Nationally registered neuropeptides and the retrievability of their evidence base
For neuropeptides holding a national marketing registration outside the jurisdictions the Institute routinely reviews, what evidence is retrievable and what can be concluded from it?
§1Abstract
§1.1Review question
For neuropeptides holding a national marketing registration outside the jurisdictions the Institute routinely reviews, what evidence is retrievable and what can be concluded from it?
§1.2PICO frame
Table 1. The registered PICO frame. Any change made after protocol registration is recorded in the amendment log at §5 and is identified there as post hoc.
| Element | As registered |
|---|---|
| Population | Any population in which a nationally registered neuropeptide has been studied. |
| Intervention | Semax, selank, thymalin, epithalon or a related compound. |
| Comparator | Any. |
| Outcomes | Any clinical outcome; and, as a methodological outcome, the retrievability of a protocol, randomisation procedure and analysis plan. |
§1.3Method in brief
A review whose unit of analysis is a study characteristic rather than a treatment effect. The protocol was registered with the Institute's secretariat before the search was executed. The search was run on 29 March 2026 across 8 sources and is reproduced in full at §2. Screening, extraction and certainty assessment were performed independently by two members of the secretariat with disagreement resolved by a third.
§1.4Conclusion
For each compound in this group the Institute was able to establish that a national registration exists and was not able to retrieve a trial report containing a protocol, a randomisation procedure and a pre-specified analysis plan. The Institute therefore grades all efficacy claims very low certainty. It records explicitly that a registration granted by a competent national authority is a regulatory fact, that the Institute is not in a position to review the dossier on which it rests, and that the resulting certainty rating reflects what the Institute can verify rather than a judgement about the regulator.
The conclusion rests on 5 contributing studies, listed with their extracted data at §3 and summarised outcome by outcome at §4.
§1.5Limitations
§1.6Consultation
This review was released for public comment before ratification. Draft synthesis: Nationally registered neuropeptides and the retrievability of their evidence base received 16 submissions. Amendments arising are recorded in the amendment log and are traceable to a numbered submission.