A few plain answers to the questions that overlap
Similar names can make the reading more confusing than it needs to be. These are the distinctions I keep coming back to.

It’s fine to pause over a name
The names here share a history, but their findings and approvals don’t all travel together. If you’ve had to reread a sentence to work out which compound it means, these answers can help.
I use PT-141 and bremelanotide for the compound, and Vyleesi for the approved medicine. Melanotan 2 gets its own page. That keeps a medicine’s approval from spilling over into a claim about research material.
Follow an answer to its source or open the longer essay. There’s no need to learn every technical term first, or share a personal reason for reading.
The longer essays give each topic more room. Each keeps the findings and safety concerns together, with sources you can follow at your own pace.
Find the sources behind these answers