🌿 Aromatic Plants

THYME THYMOL Thymus vulgaris L. and Thymus zygis L.

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🌿 Thyme oil thymol type 🌿 Plants the name covers ⚗️ Part of the plant distilled 🧬 Composition of the oil 🌿 Standards and registers 🌿 Thymol as a substance 🌿 References
Introduction
Thyme oil, thymol type

Species

BinomialThymus vulgaris
Accepted nameThymus vulgaris L.
POWO statusaccepted
FamilyLamiaceae
GenusThymus
IPNI identifierurn:lsid:ipni.org:names:461765-1
ISO standardISO 19817:2017

Source: Govaerts R. (ed.), World Checklist of Vascular Plants (WCVP), Royal Botanic Gardens, Kew, accessed on 21/09/2026.

Source: ISO 19817:2017.

What is thyme oil, thymol type?

“Thyme oil, thymol type” is the English name of European Pharmacopoeia monograph 01374, which has the status “In use” in the EDQM knowledge database consulted on 28/09/2026. On the same EDQM page, the status “in use” means that the monograph is published in the European Pharmacopoeia. According to the ISO catalogue for ICS 71.100.60 (archived copy of 19/03/2026), ISO 19817:2017 is titled “Essential oil of thyme [Thymus vulgaris L. and Thymus zygis L.], thymol type”, falls under ISO/TC 54 and is at stage 90.93. According to the EMA page on Thymi aetheroleum, “thyme oil” is the common name for the essential oil of the plants Thymus vulgaris L. or Thymus zygis L. According to the HMPC assessment report (EMA/HMPC/52980/2017, revision 1), which cites Ph. Eur. monograph 01/2012:1374, the essential oil is defined as obtained by steam distillation from the fresh flowering aerial parts of Thymus vulgaris L., T. zygis L. or a mixture of both species. In the opinion of the EFSA FEEDAP Panel (EFSA Journal 2025;23(12):e9691), the thyme oil assessed is an essential oil obtained from the fresh flowering aerial parts of T. vulgaris L., T. zygis L. or their mixtures.

Which plants does the name cover?

According to the World Checklist of Vascular Plants (WCVP, Kew), in the extract read on 21/09/2026, Thymus vulgaris L. has the status “Accepted” and is placed in the family Lamiaceae. In the same extract, Thymus zygis L. has the status “Accepted” and is placed in the family Lamiaceae. According to the EFSA FEEDAP opinion (2025), T. zygis L. (Spanish thyme) is the primary source of most thyme essential oil, the bulk of which is produced in Spain. According to the HMPC assessment report (revision 1), citing Thompson et al. (2003), there are at least 6 chemotypes of Thymus vulgaris L. with different essential oil compositions, and only the “thymol” type, in which thymol is the predominant compound, complies with the definition in the European Pharmacopoeia.

What does Thymus vulgaris look like, and where does it grow?

According to the EFSA FEEDAP opinion (2025), T. vulgaris L. (common thyme or garden thyme) is a small, semi-evergreen, perennial shrub of the family Lamiaceae. According to the EFSA FEEDAP Panel opinion (2025), T. vulgaris has a horizontal and upright growth habit, stems that become woody with age, small grey-green leaves (up to 5 mm long) and branches terminated in season by purple to pink flowers. The same opinion states that T. vulgaris is native to France, Italy and Spain, and is now commonly found throughout mainland Europe, the UK and parts of north Africa. The same opinion states that T. vulgaris, like many Thymus species, readily hybridises when flowering periods overlap, so that numerous hybrids and cultivars exist in addition to three recognised subspecies.

Which part of the plant is distilled, and how?

According to the EMA page on Thymi aetheroleum, the HMPC conclusions only cover thyme oil obtained by steam distillation from the fresh flowering above-ground parts of either species or a mixture of both. According to the EFSA FEEDAP opinion (2025), the product assessed is extracted from the flowering aerial parts (fresh leaves, flowering tops and twigs) of T. vulgaris and/or T. zygis by steam distillation; the volatile constituents are condensed and then separated from the aqueous phase by decantation.

According to Najar et al. (2021), reporting work by Andolfi et al., the flowers of T. vulgaris have a higher essential oil content than the apical leaves, which are followed by the intermediate leaves, while in the stems the oil is present only in traces or is completely absent. According to Najar et al. (2021), steam distillation is the method most widely used to produce essential oils on a large scale, because it takes less time and allows better oil recovery.

What did a field trial in central Italy measure?

In the trial by Najar et al. (2021), on organically grown plants in Tuscany (central Italy), yields obtained by farm-scale steam distillation in 2018 and 2019 ranged between 0.55 and 0.60 % for the “thymol” chemotype of Thymus vulgaris L. In both years, thymol was the main compound of this steam-distilled oil, although at almost half the percentage obtained by hydrodistillation. In the same trial, the essential oil yields of the “thymol” chemotype obtained by hydrodistillation (Clevenger) were 1.2 % in 2017 and 0.47 % in 2019. In the same trial, the oil of the “linalool” chemotype of T. vulgaris contained about 90 % oxygenated monoterpenes, with linalool (75 %), linalyl acetate (8.15 %) and b-caryophyllene (3.2 %) as main constituents.

What is the composition of the oil?

According to the HMPC assessment report (revision 1), the dried herbal substance contains up to 2.5 % essential oil, whose main components are thymol, p-cymene, carvacrol, γ-terpinene, linalool, β-myrcene and terpinen-4-ol. Citing Takeuchi et al. (2004), Kitajima et al. (2004) and Stahl-Biskup (1991), the same report states that some compounds occur partly as glycosides (for example p-cymene-9-ol). According to the EFSA FEEDAP opinion (2025), GC-MS analysis of seven batches from T. vulgaris and six batches from T. zygis indicates that the two oils are similar with regard to the 28 components detected at more than 0.1 % of the chromatographic area. In Table 1 of the EFSA FEEDAP opinion (2025), across seven batches of oil from Thymus vulgaris L., thymol accounted for a mean of 53.71 % of the chromatographic area (range 47.78–57.65 %). In the same seven batches, p-cymene accounted for a mean of 17.87 % of the chromatographic area (range 15.16–21.07 %). In these batches, γ-terpinene accounted for a mean of 8.83 % of the chromatographic area (range 7.38–10.34 %). In these batches, carvacrol accounted for a mean of 3.95 % of the chromatographic area (range 2.81–4.56 %). In these batches, linalool accounted for a mean of 3.59 % of the chromatographic area (range 2.94–4.63 %). Table 2 of the same opinion covers thyme oil from Thymus vulgaris L. and Thymus zygis L. taken together: the applicant’s specification for thymol is 35–60 % of the chromatographic area, and the analysis of 10 batches by GC-FID gave a mean of 49.6 % (range 42.6–54.8 %).

What limits does the HMPC assessment report give from the Ph. Eur. monograph?

According to the HMPC assessment report (revision 1), the European Pharmacopoeia monograph sets a thymol content of 37.0 % to 55.0 %. According to the same HMPC assessment report, the limit for p-cymene is 14.0 % to 28.0 %. According to the same HMPC assessment report, the limit for γ-terpinene is 4.0 % to 12.0 %. According to the same HMPC assessment report, the limit for carvacrol is 0.5 % to 5.5 %. According to the same HMPC assessment report, the limit for linalool is 1.5 % to 6.5 %. According to the same HMPC assessment report, the limit for β-myrcene is 1.0 % to 3.0 %. According to the same HMPC assessment report, the limit for terpinen-4-ol is 0.1 % to 2.5 %. According to the same HMPC assessment report, the limit for carvacrol methyl ether is 0.05 % to 1.5 %.

What did two studies of thyme grown in Italy find?

In the trial by Najar et al. (2021), organically grown on the hills of central Italy (2017–2019), thymol was the main constituent of the essential oil of the “thymol” chemotype of Thymus vulgaris L. In the study by Mancini et al. (2015), hydrodistillation of the aerial parts of five samples of T. vulgaris harvested in Campania gave yellow oils with a typical odour, with yields of 0.068, 0.070, 0.092, 0.019 and 0.081 % (v/w, fresh weight basis). In the same study, 134 compounds were identified in total; the oils were mainly composed of phenolic compounds, and all of them belonged to the thymol chemotype. In all five oils, thymol (46.2–67.5 %), carvacrol (5.7–7.3 %) and caryophyllene oxide (1.7–7.3 %) were the most abundant compounds (relative %, GC).

What does the oil look like?

According to the HMPC assessment report (revision 1), which cites Ph. Eur. monograph 01/2012:1374, the oil is a clear, yellow or very dark reddish-brown, mobile liquid with an odour reminiscent of thymol. According to the EFSA FEEDAP opinion (2025), the oil assessed (the applicant’s additive), obtained from the flowering aerial parts of T. vulgaris and/or T. zygis sourced from Europe, is a clear, yellow to brown, mobile liquid with a characteristic odour. In nine batches of this additive, the refractive index (20 °C) was between 1.500 and 1.5021; in three batches, the density (20 °C) was between 925 and 929 kg/m³; in six batches, the optical rotation (20 °C) was between −0.73° and −2.0°.

How is the oil identified in standards and registers?

According to the EFSA FEEDAP opinion (2025), thyme oil is identified by the single CAS number 8007-46-3, the EC numbers 284-535-7/285-397-0, the FEMA numbers 3064/3065 and the Council of Europe numbers 456/457. In the EDQM knowledge database, monograph 01374 has the French name “Thym type thymol (huile essentielle de)” and the Latin name “Thymi typo thymolo aetheroleum”. In the ISO catalogue for ICS 71.100.60 (archived copy of 19/03/2026), ISO 14715:2010 “Oil of thyme containing thymol, Spanish type [Thymus zygis (Loefl.) L.]” is marked “Withdrawn”, at stage 95.99. According to the EFSA FEEDAP opinion (2025), the applicant’s product specifications are based on ISO 19817:2017 and on the European Pharmacopoeia, adapted; four components contribute to the specifications, with thymol selected as the phytochemical marker. According to the HMPC assessment report (revision 1), citing Böhme et al. (2008), crude thyme oil is commercially called “red thyme oil” because of its deep colour; after redistillation, “white thyme oil” is obtained, a light-yellow oil that smells similar but sweeter and less pungent. Section 2 of the European Union herbal monograph of the HMPC on Thymus vulgaris L., Thymus zygis L., aetheroleum (EMA/HMPC/59032/2017, revision 1) covers “Thymus vulgaris L. or Thymus zygis L. or a mixture of both species, aetheroleum (thyme oil)”, as an essential oil. According to note 3 of section 2 of the same monograph, the material complies with the European Pharmacopoeia monograph with reference 1374.

What is documented about thymol as a substance?

According to the ECHA CHEM identity record consulted on 28/09/2026, thymol has the identifier 100.001.768, EC number 201-944-8, CAS number 89-83-8 and index number 604-032-00-1. The same record gives thymol the IUPAC name 5-methyl-2-(propan-2-yl)phenol and the molecular formula C10H14O. In the original text of Regulation (EC) No 1272/2008 (CLP), Annex VI, Part 3, Table 3.1, thymol (index 604-032-00-1, EC 201-944-8, CAS 89-83-8) carries the classification “Acute Tox. 4 * Skin Corr. 1B Aquatic Chronic 2”, the hazard statements H302, H314 and H411, and the pictograms GHS05, GHS07, GHS09 with the mention “Dgr”. In the original text of the same regulation, H302, H314 and H411 read “Harmful if swallowed”, “Causes severe skin burns and eye damage” and “Toxic to aquatic life with long lasting effects”. On 28/09/2026, a search for “thymol” in the IFRA Standards Library returned “No results found”. On the same date, a search for “thyme” in the IFRA Standards Library returned “No results found”. On the same date, a search for “thymus” in the IFRA Standards Library returned “No results found”.

What hazards are documented for the oil itself?

According to the EFSA FEEDAP opinion (2025), the safety data sheet provided by the applicant for thyme oil identified concerns for skin and eye irritation and for skin and respiratory sensitisation; no specific data were provided by the applicant and the literature search retrieved no relevant publication; the FEEDAP Panel considers the oil assessed as irritant to skin and eyes and as a dermal and respiratory sensitiser, and considers exposure of the people handling the additive, by any route, a risk. According to the HMPC assessment report (EMA/HMPC/52980/2017, revision 1), citing Von Skramlik (1959), the oral LD50 of the essential oil in rats was 2.84 g/kg body weight. Citing Jimenez et al. (1993), the same report gives an intraperitoneal LD50 of Thymus zygis oil in mice of 600 mg/kg body weight. The HMPC assessment report states that the mutagenicity and genotoxicity of thymol and carvacrol, the main components of thyme oil, have been assessed in several in vitro and in vivo studies on prokaryotic and eukaryotic systems; these studies have many weaknesses, their findings are often contradictory and their “reporting does not always contain sufficient details”, which makes interpretation difficult and the conclusion “equivocal”. According to the same report, “it seems” that in some studies thyme oil and its main components give weak indications towards genotoxicity, but these indications are at best weak and debatable. The same report states that, in most cases, the in vitro genotoxicity and mutagenicity tests were not performed with a thyme oil whose composition complies with the limits of the recent European Pharmacopoeia monograph for the thymol chemotype. Section 5.3 of the HMPC European Union herbal monograph (EMA/HMPC/59032/2017, revision 1) reports “equivocal results” for thymol and carvacrol, constituents of thyme oil, in in vitro and in vivo genotoxicity assays. According to the HMPC assessment report (revision 1), tests on carcinogenicity “have not been performed”. Citing Urbach and Forbes (1973) as reported by Opdyke (1979), the same report states that “there were no phototoxic effects recorded for thyme oil”. Citing Hänsel et al. (1994), the report states that in very rare cases allergic reactions “may occur” due to the thymol content. Under adverse events related to the essential oil, citing Blaschek et al. (2008), the report states that daily application in gargles, mouthwashes and toothpastes over a longer period, with no exact data available, “may cause” allergic reactions. The report mentions a case of acute hepatitis “reported” by Yürüktümen (2011) after ingestion of 25 ml of thyme essential oil of unknown composition obtained from a local market in Turkey; the HMPC considers this case not relevant for the monograph because of the unknown quality of the product and the high dose. According to the EFSA FEEDAP opinion (2025), the EFSA Compendium of botanicals reports the occurrence of 1,8-cineole (2.4 %) and myrcene (2.1 %) in the essential oil from the leaves of T. vulgaris as substances “of potential concern” for human and animal health. In the original text of Regulation (EC) No 1223/2009 on cosmetic products, Annex III, entry 84 requires the presence of linalool (CAS 78-70-6) to be indicated in the list of ingredients when its concentration exceeds 0.001 % in leave-on products and 0.01 % in rinse-off products.

References