Peptide research in 2026 is organized around three converging scientific programs that reflect both the maturation of GLP-1R agonist pharmacology and emerging mechanistic insights in mitochondrial biology and telomere maintenance. This review summarizes the current scientific rationale, key investigational compounds, and methodological considerations for each priority area.
Triple GLP-1, GIP and glucagon receptor agonism
The success of Tirzepatide (dual GLP-1R/GIP-R) and the Phase 2 publication of Retatrutide (triple GLP-1R/GIP-R/GCG-R, Jastreboff et al., NEJM, 2023) have stimulated interest in further receptor combinations. Active research programs include: (1) AMG 133 (Amgen), GLP-1R agonist/GIP-R antagonist conjugate, in Phase 2; (2) Mazdutide (Innovent Biologics), GLP-1R/GCG-R dual agonist Phase 3; (3) peptide-based GIP receptor antibody combinations. The theoretical basis for triple agonism is additive-to-synergistic receptor coverage: GLP-1R reduces appetite and slows gastric emptying; GIP-R augments insulin secretion and modulates adipose tissue energy storage; GCG-R increases hepatic glucose output and thermogenesis.
SS-31 and cardiolipin binding
Elamipretide (SS-31, Ac-Arg-2',6'-Dmt-Lys-Phe-NH₂) is an aromatic-cationic mitochondria-targeting peptide that selectively binds cardiolipin in the inner mitochondrial membrane, stabilizing cristae architecture and preserving respiratory complex superassembly. Phase 3 enrollment continues. SLU-PP-332, an ERRα/γ agonist, activates mitochondrial biogenesis gene networks (PGC-1α, TFAM, CPT1) through nuclear receptor activation, complementary to SS-31's structural mitochondrial support. Combination protocols investigating SS-31 + SLU-PP-332 in aged murine models represent current frontier research.
Epitalon and telomerase activation
Epitalon (Ala-Glu-Asp-Gly, MW 390.3 Da) is a synthetic tetrapeptide derived from the bovine pineal peptide epithalamin. Its proposed telomerase-activating mechanism involves activation of telomerase reverse transcriptase (TERT) gene expression in human somatic cells, documented in vitro by Khavinson et al. in multiple publications between 1999 and 2012. The mechanistic basis involves interaction with the PCNA (proliferating cell nuclear antigen) promoter region. In vivo studies in aging murine models report elongation of leukocyte telomere length and extended mean/maximum lifespan. Critical limitation: no Phase 2/3 data in ICH-harmonized regulatory frameworks exists; the published in vitro and rodent evidence does not directly support translational assumptions. Researchers should note that TERT activation in somatic cells theoretically carries oncogenic risk, a mechanistic concern that requires tumor formation monitoring in any in vivo protocol using this compound.
What to standardise across the three areas
Across all three priority areas, researchers should standardize: (1) lot documentation for all compounds used; (2) mitochondrial function readouts (oxygen consumption rate by Seahorse XF analyzer, ATP/ADP ratio, mtDNA copy number); (3) telomere length by quantitative PCR (qPCR) or Southern blot (terminal restriction fragment analysis); (4) receptor selectivity confirmation by competitive radioligand binding assays before interpreting pharmacology endpoints. These compounds are for research and laboratory use only. Not for unsupervised human consumption.