Teenagers and young adults who reported using pre-workout dietary supplements were more than twice as likely as non-users to say they slept five hours or less per night, according to an analysis of Canadian survey data published in the journal Sleep Epidemiology.
Researchers analyzing data from the Canadian Study of Adolescent Behaviors found an association between pre-workout dietary supplement use and very short sleep among people ages 16 to 30.
According to the research team, participants who said they had used a pre-workout supplement within the past year were more than twice as likely as non-users to report sleeping five hours or less per night. The study was published in Sleep Epidemiology in 2025.
“Pre-workout supplements, which often contain high levels of caffeine and stimulant-like ingredients, have become increasingly popular among teenagers and young adults seeking to improve exercise performance and boost energy,” said lead author Kyle T. Ganson, an assistant professor at the Factor-Inwentash Faculty of Social Work at the University of Toronto. “However, the study's findings point to potential risks to the well-being of young people who use these supplements.”
Health guidelines typically recommend 8 to 10 hours of sleep per night for adolescents and 7 to 9 hours for young adults. The researchers said stimulant ingredients found in many pre-workout products could worsen existing sleep shortfalls.
“These products commonly contain large doses of caffeine, anywhere between 90 to over 350 mg of caffeine, more than a can of Coke, which has roughly 35 mg, and a cup of coffee with about 100 mg,” Ganson said. “Our results suggest that pre-workout use may contribute to inadequate sleep, which is critical for healthy development, mental well-being, and academic functioning.”
The researchers urged health and mental health professionals—including pediatricians, family physicians and social workers—to discuss pre-workout supplement use with young people and their families and to suggest harm-reduction steps, such as avoiding the products 12 to 14 hours before bedtime.
The findings also add to calls for stronger oversight of dietary supplements in Canada, the researchers said.
“Young people often view pre-workout supplements as harmless fitness products,” Ganson added. “But these findings underscore the importance of educating them and their families about how these supplements can disrupt sleep and potentially affect overall health.”
