Overview of the top five most frequently added flavourings for each individual flavour category30
| Flavour category | Top five flavouring ingredients | Prevalence (%)* | Median concentration (mg/10 mL) |
| Tobacco | Ethyl maltol | 31.2 | 6.8 |
| Methyl cyclopentenolone | 29.6 | 1.5 | |
| Vanillin | 25.9 | 4.1 | |
| 2,3,5-Trimethylpyrazine | 15.8 | 1.3 | |
| Furaneol | 13.1 | 3.0 | |
| Menthol/mint | Menthol | 58.6 | 57.6 |
| Menthone | 16.6 | 22.7 | |
| Ethyl maltol | 12.7 | 0.7 | |
| Vanillin | 11.9 | 1.2 | |
| Eucalyptol | 11.5 | 7.2 | |
| Nuts | Vanillin | 58.8 | 30.6 |
| Ethyl maltol | 47.5 | 24.5 | |
| Ethyl vanillin | 35.0 | 32.0 | |
| Acetoin | 27.5 | 24.0 | |
| Maltol | 26.9 | 6.2 | |
| Spices | Menthol | 23.5 | 20.4 |
| Anethole | 22.8 | 60.0 | |
| Ethyl maltol | 22.8 | 17.7 | |
| Ethyl butyrate | 13.0 | 2.5 | |
| Benzyl alcohol | 11.7 | 28.0 | |
| Coffee/tea | Vanillin | 36.0 | 5.7 |
| Methyl cyclopentenolone | 21.4 | 5.7 | |
| Benzyl alcohol | 20.9 | 17.0 | |
| Ethyl maltol | 15.3 | 3.3 | |
| Ethyl vanillin | 15.0 | 2.5 | |
| Alcohol | Vanillin | 50.3 | 9.0 |
| Ethyl acetate | 25.7 | 7.9 | |
| Ethyl butyrate | 23.1 | 6.0 | |
| Ethyl propionate | 18.8 | 15.0 | |
| Ethyl heptanoate | 18.5 | 2.2 | |
| Other beverages | Vanillin | 44.5 | 7.2 |
| Ethyl butyrate | 39.6 | 2.2 | |
| Ethyl maltol | 36.6 | 3.2 | |
| Ethyl acetate | 30.9 | 0.8 | |
| Ethyl vanillin | 30.8 | 5.4 | |
| Fruit (berries) | Ethyl butyrate | 52.4 | 6.2 |
| Cis-3-hexenol | 41.2 | 2.3 | |
| Vanillin | 39.1 | 3.1 | |
| Furaneol | 36.8 | 3.3 | |
| Ethyl acetate | 36.0 | 1.4 | |
| Fruit (citrus) | Ethyl maltol | 32.9 | 6.0 |
| Ethyl butyrate | 31.1 | 2.9 | |
| Vanillin | 31.0 | 6.0 | |
| Ethyl acetate | 26.3 | 0.7 | |
| Linalool | 25.8 | 1.6 | |
| Fruit (tropical) | Ethyl butyrate | 38.5 | 2.4 |
| Vanillin | 36.5 | 2.8 | |
| Isoamyl acetate | 32.0 | 2.2 | |
| Ethyl acetate | 31.2 | 1.1 | |
| Ethyl maltol | 30.7 | 1.3 | |
| Fruit (other) | Ethyl butyrate | 42.6 | 3.8 |
| Ethyl acetate | 37.7 | 3.1 | |
| Isoamyl acetate | 35.9 | 3.6 | |
| Vanillin | 32.0 | 2.8 | |
| Maltol | 28.1 | 1.4 | |
| Dessert | Vanillin | 74.5 | 21.8 |
| Ethyl maltol | 64.8 | 9.0 | |
| Ethyl vanillin | 63.0 | 13.8 | |
| Maltol | 50.9 | 1.4 | |
| Methyl cyclopentenolone | 49.2 | 1.2 | |
| Candy | Ethyl maltol | 39.4 | 0.5 |
| Isoamyl acetate | 37.4 | 2.3 | |
| Ethyl butyrate | 37.2 | 1.1 | |
| Vanillin | 35.2 | 1.1 | |
| Ethyl acetate | 35.0 | 0.4 | |
| Other sweets | Vanillin | 61.4 | 30.0 |
| Ethyl maltol | 37.5 | 28.0 | |
| Ethyl vanillin | 35.0 | 19.7 | |
| Maltol | 26.0 | 1.3 | |
| Piperonal | 24.4 | 3.2 | |
| Other flavours | Linalool | 30.5 | 3.0 |
| Ethyl butyrate | 25.2 | 6.0 | |
| Ethyl acetate | 23.2 | 8.0 | |
| Maltol | 23.2 | 4.1 | |
| Ethyl 2-methyl butyrate | 22.5 | 5.9 | |
| Unflavoured | NA | NA | NA |
For a complete overview, see online supplementary table S1. See online supplementary table S3 for flavour descriptions of these ingredients.
*Prevalence is reported as the number of e-liquids containing the respective flavouring as percentage of the total number of e-liquids within that category.