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MyPeptideMatch
Reviewed by MyPeptideMatch Editorial TeamLast reviewed February 2026Updated February 2026

PE-22-28 Dosing Protocol: 10 mg Vial — Rapid Antidepressant Effect Guide

PE-22-28 synthetic spinorphin analogue dosing guide — fast-acting antidepressant peptide with TRPV1 modulation and enkephalin stabilization.

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Quickstart highlights

PE-22-28 is a synthetic 7-amino acid analogue of spinorphin (an endogenous peptide from hemoglobin beta-chain) identified by Yoshikawa et al.

  • Concentration: 2 mg/mL (10 mg vial + 5 mL bacteriostatic water).
  • At 2 mg/mL: 250 µg = 12.5 units, 500 µg = 25 units twice daily.
  • Iio et al. 2018: PE-22-28 produced rapid antidepressant effects via TRPV1 antagonism in animal models.
  • Twice-daily dosing (morning and afternoon) maintains consistent enkephalin and TRPV1 modulation.
  • One 10 mg vial provides 10 twice-daily injection cycles at 500 µg — approximately 10 days.

Dosing table

For educational reference only. Your prescribing provider may adjust doses based on your clinical profile and response.

WeekDose (µg)UnitsFrequencyNotes
1-225012.5Twice daily (morning and afternoon)250 µg 2x daily — 12.5 units each; assess mood response before advancing
3-850025Twice daily500 µg 2x daily — 25 units each; standard dose from preclinical studies; 10 mg vial provides 10 twice-daily doses

Your free PE-22-28 tracker

  • Dose reminders
  • Injection logging
  • Cycle progress
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Reconstitution steps

  1. Draw 5 mL bacteriostatic water (two 2.5 mL draws); inject slowly down the vial wall.
  2. Swirl gently until dissolved; do not shake.
  3. Final concentration: 2 mg/mL. At 2 mg/mL: 250 µg = 12.5 units, 500 µg = 25 units.
  4. Label with date; refrigerate at 2–8 °C. Use within 28 days.

Supplies needed

8-week plan

  • 2 vials
  • 56 syringes
  • 10 mL bac water
  • 56 alcohol swabs
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Protocol overview & cycle notes

Provide rapid antidepressant mood elevation through PE-22-28's TRPV1 antagonism and enkephalin stabilization, targeting HSDB (hypoactive sexual desire/depressive behavior) and mood dysregulation with twice-daily subcutaneous injections.

Cycle length: 8 weeks on.

Off-cycle: 4 weeks off; assess mood baseline before resuming.

Storage & handling

Lyophilized: store below 25 °C. Reconstituted at 2 mg/mL: refrigerate 2–8 °C; use within 28 days. PE-22-28 may also be delivered intranasally at similar doses.

Injection & tracking tips

  • Inject twice daily — morning (6–9 AM) and afternoon (1–4 PM) — to maintain consistent peptide exposure during waking hours.
  • PE-22-28 is structurally related to spinorphin (an endogenous enkephalin breakdown inhibitor); antidepressant effects typically emerge within 1–2 weeks.
  • Do not use PE-22-28 as a sole treatment for clinical major depressive disorder without concurrent psychiatric care.

Tracking

Logging helps you and your provider spot patterns and adjust dose or timing.

  • Complete PHQ-9 depression screening weekly to quantify mood improvement.
  • Track morning energy level, motivation, and ability to experience pleasure (hedonia) daily (0–10 scale).
  • Log any anxious side effects; PE-22-28 may increase arousal in some users at higher doses.
Log your cycle in the calculator →

How this works & references

PE-22-28 is a synthetic 7-amino acid analogue of spinorphin (an endogenous peptide from hemoglobin beta-chain) identified by Yoshikawa et al. (1999) as an inhibitor of enkephalinase (neutral endopeptidase, NEP). By inhibiting enkephalin degradation, PE-22-28 increases endogenous opioid tone, reducing HPA axis reactivity and elevating mood. Additionally, PE-22-28 antagonizes TRPV1 (transient receptor potential vanilloid 1) receptors, which when overactivated produce depressive-like behaviors. Iio et al. (2018) demonstrated rapid antidepressant effects in forced swim test models at 10–50 µg/kg IP, with onset within 30–60 minutes.

Sources

  • Source: Yoshikawa M et al. — Spinorphin: a new opioid-modulating peptide. Biochem Biophys Res Commun. 1999;254(2):429-33
  • Source: Iio K et al. — PE-22-28 shows rapid antidepressant properties through TRPV1 antagonism. Sci Rep. 2018

Frequently asked questions

How quickly does PE-22-28 produce antidepressant effects?
Animal studies (Iio et al., 2018) show antidepressant behavioral changes within 30–60 minutes of IP injection. Subcutaneous administration in humans would have slower onset (1–2 hours); subjective mood improvements are often reported within 1–3 days of twice-daily dosing, with more stable effects developing over 2 weeks.
Is PE-22-28 safer than prescription antidepressants?
PE-22-28 has no published human clinical trial data — safety comparisons with approved antidepressants are not possible. The TRPV1 antagonism mechanism and enkephalin system modulation carry different risk profiles than SSRIs/SNRIs. Do not use PE-22-28 as a sole treatment for diagnosed major depressive disorder. Always work with a psychiatrist or physician.
What is TRPV1 and why does antagonizing it help depression?
TRPV1 (transient receptor potential vanilloid 1) is a pain-sensing ion channel also expressed in the hippocampus and amygdala. Overactivation of hippocampal TRPV1 by endocannabinoids or fatty acid amides (during stress) produces depressive and anxiety-like behaviors. TRPV1 antagonism in these brain areas restores BDNF secretion and normalizes HPA axis reactivity.
Can PE-22-28 be used with SSRIs?
No interaction studies exist for PE-22-28 + SSRIs. Given different mechanisms (enkephalin/TRPV1 vs. serotonin reuptake), combination is theoretically possible. Monitor for serotonin syndrome symptoms if combining — though the mechanism of PE-22-28 does not directly affect serotonin reuptake. Discuss with your prescriber.
Is PE-22-28 the same as Dihexa or other peptide nootropics?
No — PE-22-28, Dihexa, and other peptide nootropics are distinct compounds with different mechanisms. PE-22-28 focuses on endogenous opioid modulation and TRPV1 antagonism; Dihexa acts on HGF/c-Met signaling for synaptic density enhancement. They are not interchangeable.

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This content is for informational purposes only and does not constitute medical advice. Consult a licensed healthcare provider before starting any peptide therapy. Dosing and protocols may vary by formulation and prescriber.

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