SHLP-6

SHLP-6 is one of the small humanin-like peptides encoded within the mitochondrial 16S rRNA region. The original 2016 report found increased DNA-fragmentation apoptosis after SHLP-6 exposure in two cultured cell lines: mouse NIT-1 cells and human-derived 22Rv1 prostate cancer cells. The same paper studied SHLP-2 and SHLP-3 more deeply in metabolic and stress experiments; those results should not be assigned to SHLP-6. The apoptotic target and pathway for SHLP-6 were not established by the two assays. Cobb et al., 2016, PMID:27070352

What later studies add

• A 2018 experiment profiled mitochondrial-derived peptides, including SHLP-6, in senescent human fibroblast cultures. Its peptide interventions focused on humanin and MOTS-c; it did not test SHLP-6 as a senolytic. PMID:29886458
• In 2020, investigators measured circulating endogenous SHLP-6 around high-intensity exercise in ten untrained men. This was a physiological observation, with no SHLP-6 administered and no therapeutic endpoint. PMID:32271093
• A 2023 comparative genetics paper described a predicted 20-amino-acid canonical human SHLP-6 and a 9-amino-acid truncation associated with heterothermy in some rodents; it also analyzed public human mass-spectrometry data. This does not validate the dossier’s former 22-amino-acid sequence or a therapeutic formulation. A separate 2023 sequence-analysis paper reported evolutionary selection signals for SHLP-6, which speak to possible biological function rather than treatment benefit. PMID:37675281 · PMID:37644144
• A study first published in September 2024 tested a synthetic, non-formylated 20-amino-acid SHLP-6 (MLDQDIPMVQPLLKVRLFND) in HEK293 cells engineered to express human formyl peptide receptor FPR1 or FPR2. The peptide activated receptor-dependent signaling assays at both receptors; ERK1/2 activation was detected at FPR1 but not FPR2, and it did not induce receptor internalization in this model. The paper’s separate ex vivo human-neutrophil experiment tested other ligands, not SHLP-6. These cell results do not establish direct physical binding, an effect in people, or that FPR signaling caused the 2016 apoptosis result. Pajonczyk et al., PMID:39294930
• Two 2025 reports from the same three authors tested SHLP-6 in stressed zebrafish larvae. One used a copper-sulfate model and reported changes in malformations, oxidative-stress markers, and locomotion. The other combined computational docking predictions with an H₂O₂ zebrafish experiment reporting stress-related and behavioral measures. Docking is not measured protein binding; neither fish model tests the 2016 cell-apoptosis finding directly or establishes human neuroprotection. PMID:40292418 · PMID:40915070
• An April 2026 paper analyzed human mitochondrial sequences and HEK293 mitochondrial ribosome-profiling data, finding a SHLP-6 translation-initiation signature. A July 2026 placental study compared 20 controls with 19 gestational-diabetes cases and measured SHLP-6 mRNA among SHLP1–6 transcripts. It measured humanin and SHLP-2 peptides, not SHLP-6 peptide, and did not administer SHLP-6. Neither paper is a human treatment trial. PMID:41923600 · PMID:42453115

What the evidence does not establish

The findings span different tissues, species, exposures, and outcomes. A 2010 AACR conference abstract reported reduced growth and angiogenesis after one week of SHLP-6 treatment of 22Rv1 xenografts in SCID mice, as well as apoptosis in several prostate cancer cell lines. Its limited methods, absence of a full animal-study report in the sources reviewed, and repeated conference presentations do not amount to independent replication or clinical evidence. AACR abstract 4537, DOI:10.1158/1538-7445.AM10-4537

The 2016 cell-apoptosis result and later zebrafish stress results are not direct replications or contradictions. The FPR cell assay identifies a signaling response but does not show that it drives apoptosis or a therapeutic effect. No cited experiment shows selective removal of senescent cells, selective killing of cancer cells, or a clinical effect from administering SHLP-6 to a person. A single molecular-weight or chain-length widget would also obscure the distinction between the synthetic 20-amino-acid reagent and isoform questions about endogenous SHLP-6. PMID:27070352 · PMID:37675281 · PMID:39294930 · PMID:40292418 · PMID:40915070

Evidence grade: very low for human therapeutic benefit. This page describes research, not a recommendation to use SHLP-6 or an assessment of personal safety. Human treatment, dosing, and interaction evidence cannot be inferred from these studies.