P21 Reconstitution Calculator, Units & Half-Life
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[Peptide · Compound guide]

P21: reconstitution, units and half-life

Vial sizes · Worked example · Units chart · Half-life notes

What is P21?

P21 (also written P021) is a small synthetic peptide modeled on part of ciliary neurotrophic factor (CNTF), a protein that supports nerve cells, with an adamantane group added. It was made by researchers at the New York State Institute for Basic Research in Developmental Disabilities and has been studied only in animals. It is not approved for human use.

Also known as: P021, CNTF peptide mimetic.

Common vial sizes

We could not confirm a standard vial size for P21, so check the label on yours. The 10 mg vial in the example below is only there to show the math.

Worked reconstitution example

Here is the math for a 10 mg vial mixed with 2 mL of bacteriostatic water, drawing 500 mcg with a U-100 insulin syringe (1 mL = 100 units).

  1. Concentration. 10 mg ÷ 2 mL = 5 mg/mL
  2. Volume to draw. 500 mcg ÷ 5 mg/mL = 0.1 mL
  3. Syringe units. 0.1 mL × 100 = 10 units
The amount here is an example to show the math, not a recommendation. How much to take is a decision for you and your prescriber.

Units chart at 5 mg/mL

10 mg vial + 2 mL water. Amounts are examples for the conversion, not doses.
AmountVolumeU-100 syringe
250 mcg0.05 mL5 units
500 mcg0.1 mL10 units
1 mg0.2 mL20 units

Same amount, different water volumes

Adding more water doesn't change how much P21 is in the vial. It only spreads it over more liquid, so each draw is bigger and easier to read.

500 mcg from a 10 mg vial.
Water addedConcentrationVolumeU-100 syringe
1 mL10 mg/mL0.05 mL5 units
2 mL5 mg/mL0.1 mL10 units
3 mL3.33 mg/mL0.15 mL15 units
5 mL2 mg/mL0.25 mL25 units

For any other vial size or amount, the free peptide reconstitution calculator works backwards from the amount you want and suggests a water volume that lands on a clean syringe mark.

What is known in people?

Nothing yet: we could not find any published study or registered trial that gave P21 to people. In normal adult mice it improved learning and memory and increased new nerve cells (Li 2010). In mice bred to develop Alzheimer's-like disease, 12 months of P021 in their food lowered tau buildup and improved memory (Kazim 2014), and starting it early prevented much of the damage (Baazaoui 2017). These studies come from the lab that developed it. Mouse results often do not carry over to people.

P21 half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

We could not find a published human half-life for this compound. Figures quoted online usually come from animal or cell studies, so we do not list one here.

How to track P21 in Dose Track

  1. Add P21 as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Save your vial: enter the vial size and how much water you added. From then on every amount you log shows as syringe units, and the reconstitution planner suggests a water volume that lands on a clean mark.
  3. Log each shot. The app subtracts it from the vial, shows what is left, and warns you before you run out.
  4. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  5. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

DihexaN-hexanoic-Tyr-Ile-(6) aminohexanoic amide SemaxACTH (4-10) analog PE-22-28PE 22-28, Spadin analog

Frequently asked questions

How much bacteriostatic water do I add to a 10 mg P21 vial?+
There is no single right amount. More water makes each draw bigger and easier to measure; less water makes it smaller. For example, 2 mL in a 10 mg vial gives 5 mg/mL, so 500 mcg is 0.1 mL, or 10 units on a U-100 insulin syringe. That amount is only an example for the math, not a recommendation. The free Dose Track reconstitution calculator works it out for any vial and amount.
How many units is 500 mcg of P21?+
It depends on the concentration in your vial. At 5 mg/mL (10 mg mixed with 2 mL), 500 mcg is 0.1 mL, which is 10 units on a U-100 insulin syringe, where 1 mL is 100 units. Divide the amount by the concentration to get mL, then multiply by 100.
What is the half-life of P21?+
We could not find a published human half-life for this compound. Figures quoted online usually come from animal or cell studies, so we do not list one here.
Can I track P21 in Dose Track?+
Yes. P21 is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each shot next to your other compounds, save your vial and how much water you added so every amount shows in syringe units, see how much is left in the vial, and get reminders. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. Li B, et al. Neurotrophic peptides incorporating adamantane improve learning and memory, promote neurogenesis and synaptic plasticity in mice. FEBS Lett. 2010;584(15):3359-3365.
  2. Kazim SF, et al. Disease modifying effect of chronic oral treatment with a neurotrophic peptidergic compound in a triple transgenic mouse model of Alzheimer's disease. Neurobiol Dis. 2014;71:110-130.
  3. Baazaoui N, Iqbal K. Prevention of amyloid-β and tau pathologies, associated neurodegeneration, and cognitive deficit by early treatment with a neurotrophic compound. J Alzheimers Dis. 2017;58(1):215-230.
  4. Baazaoui N, Iqbal K. Alzheimer's disease: challenges and a therapeutic opportunity to treat it with a neurotrophic compound (review). Biomolecules. 2022;12(10):1409.

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