Hair color - and loss - is one of the aspects of aging that people care about too much in comparison to its effects on health. There are far more important degenerations to consider. Nonetheless, here is a report suggesting that better control over the cell signaling could restore lost hair color by directing pigment cells to get back to work: "We report the first case of progressive hair repigmentation associated with the use of lenalidomide in an elderly patient with multiple myeloma. The influence of lenalidomide on follicular melanogenesis may involve removing the inhibitory influences of some cytokines such as IL-1, IL-6 and TNF-α. In addition, certain endocrine effects of lenalidomide on the hypophyseal-adrenal axis could explain its action on hair pigmentation. We further hypothesize that lenalidomide may be capable of stimulating migration and/or differentiation of melanocytes to promote repigmentation of gray hair follicles. Pending the clarification of how hair repigmentation occurs with lenalidomide, our observation materializes the concept that hair graying may not be an irreversible process." This sort of brute force approach is, however, far less desirable than working to fix the underlying levels of cellular damage that lead to changed signaling and the decline of melanocyte activity in the first place.

Link: http://www.ncbi.nlm.nih.gov/pubmed/22440400