Epithalon vs FOX-04

Epithalon

Epithalon (also known as Epitalon or epithalamin) is a synthetic tetrapeptide (Ala-Glu-Asp-Gly) developed by Vladimir Khavinson at the Saint Petersburg Institute of Bioregulation and Gerontology in Russia. Its primary mechanism of action involves activation of telomerase, the enzyme responsible for adding telomeric repeats (TTAGGG) to chromosome ends, thereby counteracting the progressive telomere shortening associated with cellular aging. Published research by Khavinson and colleagues (Bulletin of Experimental Biology and Medicine, 2003) demonstrated that epithalon increased telomerase activity in human somatic cells and extended the replicative lifespan of fibroblast cultures beyond the Hayflick limit. In animal studies, chronic epithalon use in aging rats was associated with increased lifespan and restoration of melatonin secretion rhythms from the pineal gland, which naturally declines with age (Anisimov et al., Mechanisms of Ageing and Development, 2003). The peptide also appears to modulate expression of genes involved in antioxidant defense and circadian rhythm regulation. Compared to other telomerase activators such as TA-65 (a small molecule derived from astragalus), epithalon is a direct peptide bioregulator with a well-characterized tetrapeptide sequence. Research also suggests potential effects on retinal health, with studies indicating photoreceptor preservation in aging retinal models. Store lyophilized powder at -20C protected from moisture; reconstitute with bacteriostatic water and refrigerate at 2-8C for up to 21 days. Epithalon is studied by gerontology research centers, telomere biology laboratories, and chronobiology departments investigating age-related decline in pineal gland function.

FOX-04

FOXO4-DRI (Proxofim) is a D-retro-inverso peptide designed to disrupt the interaction between FOXO4 (Forkhead box O4) and p53 in senescent cells. In cellular senescence, FOXO4 sequesters p53 in the nucleus, preventing p53-mediated apoptosis and allowing damaged senescent cells to persist. FOXO4-DRI competitively binds FOXO4, displacing p53, which then translocates to mitochondria and triggers the intrinsic apoptotic pathway selectively in senescent cells, while leaving healthy cells unaffected due to their low FOXO4 expression. The landmark study by Baar et al. (2017) published in Cell demonstrated that FOXO4-DRI selectively induced apoptosis in senescent human fibroblasts in vitro and cleared senescent cells in naturally aged and fast-aging XpdTTD/TTD mice in vivo. Treated mice showed restored fur density, improved renal function, and increased exploratory behavior. This study established FOXO4-DRI as one of the first peptide-based senolytics with demonstrated in vivo efficacy. Follow-up research has explored its effects on senescence-associated secretory phenotype (SASP) reduction and tissue rejuvenation markers. Compared to small-molecule senolytics like dasatinib plus quercetin (D+Q) or navitoclax (ABT-263), FOXO4-DRI operates through a fundamentally different mechanism targeting the FOXO4-p53 protein-protein interaction rather than Bcl-2 family anti-apoptotic proteins or tyrosine kinases. The D-retro-inverso design provides protease resistance while maintaining binding specificity, though at a higher molecular weight than small-molecule alternatives. FOXO4-DRI must be stored lyophilized at -20°C and protected from light and moisture. Reconstitute with bacteriostatic water and store at 2-8°C, using within 2-3 weeks. This peptide is studied by aging biologists, senescence researchers, geroscientists, and nephrology and dermatology researchers investigating senolytic interventions for age-related tissue deterioration.

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