The present invention generally relates to compositions and methods for treatment of subjects in need of muscle growth or repair. In some cases, the composition may include nitric oxide. The nitric oxide may be present within a first phase comprising a lecithin, such as phosphatidylcholine. In certain embodiments, the lecithin is present in liposomes, micelles, or other vesicles containing nitric oxide. The composition can take the form of a gel, a cream, a lotion, an ointment, a solution, a solid “stick,” etc., that can be rubbed or sprayed onto the skin, e.g., onto a location where muscle growth is desired, or on another suitable portion of the skin. Other aspects of the present invention are generally directed to methods of making or using such compositions, methods of promoting such compositions, kits including such compositions, or the like.
