The present application is concerned with methods for increasing the bioavailability and/or activity of agents and in particular allows selective targeting of an agent to, or via, the liver or allows the liver to be bypassed. By selecting which of saturated fatty acids (SFA), short chain fatty acids (SCFA), medium chain fatty acids (MCFA), polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFAs) and long chain fatty acids (LCFA)are present in a composition and which predominates it is possible to substantially boost bioavailability and also to selectively target whether an agent is delivered to, or via, the liver or alternatively bypasses the liver. The approach is a versatile platform technology which may be applied to agents in general helping achieve better and more efficient delivery.In one preferred embodiment particular carotenoids are employed to further influence whether delivery is to, or via, the liver, or bypasses the liver.
