Last reviewed: January 2026
When protocols specify mcg/kg, enter your weight and dose-per-kg to calculate your total dose and exact syringe draw.
| Peptide | Low Dose (mcg/kg) | Standard (mcg/kg) | High (mcg/kg) | Notes |
|---|---|---|---|---|
| BPC-157 | 1–2 mcg/kg | 3–5 mcg/kg | 7–10 mcg/kg | Most studies use 10 mcg/kg in animals; human equiv ~1–2 mcg/kg |
| Sermorelin | 0.5 mcg/kg | 1–2 mcg/kg | 3 mcg/kg | Pediatric dosing standard; adult protocol often flat 200–500 mcg |
| IGF-1 LR3 | 0.3 mcg/kg | 0.5–1 mcg/kg | 1.5 mcg/kg | Very potent — start at low end; max ~100 mcg/day absolute |
| Epithalon | 0.05 mcg/kg | 0.1 mcg/kg | 0.15 mcg/kg | Often expressed as flat 5–10 mg/course; weight-based less common |
| GHK-Cu | 0.01 mcg/kg | 0.02 mcg/kg | 0.03 mcg/kg | Most protocols use flat dosing (1–2 mg/day); weight-based in research |
| PT-141 | 0.006 mcg/kg | 0.012 mcg/kg | 0.025 mcg/kg | FDA-approved dose is flat 1.75 mg; weight-based in older trials |
| KPV | 2 mcg/kg | 5 mcg/kg | 10 mcg/kg | Anti-inflammatory; flat dosing (250–500 mcg) also standard |
→ Use this as an educational reference. Peptide dosing information is provided for research and educational purposes. Always consult a healthcare provider before starting any peptide protocol.
→ Double-check your math. Small reconstitution or dosing errors can significantly affect concentration. Verify your calculations before drawing a dose.
→ Bookmark for repeat reference. Peptide calculations are needed every time you reconstitute a new vial — save this page for quick access.
→ Explore related peptide tools. Use this alongside the other peptide calculators on the site for a complete protocol planning workflow.
→ Use this as a starting point, not a diagnosis. Online calculators provide estimates based on population averages. Your individual results may vary — consult a healthcare professional for personalized medical advice.
→ Measure consistently. For the most accurate tracking, take measurements at the same time of day under the same conditions each time you use this calculator.
→ Track trends, not single data points. One measurement is a snapshot. Track results over weeks and months to see meaningful patterns and progress.
→ Combine with related tools. Use this alongside other health calculators on this site for a more complete picture of your fitness and wellness metrics.
See also: Peptide Storage Calculator · GLP-1 Titration Tracker · Sweat Rate & Hydration Calculator · Body Surface Area Calculator · Exercise Calorie Burn
A peptide dose by body weight calculator converts a research-protocol dose expressed in mcg per kilogram (mcg/kg) into the actual milligrams or micrograms you'd draw for a person of a specific weight, and then converts that into a syringe-volume measurement based on your reconstitution. The math is simple but easy to make mistakes on under fatigue or distraction, especially when you're working across three different units of measurement (kg ↔ lb, mcg ↔ mg, mL ↔ IU on an insulin syringe). The calculator catches these conversion errors before they become injection errors.1
Body weight scaling matters because most peptides reach their target tissues through the systemic circulation. A 60 kg person and a 110 kg person who both inject 250 mcg of BPC-157 reach noticeably different plasma concentrations — the lighter person sees roughly 1.8× the concentration. For peptides with a wide therapeutic window this might not matter much, but for compounds where benefit and side-effect dose ranges overlap, weight-scaled dosing is the safer default. This is why most published research protocols and clinical-trial protocols specify mcg/kg or mg/kg rather than a flat dose.
| Step | What you provide | What the calculator computes |
|---|---|---|
| 1. Convert weight | Body weight (lb or kg) | Weight in kilograms |
| 2. Apply protocol | Dose-per-kg from your source | Total dose in mcg |
| 3. Apply concentration | Vial size and BAC water volume | mcg per mL after reconstitution |
| 4. Compute draw | — | Volume in mL and units on insulin syringe |
The most error-prone conversion is step 4. A standard U-100 insulin syringe is marked in "units" — but those units are based on insulin concentration (100 IU/mL), so 1 mL = 100 units. Drawing "20 units" means drawing 0.2 mL. If your peptide is reconstituted at 1 mg in 2 mL of bacteriostatic water, that's 500 mcg/mL, so 20 units = 0.2 mL = 100 mcg. The calculator handles this automatically once you enter vial size and water volume.
The protocols below are summarized from published research and reported clinical practice. They are illustrative — your specific protocol should come from your physician or from the source paper for your compound of interest.
| Peptide | Typical research range | Notes |
|---|---|---|
| BPC-157 | 2.5–10 mcg/kg twice daily | Often quoted as 250–500 mcg flat per dose |
| TB-500 | 2.0–4.0 mg twice weekly (loading); 2.0 mg weekly (maintenance) | Often dosed flat rather than per-kg |
| Sermorelin | 1–5 mcg/kg evening | Once daily, fasted, before sleep |
| CJC-1295 (no DAC) | 1–2 mcg/kg per dose, 2–3×/day | Usually paired with a GHRP |
| Ipamorelin | 1–3 mcg/kg per dose, 2–3×/day | Pulse dosing, fasted preferred |
| IGF-1 LR3 | 0.5–2.0 mcg/kg daily | Narrow therapeutic window — start low |
| Tesamorelin | ~25 mcg/kg daily | Approved at 2 mg flat dose for HIV-related lipodystrophy |
Suppose you weigh 175 lb and your protocol calls for BPC-157 at 5 mcg/kg twice daily. You have a 5 mg vial reconstituted with 2 mL of bacteriostatic water.
That single dose comes from a fraction of one milliliter — which is why precision matters. A 4-unit difference (drawing 20 instead of 16) is a 25% dose error.
The same vial of peptide reconstituted with different volumes of bacteriostatic water produces different concentrations and therefore different syringe draws. A 5 mg vial diluted in 1 mL gives 5,000 mcg/mL — for a 397 mcg dose, that's 8 units on an insulin syringe, hard to draw accurately because small variations are amplified. The same 5 mg vial diluted in 5 mL gives 1,000 mcg/mL — the same 397 mcg dose is 40 units, which is much easier to measure precisely. The trade-off: more dilute solutions take up more space in the vial and require larger injection volumes for higher doses. A common sweet spot is 2 mL water for a 5 mg vial, giving doses in the 10–50 unit range for typical body weights and protocols. See our Peptide Reconstitution Calculator for diluent planning.
This is the most common arithmetic error. The conversion is 1 kg = 2.2046 lb. To convert pounds to kilograms, divide by 2.2046 (or roughly by 2.2). To convert kilograms to pounds, multiply by 2.2046. Worked examples: 150 lb = 68 kg, 180 lb = 81.6 kg, 200 lb = 90.7 kg, 220 lb = 99.8 kg. Doing this conversion by hand under fatigue is where dose errors creep in — using a calculator is not optional for any precision-sensitive peptide.
Not every peptide protocol uses weight-based dosing. Tirzepatide and semaglutide for type 2 diabetes and obesity are titrated flat doses (e.g., 2.5 mg → 5 mg → 7.5 mg → 10 mg over weeks regardless of body weight). Tesamorelin is approved at 2 mg per day flat. Many GHRP protocols specify flat doses (e.g., 100 mcg or 200 mcg of Ipamorelin per pulse) because the dose-response curve is shallow within a normal adult body-weight range. The general rule: peptides with narrow therapeutic windows or strong dose-dependent side-effect profiles tend to use weight-based dosing; peptides with wide windows often use flat dosing for protocol simplicity.2
Mixing up mg and mcg. 1 mg = 1,000 mcg. A 1 mg dose is one thousand times larger than a 1 mcg dose. If your protocol says 250 mcg and you accidentally read it as 250 mg, you'd be administering 1,000× the intended dose. Always double-check unit symbols, especially in handwritten or quickly-typed notes.
Forgetting the BAC water dilution. Your vial is labeled "5 mg" but the syringe draws from a solution. Always factor in your reconstitution volume — 5 mg in 1 mL is five times more concentrated per unit volume than 5 mg in 5 mL.
Using wrong syringe units. U-100 insulin syringes (100 units = 1 mL) are standard for SQ peptide injection. U-40 insulin syringes (used for some veterinary insulin) read differently — 100 units on a U-40 syringe is 2.5 mL, which would be 2.5× the intended dose. Verify your syringe is U-100.
Rounding aggressively to whole units. Calculated dose of 6.4 units rounds to 6 — that's a 6.25% under-dose. For peptides where precision matters, draw between two marks or use a smaller-graduation syringe (some U-100 1/2-unit syringes exist).