All good so far. For several months I've been pinning a range of peptides: Tesa, Reta, 5-Amino, CJC-IPA, SS-31, MOTS-C, a GHK-Cu blend, and more recently Tirz plus a newer blend replacing the first, and Semax, with a few more in the freezer waiting for a test drive. Each got introduced one by one with slow titration, and I cycle them per usual protocols, and I'll drop anything too costly or merely meh. Reta, Tirz and the blend have clear effects. My only negatives: now and then a reaction at the injection site, nearly always from the blends, and they pass. Someone mentioned filtering, worth thinking about since you're focused on caution. I doubt many of us bother, it seems too onerous to me, though I get that for some it's an important risk reducer.