Peptide-by-peptide comparisons

The peptides covered on this site operate through fundamentally different mechanisms, even when their therapeutic framing overlaps. A reader scanning the field for the first time can be forgiven for treating Epitalon, Humanin, SS-31 and GHK-Cu as broadly interchangeable longevity research compounds; the comparison pages exist to make the differences explicit.

Each pairwise comparison addresses the same four questions: what is the compound and where did it come from, how does it work, how strong is the evidence base relative to the comparator, and what is the UK regulatory framing. The fourth question matters more than it might seem: research-context positioning under UK law differs substantially between compounds that have never been clinical-stage (Epitalon, Pinealon), compounds in active clinical development (SS-31/elamipretide), compounds licensed elsewhere but not in the UK (Thymosin Alpha-1), and compounds with CPNP cosmetic notification but no medicinal authorisation (GHK-Cu). Conflating these regulatory categories is the single most common error in informal peptide-research writing.

The nine comparisons published so far cover the most-asked pairings in the longevity research literature: a telomere-axis vs mitokine comparison (Epitalon vs Humanin), a cellular-repair vs immune-restoration comparison (GHK-Cu vs Thymosin Alpha-1), a signalling-mitokine vs structural-stabiliser comparison within the mitochondrial peptide field (MOTS-c vs SS-31), an overview of the combination protocols most frequently discussed in research-context literature (Best longevity stacks), a comparison of the two founding mitochondrially-derived peptides (MOTS-c vs Humanin), an unlicensed-vs-licensed GHRH analogue comparison (Sermorelin vs Tesamorelin), a single-defined-peptide-vs-polypeptide-fraction thymic comparison (Thymosin Alpha-1 vs Thymalin), the canonical recovery-peptide pairing (BPC-157 vs TB-500), and a Russian cognitive-peptide comparison (Pinealon vs Semax). New comparisons are added as the published evidence base warrants them, with the same editorial structure across each new entry.

As with the rest of this site, comparison pages are research-context only. We do not recommend specific compounds for human therapeutic use, and we do not endorse a "best longevity peptide" on the available evidence — the published literature does not support that level of confidence. The point of a comparison is to make the mechanistic and evidence-base differences explicit so that any subsequent research decision is well-informed.