The present invention relates to compositions and methods for modulating melanin production, secretion and/or accumulation in human skin cells. In particular, the present invention relates to the use of A3 adenosine receptor antagonists in compositions and methods for the treatment and amelioration of hyper-pigmentation conditions and for the lightening of skin, and to the use of A3 adenosine receptor agonists in compositions and methods for the treatment and amelioration of hypo-pigmentation conditions and for the tanning of skin.