I guess "feeling like", sounds like a placebo.
From what I've read there is some real risks associated with using them. Sounds a bit like the marketing of steroids in the 70s.
Insulin is a peptide. Not sure if it is really a placebo when a diabetic needs insulin.
Hormones control a lot of what you describe as "feeling like."
The drugs (coincidentally of shape "peptide") that have been through clinical trials are obviously measured against placebo, and they (like the approved GLP-related set of drugs) are outrageously effective beyond placebo. And have very little downsides compared to the downsides of being obese, which are far more immense than people appreciate.