The Clary Sage and Cortisol Study Explained

The "clary sage lowers cortisol" line traces to one 2014 paper in 22 menopausal women, and what that paper can support is narrower than the headline. Cortisol did fall after the women inhaled the oil. But the abstract describes no oil-free comparison group, the sample is small, and cortisol was a blood-chemistry outcome, not a measure of how anyone felt. Here is the paper, the two other clary sage inhalation trials we found, and what a reader can fairly take from them.

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The study in numbers

Lee, Cho and Kang, Phytotherapy Research, 2014, from the College of Pharmacy at Sookmyung Women's University in Seoul. The abstract reports:

The paper's own conclusion calls clary sage "antidepressant-like". We could read only the abstract; the publisher blocked the full text, and PubMed lists an erratum (Phytotherapy Research, December 2014) that we did not see. Where the abstract is silent, such as oil concentration, duration or any control condition, we cannot report it, and you should not assume it.

What a cortisol drop in 22 women does and does not tell you

Three reasoning steps, labelled as ours rather than the authors'.

  1. No control means no baseline for "sitting quietly". Cortisol follows a daily curve and drops when people rest, so a before-and-after fall after a calm session is expected even without an oil. The abstract describes a comparison between questionnaire groups, which tests who changed more, not whether the oil caused any change.
  2. Split 22 ways, each group is tiny. If the women divided evenly, each group is around 11. Differences such as 31% versus 16% come from handfuls of people, and the abstract does not give group sizes.
  3. Percent changes in the hundreds are a warning sign. A rise of 828% in a neurotransmitter measured in blood is far larger than a typical biological shift, which makes measurement noise and very low baseline values likelier explanations than an effect of that size. We cannot check that without the raw values; that is a reason for caution, not a finding of error.

A cortisol drop also is not a mood outcome. Whether a woman felt calmer was not what produced the "significant" result.

The other two clary sage inhalation trials

Seol et al., 2013. A double-blind randomized trial in 34 women with urinary incontinence undergoing urodynamic testing (Seol et al., Journal of Alternative and Complementary Medicine, 2013). Women inhaled 5% (vol/vol) clary sage, lavender or almond oil (the control) for 60 minutes. The clary group had a significant systolic blood pressure drop against control (p=0.048) and against lavender (p=0.026), and a respiratory rate drop against control (p<0.001). Salivary cortisol was measured, but the abstract reports no cortisol result, which is worth noticing given how the cortisol line circulates. Note that lavender trended in the other direction on blood pressure; the authors concluded lavender "may be inappropriate" for stress during that exam. With 34 women across three arms, about 11 per arm if evenly split.

Son et al., 2025. A randomized blinded trial in 72 patients with diabetic foot ulcers who inhaled 5% clary sage oil, 5% linalyl acetate or almond oil (Son et al., Frontiers in Medicine, 2025). Patients were split by depression level into six arms of 9 to 15 people. Against almond oil, clary sage reduced stress scores in the mild-depression group (the abstract reports p<0.05 and p<0.01 for its stress results), while linalyl acetate, one of clary sage's main constituents, reduced anxiety and depression scores in the moderate-to-severe group. The outcomes were visual analog scales, which are self-ratings, and the authors report no commercial conflicts.

Put side by side: three small trials in three different populations (menopausal women, women having a bladder test, patients with a chronic wound), three different outcome sets, only one of them cortisol. The only thing they share is the Korean research environment, and two of the three are from the same lead lab (Seol) that tested the oil. That does not invalidate them. It means no one outside has replicated the result, which is the evidence you would want before generalizing.

How to read a trial like this before you buy

Three questions sort most of these papers. Was there a control that smelled of something (almond oil in two of these, none described in the third)? How many people sat in each arm, not in the whole study? And what was measured: a blood level, a blood pressure, or how a person rated their own stress? A number such as p=0.048 on blood pressure in about 11 women per arm is a signal worth repeating, not a result to build a routine on. The lavender comparison in the 2013 trial is the best reminder: an oil that is popular for stress raised blood pressure compared with control in the same small study, which is what small trials do.

What this means for using our oil

These trials used inhalation at 5% (vol/vol) oil in a carrier for up to 60 minutes. Our pages give 0.5% to 2% in a carrier as the range for skin, and the two do not transfer: a trial's 5% was a vapour condition, not a skin recipe. We sell two clary sage oils, Botanical and Purity, undiluted, and we do not sell diffusers, so you would choose the device. Neither oil comes with a claim from us about stress. If you are experiencing persistent low mood or heightened anxiety, a physician or mental health professional is the right first stop, and a scent is not a substitute. Our stress and mood article and the menopause evidence review and the lavender comparison take the neighbouring questions; if the hormone angle is what brought you here, the estrogen piece traces that claim.

The fair reading is this: one small, uncontrolled-as-described paper found lower cortisol after inhalation, two small trials with controls found changes in blood pressure and self-rated stress in different groups, and nobody has yet shown any of it in a trial big enough to rely on. If you buy the oil, buy it as a scent. The studies do not support buying it to lower stress.

Clary Sage Essential Oil bottle

Clary Sage Essential Oil

Clary Sage Essential Oil from our own shop, in sizes from 0.5 oz to bulk.

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Sources & Further Reading