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PeptideHub

Peptide Injection Calculator

Calculate the precise draw volume for subcutaneous or intramuscular peptide injections based on your reconstituted concentration and target dose. Includes syringe selection guidance, injection site reference, and a comparison of U-100 versus U-40 syringe types.

Common research range for BPC-157: 250–500 mcg, 2× daily, subcutaneous. Cycle: 4 weeks on / 2 off.

Educational use only. This calculator performs unit math on the values you provide and is not a substitute for medical advice. Verify every calculation independently.

Result

Concentration
2500 mcg / mL
Per syringe unit
25.00 mcg / unit
Draw to this mark
15.0 units (0.15 mL)
Dose, all units
375 mcg · 0.375 mg
Doses per vial
13.3 doses
Days per vial
6.7 days
Vials needed for 4-week cycle
5 vials

Numbers are computed from your inputs. Verify all calculations independently. Educational use only.

How to Use This Calculator

  1. Select injection route: Choose subcutaneous (SubQ) or intramuscular (IM) based on the research protocol. SubQ is used for most research peptides.
  2. Select syringe type: Choose U-100 (most common) or U-40. Confirm the total syringe volume — 0.5 mL or 1 mL — is sufficient for your dose.
  3. Enter reconstituted concentration: Input the concentration of your reconstituted solution in mcg/mL. This comes from your BAC water volume and vial size.
  4. Enter target dose: Enter the dose in mcg. The calculator returns the draw volume in both mL and syringe units.
  5. Confirm the draw fits the syringe: Verify the draw volume does not exceed your syringe capacity. If it does, the calculator will suggest adjusting reconstitution concentration.

Example Calculation

A researcher has reconstituted a 5 mg TB-500 vial with 2 mL BAC water (2,500 mcg/mL) and wants to inject 500 mcg subcutaneously using a U-100 syringe.

StepCalculationResult
Concentration5,000 mcg ÷ 2 mL2,500 mcg/mL
Volume for dose500 mcg ÷ 2,500 mcg/mL0.20 mL
U-100 units0.20 mL × 10020 units
Syringe fits?20 units in 0.5 mL syringeYes (max 50 units)

Subcutaneous vs Intramuscular Comparison

FeatureSubcutaneous (SubQ)Intramuscular (IM)
DepthFat layer below skinMuscle tissue
Needle gauge28–31G23–25G
Needle length4–8 mm16–38 mm
Angle45° or 90°90°
Max volume1 mL per site2–5 mL per site
Absorption rateSlower, sustainedFaster
Used for peptidesMost protocolsSome TB-500 protocols

Frequently asked questions

What is the difference between subcutaneous and intramuscular peptide injection?+

Subcutaneous (SubQ) injection deposits the solution into the fat layer just below the skin. Intramuscular (IM) injection goes deeper into muscle tissue. Most peptide research protocols specify SubQ due to slower, more sustained absorption and lower injection-site discomfort.

What syringe should I use for subcutaneous peptide injections?+

A U-100 insulin syringe with a 28–31G needle in 0.5 mL or 1 mL capacity is the standard choice for SubQ peptide injections. The fine gauge minimises discomfort and is appropriate for the small volumes involved.

How deep should a subcutaneous peptide injection be?+

A 45-degree angle at the skin surface is typically used for SubQ injections with a short (8 mm) needle. With a 4–6 mm needle, a 90-degree angle can be used. The goal is to deposit the fluid into the subcutaneous fat layer, not dermis or muscle.

Where are common subcutaneous injection sites for peptide research?+

Common sites referenced in preclinical literature include the abdomen (at least 2 inches from the navel), outer thigh, and upper arm. Rotating sites between injections helps prevent lipodystrophy and injection-site reactions.

What volume can be injected subcutaneously?+

For research purposes, SubQ volumes are typically kept under 1 mL per site to minimise discomfort and ensure complete absorption. Larger volumes may be split across multiple sites.

Do I need an alcohol swab before injecting?+

Standard laboratory and clinical practice is to wipe the injection site with a 70% isopropyl alcohol swab and allow it to dry fully before injection. This reduces surface contamination risk.