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Just Smelling Coffee May Change Your Mood And Brain Activity : ScienceAlert (opens in a new tab)

sciencealert.com · 2026-09-17

Short answerEvidenceSource

Short answer

Mixed

Mixed.

The claims we could check match the study, but some claims were not covered by the evidence reviewed.

  • 3 supported
  • 3 not covered

Checked against the study summary. The full text wasn't available, so some details couldn't be settled either way.

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Follow the evidence trail
1
2

NewsLink checks it

Mixed

Every claim we could check holds up. Three of six claims match the study. This overall rating is based only on the claims we could check. Three claims the study doesn't address.

  • 3 supported
  • 3 not covered
Open claim evidence
3
Then inspect each claim

Evidence layer

Claim by claim

Each claim gets a verdict. Expand it to see the evidence directly below.

6 claims in this story

Showing all 6 claimsChoose a verdict to focus the list.

Claim 1 of 6Not coveredTheir study, published in Nutrients, involved 20 university students aged 20 to 29 who sat beside freshly brewed coffee without drinking it.View evidenceHide evidence

As stated20 university students aged 20 to 29

Why this verdict

The abstract-level profile supports the core sample size and age range—20 healthy adults aged 20–29—and 5-minute coffee aroma exposure. However, it does not verify several story specifics: that participants were university students, that the coffee was freshly brewed, that they sat beside it, that they did not drink it, or the publication venue beyond the DOI/profile context.

1

Study evidence

Total Mood Disturbance decreased after 5-minute coffee aroma exposure.mean change = −20.54 (95% CI −30.65 to −10.43); Cohen’s dz = −0.95

“Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min.”
Claim 2 of 6Not coveredAfter adjustment for multiple comparisons, reductions in fatigue, tension and anxiety, confusion, and depression and dejection remained significant, but vigor did not increase significantly.View evidenceHide evidence

Why this verdict

The profile supports significant Holm-adjusted reductions in Fatigue, Tension–Anxiety, Confusion, and Depression–Dejection. However, at abstract depth it does not provide enough detail to verify the stated result for Vigor specifically, so the full claim is not verifiable at this depth.

1

Study evidence

Total Mood Disturbance decreased after 5-minute coffee aroma exposure.mean change = −20.54 (95% CI −30.65 to −10.43); Cohen’s dz = −0.95

“Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min.”
Claim 3 of 6Not coveredThe biggest limitation was that there was no control condition, so the researchers could not determine whether coffee itself caused the changes.View evidenceHide evidence

Why this verdict

The profile supports that the study lacked a randomized/non-exposed control condition and that this limits causal inference about whether coffee aroma caused the observed pre–post changes. However, the story’s superlative framing that this was the “biggest” limitation is not ranked or otherwise verified in the abstract-level profile.

1

Study evidence

Total Mood Disturbance decreased after 5-minute coffee aroma exposure.mean change = −20.54 (95% CI −30.65 to −10.43); Cohen’s dz = −0.95

“Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min.”
2

Study evidence

EEG-derived relaxation index increased following a 5-minute coffee aroma exposure in a within-subject pre–post sample of 20 healthy adults (mean change = 0.0378; 95% CI 0.0248–0.0508).Cohen’s dz = 1.36; mean change = 0.0378 (95% CI 0.0248–0.0508)

“This exploratory study used a multimodal approach to assess subjective mood, electroencephalographic (EEG) activity, heart rate (HR), and heart rate variability (HRV) following short-term coffee aroma exposure.”
Claim 4 of 6SupportedResearchers at Showa Pharmaceutical University in Japan investigated whether the smell of coffee alone can change mood and brain activity.View evidenceHide evidence

Why this verdict

The abstract-level profile supports that the researchers assessed whether 5-minute coffee aroma exposure was followed by short-term changes in subjective mood and EEG-derived cortical activity. The claim is framed as what the researchers investigated, not as a proven causal effect.

1

Study evidence

Total Mood Disturbance decreased after 5-minute coffee aroma exposure.mean change = −20.54 (95% CI −30.65 to −10.43); Cohen’s dz = −0.95

“Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min.”
2

Study evidence

EEG-derived relaxation index increased following a 5-minute coffee aroma exposure in a within-subject pre–post sample of 20 healthy adults (mean change = 0.0378; 95% CI 0.0248–0.0508).Cohen’s dz = 1.36; mean change = 0.0378 (95% CI 0.0248–0.0508)

“This exploratory study used a multimodal approach to assess subjective mood, electroencephalographic (EEG) activity, heart rate (HR), and heart rate variability (HRV) following short-term coffee aroma exposure.”
Claim 5 of 6SupportedWithin 5 minutes, participants reported fewer negative feelings and showed a shift in an EEG-derived index linked to relaxation, while heart measures appeared unchanged.View evidenceHide evidence

As statedwithin 5 minutes

Why this verdict

The profile reports that after 5-minute coffee aroma exposure, mood disturbance and several negative POMS subscales decreased, the EEG-derived relaxation index increased, and HR/HRV showed no statistically significant changes. The story’s hedged associational framing matches the single-group pre–post evidence.

1

Study evidence

Total Mood Disturbance decreased after 5-minute coffee aroma exposure.mean change = −20.54 (95% CI −30.65 to −10.43); Cohen’s dz = −0.95

“Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min.”
2

Study evidence

EEG-derived relaxation index increased following a 5-minute coffee aroma exposure in a within-subject pre–post sample of 20 healthy adults (mean change = 0.0378; 95% CI 0.0248–0.0508).Cohen’s dz = 1.36; mean change = 0.0378 (95% CI 0.0248–0.0508)

“This exploratory study used a multimodal approach to assess subjective mood, electroencephalographic (EEG) activity, heart rate (HR), and heart rate variability (HRV) following short-term coffee aroma exposure.”
Claim 6 of 6SupportedThe article says the result shows a change in a calculated EEG index, not proof that coffee aroma relaxed the brain, and notes that mood and EEG changes were not significantly correlated at the individual level.View evidenceHide evidence

Why this verdict

The profile supports that the EEG result concerns an EEG-derived relaxation index rather than direct proof of brain relaxation, and it notes important limitations around the index and the uncontrolled exploratory design. The profile also supports that exploratory cross-domain analyses found no significant associations among individual changes in subjective, cortical, and cardiovascular measures.

1

Study evidence

EEG-derived relaxation index increased following a 5-minute coffee aroma exposure in a within-subject pre–post sample of 20 healthy adults (mean change = 0.0378; 95% CI 0.0248–0.0508).Cohen’s dz = 1.36; mean change = 0.0378 (95% CI 0.0248–0.0508)

“This exploratory study used a multimodal approach to assess subjective mood, electroencephalographic (EEG) activity, heart rate (HR), and heart rate variability (HRV) following short-term coffee aroma exposure.”
2

Study evidence

Exploratory cross-domain analyses identified no significant associations among individual pre–post changes in subjective mood (POMS), an EEG-derived relaxation index, heart rate, and heart rate variability.

“Effect sizes, 95% confidence intervals (CIs), and exploratory cross-domain correlations were also examined.”
Then look for missing context

Context layer

What the story left out

Important study details the story did not include.

  • Short-term exposure and immediate assessment: durability of effects beyond the brief 5-minute exposure is unknown.

    The story reports the 5-minute timing, but its listed caveats do not explicitly acknowledge that longer-term or durable effects were not assessed.

    From single-group within-subject pre–post exposure (human); within-subject pre–post; within-subject pre–post

9 things the story did carry across
  • Single-group within-subject pre–post design with 20 healthy young adults aged 20–29 exposed to coffee aroma for 5 minutes.
  • Subjective mood finding: Total Mood Disturbance and several negative POMS subscales decreased after exposure; Fatigue, Tension–Anxiety, Confusion, and Depression–Dejection remained significant after Holm adjustment.
  • EEG finding: an EEG-derived relaxation index increased after 5-minute coffee aroma exposure.
  • Cardiovascular finding: no statistically significant changes were detected in heart rate or heart rate variability.
  • Exploratory cross-domain analyses found no significant associations among individual changes in mood, EEG-derived relaxation index, HR, and HRV.
  • Major causal-inference limitation: no randomized, sham, or non-exposed control condition was reported; the single-group pre–post design cannot establish that coffee aroma caused the changes.
  • Small sample size limits precision and statistical power.
  • Generalizability limitation: participants were healthy young adults aged 20–29, limiting applicability to other ages or clinical populations.
  • EEG-method limitation: abstract-level profile lacks detailed EEG acquisition, signal-processing methods, and validation/definition of the relaxation index.
Then read the study layer

Study layer

Study at a glance

Scan the study first. Expand only the parts you want to inspect.

Pieces of work

4

Evidence read

study summary

Lead result

human in vivo

1Lead resulthuman in vivoAssess whether a brief (5 min) coffee aroma exposure produces short-term changes in subjective mood in healthy young adults (pre–post within-subject).single-group within-subject pre–post exposure (human)Expand

In plain English

Single-group, within-subject pre–post study in 20 healthy adults (ages 20–29) found that 5-minute coffee aroma exposure was followed by reductions in Total Mood Disturbance (mean change −20.54, 95% CI −30.65 to −10.43; Cohen’s dz = −0.95) and significant reductions in several POMS subscales after Holm correction (Fatigue, Tension–Anxiety, Confusion, Depression–Dejection). Paired t-tests with Holm adjustment, effect sizes, and 95% CIs were reported.

Key findings

  • Total Mood Disturbance decreased after 5-minute coffee aroma exposure.mean change = −20.54 (95% CI −30.65 to −10.43); Cohen’s dz = −0.95
  • Several POMS subscales (Fatigue, Tension–Anxiety, Confusion, Depression–Dejection) were significantly reduced after Holm adjustment.
“Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min.”
What this piece can’t prove
  • Small sample size (n = 20).
  • Exposure was brief (5 minutes) and outcomes were assessed short-term; durability of effects unknown.
  • Participants were healthy young adults (20–29 years), limiting generalizability to other ages or clinical populations.

2 further details could not be confirmed from the summary.

2human in vivoAssess whether the same coffee aroma exposure produces short-term changes in cortical activity measured by EEG (e.g., an EEG-derived relaxation index).within-subject pre–postExpand

In plain English

In a single-group, within-subject pre–post study of 20 healthy adults (age 20–29) exposed to coffee aroma for 5 minutes, an EEG-derived relaxation index increased from pre- to post-exposure (mean change = 0.0378, 95% CI 0.0248–0.0508; Cohen’s dz = 1.36) on paired pre–post comparison.

Key findings

  • EEG-derived relaxation index increased following a 5-minute coffee aroma exposure in a within-subject pre–post sample of 20 healthy adults (mean change = 0.0378; 95% CI 0.0248–0.0508).Cohen’s dz = 1.36; mean change = 0.0378 (95% CI 0.0248–0.0508)
“This exploratory study used a multimodal approach to assess subjective mood, electroencephalographic (EEG) activity, heart rate (HR), and heart rate variability (HRV) following short-term coffee aroma exposure.”
What this piece can’t prove
  • Single-group, within-subject pre–post design without a control or sham condition limits causal inference.
  • Small sample of 20 healthy young adults (age 20–29) limits generalizability and precision.
  • Exploratory study; multiple outcomes assessed (multimodal) and some domain-specific adjustments (e.g., Holm) were applied to mood subscales but not reported for EEG.
  • Abstract lacks detailed EEG acquisition and signal-processing methods and the exact definition/validation of the relaxation index.
  • Findings pertain to short-term (5-minute) exposure only.
3human in vivoAssess whether the same coffee aroma exposure produces short-term changes in cardiovascular physiology (heart rate and heart rate variability).within-subject pre–postExpand

In plain English

In a single-group within-subject pre–post study (20 healthy adults, 20–29 years) with 5-minute coffee aroma exposure, heart rate (HR) and heart rate variability (HRV) were measured before and after exposure. Paired t-tests showed no statistically significant pre–post changes in HR (Cohen’s dz = 0.19) or HRV (Cohen’s dz = 0.13) as reported in the abstract.

Key findings

  • No statistically significant pre–post change in heart rate following 5-minute coffee aroma exposure in 20 healthy adults.Cohen’s dz = 0.19
  • No statistically significant pre–post change in heart rate variability following 5-minute coffee aroma exposure in 20 healthy adults.Cohen’s dz = 0.13
“This exploratory study used a multimodal approach to assess ... heart rate (HR), and heart rate variability (HRV)”
What this piece can’t prove
  • Single-group within-subject pre–post design without a control condition as reported in abstract.
  • Short exposure duration (5 minutes); abstract does not report timing of cardiovascular measurements relative to exposure onset/offset.

2 further details could not be confirmed from the summary.

4human in vivoExplore whether individual pre–post changes in mood, EEG, and cardiovascular measures are correlated across domains (cross-domain associations).exploratory change-score correlation analysisExpand

In plain English

Exploratory cross-domain correlation analyses tested whether individual pre–post changes in mood (POMS), an EEG-derived relaxation index, heart rate, and heart rate variability were associated in 20 healthy adults; the analyses identified no significant associations among these change scores.

Key findings

  • Exploratory cross-domain analyses identified no significant associations among individual pre–post changes in subjective mood (POMS), an EEG-derived relaxation index, heart rate, and heart rate variability.
“Effect sizes, 95% confidence intervals (CIs), and exploratory cross-domain correlations were also examined.”
What this piece can’t prove
  • Small sample size (n = 20) limits precision and power to detect associations.
  • Null findings may reflect limited power or reporting limitations rather than definitive absence of associations.

3 further details could not be confirmed from the summary.

Finally, the search trail

Method layer

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Open the paper in Tessa

Short-Term Psychological and Physiological Changes Following Coffee Aroma Exposure: A Multimodal Assessment

Nutrients · 2026

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Why this one

Near certain

NewsLink found the paper. Tessa is where you inspect it deeply.

Papers considered

The selected paper, plus nearby candidates.

Crossref, PubMed, Europe PMC · 16 candidate papers

Selected

Short-Term Psychological and Physiological Changes Following Coffee Aroma Exposure: A Multimodal Assessment

Nutrients · 2026 · Crossref

Source (opens in a new tab)
Candidate

Evaluation of human electroencephalogram change for sensory effects of fragrance.

Skin Research and Technology : Official Journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) · 2019 · PubMed

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And 10 more candidates considered.