PACAP-38 dosing & administration
Neuroprotective polypeptide with potent anti-inflammatory and cytoprotective properties discovered in 1989
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Dosing
How much do I take?
Intravenous: Delivered straight into a vein through a drip (IV), done by a clinician.
Bioavailability Complete (about 100%) — delivered straight into the bloodstream.
10 pmol/kg/min
Frequency
Continuous infusion
Duration
20-minute single infusion
Timing
Best time to take
PACAP-38 is administered intravenously in a clinical setting. Timing is determined by your healthcare provider based on the treatment protocol and your medical needs.
With food?
IV administration of PACAP-38 is not dependent on meal timing. Your healthcare team will provide specific instructions regarding food and fluid intake around treatment sessions.
If stacking
PACAP-38 should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting your dose
Increase if
- You've tolerated the current dose for the recommended period without significant side effects
- Therapeutic goals haven't been met at the current dose level
- Your healthcare provider recommends dose escalation based on your response
- Lab work or clinical assessments support a higher dose
Decrease if
- Side effects are bothersome or impacting daily life despite management strategies
- You experience any signs of an adverse reaction
- Lab results indicate the need for dose reduction
- Your healthcare provider recommends a lower dose based on your response
Signs of right dose
- Therapeutic goals being met with minimal side effects
- Stable and consistent response to treatment
- Lab values or clinical markers trending in the right direction
- Good tolerance with manageable or absent side effects
Administration
How do I use it?
Reconstitution
What you need
Injection
Route
Subcutaneous injection (into the fatty tissue just under the skin)—allows for consistent absorption and can be self-administered at home after proper training
Best sites
Storage
Before reconstitution
Store PACAP-38 in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
After reconstitution
Once reconstituted, PACAP-38 should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Signs of degradation — discard the vial
Sample daily schedule
As prescribed (once daily)
As prescribed by your healthcare provider injection
Site: Intravenous infusion—rotate sites if applicable
Maintain a consistent schedule for optimal results with PACAP-38. Set reminders if needed. If you miss a dose, follow your healthcare provider's instructions—do not double up on doses to compensate.
Safety
Is it safe?
Side effects
Commonly reported: Flushing, Tachycardia, Gastrointestinal Effects, Transient Warmth Sensation
Less common: Headache and Migraine Triggering, Hypotension
Stop and seek help if
- Severe or worsening side effects that don't improve with dose adjustment or supportive care
- Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
- Your healthcare provider recommends discontinuation based on your clinical response
- Development of any new medical condition that may be contraindicated with PACAP-38
- Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- Abnormal lab results or clinical markers that suggest adverse effects
PACAP-38 should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
Flagged pairings
- Triptans — PACAP-38 triggers migraine through cranial vasodilation; triptans target the same trigeminal pathway creating pharmacological conflict
- Strong Vasodilators — Additive vasodilation through multiple pathways may cause dangerous hypotension
- PAC1 Receptor Antagonists — Direct pharmacological antagonism blocks PACAP-38 primary neuroprotective mechanism
Published research
What the studies show
Cherait A, et al. · 2025
No abstract available for comprehensive analysis.
Ashina H, et al. · 2017
No abstract available for comprehensive analysis.
Rasmussen NB, et al. · 2023
Lu AG09222, a humanized antibody against PACAP, significantly reduced PACAP38-induced artery dilation and inhibited heart rate increases—demonstrating proof-of-mechanism for migraine prevention. Concomitant headache was reduced.
Bernard K, et al. · 2024
PACAP glycosides retained neurotrophic activity in vitro while improving blood-brain barrier penetration, reducing infarct size by approximately 36% in stroke models. These modified peptides show promise for neuroprotection.
Cherait A, et al. · 2020
Intranasal PACAP administration proved far more efficient than intravenous injection for reducing infarct volume after middle cerebral artery occlusion. Neuroprotection and functional recovery improved within 6 hours of stroke onset.
Birk S, Sitarz JT, Petersen KA, Oturai PS, Kruuse C, Fahrenkrug J, Olesen J · 2007
Amin FM, Asghar MS, Guo S, Hougaard A, Hansen AE, Schytz HW, et al. · 2012
Al-Khazali HM, Christensen RH, Dodick DW, et al. · 2024
Head to head
PACAP-38 compared
Want the full picture?
The complete PACAP-38 research profile: mechanism of action, clinical studies, effectiveness timeline, and FAQ.