Stimulant drinks contain three active ingredients, caffeine, glucuronolactone and taurine. In 1999 the European Scientific Committee for Food, SCF, was asked by the European Commission for an opinion on caffeine, taurine and glucuronolactone as constituents of so-called energy drinks. This committee, which carries out risk assessment on foodstuffs in Europe, reached a number of conclusions in its opinion. These were based on an assumed maximum intake level of 0.5 litre of energy drink per day. It concluded that the contribution of energy drinks to overall caffeine intake is not a matter of concern for non-pregnant adults; moderation of caffeine intake, from whatever source, is advisable during pregnancy; substitution of energy drinks for normal beverages by children could lead to increased caffeine levels in this group; this could result in transient behavioural changes such as arousal, irritability, nervousness or anxiety; the interaction of energy drinks has not been well studied; nor has the interaction of caffeine and taurine with alcohol particularly under conditions of exercise and consequent dehydration through sweating; the safety-in-use of taurine and glucuronolactone as delivered in energy drinks has not been established; and further studies would be required.
This opinion makes it clear that the scientific data were not available to answer all questions about the safety of these energy drinks under all circumstances of usage.