Repair and pain
Does it help the immune system?
Vague as a goal and specific as a measurement. The trials here counted infections or counted cells; those are very different claims.
1,109
people in trials
5
human studies
5
compounds, animal or cell only
1
trials found nothing
Measured in people
Ranked by how many people, which is a fact about the evidence and not a judgement about the compound. The one at the top is the most studied, which is not the same as the best. Counts are never added across compounds, because the same person can appear in more than one trial.
- 1,106 people1 human study1 found nothing
found nothing1,106 adults with sepsis, 22 centres, double blinded and placebo controlled. 28 day all cause mortality was 23.4% on thymosin alpha-1 and 24.1% on placebo, hazard ratio 0.99, p = 0.93. Included here as the contrast: this is what a defined thymic peptide looks like when tested under modern conditions, and the result was null.
BMJ, 2025 · 1,106 people
What people using it report
- Fewer colds over a winter, attributed to the thymic peptide.
- 3 people1 human study
Three children with congenital leptin deficiency treated with daily subcutaneous recombinant human leptin for up to 4 years: sustained reductions in appetite, fat mass, hyperinsulinaemia and hyperlipidaemia, rapid rise in thyroid hormones, appropriately timed puberty, and reversal of reduced CD4 T cell numbers and impaired T cell function. Non-US government funded.
Journal of Clinical Investigation, 2002 · 3 people
- no headcount stated1 human study
Novosibirsk clinical trial in chronic salpingitis and oophoritis timing thymalin to each patient's own lymphocyte succinate dehydrogenase response. Clinical, laboratory and immunological improvement was more frequent when the drug was given while that response was present. An example of the broader Russian clinical literature; small, unblinded, and not designed to isolate thymalin's effect.
Bulletin of Experimental Biology and Medicine, 2015 · no headcount in the line
Also measured, in animals or cells
In cultured human hematopoietic stem cells, Thymalin reduced CD44 and CD117 expression 2 to 3-fold and raised the mature T-cell marker CD28 6.8-fold, which the authors read as differentiation toward mature T lymphocytes.
Bulletin of Experimental Biology and Medicine, 2020 · in vitro
- no headcount stated1 human study
Thymopentin-treated asymptomatic patients maintained higher CD4+ cell percentages over 24 weeks.
AIDS, 1992 · no headcount in the line
- no headcount stated1 human study
The multicentre follow-up reporting enhanced immune function and reduced infections in older adults with TORC1 inhibition. Together with the 2014 trial this is the positive half of the programme, and the phase 3 that followed is on the RTB101 page.
Science Translational Medicine, 2018 · no headcount in the line
Measured in animals or cells, not yet in people
These are separated from the trials above rather than ranked against them, because they answer a different question. A result in a rat is a real result and a reason somebody ran the study; it is not a measurement of what happens in you. Where the human work is missing, the reason is usually money rather than failure, and that is set out at the bottom of this page.
- 1 preclinical study
Measured in animals or cells
Increased CD5 expression and T-helper precursor differentiation in cultured human and rat thymic cells.
Bulletin of Experimental Biology and Medicine, 2013 · in vitro
- 1 preclinical study
Measured in animals or cells
Calorimetry showed bronchogen raised the melting temperature of calf-thymus and mouse-liver DNA by 3.1 degrees C, with no base-pair specificity. This is a physical-chemistry result, not evidence of a lung effect, and like the rest of the bronchogen literature it comes from the single Khavinson research lineage. The paper spells the sequence Ala-Asp-Glu-Leu rather than the Ala-Glu-Asp-Leu used by vendors.
Bulletin of Experimental Biology and Medicine, 2011 · in vitro
- 1 preclinical study
Measured in animals or cells
Cells and mice. Activity against BCL-xL-dependent T cell lymphoma models, extending the preclinical case for selective degradation over inhibition.
- 1 preclinical study
Measured in animals or cells
The ageing result, and the only one. ISRIB reversed integrated stress response activation in the aged mouse brain, reversed spatial memory deficits and improved working memory in old mice, and in hippocampus restored intrinsic neuronal electrophysiological properties and spine density while reducing interferon and T cell mediated immune profiles. Memory endpoints, not lifespan or healthspan. Several authors disclose commercial interests in the compound class.
eLife, 2020 · animal
- 1 preclinical study
Measured in animals or cells
Mouse. A separate group built a self-assembling nanovaccine carrying a Gpnmb seno-antigen peptide. After subcutaneous immunisation it activated CD8-positive T cells and selectively eliminated senescent adipocytes and cardiomyocytes in high-fat-diet progeroid mice, improving adipose metabolic measures and cardiac function. Independent replication of the concept, still in mice.
What people using these actually report
Uncontrolled self-reports, gathered from clinic write-ups, regulatory complaint records and public forums, and reproduced here as written. They are the best guide on this page to what people actually do, what they expect, and what goes wrong, and they cannot show that anything works, because nobody was measured against a placebo and the people who saw no effect mostly stopped posting. Both halves of that are true at once. The negative reports are kept in for the same reason.
- Fewer colds over a winter, attributed to the thymic peptide.
Sources: Longevity and peptide forums including r/peptides, and vendor pages. Uncontrolled self-reports on outcomes that cannot be assessed by an individual over a short period, since the claimed endpoint of the original study was mortality.
- Flu-like symptoms or fatigue in the first days, which people describe as an immune response.
Sources: Clinic write-ups, chronic infection and peptide forums. Uncontrolled self-reports in a domain where seasonal variation dominates and where infection frequency is rarely counted before starting.
Why the trial record looks like this
A missing trial is usually a missing sponsor. Nobody runs a nine-figure programme on a molecule they cannot own, so the compounds with the thinnest human records are often the oldest and most freely available ones rather than the weakest. Taking DT2216 as the example, because it states the problem most clearly:
DT2216 is the clearest case in this field of a rational fix to a mechanism problem being carried into people. The problem, stated in 2010, was that BCL-xL inhibition kills platelets. The fix, published in 2019, was to degrade BCL-xL through a ligase platelets barely express. The first human data, published in 2025, are consistent with the fix: a single dose-limiting thrombocytopenia that resolved in 48 hours, against 29 of 55 patients with grade 3 or 4 thrombocytopenia on navitoclax.
That is a pharmacology success, not a geroscience result. Every DT2216 trial is in cancer, no ageing indication is registered, and the senolytic case for it remains entirely in mice. A Children's Oncology Group trial is suspended for unacceptable toxicity, which belongs on the same page as the phase 1 tolerability finding.
A compound appears here only when a citation on its own page states this outcome and reports a result for it; naming it is not enough. Human, animal and cell work are counted separately and never merged. Participant counts are read from the study lines and deliberately undercount. Nothing here is advice, and nothing here is a recommendation to take or to avoid anything.