Mine seems to get worse over time and non zinc sunscreen doesn't seem to halt it as much as a zinc based sun screen. I have been having good success with doing the copper detox approach. I noticed my favorite foods are high in copper. Beer, wine, chocolate and coffee. I would at least have something from that group everyday of my life. So I have cut way down on them :(.
The next step is detoxing copper out of your system. I am taking MSM, 50 mg of zinc, cilantro with chorella. On day three of this regime I noticed my brown spots had lighter sports in them. It's faint and small but there is a little more everyday. I think in a couple of months it will clear up if I stick with it. There is also the other theory that melasma is a fungus. I don't think that would be classified as melasma but skin fungus. I think they are so similiar looking it's hard to tell the difference on some people. Mine is melasma because I have tried the fungus approach with not change. Also I do have one new patch on my eyebrow which is more uniform and has a roundish edge. I suspect that might be fungus. The Melasma patches are less uniform especially on the edges.