Sounds like you went through some real changes after dropping that much weight. Once you hit a goal like that, you fight like hell to keep it. That's the kind of motivation people need.
Not much actual science behind most peptide vendor claims. No real studies for most of what they push. You get animal mechanistic data and anecdotes but nothing solid. These companies have huge financial reason to hype things - books, clinic partnerships, affiliate deals. Take it with skepticism.