Does melanostatin peptide whiten the skin in a similar manner as to how melanotan darkens it?

Question

I was reading about peptides and came across an interesting peptide that bodybuilders use to darken their skin.

How can peptides change the genetic makeup of someone's skin and darken it?

I also found another peptide called melanostatin that inhibits alpha-MSH. So my question is, can it whiten the skin?

Because bodybuilders aren't very much interested in whitening their skin, there were no trials and experiences with that peptide.

So does melanostatin work similarly to how Melanotan darkens the skin?

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Disclaimer: I do not intend on using this peptide on animal experiment, nor humans for that matter. My question is purely theoretical and for educational purposes.

Answer 1

Melanotan

The "Melanotan" you're referring to is probably Melanotan I, also known as afamelanotide, which is an analogue of α-melanocyte stimulating hormone (α-MSH). In other words, it activates (some of) the same receptors as α-MSH.

α-MSH has several functions, one of which is to stimulate the cells that darken the skin (melanocytes), so they produce more melatonin. It activates these cells via the MC₁ receptor. Afamelanotide is more specific to that receptor, so it darkens the skin without some of the other effects.

It acts at the hormone level, so it won't be changing anyone's genetic makeup - stop using it and you'll go back to your normal colour.

Melanostatin

Confusingly, the name Melanostatin has been applied to more than one compound. I've found two short peptides that might fit the bill.

The most likely candidate is described in this leaflet, which says it is used for skin lightening. It's a receptor antagonist - it prevents α-MSH from binding to the MC₁ receptor, so reducing melanin production. So yes, it's working at the same site as Melanotan I but having the opposite effect.

The other possibility is also known as Melanocyte-inhibiting factor, which inhibits production of (natural) α-MSH, so it would be expected to lighten the skin. However, since α-MSH has several other functions, reducing its production would also affect other systems - there would be side-effects, and skin lightening doesn't seem to be the main thing it's known for. More here: Wikepedia