The top 25 most frequently added flavouring ingredients in e-liquids from the EU-CEG dataset
| Flavouring ingredient | Prevalence (% of total e-liquids) | Median concentration (mg/10 mL) | Flavour description | GHS code* | |
| 1 | Vanillin | 35.2 | 7.0 | Sweet, powerful, creamy, vanilla-like. | H317 and H319. |
| 2 | Ethyl maltol | 32.0 | 5.9 | Sweet, fruity-caramellic, cotton candy. | H302. |
| 3 | Ethyl butyrate | 28.4 | 3.6 | Ethereal, fruity with buttery-pineapple-banana, ripe fruit and juicy notes. | H226. |
| 4 | Ethyl acetate | 23.2 | 1.1 | Ethereal, sharp, wine-brandy-like. | H225, H319 and H336. |
| 5 | Maltol | 22.8 | 1.3 | Sweet, fruity, berry, strawberry, caramellic. | H302. |
| 6 | Ethyl vanillin | 19.4 | 6.8 | Intense, sweet, creamy, vanilla-like. | H302, H315, H319, H335 and H412. |
| 7 | Furaneol | 19.3 | 2.0 | Fruity, caramelised, roasted, pineapple-strawberry. | H302, H317 and H319. |
| 8 | Methyl cyclopentenolone | 18.3 | 2.0 | Very strong, caramellic-maple, lovage. | n/a |
| 9 | γ-Decalactone | 18.2 | 0.5 | Coconut-peach. | n/a |
| 10 | Cis-3-hexenol | 17.8 | 1.5 | Strong, fresh, green, grassy. | H226 and H319. |
| 11 | Isoamyl acetate | 16.3 | 2.3 | Sweet, fruity, banana, pear. | H226. |
| 12 | Ethyl 2-methyl butyrate | 16.0 | 2.2 | Strong, green, fruity, apple with strawberry notes. | H226. |
| 13 | Acetic acid | 15.7 | 1.2 | Pungent, sour, acid, vinegar. | H226 and H314. |
| 14 | Butyric acid | 15.0 | 0.8 | Tropical fruity floral, plum, apricot-pear-like. | H314. |
| 15 | Linalool | 14.5 | 0.9 | Sweet floral-woody with slight citrus notes. | H315, H317 and H319. |
| 16 | Benzyl alcohol | 14.2 | 3.3 | Faint, sweet, almond fruity, somewhat chemical. | H302 and H332. |
| 17 | Ethyl hexanoate | 13.6 | 0.5 | Strong, fruity, pineapple, banana with strawberry, pear and tropical notes. | H226. |
| 18 | Benzaldehyde | 12.4 | 0.3 | Bitter almond oil, sweet cherry. | H302. |
| 19 | Menthol | 12.1 | 18.4 | String trigeminal cooling sensation with a slight mint note. | H315 and H319. |
| 20 | Isoamyl isovalerate | 11.5 | 0.8 | Fruity, green-apple, pineapple, tropical, mango, apricot, cognac. | H411. |
| 21 | δ-Decalactone | 11.2 | 0.3 | Sweet, creamy, milky, peach, nut, buttery. | n/a |
| 22 | Hexanoic acid | 11.1 | 0.4 | Heavy, fatty, cheesey-sweaty. | H311, H314 and H318. |
| 23 | Ethyl propionate | 10.9 | 0.5 | Strong, ethereal, fruity, rum-like. | H225. |
| 24 | γ-Undecalactone | 10.9 | 0.4 | Strong fatty, peach-apricot. | H411 and H412. |
| 25 | Hexyl acetate | 10.3 | 1.0 | Sweet, fruity, pear-apple, green, banana. | H411. |
Prevalence is reported as the number of e-liquids containing the respective flavouring as percentage of the total number of e-liquids. Flavour descriptions were retrieved from a commercial flavour database.34 GHS codes were retrieved from PubChem (https://pubchem.ncbi.nlm.nih.gov/)
*GHS=Globally Harmonized System of Classification and Labeling of Chemicals; hazard statements can be found at https://pubchem.ncbi.nlm.nih.gov/ghs/.
EU-CEG, European Common Entry Gate.