Pre‑Workout Supplements Are Robbing Teens of Sleep

They are everywhere, inside the gym, on fitness influencers’ feeds, or in sports store supplement aisles. Brightly colored tubs that promise energy, focus, and performance. 

Millions of pre-workouts have been sold to teenagers and youth. A pre-workout supplement to them has become as regular as a gym bag. These products are aggressively marketed, sold by athletes, and normalized via social media fitness culture platforms.

Beneath the flashy packaging and bold claims, a growing body of research is raising serious questions about what these products are doing to young people, especially their sleep. The results from the latest research deserve attention.

Key Findings of the Study

The study published in November 2025 in the journal Sleep Epidemiology, conducted by researchers at the University of Toronto as part of the Canadian Study of Adolescent Health Behaviors examined the supplements and sleep habits of young adults all aged between 16 and 30.¹

The findings were contrasting. The survey found that teens and young adults who said they used pre-workout four times in the past year, were more than two times likely to sleep five hours or less each night compared to those who didn’t use them.

8 hours of sleep is generally recommended for a good night’s sleep. However, depending on who you ask, this number may vary. Boys and girls get a good night of sleep for about 8 to 10 hours, according to the health guidelines. Young adults should sleep for a total of 7-9 hours a night.

Researchers at the University of Toronto studied the link between pre-workout supplements and sleep deprivation among young adults in the country.

According to lead researcher Dr Kyle T. Ganson, assistant professor at the Factor-Inwentash Faculty of Social Work at the University, teens and young adults may want to use pre-workout supplements to spice up their work out and get energized.

But all this may come at the cost of missing out on essential sleep hours. These sleep hours are required for replenishing energy levels, overall recovery and muscle repairs.

Pre-Workout Supplements Affect Sleep

To understand just how pre-workout supplements interfere with sleep, we need to see what actually is in these products. These are not just some protein shakes.

For the most part, pre-workout products are multi-ingredient formulations that may contain caffeine, creatine, nitrates, amino acids, artificial sweeteners and several other stimulant compounds aimed at giving the user a quick spike in energy levels.

Just the caffeine level is shocking. As Ganson’s research tells us, these products generally contain anywhere between 90 and 350 milligrams of caffeine per serving.

For perspective, a can of Coke generally contains about 35 milligrams while a cup of coffee, about 100 milligrams. So, if a pre-workout has caffeine on the higher end, it would necessarily have about three to four times the caffeine of a coffee.

 Caffeine works by hindering adenosine receptors. Adenosine is a compound that builds up naturally over the course of a day, and its purpose is to tell your body that it’s time to go to sleep.

When this chemical is blocked by caffeine, the brain will be put into a state of heightened alertness for hours after the supplement has been consumed.

The Timing Problem

Teenage routines are where the problem lies. A majority of adolescents practice after their school hours. This indicates that those teenagers are usually taking their pre-workouts in the mid-afternoon till late evening between 4 PM and 8 PM.

The body processes caffeine for about five to six hours because it has a half-life of this duration. The researchers explicitly suggest staying away from these things for 12 to 14 hours before bed - essentially a ban on all evening use.

When bedtime is 10 PM for a teen, that means they should not be drinking their pre-workout after 8 or 10 AM at the latest. In reality, most young people do not use these products in this manner.

The Unspoken Cycle

One of the strangest patterns may be a self-reinforcing cycle, per study. When teens average just five hours or less of sleep, they wake up tired. When you are exhausted, it is harder to motivate yourself to train.

Thus, they turn to some pre-workout supplement to power through the session and so on, their sleep is disrupted again the next night.

In due time, the supplement stops solving the energy problem and starts causing it. The body relies on stimulants to meet its needs at a level natural sleep would deliver.

Deprivation Is More Serious for Teens than Adults

Sleeping doesn’t mean just resting. During adolescence, the body enters a period of deep sleep where it heals and repairs damaged tissues. It also opens up pathways of memory consolidation, hormonal regulation, etc.

The brain, specifically, is undergoing substantial changes during adolescence, or developmental milestones, and these are dependent on good sleep.

Being chronically sleep deprived at this stage of life has been associated with worse grades, more anxiety and depression, poorer immunity and decision-making, and oddly lower athlete performance and slower muscle recovery.

Sleep deprivation will counteract the very goals that led a teenager to adopt pre-workout supplements in the first place.

What Parents and Teens Need to Know

The researchers were clear that health professionals, including pediatricians, family doctors, school counsellors and social workers, should routinely ask young patients about pre-workout supplement use in the same way they ask about alcohol or tobacco.

The products exist in a grey area – legal, widely sold - not seen as dangerous and most young people don’t think they’re harmful and neither do many parents.

 If your teen is already taking pre-workout supplements, the most important immediate step is to check the timing. The use of any substance within the 12 to 14-hour window before bedtime, whether apparent or not, is causing an effect on them.

You can either switch to a stimulant-free pre-workout. Or skip the supplement altogether and replace it with a pre-training snack of complex carbs and water.

According to the University of Toronto research, pre-workout supplements might be performance-enhancing, but for teens and young adults, they come at a price.

The price being a loss of sleep that is significant and damaging, which affects mental health right up to physical recovery.

For 99% of performance goals, all you need is sleep, nutrition, regular training, and time, not any flavoured powder. 

Disclaimer: This content is for general informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider with any questions about your health or treatment options.

References

1. Sciencedirect | Pre-workout supplements affect sleep in young adults