FUN Light Vitamin Boost Lemon Lime is a sugar-free drink concentrate just like others in the FUN Light range, but now containing added vitamin B6 and B3 [Niacin], both of which can help to reduce fatigue and exhaustion. FUN Light Vitamin Boost Lemon Lime has a tangy taste of lemon with a subtle burst of lime. Dilute Vitamin Boost with water or, for an even fresher drink, try mixing it with carbonated water.