Immune & inflammation peptides

These two compounds sit at opposite ends of the evidence scale. Read both for the same reason. Each one shows what a real trial does to a claim.

Thymosin Alpha-1 met one and the result was mixed. More than 35 countries approve thymalfasin for chronic hepatitis B and C and as an adjunct in cancer immunotherapy. In severe sepsis, the earlier ETASS multicenter randomized trial in China suggested a benefit. Then the TESTS Phase 3 trial enrolled 1,106 participants and found no overall decrease in mortality (BMJ, 2025). Subgroups of elderly and diabetic patients showed possible signals. A signal in a subgroup of a null trial is a question for the next study. It is not an answer. The FDA does not approve it. Human tolerability across indications is good.

KPV has not met one yet. KPV is the C-terminal fragment of α-MSH and carries no pigmentary activity. Its anti-inflammatory action is largely intracellular: it inhibits NF-κB and MAPK signaling and decreases TNF-α, IL-1β, and IL-6. It enters cells through the PepT1 transporter, which inflamed gut tissue increases. The nanoparticle work in Gastroenterology in 2017 reached efficacy at a dose about 12,000-fold lower, in a mouse colitis model. No human randomized controlled trial has finished, and at its July 2026 meeting the FDA proposed not to add KPV to the 503A bulks list.