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[Peptide · Compound guide]

LL-37: reconstitution, units and half-life

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

What is LL-37?

LL-37 is a 37-amino-acid antimicrobial peptide, the active part of human cathelicidin. It is not FDA approved.

Also known as: Cathelicidin.

Common vial sizes

Powder vials are usually labeled 5 mg.

Worked reconstitution example

Here is the math for a 5 mg vial mixed with 5 mL of bacteriostatic water, drawing 100 mcg with a U-100 insulin syringe (1 mL = 100 units).

  1. Concentration. 5 mg ÷ 5 mL = 1 mg/mL
  2. Volume to draw. 100 mcg ÷ 1 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 1 mg/mL

5 mg vial + 5 mL water. Amounts are examples for the conversion, not doses.
AmountVolumeU-100 syringe
50 mcg0.05 mL5 units
100 mcg0.1 mL10 units
200 mcg0.2 mL20 units

Same amount, different water volumes

Adding more water doesn't change how much LL-37 is in the vial. It only spreads it over more liquid, so each draw is bigger and easier to read.

100 mcg from a 5 mg vial.
Water addedConcentrationVolumeU-100 syringe
3 mL1.67 mg/mL0.06 mL6 units
5 mL1 mg/mL0.1 mL10 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.

LL-37 half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed
  • Route in Dose TrackUnder the skin (subcutaneous)

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 LL-37 in Dose Track

  1. Add LL-37 from the built-in list. It sits next to everything else you take, so a GLP-1, TRT and a few peptides all live in one log.
  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 stays on your phone.
BPC-157Body Protection Compound 157 KPVLys-Pro-Val Thymosin Alpha-1Thymalfasin, Zadaxin · half-life about 2 hours

Frequently asked questions

How much bacteriostatic water do I add to a 5 mg LL-37 vial?+
There is no single right amount. More water makes each draw bigger and easier to measure; less water makes it smaller. For example, 5 mL in a 5 mg vial gives 1 mg/mL, so 100 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 100 mcg of LL-37?+
It depends on the concentration in your vial. At 1 mg/mL (5 mg mixed with 5 mL), 100 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 LL-37?+
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 LL-37 in Dose Track?+
Yes. LL-37 is built into Dose Track. You can 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 stays on your phone.

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