PACAP-38
Also known as: Pituitary adenylate cyclase-activating polypeptide-38
PACAP-38 (also called Pituitary adenylate cyclase-activating polypeptide-38) is an endogenous neuropeptide in the VPAC/PAC1 agonist class. Pituitary adenylate cyclase-activating polypeptide is a 38-amino-acid neuropeptide closely related to vasoactive intestinal peptide, sharing roughly two-thirds sequence identity. It binds the PAC1 receptor with high selectivity and also engages VPAC1 and VPAC2; all are Gs-coupled, so activation raises cyclic AMP in neurons and endocrine cells.
For research use only.
Key Facts
- CAS
- 137061-48-4
- Molecular Weight (MW)
- ≈4534 g/mol
- Half-life
- Very short; rapidly degraded by peptidases
- FDA status
- Not Approved
- Administration Route
- —
- Frequency
- —
- Last updated
- Aug 30, 2026
- Reviewed
- Aug 30, 2026
- Targets
- PAC1VPAC1VPAC2
Research summary
38-aa neuropeptide that activates PAC1/VPAC receptors. Research tool in migraine, neuroprotection, and metabolic models. Not FDA-approved as a drug.
Peptide Library's PACAP-38 profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Protocol
- Dosage Range
- Per research protocol
- Frequency
- —
- Cycle
- —
- Administration Route
- —
- Reconstitution Guide
- —
Not yet checked against primary sources
These figures are compiled from earlier reference material. They have not been verified against FDA labelling, registered trials or published literature, no citation is attached to them, and none of them is a recommended dose. PACAP-38 is queued for dosage evidence review.
Compare reported doses across the whole librarySequence & molecular data
| Molecular formula | C203H331N63O53S |
|---|---|
| Molecular weight | ≈4534 g/mol |
| CAS number | 137061-48-4 |
| Half-life | Very short; rapidly degraded by peptidases |
| Appearance | White lyophilized powder |
| Formulation | Lyophilized Powder |
| PubChem CID | 91935803 |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
Pituitary adenylate cyclase-activating polypeptide is a 38-amino-acid neuropeptide closely related to vasoactive intestinal peptide, sharing roughly two-thirds sequence identity. It binds the PAC1 receptor with high selectivity and also engages VPAC1 and VPAC2; all are Gs-coupled, so activation raises cyclic AMP in neurons and endocrine cells. Reported roles include neurotrophic and neuroprotective signalling, regulation of catecholamine release from the adrenal medulla, and circadian modulation. It has a distinctive place in human research because intravenous infusion reliably triggers migraine-like headache in susceptible people, which established the PACAP pathway as a migraine target and led to therapeutic antibodies against it.
Origin
Endogenous neuropeptide; synthetic research material.
Targets
Studies
- PACAP38-induced migraine attacks are independent of CGRP signaling: a randomized controlled trial
- Part I: Pituitary adenylate cyclase-activating polypeptide-38 induced migraine-like attacks in patients with and without familial aggregation of migraine
- PACAP-38 is increased in the tear fluid of patients with migraine
- Activation and sensitization of meningeal nociceptors by PACAP-38: implications for migraine headache
- Pituitary adenylate cyclase-activating polypeptide (PACAP-38) plays an inhibitory role against inflammation induced by chemical damage to zebrafish hair cells
Regulatory & research status
PACAP-38 is not an FDA-approved product. It is sold for laboratory research and has no approved medical use.
| FDA status | Not Approved |
|---|---|
| Availability | Research-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | Research-Only |
Benefits
PACAP-38 side effects
Side Effects
- Flushing
- Headache / migraine provocation
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
PACAP-38: frequently asked questions
What is PACAP-38?
38-aa neuropeptide that activates PAC1/VPAC receptors. Research tool in migraine, neuroprotection, and metabolic models. Not FDA-approved as a drug.
How does PACAP-38 work?
Pituitary adenylate cyclase-activating polypeptide is a 38-amino-acid neuropeptide closely related to vasoactive intestinal peptide, sharing roughly two-thirds sequence identity. It binds the PAC1 receptor with high selectivity and also engages VPAC1 and VPAC2; all are Gs-coupled, so activation raises cyclic AMP in neurons and endocrine cells.
Is PACAP-38 FDA approved?
No. PACAP-38 is not approved by the FDA for any indication and is categorised as research-only. It has not been reviewed for safety or efficacy as a medicine, and published research should be read as investigation rather than established use.
What is the half-life of PACAP-38?
Reported half-life for PACAP-38 is Very short; rapidly degraded by peptidases. Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied.
What peptides are similar to PACAP-38?
Compounds most often compared with PACAP-38 include 5-Amino-1MQ, Adamax, Adipotide and AICAR. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- PACAP38-induced migraine attacks are independent of CGRP signaling: a randomized controlled trial — J Headache Pain, 2025External reference
- Part I: Pituitary adenylate cyclase-activating polypeptide-38 induced migraine-like attacks in patients with and without familial aggregation of migraine — Cephalalgia, 2017External reference
- PACAP-38 is increased in the tear fluid of patients with migraine — J Neurol Neurosurg Psychiatry, 2026External reference
- Activation and sensitization of meningeal nociceptors by PACAP-38: implications for migraine headache — Brain, 2026External reference
- Pituitary adenylate cyclase-activating polypeptide (PACAP-38) plays an inhibitory role against inflammation induced by chemical damage to zebrafish hair cells — PLoS One, 2018External reference
Related research, comparisons & guides
Related peptides
Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Aug 30, 2026 · Version 1
This PACAP-38 profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
Track PACAP-38 research, inventory and reconstitution in the free Peptide Library app. Get the app for iOS or Android →