A Review of the “Estrogenic” Essential Oils: Clary Sage Oil Part I

Listen to Part I in less than 7 minutes below.

Listen to Part II in about 10 minutes below.

Many are confused about which essential oils to avoid or use for hormonal health. It’s no wonder.

There’s plenty of misinformation and over-hyped headlines. They are set as either intentional scare tactics or unintentional and unaccounted for biases, misinterpretations, and/or misrepresented inferences and generalizations.

For this reason, I wanted to start a series of articles that reviews the research, experts’ interpretations, and my conclusions on essential oils and hormonal balance. The focus will be on specific oils that are frequently associated with endocrine effects. I will make sure to be clear when I am stating my opinion and clinical experience.

In the introduction to hormonal effects of essential oils series (found here), I summarized my previous two-part series on the factors that proved that the latest report that lavender and tea essential oils were “endocrine disruptors” was not true. Understanding them is applicable to understanding the hormonal impact of specific essential oils and in helping to decipher the facts from the fiction of essential oils in the media.

I encourage you to read through them and to review the safety and usage information I provided in the same article. (Link here) Having this background will allow you to make informed and educated decisions on what is best for your body and it will give you with resources for your health care providers who may be monitoring your medications.

Now, I will begin with Clary Sage, aka “bright eyes.”

Clary Sage Oil and Hormonal Effects

Clary Sage is a member of the Salvia genus which is in the family Lamiacae (mint) and contains over 900 species. Sage species have been cultivated worldwide and have a history of use as folk medicine and for culinary purposes. Due to the differences between species and their constituents, the applications may vary depending on sourcing and quality of the essential oils or herb. (source)

There are even variations in constituents found within the same species and plant itself due to the production of clary sage and the part used for extraction (flower, leaves, or glandular structures). For this reason, it is important to trust the source and quality of the essential oil of clary sage. One study states:

The Lamiaceae is rich in aromatic plant species. Most of these species produce and store essential oils in specialised epidermal oil glands, which are responsible for their specific flavour. Two types of glands producing essential oil and possessing different morphological structure can be found in Salvia sclarea: peltate and capitate glands. The content of single oil glands from different positions on the plant (corolla, calyx and leaf) were sampled using an SPME fibre and analysed by gas chromatography in order to study variability of the essential oil composition. It was found that the composition of terpenoids is quite variable within an individual plant. Capitate oil glands mainly produce three essential oil compounds: the monoterpenes linalool and linalyl acetate, and the diterpene sclareol. Peltate oil glands, however, accumulate noticeable concentrations of sesquiterpenes and an unknown compound (m/z = 354). Furthermore, the oil composition varies within each gland type according to the plant organ. Linalool and linalyl acetate are characteristic substances of flowers, whereas the sesquiterpenes occur in higher proportions in leaves. Even within one gland type on a single leaf, the chemical variability is exceedingly high.(source)

Clary sage is often thought of in relationship to hormonal balance due to specific compounds present (which will be reviewed below). (source, source, source, source, source) Although it is believed that clary sage can increase estrogen, the results have not been conclusive. One 2017 study tested ten essential oils to evaluate salivary estrogen level after inhalation. The researchers found that with olfaction of clary sage, frankincense, geranium, lavender, jasmine absolute, neroli, rose otto, ylang ylang, orange and roman chamomile in premenopausal woman, only rose otto and geranium influenced salivary estrogen. The abstract does not provide information on quality, sourcing, and standardization of these oils. (source, source)

If we look back to our list of factors to consider from the introduction, it’s important to remember the following before using this one study to purchase click rose otto and geranium in order to “raise estrogen”:

1. There is a difference between synthetic estrogens and phytoestrogens. The later are known for their modulating effects of hormones, not manipulating them.
2. The extraction or distillation method of clary sage oil would affect individual constituents that are present, effecting outcomes. (source)
3. Essential oils will have differing effects in individuals based on their own metabolome (source).
4. The complexity of hormonal testing (please review the caveats and pitfalls here), individual variations in hormonal detoxification and metabolism, and lifestyle all impact hormonal levels.

For this reason, it’s very hard to extrapolate that one essential oil will have the same effect in all women, even though generalizations can be made. One study showed how clary sage effected women differently in pregnancy. In a pilot, quasi-experimental design, researchers sought to determine the effect of inhalation of this oil on oxytocin levels. The trial was confounded in the quality and applicability since clary sage was diluted in propylene glycol. Regardless, it demonstrated the differing effects based on the individual, its safety, and the potential placebo effects. The authors stated:

Participants were women of singleton pregnancies between 38 and 40 gestation weeks (N = 11). The experiment group (n = 5) inhaled the scent of clary sage essential oil diluted 50-fold with 10 mL of odorless propylene glycol for 20 min. Regarding limited efficacy, the oxytocin level 15 min postinhalation increased in 3 women and was unmeasurable in 2. The control group (n = 6) inhaled similarly without the 50-fold dilution of clary sage essential oil. Their oxytocin level increased in 2 women, decreased in 2, and was unmeasurable in 2. Uterine contraction was not observed in both groups. Regarding practicality, 3 of the 11 women could not collect sufficient saliva. The cortisol level decreased in both groups postinhalation. The protocol had no negative effects. Regarding acceptability, burden of the protocol was not observed. (source)

The Sclareol, Scare-All Hype: The “Clary-ifying” Difference Between Isolated Constituents and the Synergism of Essential Oils

Often, clary sage is said to be “estrogenic,” related to one component, sclareol. As mentioned above, depending on the source, extraction, and plant part used, this constituent could be or could not be present in clary sage oils in varying quantities.

In Robert Tisserand’s review of clary sage, he states:

Therefore, on the basis of its structure, sclareol is unlikely to have any estrogenic action. Even if sclareol was estrogenic, at about 4% of clary sage oil, it would have to have a very high binding affinity for estrogen receptor sites for the essential oil to have any effect, and this is extremely unlikely.

This does not mean that clary sage oil is not effective. It may well be useful in relieving menstrual pain, pre-menstrual symptoms, menopausal symptoms and other problems, but none of this necessitates an estrogen-like action. And, I’m not saying that sclareol could not possibly be estrogen-like, I’m just saying there’s no evidence that it is, nor does its structure suggest such an effect. This also means that there’s no evidence to support clary sage oil “balancing hormones”, mimicking estrogens only if there is an estrogen deficiency, or stimulating the body to produce natural estrogens. (source)

Sclareol has; however, been studied in vitro to have antitumor activities. (source, source) The above article continues:

Sclareol does have an interesting anticancer activity, including in vitro action against human breast cancer MCF-7 cells (Dimas et al 2006). An isomer, 13-epi-sclareol, which is also present in clary sage oil, inhibits the growth of breast and uterine cancers in vitro, and was slightly more potent than Tamoxifen, but was not toxic to normal cells (Sashidhara et al 2007). This suggests the possibility that sclareol might actually inhibit estrogen, and might after all have some capacity to interact with estrogen receptor sites. What we do know is that sclareol will not give you breast cancer. (source)

There is a subtle difference in wording here that needs to be highlighted.

Essential oils are not estrogen-like molecules; however, due to their synergism, they may act in other means to modulate and balance hormones in some women. This does not mean they are “hormone mimickers,” rather, their overall properties assist with balancing the physical, biochemical, and emotional aspects of the individual.

My Opinion, Clinical Experience, and Summary

As stated below, they act holistically. Several clinical trials have reported effects on endocrine issues, which I will highlight in Part II.

Below is an explanation of how essential oils accomplish this hormonal and stress modulation in a holistic way:

Usually, a psychological action also has a physiological or biochemical impact on the body. For example, hormonal support could be provided by calming emotion from inhalation, effecting stress hormones or enzymes, and providing direct physiological effects as a result of phytoesterogens modulating estrogen levels. (possibly)

Next week, I’ll conclude with Part II in my review of clary sage in my review of the “estrogenic” essential oils. I will summarize several clinical studies that support the use of clary sage oil in menopause, premenstrual discomfort, and labor. I will also briefly discuss some additional actions of clary sage oil.

I know, there’s a lot of information here! This is why I’m breaking it in up parts!

Understanding the impact of essential oils on hormones is a popular topic, and it’s not straightforward. It’s not supposed to be scary either. I’ll repeat some things, so that learning can be optimized.

This weekend, I’ll summarize what we learned so far for our oily tip in this post and previous posts on hormonal health.

Many blessings from my heart to yours!

This material is for information purposes only and is not intended to diagnose, treat, or prescribe for any illness. You should check with your doctor regarding implementing any new strategies into your wellness regime. These statements have not been evaluated by the FDA. (Affiliation link.)

Disclaimer: This information is applicable ONLY for therapeutic quality essential oils. This information DOES NOT apply to essential oils that have not been tested for purity and standardized constituents. There is no quality control in the United States, and oils labeled as “100% pure” need only to contain 5% of the actual oil. The rest of the bottle can be filled with fillers and sometimes toxic ingredients that can irritate the skin. The studies are not based solely on a specific brand of an essential oil, unless stated. Please read the full study for more information.

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