Aging research is organized around a set of shared biological processes rather than a single cause. The widely cited “hallmarks of aging” framework first listed nine: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion and altered intercellular communication (López-Otín et al., 2013). An updated version expanded the list as the field grew (López-Otín et al., 2023).
The compounds below are research tools for studying specific hallmarks in cell culture and animal models. They are sold for laboratory research only. They are not medicines, are not for human or veterinary use, and none is presented here as slowing or reversing aging in people.
Key Cellular Aging Research Compounds
1. Epithalon: Telomerase and Telomere Research
Epithalon (also spelled Epitalon) is the synthetic tetrapeptide Ala-Glu-Asp-Gly (Anisimov et al., 2003). It is the compound most often searched for in connection with telomeres, and the core study is a cell-culture experiment: adding Epithalon to telomerase-negative human fetal fibroblasts induced expression of the telomerase catalytic subunit, telomerase enzyme activity and telomere elongation (Khavinson et al., 2003). The authors suggested this could prolong the life span of a cell population, but replicative life span itself was not the reported endpoint.
In a long-term study in female SHR mice, Epithalon did not change food consumption, body weight or mean life span. It did slow the age-related switching-off of estrous function, reduce chromosome aberrations in bone marrow cells, increase the life span of the last 10% of survivors, and reduce leukemia development, without changing total spontaneous tumor incidence (Anisimov et al., 2003). These are single-laboratory animal findings, and independent replication is an open research need.
2. NAD+: A Central Metabolic Coenzyme
NAD+ is a coenzyme for redox reactions and a co-substrate for enzymes such as sirtuins, CD38 and poly(ADP-ribose) polymerases, linking it to DNA repair, chromatin remodelling, senescence and immune function (Covarrubias et al., 2021). NAD+ levels gradually decline with age in tissues of several model organisms, including rodents and humans, and modulating NAD+ production or use has extended health span and life span in model systems (Verdin, 2015; Covarrubias et al., 2021). Our article What Is NAD+? covers the biochemistry in more depth.
3. SS-31 (Elamipretide): Cardiolipin and Mitochondrial Research
SS-31 is a Szeto-Schiller peptide that targets the inner mitochondrial membrane and binds selectively to cardiolipin, a phospholipid that supports cristae structure and the organization of respiratory complexes (Szeto, 2014). Using a fluorescent analog, researchers showed that SS-31 binds cardiolipin with high affinity and that the SS-31/cardiolipin complex inhibits cytochrome c peroxidase activity. In a rat model of renal ischemia, pretreatment protected cristae membranes and supported prompt ATP recovery on reperfusion (Birk et al., 2013). For broader context, see our guide to mitochondrial function and energy metabolism.
4. Glutathione: Redox Homeostasis
Glutathione (GSH) is the most abundant low-molecular-weight thiol in cells. It protects against oxidative damage and electrophile toxicity and helps maintain redox balance. Published methods describe how to measure cellular GSH status, which is a common endpoint in oxidative stress studies (Forman et al., 2009). Our glutathione research overview covers synthesis and measurement.
5. Thymalin: Thymic Peptides and Immunosenescence
Thymalin is a polypeptide complex originally extracted from calf thymus, not a single defined dipeptide. The dipeptide Glu-Trp (EW) was isolated from thymalin and later synthesized as a separate compound (Morozov & Khavinson, 1997). Recent work describes the Lys-Glu (KE) and Glu-Trp (EW) dipeptides as active components of thymalin (Linkova et al., 2023). In human hematopoietic stem cells in vitro, thymalin reduced the stem-cell markers CD44 and CD117 and increased CD28, a marker of mature T lymphocytes, suggesting it promoted T-cell differentiation (Khavinson et al., 2020). This makes thymalin a research tool for immunosenescence, the age-related decline in immune function.
Mapping Compounds to Hallmarks
| Compound | Hallmark studied | Typical published endpoints |
|---|---|---|
| Epithalon | Telomere attrition | Telomerase activity, telomere length, life span in mice |
| NAD+ | Mitochondrial dysfunction; deregulated nutrient sensing | NAD+ levels, sirtuin and PARP activity |
| SS-31 | Mitochondrial dysfunction | Cardiolipin binding, cristae structure, ATP recovery |
| Glutathione | Redox balance and oxidative damage | GSH status |
| Thymalin | Altered intercellular communication (immune aging) | T-cell differentiation markers |
Multi-Target Aging Research Designs
Because the hallmarks are interconnected (López-Otín et al., 2013), studies often use more than one tool. For example, NAD+ and SS-31 act on mitochondria at different points: coenzyme availability versus membrane structure. Pairing them with appropriate controls can help separate the two. Epithalon work typically needs telomerase and telomere-length assays, and thymalin work needs immune phenotyping. Most of the data above come from cell culture or rodents. Every lot is third-party tested, with identity confirmed by mass spectrometry, and certificates are published on our COA page.
Browse all Cellular Aging Research peptides →
References
- Anisimov VN, Khavinson VKh, Popovich IG, et al. (2003). Effect of Epitalon on biomarkers of aging, life span and spontaneous tumor incidence in female Swiss-derived SHR mice. Biogerontology, 4(4), 193-202. PMID: 14501183 · DOI: 10.1023/a:1025114230714
- Birk AV, Liu S, Soong Y, et al. (2013). The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. Journal of the American Society of Nephrology : JASN, 24(8), 1250-61. PMID: 23813215 · DOI: 10.1681/ASN.2012121216
- Covarrubias AJ, Perrone R, Grozio A, et al. (2021). NAD(+) metabolism and its roles in cellular processes during ageing. Nature reviews. Molecular cell biology, 22(2), 119-141. PMID: 33353981 · DOI: 10.1038/s41580-020-00313-x
- Forman HJ, Zhang H, Rinna A (2009). Glutathione: overview of its protective roles, measurement, and biosynthesis. Molecular aspects of medicine, 30(1-2), 1-12. PMID: 18796312 · DOI: 10.1016/j.mam.2008.08.006
- Khavinson VKh, Bondarev IE, Butyugov AA (2003). Epithalon peptide induces telomerase activity and telomere elongation in human somatic cells. Bulletin of experimental biology and medicine, 135(6), 590-2. PMID: 12937682 · DOI: 10.1023/a:1025493705728
- Khavinson VK, Linkova NS, Kvetnoy IM, et al. (2020). Thymalin: Activation of Differentiation of Human Hematopoietic Stem Cells. Bulletin of experimental biology and medicine, 170(1), 118-122. PMID: 33237528 · DOI: 10.1007/s10517-020-05016-z
- Linkova N, Khavinson V, Diatlova A, et al. (2023). The Influence of KE and EW Dipeptides in the Composition of the Thymalin Drug on Gene Expression and Protein Synthesis Involved in the Pathogenesis of COVID-19. International journal of molecular sciences, 24(17). PMID: 37686182 · DOI: 10.3390/ijms241713377
- López-Otín C, Blasco MA, Partridge L, et al. (2013). The hallmarks of aging. Cell, 153(6), 1194-217. PMID: 23746838 · DOI: 10.1016/j.cell.2013.05.039
- López-Otín C, Blasco MA, Partridge L, et al. (2023). Hallmarks of aging: An expanding universe. Cell, 186(2), 243-278. PMID: 36599349 · DOI: 10.1016/j.cell.2022.11.001
- Morozov VG, Khavinson VK (1997). Natural and synthetic thymic peptides as therapeutics for immune dysfunction. International journal of immunopharmacology, 19(9-10), 501-5. PMID: 9637345 · DOI: 10.1016/s0192-0561(97)00058-1
- Szeto HH (2014). First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. British journal of pharmacology, 171(8), 2029-50. PMID: 24117165 · DOI: 10.1111/bph.12461
- Verdin E (2015). NAD⁺ in aging, metabolism, and neurodegeneration. Science (New York, N.Y.), 350(6265), 1208-13. PMID: 26785480 · DOI: 10.1126/science.aac4854
Research These Compounds: High-purity research peptides available from BioSim: Epithalon, NAD+, GHK-Cu, Thymalin. All 99%+ purity by HPLC; available certificates are published on our COA page.
