Terpinyl Acetate

Aroma and sensory profile

Terpinyl acetate is the smell of a cardamom pod before you crack it. Fragrance references type alpha-terpinyl acetate herbal with medium strength and describe it neat as herbal, bergamot, lavender, lime, and citrus, with a flavor at 12.5 parts per million that is woody, citrus, spicy, floral, grapefruit, and seedy [1]. It is the acetate of alpha-terpineol, and where the alcohol is lilac and pine, the ester is cooler, fresher, and more like bergamot and lavender, a soft citrus-herbal note that carries the sweetness of cardamom without its eucalyptol sharpness.

The molecule has one stereocenter, inherited from alpha-terpineol, and is chiral; commercial terpinyl acetate is an isomer mixture, sold under its own registry number and assessed as such [5][6]. No panel description of the individual enantiomers was found, so no claim about how they differ in odor is made here. Beta- and gamma-terpinyl acetates, esters of the other terpineols, accompany it in some oils and in the commercial mixture.

Effects and research

No animal or human trial of terpinyl acetate was found. The Research Institute for Fragrance Materials assessed the isomer mixture in 2018 and updated the assessment in 2024 [5][6]. Its research is a scatter of mechanism and ecology.

The result most relevant to people is enzymatic. Against recombinant human cytochrome P450 2B6, alpha-terpinyl acetate bound with a dissociation constant of 5.4 micromolar and acted as a competitive inhibitor of bupropion hydroxylation with an IC50 of 10.4 micromolar, which the authors flagged as a potential herb-drug interaction for cardamom-rich preparations [7]. In rats, terpinyl acetate altered the percutaneous absorption of caffeine, a penetration-enhancer effect shared with other terpene esters [8].

The ecology is unexpected. In honey bee cell cultures, terpinyl acetate was a potent and specific inhibitor of mitochondrial ATP production, non-cytotoxic because glycolysis compensated, and bees that ingested it showed disrupted reversal learning, holding on to a flower-color preference past the point where it paid [9]. A 2021 study found alpha-terpinyl acetate rare in Thymus pulegioides, present in only 35 percent of 131 habitats, with strong antifungal and antidermatophyte activity but weak antibacterial action, and with phytotoxicity that inhibited a grass but stimulated a clover [4]. None of this is a pharmacology of terpinyl acetate in a person.

Natural sources

Terpinyl acetate is cardamom's ester. Fragrance databases log it at 40.9 percent in a Guatemalan cardamom carbon dioxide extract and 24.6 percent in cardamom seed oil, with 5.3 percent in carrot weed oil, 0.85 percent in Polish sweet basil oil, and traces in armoise, Artemisia, bergamot, blood orange, carrot seed, cascarilla, cassis bud, cedarleaf, and citronella oils [1]; a 2023 analysis of cardamom oil found alpha-terpinyl acetate among its most abundant constituents [3]. It is a rare constituent of Thymus pulegioides, present in a third of populations [4]. In cannabis terpinyl acetate is a trace terpenoid, occasionally reported and usually absent.

Boiling point and vaporization

PubChem compiles alpha-terpinyl acetate's boiling point as 220 °C from the Joint FAO/WHO Expert Committee on Food Additives and 115 °C at 2 mmHg from fragrance references, which also give 220 °C at 760 mmHg [1][2]. This profile keeps 220 °C (428 °F), the JECFA value, which matches what the site already listed. That places it with alpha-terpineol and isopulegol in the heart-note band, persistent on skin and paper and slow to leave a spice jar. As an ester of a tertiary alcohol with one ring double bond it is oxidation-stable, though esters hydrolyze slowly in the presence of water and acid, returning to terpineol and acetic acid. No thermal degradation study of terpinyl acetate was found.

Safety and regulation

Terpinyl acetate is listed by the US Food and Drug Administration as a permitted synthetic flavoring substance at 21 CFR 172.515, as "Terpinyl acetate" [10]. The Research Institute for Fragrance Materials assessed the isomer mixture in 2018 and 2024 [5][6]. No cancer classification applies.

Its hazard record is about water, not skin. Under Europe's classification inventory, 85 percent of notifications flag it as toxic to aquatic life with long-lasting effects, and 12 percent report no hazard at all, with no skin sensitization, irritation, flammability, or aspiration code above threshold [2]. No patch-test series naming terpinyl acetate was found. The one caution with any human relevance is the enzyme result: it inhibits CYP2B6 competitively at low micromolar concentrations [7], which matters for anyone taking bupropion or other 2B6 substrates alongside concentrated cardamom preparations, and not for anyone eating cardamom. Neat material should not go down a drain.

Industries and uses

Fragrance: terpinyl acetate is a foundation herbal-bergamot material in lavender, fougère, and citrus accords and is stocked as the isomer mixture [1][5]. Culinary: it holds FDA flavoring status and is the defining sweet-cool note of cardamom, used to build cardamom, bergamot, and lime flavors [1][3][10]. Aromatherapy: cardamom and laurel oils are its carriers; its clean sensitization record and the enzyme interaction are the two relevant notes [2][7].