Neutral muonic helium is an exotic atomic system consisting of an electron, a muon, and a nucleus. Being a three-body system, it possesses a clear hierarchy. This allows us to consider it as a hydrogenlike atom with a compound nucleus, which is, in turn, another hydrogenlike system. There are a number of corrections to the Bohr energy levels, all of which can be treated as contributions of generic hydrogenlike theory. While the form of those contributions is the same for all hydrogenlike atoms, their relative numerical importance differs from atom to atom. Here, the leading contribution to the (electronic) Lamb shift in neutral muonic helium is found in a closed analytic form together with the most important corrections. We believe that the Lamb shift in neutral muonic hydrogen is measurable, at least through a measurement of the (electronic) i.r-2.? transition. We present a theoretical prediction for the li-2 s transitions with an uncertainty of 3 ppm (9 GHz), as well as for the 2s-2p Lamb shift with an uncertainty of 1.3 GHz.The hydrogen atom is the simplest one and the easiest to access, but its study is not free of problems. For instance, a recent determination of the proton radius by measuring the Lamb shift in muonic hydrogen [1] led to a result inconsistent with that from hydrogen spectroscopy [2] (on various determinations of the proton charge radius see, e.g., Ref.[3]). The muonic hydrogen atom is only one example of exotic "editions" of hydrogen. Due to the "proton-radius puzzle" one may wonder, in particular, whether a theory of the ordinary or muonic hydrogen atoms is adequate. To probe it one may consider various isotopes of hydrogen, including exotic ones.In particular, the muonium atom, a bound system of an electron and a positive muon, is such a system, where the quantum electrodynamics (QED) effects are about the same as in hydrogen, the nuclear recoil effects are enhanced, and the nuclear structure contributions are suppressed. (One may treat various radiative corrections to the muon line as the nuclear structure corrections.) On the contrary, the neutral muonic helium atom, a neutral three-body system, which consists of a nucleus (either an a particle or a helion, the nucleus of the 3 He atom), a muon, and an electron, is a kind of hydrogenlike atom with a compound nucleus [4][5][6], where the effective nuclearstructure effects are enhanced. The recoil contributions there are less important than in ordinary hydrogen, while the hyperline effects are enhanced. Remarkably, the effective nuclear-structure effects are under control.There are a number of exotic atoms, which are of interest because of specific relations between numerical values of their ' savely.karshenboim@mpq.mpg.de parameters. The specifics of neutral muonic helium is in certain properties of its compound nucleus. Muonic helium is a system with a well-defined hierarchial structure. Its atomic part is similar to that of an ordinary hydrogen atom, possessing an electron and a compound nucleus. Such a nucleus consists of an "internal"...