What Is Testagen?
Testagen is a tetrapeptide bioregulator developed by Professor Vladimir Khavinson targeting testicular tissue — specifically the Leydig cells (testosterone-producing) and Sertoli cells (spermatogenesis-supporting) of the testis. It is designed to restore normal testicular cell function that declines with aging. It was developed by Prof. Vladimir Khavinson at the St. Petersburg Institute of Bioregulation and Gerontology.
Testicular Aging
Testosterone production declines by approximately 1–2% per year after age 30, driven by progressive Leydig cell loss, reduced LH receptor sensitivity, and impaired intratesticular signaling. Sertoli cell function also declines, contributing to age-related reductions in sperm quality and fertility. These changes underlie male hypogonadism of aging, manifesting as fatigue, reduced libido, loss of muscle mass, and increased fat.
Research Applications
Animal studies have demonstrated improved testicular histology in aged animals — with better preservation of Leydig cell numbers, improved Sertoli cell architecture, and higher intratesticular testosterone concentrations. Russian clinical research documents improved testosterone levels and sperm quality parameters in men receiving Testagen as part of anti-aging bioregulator protocols. It is often combined with Libidon and Prostamax for comprehensive male reproductive health support.
Quick Reference
Member reference tables summarize the compound's research parameters.
Research Indications
Research Protocols
As reported in cited literature and research-community logs (see Research Citations below), not a personal dosing recommendation.
This member section describes parameters reported in the research literature.
Peptide Interactions
This member section summarizes reported compound interactions and evidence limitations.
Reported Research Time Points
This member section summarizes reported research time points.
Safety Notes
Included for harm-reduction awareness only, in the event this compound is encountered outside its labeled research use. Inclusion here does not imply RUO Codes endorses, recommends, or instructs human use.
This member section discusses research safety considerations and uncertainties.
Quality Indicators
Research Citations
- Peptide bioregulators: A new class of geroprotectors
Khavinson VKh, Kuznik BI, Ryzhak GA, 2013, Advances in Gerontology - Peptide bioregulator efficacy in the correction of reduced thyroid gland function in the residents of Magadan Region
Gorbachev AL, Lugovaia EA, Ryzhak GA, Khavinson VKh, 2005, Advances in Gerontology - Peptide Regulation of Gene Expression: A Systematic Review
Khavinson V, Linkova N, Dyatlova A, et al., 2021, Molecules - Penetration of short fluorescence-labeled peptides into the nucleus
Fedoreyeva LI, Kireev II, Khavinson VKh, Vanyushin BF, 2011, Biochemistry (Moscow) - Penetration of short fluorescence-labeled peptides into the nucleus in HeLa cells and in vitro specific interaction of the peptides with deoxyribooligonucleotides and DNA
Fedoreyeva LI, Kireev II, Khavinson VKh, 2011, Biochemistry (Mosc) - Khavinson development attribution. Existing stored entry reference; Existing stored entry reference
Testagen is a tetrapeptide bioregulator developed by Professor Vladimir Khavinson targeting testicular tissue — specifically the Leydig cells (testosterone-producing) and Sertoli cells (spermatogenesis-supporting) of the testis. It is designed to restore normal testicular cell function that declines with aging.