Table 1

Classes of additives implicated in IF: mechanisms and effects

AdditiveKey mechanism or characteristicReported sensory effectsComments about evidence base
MentholActivating cooling receptor TRPM-8Increase cooling, reduce harshness of nicotine, minty flavourData for both tobacco products and e-cigarettes
Increased inhalation behaviour in rodents but inconclusive effects on inhalation behaviour in humans
Wilkinson Sword (WS) compounds, such as WS-3, WS-5, WS-14 and WS-23Activating cooling receptor TRPM-8Increase cooling, reduce harshness, reduce bitternessData predominately for e-cigarettes
Often combined with other flavours in ‘ice’ hybrid flavours in e-cigarettes
Organic acids and nicotine salts in e-cigarettespH loweringIncrease mildness, reduce harshness and irritationEffects mainly for higher nicotine concentration products
Higher blood nicotine levels
Sugars in tobaccopH loweringCombust to acids, increase mildnessMainly industry data
Organic acids in tobaccopH loweringIncrease mildness, decrease irritationMainly industry data
Flavourings with sweet propertiesOlfactory and orosensory mechanismsIncrease sweetness, reduce bitterness, partial evidence of increased smoothness and reduced harshnessData predominately in e-cigarettes, hookahs and cigars
SugarsOlfactory and orosensory mechanismsImpart a sweet flavourPredominately in cigarettes; mainly industry data