Immunomodulator

Crystagen is one of the immune-designated short peptides in the Khavinson family, and its indexed literature consists of a single Russian-language paper: a study of the molecular aspects of immunoprotective activity of Vilon, Timogen, Crystagen and R-1 in spleen during ageing. That is the entire file. There is no animal efficacy study specific to it, no human study, no pharmacokinetics and no published sequence in the sources available here. Everything else asserted about it - the organ it regulates, what it does, how to take it - comes from sellers and from the general claims made for the family as a whole.

Thymalin is a polypeptide extract of calf thymus, made in St Petersburg from the 1970s and the thymic half of Vladimir Khavinson's bioregulator programme - epitalon's parent extract Epithalamin being the pineal half. Its most striking claim is also its most-cited paper: a controlled study in elderly people reporting that mortality fell 2.0-2.1-fold in the Thymalin group, and 4.1-fold in those given Thymalin with Epithalamin annually for six years. That is an extraordinary result, published in a journal with limited reach, from the group that developed the compound, and never independently replicated. It is not a defined molecule: it is a tissue hydrolysate whose composition is set by a manufacturing process, and the dipeptides KE and EW have since been identified within it.

Thymosin alpha-1 is a 28-residue peptide from thymosin fraction 5, a thymus extract, and it is licensed in around thirty countries as an immunomodulator - mainly for chronic hepatitis B and as an adjunct in sepsis. It has a better evidence base than anything else in this group except teriparatide, and it has just had the reckoning that comes with proper trials. In 2013 ETASS reported 28-day mortality in severe sepsis of 26.0% against 35.0% on control, and a decade of meta-analyses built on that. Then TESTS, a 1106-patient double-blind placebo-controlled phase 3 trial published in the BMJ in 2025, found 28-day mortality of 23.4% against 24.1%, hazard ratio 0.99 - no benefit. A 2026 Cochrane review of hepatitis B rates all its evidence as very low certainty.

Vilon is the dipeptide Lys-Glu (KE), the shortest compound in the Khavinson bioregulator programme and the thymic counterpart to epitalon. Its mouse data are the most substantial in this group: subcutaneous vilon from the sixth month of life increased physical activity and endurance, lowered body temperature, prolonged lifespan and prevented spontaneous tumours, with no unfavourable effects on development. It also has a genuinely interesting mechanistic result - DNA microarray of 15,247 clones in mouse heart found vilon changed expression of 36, and epitalon of 98, which is a specific and modest effect rather than the sweeping one the marketing implies. As with the rest of the programme, the human work is chromatin studies in lymphocytes from elderly donors, not clinical trials.