.1080/15563650.2021.1894333.
- Geller AI, Shehab N, Weidle NJ, Lovegrove MC, Wolpert BJ, Timbo BB, Mozersky RP, Budnitz DS. "Emergency Department Visits for Adverse Events Related to Dietary Supplements." New England Journal of Medicine, 2015;373(16):1531–1540. PMID: 26465985. DOI: 10.1056/NEJMsa1504267.
- Cohen PA. "Hazards of Hindsight — Monitoring the Safety of Nutritional Supplements." New England Journal of Medicine, 2014;370(14):1277–1280. PMID: 24693886. DOI: 10.1056/NEJMp1315559.
- Eliason MJ, Eichner A, Cancio A, Bestervelt L, Adams BD, Deuster PA. "Case reports: death of active duty soldiers following ingestion of dietary supplements containing 1,3-dimethylamylamine (DMAA)." Military Medicine, 2012;177(12):1455–1459. PMID: 23397688. DOI: 10.7205/MILMED-D-12-00265.
- Trexler ET, Smith-Ryan AE, Stout JR, Hoffman JR, Wilborn CD, Sale C, Kreider RB, Jäger R, Earnest CP, Bannock L, Campbell B, Kalman D, Ziegenfuss TN, Antonio J. "International society of sports nutrition position stand: Beta-Alanine." Journal of the International Society of Sports Nutrition, 2015;12:30. PMID: 26175657. DOI: 10.1186/s12970-015-0090-y.
- U.S. Food and Drug Administration. "DMAA in Dietary Supplements." Updated 2022. fda.gov. (Status of DMAA as an unsafe food additive; warning letters and seizures since 2012.)
- U.S. Food and Drug Administration. "Final Rule Declaring Dietary Supplements Containing Ephedrine Alkaloids Adulterated." Federal Register, 2004;69(28):6788–6854. federalregister.gov.
- U.S. Food and Drug Administration. "Tainted Products Marketed as Dietary Supplements." CDER tainted-products database. Accessed 2026. accessdata.fda.gov.
Reviewed against 9 peer-reviewed and regulatory sources.