There is an FDA approved prescription drug for low sexual desire whose own label says its strongest binding is not at the arousal receptor.

It is at the pigment receptor in your skin. And that same label states plainly that nobody knows exactly how the drug produces the desire effect.

That is not a flaw in the drug. It is the clearest window you will get into a hormone family that almost nobody in this space explains properly. Two of the peptides sitting in front of you right now come from that family, and the difference between them is not what they do. It is which switch they land on.

Your body makes a large protein called POMC and cuts it into smaller hormones. One of those pieces is alpha-MSH.

Alpha-MSH does not have one job. It talks to five different receptors, numbered MC1 through MC5, and each one runs something different.

Melanotan 1 and PT-141 are both synthetic copies of that same hormone. Both came out of the same research program at the University of Arizona.

Not reviewed. Not recommended. Approved, with labels you can read yourself.

Two approvals inside four months, from the same parent hormone. A 2023 review in Nature Reviews Endocrinology credits those two approvals with demonstrating the safety of this whole class of peptides.

PT-141's label lists the receptors in order of how strongly it hits them: MC1 first, then MC4, then MC3, MC5, MC2.

MC1 is the pigment switch. MC4 is the brain switch. So a drug sold for desire is landing hardest on skin.

You can see it in the trial data. Focal pigment changes showed up in 1% of women using up to 8 doses a month. In a separate study where it was given daily for 8 straight days, that number was very different.

1% on an as-needed schedule. 38% after 8 consecutive daily doses.

Melanotan 1 is the clean one. It binds mostly to MC1, and its listed pharmacology is a single line: it increases eumelanin in skin independently of sunlight or UV.

Same parent hormone. Same five switches. Different pressure on each one.

That last one matters more than people think. You are not chasing a blood level here. You are waiting on pigment cells to do their work.

The reason Melanotan 1 got approved has nothing to do with looks. It got approved so people with a painful light sensitivity condition could stand in daylight, and it does that by building eumelanin without any sun exposure at all.

In the trial, patients averaged 64 hours of pain free time in direct sunlight over 180 days, against 41 hours on placebo.

A separate study in patients with a different light-triggered condition tracked what that pigment actually does. Melanin density rose by day 7, peaked around day 15, and was still elevated at day 60 from a single dose. The skin reaction to light dropped significantly across the entire tested range, from ultraviolet all the way into visible light.

That is pigment doing real work, with the UV part removed. Given what UV does to collagen over time, a pigment pathway that runs without sunlight is a bigger idea than a tan.

BioLongevity is at 50% off, and this is the one that matters for today's piece. Melanotan 1 and PT-141 are both on it. Code LEE15 stacks on top. Ends tonight at 11:59 PM.

Limitless End of Summer: 15% off sitewide, 25% off all capsules, code LEE20 on top. Also ends tonight, Sunday August 16 at 11:59 PM CST. Nothing from today's piece is on it, but if a cart has been sitting there all week, close it out.

Peptira has most of the warehouse at 50%, and this one is not on a clock. It runs while supplies last.

But the 50% only happens if you stack all three steps: 35% comes off automatically, code LEE adds 10%, and paying by ACH adds the last 5%.

Two clocks, one deadline, and no version of this where you get it tomorrow.

Melanotan 1 and PT-141 are two copies of the same hormone, and the only real difference is which of five receptors they push hardest.

That is why the tanning one and the arousal one keep showing up in each other's side effect columns.

Both are FDA approved drugs, which makes this one of the few peptide families with a paper trail you can read straight off a government website.

Talk soon,

Lee

Stop guessing. Start optimizing.

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