The present invention generally relates to compositions and methods for transdermal delivery, and treatment of hair related conditions. The compositions can be used in a variety of applications, including causing or promoting hair growth and/or hair pigmentation. In some cases, the composition may include nitric oxide and/or peptides. The nitric oxide and/or peptide 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, peptides, or both. 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 the scalp, or other 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.