Surprising gym hack: Study says smelling 90% dark chocolate before a workout helped lifters do 18 more reps

A new study reveals that inhaling the aroma of 90 percent dark chocolate before a workout helped lifters crush an average of 18 more reps on leg extensions.

The secret to smashing your next lower-body workout might just be the scent of 90 percent dark chocolate. A study published in Frontiers in Physiology on July 9, 2026 suggested that simply inhaling the aroma of dark chocolate before and during a training session can significantly boost muscular endurance, allowing lifters to push through more volume without swallowing a single calorie.

Want more reps? Sniff 90 percent dark chocolate before lifting. New study finds 18 extra leg extensions compared to control. (Freepik)

The experiment

Researchers recruited 23 resistance-trained young men to test how different scents affected performance during a leg-extension workout to failure. After fasting overnight, the lifters smashed out sets under three distinct conditions, sniffing a scent for 30 seconds before lifting and between sets:

⦿ 90 percent dark chocolate: Yielded an average of 18 more total repetitions and about one extra full set compared to the control group.

⦿ 60 percent milk chocolate: Yielded 9 more repetitions compared to the control group.

⦿ Water (control): Baseline performance.

How it works

While the exact biological pathways are still being mapped, researchers believe these sweet aromas trigger the cephalic phase response — the body’s anticipatory physical reaction to the mere smell or sight of food. Interestingly, the two types of chocolate seemed to hack the brain using completely different psychological mechanisms.

The 90 percent dark chocolate odour drove performance primarily by suppressing appetite, significantly reducing the lifters' hunger while boosting their feelings of fullness — a state of physical satiety that sports science has long linked to better training output.

In contrast, the 60 percent milk chocolate aroma did not curb appetite. Instead, it improved performance to a lesser degree by simply being highly pleasant, giving lifters an acute psychological boost that helped them power through those final, painful reps.

The reality check

Before you replace your smelling salts with a Hershey’s bar, experts urge a bit of cautious curiosity. "It is important to highlight that the improvements remain small and that you will not double your performance simply by using a smell," noted Marie-Eve Mathieu, PhD, a researcher at the Universite de Montreal who was not involved in the study, as per a July 9 Healthline.com article.

Furthermore, the study was small and strictly limited to young, experienced male lifters performing a single exercise after a 10-hour fast. Whether these findings translate to a fully fuelled, heavy squat session or apply to female athletes remains to be tested.

However, if you want to experiment, aromatherapy is a completely safe, low-stakes avenue to try. While dark chocolate is the newcomer to the sports science scene, Healthline.com reported several other everyday odours have been documented in a 2024 review by Marie-Eve Mathieu and colleagues to have modest benefits for athletes:

⦿ Peppermint: Linked to improved sprint times, push-up counts, and lower perceived effort.

⦿ Citrus: Boosts mood and overall well-being during intense cardio.

⦿ Ammonia: Common in powerlifting cages to spike acute neurological alertness.

⦿ Lavender: Used post-workout to lower anxiety and kickstart nervous system recovery.

It won't fix a bad diet or a poor program, but keeping a block of high-percentage dark chocolate in your gym bag just to sniff between sets might give you the edge you need to lock out those final few reps.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.