According to Franchomme & Pénöel (1990), clary sage oil is estrogen-like, due to its content of sclareol, which is said to be structurally similar to human estrogens. The sclareol content of clary sage oil is given as 1.6-7.0%. In gas chromatographic analyses of clary sage oil, a sclareol content of 0.1-0.4% is typical. However sclareol concentrations tend to be underestimated due to the very low volatility of the molecule, so 1.6-7.0% is probably reasonable. Clary sage absolute is a solid material, and contains about 70% sclareol, which is also solid.
Some of the more common Internet comments about the hormonal effects of clary sage oil include:
* Clary sage essential oil contains sclareol, which mimics the effects of estrogen.
* Sclareol has an estrogen-like structure, contributing to clary sage’s effectiveness in treating amenorrhea, cramps, and menstrual pain.
* Sclareol, a compound in clary sage, is not an estrogen, although it can mimic estrogen if there is an estrogen deficiency. If there is not an estrogen deficiency, sclareol will not create more estrogen in the body.
* Certain essential oils have phytoestrogenic activity. For example, sclareol, a constituent of clary sage, stimulates the body to produce its own estrogen.
* The high sclareol content gives clary sage essential oil its powerful action for relieving premenstrual tension in women as it has a balancing effect on hormones.
Note that four distinct claims are made in the above:
1) Clary sage/sclareol mimics the effects of natural estrogens.
2) Clary sage/sclareol mimics the effects of natural estrogens, but only if there is an estrogen deficiency.
3) Clary sage/sclareol stimulates the body to produce its own estrogen.
4) Clary sage/sclareol balances hormones.
Only the first of these is in line with the original statement made by Franchomme & Pénöel (1990). But is any of this supported by evidence? One of my first blogs was about parabens, and I made reference to the possibility that these chemicals might have estrogen-like effects. Many people avoid parabens for this very reason. Substances with such “hormone-disrupting” action are suspected of adversely affecting male fertility and breast cancer, among others.
So, let me pose an obvious question: if clary sage oil has an estrogen-like effect, and if you avoid parabens because you believe that they have estrogen-like effects, do you similarly avoid clary sage oil?
If you look at Dene Godfrey’s comment on The Paraben Parable you will see that butylparaben was indeed estrogen-like in an in vitro study, with an action 100,000 times weaker than estradiol. But one in vitro test tells us very little about in vivo effects. As for sclareol, I am aware of no research that has any bearing on a possible hormonal action.