Increasing Direct-to-Consumer Use of Semax and Selank Peptides Decoded from LLM-Curated Clinical Notes and Physician Adjudication

Semax and Selank are synthetic regulatory peptides that are not FDA-approved for human use but are marketed direct-to-consumer for cognition, mood and stress resilience. The extent of the documented use of these unapproved peptides in routine clinical care remains poorly characterized and, because neither is dispensed through regulated pathways, is largely absent from structured medication data of Electronic Health Records (EHRs). Using Large Language Model (LLM) curation of de-identified clinical notes from the nference federated data network with manual adjudication of the LLM-curated insights, here we characterize the clinically documented use of each peptide and the real-world medical contexts in which their use occurs. Clinical note documentation of both Semax and Selank increased starting in 2024, with an average quarter-over-quarter growth of 14% for Semax and 16% for Selank over the past year. Among 43 and 39 patients with clinical note-mentions of Semax or Selank, use was confirmed via LLM curation in 22 (51%) and 27 (69%) patients, respectively. Physician adjudication agreed with the LLM’s use classification in 164 of 165 individual note-level assessments (99.4%) across patients with a Semax or Selank mention, including patients whose use was not confirmed. In the pooled cohort of patients with confirmed Semax or Selank use (N = 49), cognitive enhancement (28.6%) and mood/anxiety/stress support (28.6%) were the most common reasons for use provided by the patients, with less common reasons including energy or performance, sleep, musculoskeletal and gastrointestinal indications. Manual adjudication showed 86.7% agreement with the LLM-curated reasons for use. Both peptides were commonly administered intranasally (37%), and there was documentation of “stacking” with other peptides in 33 patients (67%), such as CJC-1295, ipamorelin, semaglutide, and tirzepatide. In the pooled cohort, clinical notes recorded patient-reported positive or effective responses in 16 of 49 patients (33%) and product- or administration-related safety concerns or adverse-event sentiments in 13 of 49 (27%). Manual adjudication agreed with LLM-curated self-reported-effect classifications in 94.2% of 103 reviewed records. Manual review showed isolated dyspnea, palpitations, flushing, and emergency department visits during the temporal periods overlapping with patient-reported use of Semax or Selank (n<11). This study is not designed to evaluate the effectiveness or harm of Semax or Selank. Rather, it highlights the rising use of unapproved direct-to-consumer peptides without any structured coding mechanism in EHR systems, emphasizing the need for greater awareness among healthcare practitioners.