Why Synergy Is Often Assumed, Not Demonstrated

The word ‘synergy’ carries a specific meaning in pharmacology. Most peptide-stack claims that invoke synergy are doing something looser — and weaker.

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Additive vs synergistic

Two compounds are additive if their combined effect equals the sum of their individual effects. They are synergistic if the combined effect is greater than the sum.

Synergy is a strong claim. Demonstrating it requires a study with dose arms for each compound alone and for the combination, with statistical analysis (e.g. isobologram) to confirm a more-than-additive effect. Such studies are rare in peptide research.

Mechanism stacking

A more common move is to assert synergy on the basis of complementary mechanisms. “Peptide A drives angiogenesis; peptide B drives progenitor cell recruitment; together they synergise.”

This is mechanism-stacking inference. It is not a demonstrated synergy. It may be additive, sub-additive, or sometimes even antagonistic — none of these are excluded by the mechanism overlap.

Why this matters

Stack pages that imply guaranteed synergy from inference oversell the evidence. On PeptideStacks, our stack evidence dashboards flag direct combination evidence explicitly. Most stacks are graded as inferred, not directly studied.

The one well-known exception in this space

BPC-157 + TB-500 has multiple rodent studies that investigate the combination directly. Even there, the human translation step is unproven and the studies are dominated by a small number of laboratories. We grade it conservatively.