Definitive Peptides, including the null results
A large thymosin alpha-1 trial found no clear survival benefit in sepsis. I think that disappointing answer deserves a prominent place in a peptide collection.
The sepsis trial
In 2025, TESTS enrolled 1,106 adults with sepsis across 22 centres. Sepsis is an infection response severe enough to damage organs. The trial compared thymosin alpha-1 with placebo and counted deaths over 28 days. Mortality was 23.4% with the peptide and 24.1% with placebo, with no statistically significant difference.
This unglamorous result has my affection. A treatment with years of use abroad and an appealing immune mechanism received a demanding test; the hoped-for survival advantage failed to emerge. That is useful knowledge.
The result leaves room for uncertainty about the size of any effect, and its scope is sepsis. Other illnesses have their own questions. I accept the trial's limits. Vague talk about immune support offers no rescue for this result.
An earlier hint
The earlier ETASS sepsis trial involved 361 patients. Its roughly 9-percentage-point mortality difference sounded encouraging, although chance remained a plausible explanation. After TESTS, I doubt that earlier number deserves the last word.
A null result means the trial did not establish a difference under its statistical test. It leaves a more precise question than either enthusiasm or dismissal: which benefit, in which patients, did the experiment actually establish? The thymosin alpha-1 page follows that history.
Five compounds, five unfinished conversations
An answer about sepsis survival sits beside very different work here. SELECT measured serious cardiovascular events in adults with existing cardiovascular disease and excess weight or obesity, without diabetes. CJC-1295 trials measured prolonged hormone rises in healthy adults. Those are different achievements.
| Compound | A question the research addressed | Where the answer stops |
|---|---|---|
| Thymosin alpha-1 | Did fewer adults with sepsis die within 28 days? | TESTS found no clear survival advantage. |
| Semaglutide | Did weight and major organ outcomes improve in defined patient groups? | Benefits and harms depend on the outcome and population. |
| BPC-157 | Did injured animal tissues repair? | Human healing remains unproved in large controlled trials. |
| CJC-1295 | Did growth hormone and IGF-1 stay elevated? | Lasting gains in health remain unsettled. |
| MOTS-c | How do cells and mice respond to this mitochondrial signal? | Giving MOTS-c to people still lacks published efficacy trials. |
A precise answer suits me. Semaglutide can have substantial clinical benefits while CJC-1295 remains an interesting hormone experiment; the word peptide gives neither compound the other's results.
Medical approval
Semaglutide has FDA-approved medical uses. Thymosin alpha-1, as thymalfasin, is approved in more than 35 countries and lacks US approval. BPC-157, CJC-1295 and MOTS-c have no approval for human treatment. Laboratory-use material carries no assurance of safe human use.
The questions page deals with names that blur these distinctions. The reading list gathers the papers. I’m still interested when an experiment disappoints; a collection with only successes would be much less informative.