Reviewed by the PeptideMind Team · Updated July 15, 2026

PE-22-28 Dosage Guide, Benefits & Side Effects

PE-22-28 is studied for producing rapid antidepressant-like effects and hippocampal neurogenesis in preclinical models, longer-acting than parent spadin.

Chemical Makeup

7

Amino Acids

PE-22-28

Gly

G

Position 1

Val

V

Position 2

Ser

S

Position 3

Trp

W

Position 4

Gly

G

Position 5

Leu

L

Position 6

Arg

R

Position 7

Amino acid sequence
GlycinePosition 1
ValinePosition 2
SerinePosition 3
TryptophanPosition 4
GlycinePosition 5
LeucinePosition 6
ArgininePosition 7

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PE-22-28 Dosage Guide for Cognitive Enhancement

PE-22-28 is an experimental peptide being studied as a fast-acting option for depression, anxiety, and brain protection. It's thought to work by boosting serotonin activity and encouraging new brain cell growth.

Vial size

5 mg

Bacteriostatic water

2 mL

Dosing

500 mcg–1 mg

Frequency

Daily

Cycle

4–8 weeks

Benefit

Cognitive Enhancement

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What is PE-22-28?

PE-22-28 is a lab-made peptide, engineered from a natural fragment found in the body, designed to work faster and more potently on a specific target in the brain linked to mood and depression. In animal studies, it produced antidepressant-like effects within just a few days and supported the growth of new brain cells, while also improving on the natural version's short-lived effects. It's studied in early research for depression, brain protection, and stroke recovery.

Cognitive

pe2

Longevity

Is PE-22-28 FDA approved?

PE-22-28 is not an FDA-approved drug. It is intended for research purposes only and is not approved for human consumption, diagnostic, or therapeutic use.

Research Use Only

PE-22-28 has not been evaluated by the FDA for safety or efficacy in humans.

No Clinical Oversight

Not manufactured under FDA-regulated quality or clinical standards.

Unregulated Sourcing

Purity, dosing, and sourcing are not verified through FDA testing or oversight.

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How Does PE-22-28 Work?

It blocks a channel in nerve cells that normally acts as a brake on their activity, so blocking it makes those cells, especially ones that release serotonin, more active. This ripple effect raises a brain-growth protein (BDNF), encourages new brain-cell growth, and strengthens the connections between neurons.

Blocks a brake channel

Blocks a channel that normally limits nerve cell activity.

Boosts serotonin cells

Makes serotonin-releasing neurons more active.

Grows new connections

Raises BDNF and strengthens the connections between neurons.

PE-22-28 Targeted areas

How to reconstitute PE-22-28

View guide

The materials you'll need and step-by-step instructions for safely mixing PE-22-28 with bacteriostatic water.

Materials needed

Your PE-22-28 vial (lyophilized)

Alcohol swabs

Bacteriostatic sterile water

3 mL syringes (Luer Lock tip)

25G or 27G needles (Luer Lock). Other gauges may also be acceptable.

Sharps container (optional)

1

Remove the caps

Remove the caps from both your PE-22-28 vial and your bacteriostatic water vial.
2

Sanitize the rubber stoppers

Wipe down the rubber stoppers on both vials with alcohol swabs and let them dry for about 3 minutes.
3

Attach the needle

Take your 3 mL syringe and needle. Twist the needle's plastic hub into the Luer Lock tip on the syringe to secure it.
4

Draw the bac water

Pull back on the plunger to draw your desired volume of bacteriostatic water. If you overfill, just push the excess back in until you reach the right marker on the syringe.

How much bac water? PE-22-28 typically comes in a 5 mg vial. We recommend 2 mL of bacteriostatic water, though anywhere between 1 mL and 3 mL is acceptable. For larger vials you can use up to 5 mL — more bac water makes microdosing easier, but insulin needles usually max out at 1 mL per injection. That means a lot of bac water might force you into multiple injections to hit your target dose. Unless you're microdosing, 2 mL per vial is a solid rule of thumb.
5

Insert the needle into the PE-22-28 vial

With the bac water in your syringe, insert the needle into the PE-22-28 vial at a slight angle to avoid pressure buildup.

Use a thin needle: Stick to 25G or higher to avoid damaging the rubber stopper. Higher gauge means a thinner needle.
6

Release the water gently

Let the water run gently down the side of the vial. Don't inject it forcefully.

Heads up: Sometimes the plunger pushes itself in as soon as the needle enters the vial. Hold the plunger back so you have full control over how fast the bac water enters.
7

Swirl to dissolve

Avoid shaking. Gently swirl, flip, and roll the vial to dissolve the powder.

Be patient: This usually takes 2 to 5 minutes of consistent swirling, mixing in a circular motion, and gently flipping the vial up and down. The water needs to run through the powder many times to fully dissolve it. Don't shake or get aggressive with it.
8

Check for full dissolution

The solution should be clear with no visible particles. If it's cloudy or clumpy, wait a minute and repeat the swirling step.
9

Cap, dispose, and store

Once you're done, cap the needle and dispose of it (ideally in a sharps container). Store the reconstituted PE-22-28 vial in the fridge whenever it's not in use. It will stay good for approximately 30 days.

How to Store PE-22-28

Freeze the dry powder. Once mixed with liquid, refrigerate and use within about a month.

Lyophilized Storage

Store at -20°C.

Reconstituted Storage

Refrigerate at 2–8°C, use within 28 days.

A smartphone displaying a "Storage Guide" for peptides, indicating a safe storage temperature range of 2–8°C, with warnings to keep away from light, heat, and freezing. The background is light blue, and additional tips on protecting the peptides are visible below the temperature range.

What Are the Benefits of PE-22-28?

What research says it may help with, and how it works in the body.

mental health

Shown to reduce anxiety-like behavior in animal studies.

This is the main area researchers are studying, since noticeable effects on behavior showed up in animal studies within just 4 days.

neurogenesis

After 4 days of treatment, it nearly doubles the number of newly formed brain cells (measured using a marker called BrdU that labels dividing cells).

Encourages the formation of new connections between nerve cells by activating a protein (CREB) that switches on genes involved in learning and memory.

cognition

Affects a particular protein channel (TREK-1) in two brain regions tied to memory and decision-making (the hippocampus and prefrontal cortex), helping support memory function.

May help protect brain cells from damage caused by reduced blood flow and support their survival.

What Are the Side Effects of PE-22-28?

Who should avoid it, warning signs to watch for, and what to know before combining it with other compounds.

Who Should Avoid It

Pregnancy and breastfeeding

Concurrent MAOI use

Stop Right Away If You Notice

Serotonin syndrome signs

Severe persistent headaches

Cardiac symptoms

Seizure activity

Severe mood changes or suicidal ideation

Milder Signs to Watch For

Cloudy, discolored, or particulate appearanceClumped or sticky powder indicating moisture damage
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How Long Should a PE-22-28 Cycle Last?

This breaks down how long a typical PE-22-28 cycle runs and what research suggests happens at each stage. Research shows that staying on a peptide continuously, without a break, may make it less effective over time.

That's why most research protocols build in a break between cycles, often called a washout period, to let the body reset before starting again.

Day 1-4
Measurable antidepressant effects in preclinical models
Week 1-2
Neurogenesis and synaptogenesis processes established
Week 2-4
Potential mood and cognitive improvements emerge
Week 4-8
Sustained treatment allows full neurogenic effects

Cheat Sheets Featuring PE-22-28

See how PE-22-28 fits into a broader research stack with these free downloadable cheat sheets. Each one includes reference dose ranges, dosing frequency, and half-life for every peptide it covers. For research purposes only.

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Cognitive Peptide Cheat Sheet
Cognitive Peptide Cheat Sheet

16 peptides

Longevity Peptide Cheat Sheet
Longevity Peptide Cheat Sheet

42 peptides

Master Peptide Cheat Sheet
Master Peptide Cheat Sheet

78 peptides

PE-22-28 Research References

It is a preclinical compound

3Research references

PE-22-28

PE-22-28 is a preclinical compound

Spadin: A Sortilin-Derived Peptide Targeting TREK-1 Channels

Original discovery of TREK-1 blockade as antidepressant mechanism. PLOS Biology.

2010

TREK-1 Deletion Results in Depression-Resistant Phenotype

TREK-1 knockout mice show depression-resistant behavior in 5 tests. Nature Neuroscience.

2006

Shortened Spadin Analogs Display Better TREK-1 Inhibition

PE-22-28 IC50 0.12 nM vs 40-60 nM for Spadin; ~23 hour duration. Frontiers in Pharmacology.

2017

Frequently Asked Questions About PE-22-28

Straight answers on reconstitution, dosing, and safety, everything you need to research with confidence. For research reference only.