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Injection Guide
CNTF-derived neurotrophic tetrapeptide mimetic that promotes neurogenesis, enhances BDNF expression, and demonstrates disease-modifying potential in Alzheimer's models
Route
Intranasal (spray)
Sites
3 recommended
Frequency
Once daily
Preparation
P21 (P021) vial (lyophilized powder or solution)
Bacteriostatic water or sterile sodium chloride for reconstitution
Alcohol swabs for cleaning vial tops and injection sites
Appropriately sized syringes with fine-gauge needles (27-30 gauge)
Sharps disposal container
Pro Tip
Prepare all supplies on a clean surface before you begin. Having everything ready makes the process smoother and more sterile.
Mixing
Wash your hands thoroughly with soap and water. Gather all supplies on a clean, flat surface.
Remove the plastic cap from the peptide vial and wipe the rubber stopper with an alcohol swab. Let it air dry.
Draw the appropriate amount of bacteriostatic water into a sterile syringe.
Insert the needle into the vial at an angle, aiming at the inside wall of the vial. Slowly push the plunger to let the water trickle down the glass wall -- do NOT squirt directly onto the powder.
Once all water is added, gently swirl the vial in a slow circular motion. Never shake the vial, as this can damage the peptide bonds.
Continue swirling until the powder is completely dissolved and the solution is clear. If particles remain, let the vial sit for a few minutes and swirl again.
Label the vial with the date of reconstitution, the peptide name, and the concentration (e.g. 250mcg per 0.1mL).
Example Calculation
Add the recommended volume of bacteriostatic water to the P21 (P021) vial. Gently swirl (do not shake) until the powder is fully dissolved. The resulting solution should be clear. Calculate your individual dose based on the concentration and your prescribed amount.
Dose Calculation
Your dose of P21 (P021) is determined by your healthcare provider. Using an insulin syringe marked in units, draw up the exact amount prescribed. For example, if the reconstituted concentration is 1mg/mL and your dose is 0.5mg, draw up 0.5mL (50 units on an insulin syringe). Always double-check calculations before injection.
Pro Tip
Always add the bacteriostatic water slowly, letting it run down the side of the vial. Never shake the vial -- swirl gently to avoid damaging the peptide.
Location
Site 01
Abdomen
Pinch the skin 2 inches from navel. Avoid the area directly around the belly button. Rotate between left and right sides.
Site 02
Outer Thigh
Middle third of the outer thigh. Keep at least 4 inches above the knee and below the hip. Alternate legs each injection.
Site 03
Upper Arm
Back or outer area of the upper arm. This site may require assistance from another person for proper technique.
Rotate between 3 sites to prevent tissue buildup and ensure consistent absorption.
Pro Tip
Rotate your injection sites with each dose to prevent lipohypertrophy (buildup of fatty tissue). Keep a simple log of where you last injected.
Step by Step
Wash your hands thoroughly with soap and water before handling supplies
Clean the injection site with an alcohol swab and let it air dry completely
Pinch a fold of skin at the chosen injection site
Insert the needle at a 45-90 degree angle (depending on needle length and body composition)
Inject the medication slowly and steadily over 5-10 seconds
Release the skin fold and remove the needle, applying gentle pressure with a clean swab
Rotate injection sites to prevent tissue irritation or lipodystrophy
Dispose of the needle safely in a sharps container—never recap or reuse needles
Pro Tip
This peptide uses subcutaneous injection (into the fatty tissue just under the skin)—allows for consistent absorption and can be self-administered at home after proper training. Inject at a 45-90 degree angle into pinched skin. Aspirate before injecting to ensure you haven't hit a blood vessel.
Timing
Optimal Timing
Best time
Administer P21 (P021) nasal spray at the same time each day. Morning dosing is commonly preferred. Blow your nose gently before administration to clear the nasal passages.
With food?
P21 (P021) nasal administration is not significantly affected by food. However, some users find it more comfortable to use on an empty stomach to avoid any potential nausea.
Stacking notes
P21 (P021) 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.
Sample Daily Schedule
Morning
500-750 mcg injection
Site: Intranasal — one spray per nostril, alternating starting nostril each day
Administer to clean nasal passages. Tilt head slightly back and spray gently. Avoid blowing nose for 10-15 minutes after administration. Take at the same time each day for consistent neurotrophic stimulation. Pair with Alpha-GPC or citicoline.
Dosing Tiers
Dose
250-500 mcg once daily
Frequency
Once daily
Duration
2-4 weeks initial assessment
Begin at a conservative dose to assess individual tolerance. P21 works through gradual neurogenic processes, so patience is required. Intranasal spray is the most common research administration route for human-equivalent dosing. Subcutaneous injection is an alternative. The compound was originally studied in mice administered in diet at 60 nmol/g feed.
Dose
500-750 mcg once daily
Frequency
Once daily
Duration
8-12 weeks standard cycle
The commonly referenced research dosage range for human-equivalent use. Intranasal administration delivers the compound efficiently to brain tissue. Take at the same time each day to maintain consistent neurotrophic stimulation. Neurogenic effects are cumulative and build over weeks — do not expect immediate cognitive changes. This dosage approximates the allometric scaling from effective mouse doses.
Dose
750-1000 mcg once daily
Frequency
Once daily
Duration
8-12 weeks, then reassess
Higher dosing tier for experienced users seeking maximum neurogenic benefit. In preclinical studies, P21 was administered for up to 12 months without adverse effects, supporting longer treatment durations. However, human safety data does not exist, and caution is warranted at higher doses. Monitor for any unusual neurological symptoms.
Preservation
Before Mixing
Store P21 (P021) 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 Mixing
Once reconstituted, P21 (P021) 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.
Shelf Life After Mixing
30 days refrigerated
Signs of Degradation
Discard the vial immediately if you notice any of these:
Solution appears cloudy, discolored, or contains visible particles (should be clear)
Product has been exposed to temperatures outside the recommended storage range
Product has been frozen (unless specifically designed for freeze-thaw stability)
Expiration date has passed or reconstituted solution has exceeded its use-by date
Unusual odor, color change, or visible contamination
Important
When to Stop
Persistent headaches or nasal irritation that does not resolve with dose adjustment
Significant mood instability or emotional disturbance
Any unexpected neurological symptoms (visual changes, balance issues, etc.)
Completion of planned treatment cycle
Decision to try alternative compounds
P21 is a research compound with no FDA approval and no controlled human clinical trial data. All use is at the individual's own risk. While preclinical studies up to 12 months showed excellent safety without the adverse effects of parent CNTF, unknown risks cannot be excluded in human use. Consult a healthcare provider before using any research peptide.
Clean Technique Checklist
Wash hands thoroughly with soap and water before handling supplies
Swab vial tops and injection site with alcohol and let dry
Never touch the needle tip or allow it to contact non-sterile surfaces
Use a new syringe and needle for each injection
Dispose of used sharps in a proper sharps container
Store reconstituted peptides according to the storage instructions above