Supplement research
Peptides with rising trial starts: where registered research is accelerating
On this page
Counting the year each registered trial started shows where sponsors are spending. Since 2023 the spending has concentrated almost entirely in metabolic chemistry.
Retatrutide had no registered trials before 2023 and has 20 now. Orforglipron went from none to 33 and received FDA approval in April 2026. Cagrilintide, survodutide and mazdutide followed similar curves.
Tirzepatide is the extreme case: 13 trial starts in 2019, 68 registered as starting in 2026.
Rising trial starts mean commercial commitment, not proven benefit. Most compounds that enter development do not finish it, and a registration is a plan rather than a result.
This page counts registered trial start years. It does not compare compounds, recommend any of them, or state that a trial programme has produced a favourable result.
What is being counted
A trial start year is the year a registered study says it began, taken from the record's start-date field. Counting starts rather than total registrations shows where activity is now, rather than where it accumulated. As everywhere on this site, a study counts only if the compound appears in one of its registered intervention names or in an intervention's other-names field.1
The five that went from nothing to a programme
Retatrutide
No registered trial named retatrutide as an intervention before 2023. Since then: five starts in 2023, five in 2024, seven in 2025 and two recorded for 2026, for 20 registered studies, with phase 3 records among them. Its PubMed count over the same period went from nothing to 112 records naming it in title or abstract for 2023-2025.12
Orforglipron
The steepest curve that has already reached the end of it. Eight registered starts in 2023, ten in 2024, eleven in 2025 and four recorded for 2026 — 33 studies in total. On 1 April 2026 the FDA approved application NDA220934 for FOUNDAYO, containing orforglipron calcium, held by Eli Lilly and Company.137
Cagrilintide and survodutide
Both began registering in 2021 and both accelerated sharply. Cagrilintide has 39 registered studies, with starts of two, one, eight, thirteen, seven and eight across 2021 to 2026; its PubMed count for 2023-2025 is 47. Survodutide has 23, with a peak of ten starts in 2024.12
Mazdutide
The youngest of the group and the one whose activity is most concentrated in the present: twelve registered studies, of which seven carry a 2026 start date. Its literature is correspondingly thin, at 28 PubMed records for 2023-2025.12
The established two, for scale
Tirzepatide had 13 registered starts in 2019, six in 2021, then 20, 36, 55 and 68 across 2023 to 2026, for 222 registered studies. Semaglutide, with 589, is registering at a comparable rate — 89 starts in 2024, 85 in 2025, 88 for 2026 — and has records with start dates in 2027 and 2028.1
The comparison worth making is not between these compounds. It is between this whole group and the rest of the directory. 25 of the 68 tracked compounds have no registered trial at all, and none of them is metabolic chemistry with a commercial sponsor. The acceleration is not spread across peptides; it is concentrated in one category with one funding model.1
What acceleration indicates, and what it does not
A rising trial-start count is a reliable indicator of exactly one thing: someone is spending money on the expectation of an approvable product. Registered trials are expensive, and the 2016 registration rule attaches the obligation to the responsible party, meaning a named sponsor stands behind every record.16
It indicates nothing about outcomes, because it is measured before them. Historical estimates of clinical development are consistent on this: an analysis of more than 400,000 development-phase records put the overall probability of a compound entering phase 1 reaching approval in the low double digits, and an earlier analysis of over 4,000 drugs and 800 companies reached the same order of magnitude. Phase 3 is where the largest absolute losses occur.45
Why the contrast is the story
Set the two halves of this site's data side by side. On one side, five compounds that did not exist in the registry four years ago now carry 127 registered studies between them and one approved application. On the other, Semax, Selank, Epithalon, GHRP-2, GHRP-6, Hexarelin, MGF, Dihexa, Noopept and DSIP carry none, and several of them have been discussed publicly for decades.1
The difference is not obviously about the molecules. It is about who stands to own the result. That observation explains the shape of the evidence base without excusing it, and it is the reason this site reports registered study counts next to readership: the two numbers answer different questions, and only one of them is about what is known.1
Does a large trial programme mean a compound works?
No. It means a sponsor has committed to finding out. Historical development success rates are low, and the phase where most programmes fail is the expensive one at the end.
Why does orforglipron have an approval but only 33 trials?
Trial counts and approvals measure different things. An approval rests on the specific studies submitted in the application, which can be a small number of large ones. A high registration count can equally reflect many small studies that never support an application.
Do trials recorded as starting in 2026 exist yet?
Some do. A start date on a registry record is what the responsible party entered, and it can be prospective. Records showing 2027 and 2028 start dates exist for semaglutide, which makes the point clearly.
Is anything outside metabolic chemistry accelerating?
Not materially, among the compounds tracked here. Cerebrolysin is the one non-metabolic compound whose publication count and registered trial starts have both risen across the decade, and it does so from a modest base. The concentration of new trial starts in GLP-1 and dual-agonist chemistry is the dominant pattern in the data.
Sources
- RegulatoryClinicalTrials.govU.S. National Library of Medicine, National Institutes of Health, 2026clinicaltrials.gov/ ↗↩ Back to text
- Secondary sourcePubMedNational Center for Biotechnology Information, U.S. National Library of Medicine, 2026pubmed.ncbi.nlm.nih.gov/ ↗↩ Back to text
- RegulatoryDrugs@FDA application NDA220934 (FOUNDAYO, orforglipron calcium), openFDA recordU.S. Food and Drug Administration, 2026api.fda.gov/drug/drugsfda.json?search=application_number:%22NDA2 ↗↩ Back to text
- Primary studyEstimation of clinical trial success rates and related parametersWong CH, Siah KW, Lo AW. Biostatistics, 2019 · doi:10.1093/biostatistics/kxx069 · PMID 29394327doi.org/10.1093/biostatistics/kxx069 ↗↩ Back to text
- Primary studyClinical development success rates for investigational drugsHay M, Thomas DW, Craighead JL, Economides C, Rosenthal J. Nature Biotechnology, 2014 · doi:10.1038/nbt.2786 · PMID 24406927doi.org/10.1038/nbt.2786 ↗↩ Back to text
- RegulatoryClinical Trials Registration and Results Information Submission (Final Rule), 81 FR 64982U.S. Department of Health and Human Services, Federal Register, 2016www.federalregister.gov/documents/2016/09/21/2016-22129/clinical ↗↩ Back to text
- RegulatoryDrugs@FDA: FDA-Approved DrugsU.S. Food and Drug Administration, 2026www.accessdata.fda.gov/scripts/cder/daf/index.cfm ↗↩ Back to text