A ready-to-drink formulation in bottled form comprises still spring water, an active ingredient, one or more flavouring agents, one or more sweeteners and an organic acid, the formulation having a shelf-life in excess of six months. The formulations have excellent oganoleptic properties and a shelf life which is generally in excess of twelve months, while at the same time acting as a vehicle for a range of active ingredients which have a functional effect. Thus, the active ingredient can be a combination of saccharide materials and salts which can be used by consumers to boost their energy levels throughout the day during normal work and recreation, but also in situations where extra energy is required, such as when engaging in strenuous activity, for example sporting activities. The active ingredient can also be potassium hydroxycitric acid, a known appetite suppressant, such that the formulation can have beneficial effects for those wishing to reduce their calorie intake and thus achieve weight loss.