Faradiol in Calendula: What the Research Does and Doesn't Show

Faradiol is the compound most often named when people explain why calendula is studied for skin, and it is real, measured and well documented in the flower. What nobody has published, as far as we could find, is how much of it ends up in an infused oil, or whether an infused oil does anything on human skin because of it. This page walks up the evidence one step at a time and marks the step where it stops.

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Step 1: faradiol esters are in the flower, and mostly in the petals

Faradiol is a triterpene diol, and in the plant it is mostly attached to fatty acids as esters. A 2025 study in Nature Communications found these triterpene fatty-acid esters "exclusively" in floral tissue, with about 8 times more in ray florets (the petals) than in disc florets. In ray florets, faradiol myristate was 13.18 mg/g dry weight and faradiol palmitate 12.46 mg/g; faradiol esters made up 77% of the triterpene esters, and none were detected in leaf or root (Golubova et al., Nat Commun, 2025). That is one cultivar grown under one set of conditions, measured in dried petals, so treat the figures as a reference point and not a standard. Older textbook values, as quoted in the EU assessment report, put triterpene diols (mostly faradiol and arnidiol mono-esters) at roughly 4% of the herb (EMA assessment report, 2008, superseded). The two sources differ in basis and method, and we do not try to reconcile them: the 2025 myristate and palmitate figures together come to about 2.5% of dried ray florets, so the true range depends on cultivar, plant part and assay.

This is a fact about the plant that sits alongside our process: we infuse petals separated by hand from sound, whole-dried flower heads, not broken florets. We are not claiming that this puts a measured amount of faradiol in our oil, because we have not measured it and do not state one. It is a reason the petal is the part worth separating, since that is where the 2025 data put the esters.

Step 2: in mice, faradiol compounds reduced induced ear swelling

In a 1994 study, fractions of a calendula CO2 extract were tested topically, and the faradiol monoester was judged most relevant because of how much of it there was; the activity of different extracts tracked their faradiol-ester content, and the authors suggested it as a quality marker. Free faradiol, which is not present in the extract, was the most active compound tested (Della Loggia et al., Planta Medica, 1994; abstract only). In 1997, isolated faradiol-3-myristate and faradiol-3-palmitate reduced croton-oil-induced swelling in mouse ears in a dose-dependent way, with nearly the same activity for both and no synergy between them; the free alcohol was more active than the esters (Zitterl-Eglseer et al., J Ethnopharmacol, 1997; abstract only).

Read that carefully. These were animal studies of isolated compounds or a CO2 extract, using an acute irritant swelling model. They tell us which constituents carry activity in that model. They do not tell us what an oil infusion does, and they were not done on people.

Step 3: from flower to oil is the gap

Here is the step the popular articles skip. Faradiol esters are fat-soluble, so it is plausible that some move into an oil during infusion; that is our reasoning, not a finding. We found no published measurement of faradiol esters in a calendula-infused oil at any defined ratio, time or temperature. The study that comes closest to testing extraction compared supercritical CO2 with solvent ultrasound, not oil: ultrasound recovered between 10.4% and 23% of the faradiol esters the CO2 process did, depending on solvent (Atwi-Ghaddar et al., Molecules, 2023). If a CO2 route beats ordinary solvent extraction by that margin, it is reasonable to suspect that extraction conditions would change how much faradiol reaches an oil, but that remains a suspicion.

So anyone who tells you their infused oil "contains X% faradiol" either ran an HPLC assay on that oil and can show you the report, or is repeating the flower numbers. Laboratories typically fingerprint faradiol esters by reversed-phase HPLC with UV detection near 210 nm (Olennikov and Kashchenko, Molecules, 2022). If a seller cites a faradiol number, ask which method, which lot and who ran it.

Our own batch documentation covers physical assays, chemical assays and contaminant screening by independent third-party labs, available on request when you email the lot number to [email protected]. We do not state a faradiol content for our oil and have not published one. If you need a faradiol assay for a formulation, ask us before you buy; do not assume it from this article.

Step 4: human skin, where faradiol was never the variable

The human trials people cite involved ointments and creams, and none of the ones we reviewed measured faradiol in what was applied. In a 2004 French trial of 254 women having breast radiotherapy, 41% of those using a calendula ointment had grade 2 or worse dermatitis against 63% of those using trolamine (P<.001); the comparator was not a placebo, and the ointment was made from fresh aerial parts in petroleum jelly, not from flowers alone (Pommier et al., J Clin Oncol, 2004). A blinded Swedish trial of 411 women compared a calendula cream with a standard cream and found no significant difference: severe reactions were 23% against 19% (Sharp et al., Eur J Oncol Nurs, 2013). Mixed results, different preparations, no faradiol assay. That is the honest state of the human evidence, and it is why we do not tie any outcome to faradiol or to our oil.

What this should change in how you buy

The science of faradiol is interesting, and we would like it to be tested in oil. Until it is, the accurate sentence is that faradiol esters are a documented constituent of the calendula flower, and that what an oil infusion carries of them is unmeasured in the literature we reviewed.

Calendula oil bottle

Calendula Oil

Nature's Golden Botanical, bottled: small-batch calendula oil in sizes from 0.5 oz to bulk.

From $13.99

Shop Calendula Oil →

Sources & Further Reading