people have been referring to forskolin increasing melanin. I might have found an interesting article on that:
It looks like an eyelash serum formula increases the pigmentation of the follicles:
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I think this could be promising to see what ingredients help to penetrate. Of course a small eyelash tool is not big enough ( and I read as forskolin is only one of the many ingredients, the effect will be even greater with a higher dose) for those wanting to darken their hair/skin
But it would be interesting to look into the ingredients to help formulating our own melanin lotion ( many of those ingredients have nothing to do with penetration, so we can skip them)
PS: here’s a pubmed article the lady is probably referring to:
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There is definitely a difference in the hair colour. I have tried lipocils before and I am glad that the company have pointed out that the lengthening is not much because I did not see much difference. Latisse/ careprost is much beter for that. The new lipocil formula seems to work well for the darkening you have been looking for. So hopefully you will be able to establish what is needed to get that darkening you are looking for especially as products like lipocils do not come cheap.

last year their new formula came out containing the hair darkening compound. I think in 2006 a study was released that forskolin darkened hair and skin in mice. They're currently working on products ( been contacting a couple of researchers but of course non of them gives me their formula) but I guess this is an excellent way to start creating a formula. Selecting the compounds ( darkeners plus penetrators) out of the ingredients of the eyelash serum ( I'm not a scientist, so I need help)

I must say it works for me too!! but how, i realized one eye has longer lashes than another now... i did apply to both eyes!!!! how how how how how?!!!