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Possibly, but only in a very narrow, preliminary setting. A 2026 randomized, double-blind crossover study found that prepared dark- and milk-chocolate odors were associated with more repetitions during a fasted leg-extension test in 23 trained men. That result does not show that smelling chocolate reliably improves workouts, endurance, strength, or sports performance in general.
What the chocolate-odor study tested
Fan and colleagues conducted an exploratory proof-of-concept trial with 23 healthy men aged 18 to 30. Every participant was moderately resistance trained, completing at least two training sessions per week for two years or longer. The crossover design meant each man completed the exercise protocol under all three odor conditions, with the order randomized. Participants and the people counting repetitions were blinded to coded conditions.
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| Condition | What participants smelled | Exposure timing |
|---|---|---|
| Dark chocolate | A preparation made from commercial 90% cocoa chocolate, distilled water and propylene glycol | 30 seconds before each set |
| Milk chocolate | A preparation combining dark chocolate, whole milk, water and propylene glycol; the chocolate component was 60% cocoa | 30 seconds before each set |
| Control | A water-based preparation containing propylene glycol | 30 seconds before each set |
The study was registered as CHOCO-PERF in the UMIN Clinical Trials Registry. The registry describes a randomized, double-blind, crossover trial of chocolate odors, appetite perception and resistance-exercise performance in the fasted state. The article reports that the protocol was preregistered with OSF and retrospectively registered with UMIN on November 4, 2025.
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The exercise protocol
Participants arrived after an overnight fast and performed repeated leg-extension sets at 80% of their individually tested 10-repetition maximum. They rested 3.5 minutes between sets and continued until volitional exhaustion. The odor was presented before every set. This is a tightly defined laboratory test of repeated volume in one single-joint lower-body movement; it is not a test of a complete workout, maximal strength, running, cycling, competition performance or training adaptation.
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What the researchers observed
Both chocolate odors produced more total repetitions than the water control under this exact protocol. The dark-chocolate condition produced 18 more repetitions than water, with a 95% confidence interval of 13.8 to 22.1 repetitions. The milk-chocolate condition produced nine more repetitions than water. These are group results from 23 men completing a specific fasted leg-extension test, not a prediction that an individual will automatically gain 18 or nine repetitions.
| Measure | Dark-chocolate odor | Milk-chocolate odor | Water control |
|---|---|---|---|
| Total repetitions | 18 higher than water; 95% CI 13.8–22.1 | 9 higher than water | Reference condition |
| Total sets | One more set than water; one more set than milk chocolate | Not stated as higher than water for this comparison | Reference condition |
| Perceived exertion | Rose as sets progressed; no clear condition difference | Rose as sets progressed; no clear condition difference | Rose as sets progressed; no clear condition difference |
| Before-exercise appetite ratings | Lower hunger, desire to eat and prospective food consumption; higher fullness | Not the strongest appetite-suppression pattern | Reference condition |
| Odor pleasantness | Lower than milk chocolate | Rated more pleasant | Reference condition |
The researchers also reported one additional set for dark chocolate compared with water and one additional set for dark chocolate compared with milk chocolate. Ratings of perceived exertion increased as participants accumulated sets, but the post-set RPE measure did not clearly differ between odor conditions. That finding means the trial did not detect a condition difference in that particular effort rating; it does not prove that odors cannot affect fatigue, motivation or other aspects of effort.
How strong is an extra 18 repetitions?
The numerical difference looks large because it is a total across repeated sets, not 18 extra repetitions on one isolated set. It also comes from a small sample and a controlled protocol in which each participant experienced every condition. Crossover studies can improve statistical efficiency because participants serve as their own comparison, but they do not eliminate learning effects, day-to-day readiness, nutrition, sleep or the possibility of an unusual response in a small group.
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Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →The 95% confidence interval for the dark-versus-water difference, 13.8 to 22.1 repetitions, describes uncertainty around the study’s estimated average effect under its protocol. It is not a personal performance range and should not be converted into a promised percentage improvement. The milk-chocolate result was smaller than the dark-chocolate result, yet it still exceeded water on total repetitions. The study did not establish a dose-response relationship between cocoa percentage and performance.
Did appetite or pleasantness cause the performance change?
Dark chocolate reduced self-reported hunger, desire to eat and prospective food consumption before exercise while increasing fullness. Milk chocolate was judged more pleasant. Those observations suggest that odor-related appetite or reward responses might be relevant, but they do not identify a mechanism.
The authors conducted exploratory mediation analyses and did not establish hunger, fullness or pleasantness as causal explanations for the performance differences. As the study conclusion states: “However, exploratory mediation analyses did not establish hunger, fullness, or pleasantness as explanatory mechanisms for the performance differences.” The trial also did not measure hormones, blood glucose, muscle metabolites, brain activity, oxygen uptake or other objective physiological pathways that could explain a change in exercise capacity.
Several mechanisms are therefore possible but unproven. A familiar food odor could alter expectations, attention, arousal, reward processing or willingness to continue. It might also change how a fasted participant interprets appetite or discomfort. None of those possibilities should be presented as the demonstrated reason for the extra repetitions.
Why the finding does not generalize to every workout
Small and homogeneous sample
Only 23 young, healthy, resistance-trained men took part. The findings may not transfer to women, older adults, adolescents, beginners, people with medical conditions, elite athletes or people with different sensory or appetite responses. A statistically detectable result in this group is not evidence that the same effect exists across the broader exercising population.
One exercise and one training state
The test used a single-joint leg-extension movement at 80% of a tested 10-repetition maximum. It took place after an overnight fast. Results could differ during fed training, compound lifts, upper-body exercise, intervals, endurance sessions, field sports or competition. The paper itself says that the findings primarily apply to resistance-exercise volume in this specific lower-limb task.
Unstandardized odor delivery
The odors were liquids presented in jars rather than delivered with precision olfactometry. That limits control over concentration, distance, evaporation and the amount each person actually inhaled. The preparation also contained propylene glycol in all three stimuli, so the experiment tested those coded mixtures, not the smell of an ordinary chocolate bar in a standardized consumer setting.
No long-term outcome
The study measured performance during individual laboratory sessions. It did not show larger gains in muscle, strength, fitness, body composition or training adherence over weeks or months. It also did not test whether repeated chocolate-odor exposure loses its effect through habituation.
One direct human trial is not replication
The available direct evidence is this recent exploratory trial. Reviews and adjacent studies about eating chocolate, cocoa compounds, food odors or exercise cannot be substituted for a replication of smelling chocolate during the same kind of workout. No independent consensus estimate or professional-body recommendation establishes chocolate odor as an ergogenic aid.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Smelling chocolate is not the same as eating it
The intervention was olfactory exposure, not chocolate consumption. Participants did not receive calories, carbohydrates, caffeine or cocoa flavanols from eating a bar before exercising. Therefore, the results cannot support claims that eating chocolate improves workout performance, that cocoa supplements reproduce the effect, or that a retail scent product has been validated.
A 90% cocoa chocolate bar is relevant only as an ingredient comparable to the dark-chocolate preparation used by the investigators. The study melted commercial chocolate and mixed it with water and propylene glycol to make a liquid sample. It did not test a bar as a food supplement, establish an effective serving size, or compare chocolate ingestion with carbohydrate or placebo nutrition.
Should you try smelling chocolate before training?
There is no validated consumer protocol, concentration, timing schedule or product standard to recommend. If you are curious, treat it as a personal observation rather than a performance intervention and keep ordinary training safeguards in place.
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1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minute- Do not replace fueling when fueling is needed. The study used an overnight fast, so it does not show that odor can substitute for food, fluids or carbohydrates during demanding training.
- Use a familiar food odor only in a safe, ventilated setting. Do not inhale concentrated fragrance oils or laboratory ingredients, and do not reproduce the study’s propylene-glycol mixture without appropriate expertise.
- Keep the workout comparable. If you compare sessions, hold exercise order, load, rest periods, warm-up, sleep and meal timing as constant as practical.
- Record more than repetitions. Note sets completed, RPE, mood, hunger, nausea and any symptoms. A single unusually good or bad session cannot establish an effect.
- Stop if the odor causes symptoms. People with asthma, migraine triggers, fragrance sensitivity, nausea or allergy concerns should avoid an exposure that worsens symptoms and seek medical advice when appropriate.
Even a repeated personal response would not demonstrate that the odor works for other people or that it improves long-term results. Established training variables—progressive overload, adequate recovery, appropriate nutrition and consistent programming—remain the factors with far stronger practical support.
What future studies need to answer
More convincing evidence would require preregistered, adequately powered trials with women and men of different ages and training levels. Researchers should test fed and fasted conditions, multiple exercises and endurance tasks, and standardized odor concentrations delivered by calibrated equipment. Blinding checks could determine whether participants guessed the chocolate condition. Objective measures of appetite, metabolism, arousal and neuromuscular fatigue could test proposed pathways, while repeated sessions would show whether any response persists or fades.
Replication is especially important because the current result combines a small sample, one laboratory task and a relatively unusual odor-delivery method. Until independent studies reproduce the finding and clarify who responds, the most defensible description is an intriguing signal—not a proven workout hack.
Bottom line
In the 2026 Fan et al. trial, smelling prepared 90% dark-chocolate or 60% milk-chocolate odors before sets was associated with more total repetitions than smelling a water control during a fasted leg-extension test in 23 trained men. Dark chocolate showed the larger difference, while milk chocolate was rated more pleasant. The study did not establish why performance differed, did not test eating chocolate, and does not justify general claims about improved workouts. For now, smelling chocolate is an interesting experimental finding, not a reliable or validated performance aid.
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