F tier · safety concern
DNSP-11 has never been given to a human being: a ClinicalTrials.gov search returns zero registered studies, and the entire literature is roughly six preclinical papers from a single University of Kentucky group. The clinical record invoked to support it belongs to the parent protein GDNF, whose only proper randomised trial missed its primary endpoint (p=0.41) and whose commercial development was halted in 2004 over preclinical irreversible brain damage.
dnsp-11
DNSP-11 is an 11-amino-acid amidated peptide (PPEAPAEDRSL-amide) predicted to be endoproteolytically cleaved from the pro-domain of proGDNF, the precursor of glial cell line-derived neurotrophic factor. It was described and developed at the University of Kentucky by Bradley, Gash and Gerhardt, and in rodent and non-human-primate work it increased striatal dopamine turnover, spared tyrosine-hydroxylase-positive neurons and reduced rotational asymmetry in 6-OHDA-lesioned rats. There is no human data of any kind: no registered clinical trial, no published pharmacokinetics, and no regulatory approval anywhere.
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available as a research reagent
≥ 98% HPLC · lyophilised powder · batch certificate published. Grade F above is our own and is not adjusted because we stock it.
the explanation
DNSP-11 is a tiny fragment snipped off the front of GDNF, a natural brain protein that supports dopamine-producing nerve cells. In rats and a small number of monkeys it raised dopamine activity and protected those cells from a toxin used to model Parkinson's disease. It has never been tested in a single human being, and the human trial results people cite for it are actually trials of GDNF itself, which did not work as hoped.
regulatory status
Unapproved; preclinical research chemical only
DNSP-11 is not approved as a medicine in the UK, EU, US or any other jurisdiction, and has no marketing authorisation, orphan designation or investigational-new-drug programme on public record. A ClinicalTrials.gov query for DNSP-11 returns zero studies; no trial has ever been registered. The composition of matter is covered by University of Kentucky Research Foundation patent US9402875B2 (published as US20130065830A1, priority 27 October 2006, granted 2 August 2016), which claims PPEAPAEDRSL-amide as SEQ ID NO:4 and cites only cell-culture, rat and single-monkey data. It is not a lawful dietary ingredient — no New Dietary Ingredient notification is on record and it appears on no FDA 503A or 503B compounding bulks list — and it is supplied in the UK strictly as a research reagent for in vitro and non-human laboratory use, not for human or veterinary administration. DNSP-11 is not named on the WADA Prohibited List and no WADA classification for it is documented, though neurotrophic and growth-factor-related peptides can fall within the Prohibited List's growth-factor provisions; athletes should assume nothing.
how it works · proposed mechanism
GDNF is synthesised as a precursor, proGDNF, whose pro-domain is cleaved away to release the mature growth factor. DNSP-11 corresponds to an 11-residue stretch of that discarded pro-domain, bounded by predicted dibasic endopeptidase cleavage sites, and the founding hypothesis is that this fragment is itself bioactive rather than inert waste. Critically, the proposed mechanism is explicitly not GDNF's mechanism — the peptide does not appear to use GDNF's receptor complex.
Pro-domain origin, not mature GDNF
DNSP-11 sits inside the proprotein region of GDNF, upstream of the mature growth factor sequence, and is predicted to be liberated by endoproteolytic cleavage at flanking dibasic sites. It is a distinct chemical entity from GDNF: 11 residues and roughly 1.2 kDa versus a ~30 kDa disulphide-linked homodimeric glycoprotein. Any inference from GDNF trial data to DNSP-11 therefore crosses a real pharmacological boundary rather than extending a dose range.
RET/GFRα1-independent signalling
The founding PLOS ONE study reported that pull-down and ELISA analyses found no interaction between DNSP-11 and the GFRα1 co-receptor, and the authors concluded the peptide likely signals through pathways not directly involving GFRα1. Proteomic analysis instead recovered metabolic proteins including GAPDH. This means the receptor pharmacology is essentially uncharacterised — there is no identified target, no binding affinity and no dose-response anchored to a receptor occupancy model.
Anti-apoptotic and mitochondrial protection in vitro
In MN9D dopaminergic cells challenged with 6-OHDA, DNSP-11 significantly reduced TUNEL-positive cell counts and caspase-3 activity, and it increased tyrosine-hydroxylase-positive neuron survival by about 75% in primary E14 rat mesencephalic culture. The associated patent frames the activity as protection against Complex I mitochondrial inhibitors. These are cell-culture endpoints in immortalised and embryonic rodent systems, not measures of function in an adult, aged or diseased human brain.
CNS delivery and striatal target engagement
Radiolabelled 125I-DNSP-11 distributed diffusely through rat brain including striatum and substantia nigra within 30 minutes of a single intranasal dose, and repeated intranasal dosing in awake rhesus macaques over 10 weeks produced bilateral striatal changes in dopamine metabolites without observed adverse behaviour or weight loss. Note that the efficacy signals in lesioned rats came from direct stereotaxic injection into the substantia nigra, not from any peripherally administered route. No human biodistribution, brain-penetration or plasma pharmacokinetic study has been published.
what’s reported
evidence shape
7 sourcesThe composition of the cited literature by study type. This describes the shape of the evidence, not its quality — and it does not by itself set the grade.
⚠ the catch
DNSP-11 has zero human evidence — not thin human evidence, zero. A ClinicalTrials.gov search returns no registered study of DNSP-11 under any name, and a PubMed search returns only about eight records, of which roughly six are primary DNSP-11 papers published between 2010 and 2019 essentially all from the same University of Kentucky group (Bradley, Gash, Gerhardt and colleagues), with no independent laboratory replication of the in vivo efficacy. The headline numbers marketers quote come from a handful of 6-OHDA-lesioned rats dosed by direct stereotaxic injection into the substantia nigra — a neurosurgical route nobody selling the peptide is proposing — plus a 10-week intranasal feasibility study in a small group of macaques whose stated purpose was to establish methodology and target engagement, not efficacy. The clinical credibility attached to DNSP-11 is borrowed almost entirely from GDNF, and that loan does not survive inspection: the only randomised, double-blind, placebo-controlled trial of intraputamenal GDNF (Whone et al., Brain 2019, n=41) missed its primary endpoint, with a between-group difference of −4.9% on OFF-state UPDRS-III (95% CI −16.9 to 7.1, p=0.41), and Amgen halted its GDNF programme in late 2004, confirming on 11 February 2005 that it would not resume treatment in the 48 trial patients because of preclinical safety findings including irreversible brain damage alongside the absence of demonstrated benefit. Since DNSP-11's own authors reported it does not bind GFRα1 and does not act through GDNF's receptor, GDNF's data cannot legitimately be transferred to it in either direction — which leaves the peptide with no human evidence base at all.
key published findings
- DNSP-11 is PPEAPAEDRSL-amide, an 11-residue C-terminally amidated peptide from the proGDNF pro-domain; formula C50H81N15O18 and free-base mass 1180.27 Da are consistent with the amidated sequence claimed as SEQ ID NO:4 in University of Kentucky patent US9402875B2.
- No human trial of DNSP-11 has ever been registered or published — ClinicalTrials.gov returns zero studies, and there is no IND, orphan designation or approval in any jurisdiction.
- In the founding PLOS ONE study (Bradley et al., 2010), a single injection into the substantia nigra of 6-OHDA-lesioned rats produced a >100% rise in resting striatal dopamine at 28 days and roughly 50% fewer apomorphine-induced rotations sustained beyond four weeks.
- DNSP-11 did not interact with the GDNF co-receptor GFRα1 in pull-down and ELISA assays; the authors concluded it signals independently of GFRα1, undercutting any read-across from GDNF clinical data.
- Repeated intranasal dosing in awake, unsedated rhesus macaques over 10 weeks achieved bilateral striatal dopamine-metabolite changes with no observed adverse behavioural effects or weight loss — but this was an explicitly methodological feasibility study.
- Radiolabelled 125I-DNSP-11 reached rat striatum and substantia nigra within 30 minutes of a single intranasal dose, establishing CNS access in rodents only.
- The parent protein GDNF has an unambiguous clinical failure record: Whone et al. (Brain 2019) missed the primary endpoint at p=0.41 despite a significant 18F-DOPA uptake increase, and Amgen terminated its liatermin programme in 2004–2005 citing preclinical irreversible brain damage and no demonstrated benefit across 48 patients.
limitations of the evidence
- Zero human exposure: no phase 1, no pharmacokinetics, no bioavailability, no dose-ranging, no immunogenicity data in humans.
- Single-centre evidence base — the in vivo efficacy findings have not been independently replicated by a laboratory unconnected to the originating University of Kentucky group.
- The strongest efficacy data used direct stereotaxic intranigral injection, a route with no relevance to how the peptide is administered outside a neurosurgical setting.
- Non-human-primate work comprises a 10-week intranasal methodology study measuring neurochemical target engagement, plus a single aged rhesus monkey in the patent record — neither is a powered efficacy or toxicology study.
- No identified molecular target or receptor; mechanism is inferred from proteomic pull-downs and downstream survival markers rather than defined pharmacology.
- No published half-life, clearance, metabolism or brain-exposure data in any species, so no basis exists for predicting human exposure.
- Rodent Parkinson's models (6-OHDA, MPTP-type lesions) are acute toxin models that have repeatedly failed to predict clinical efficacy for neurotrophic agents, GDNF itself being the canonical example.
- Marketing and vendor material routinely conflates DNSP-11 with GDNF, despite the originating authors reporting that the two do not share receptor pharmacology.
documented safety signals
- No human safety data of any kind exists — no adverse event profile, no maximum tolerated exposure, no laboratory monitoring precedent.
- No published genotoxicity, carcinogenicity, reproductive-toxicity or repeat-dose regulatory toxicology package for DNSP-11 in any species.
- Class-level flag on the parent protein: Amgen halted its GDNF Parkinson's trials in late 2004 and confirmed on 11 February 2005 that treatment would not resume in the 48 participants, citing preclinical safety risks including irreversible brain damage together with the absence of demonstrated benefit. DNSP-11 is a distinct molecule, but this is the programme whose narrative is used to legitimise it.
- Chronic elevation of dopaminergic tone and neurotrophic signalling in the human CNS has no characterised long-term safety profile for this agent; the longest documented exposure in any species is 10 weeks in macaques.
- Product-quality risk is material: DNSP-11 circulates only through research-chemical suppliers with no pharmacopoeial monograph, no marketing authorisation and no regulatory oversight of identity, purity, endotoxin content or trifluoroacetate residue.
- Not named on the WADA Prohibited List and no WADA classification is documented — absence of a listing is not a clearance, and the Prohibited List's growth-factor provisions and catch-all for non-approved substances may apply.
identity
| full name | Dopamine Neuron Stimulating Peptide-11 |
| category | Cognitive |
| modality | peptide |
| formula | C50H81N15O18 |
| molar mass | 1180.27 g/mol |
| sequence | Pro-Pro-Glu-Ala-Pro-Ala-Glu-Asp-Arg-Ser-Leu-NH2 (PPEAPAEDRSL-amide; C-terminally amidated) |
laboratory handling
| storage | Supplied as the trifluoroacetate salt and stored desiccated at -20 °C, protected from light. Reconstituted solution is aliquoted and frozen. Handling information only. |
| solubility | Soluble in sterile water and aqueous buffer. Residual trifluoroacetate from synthesis is normal for this material and is reported on the certificate of analysis. |
Handling information describes laboratory practice for a research reagent. It is not a preparation guide for use in humans.
the receipts
7 citedU.S. National Library of Medicine, ClinicalTrials.gov · 2026 · official
PLOS ONE · 2010 · preclinical
Journal of Neuroscience Methods · 2015 · preclinical
Journal of Neuroscience Methods · 2018 · preclinical
Brain · 2019 · randomized
Sigma-Aldrich (Merck KGaA) · 2026 · reference
Amgen newsroom · 2005 · press release
Sources marked tertiary or press release are the weakest citations on this page.
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