Instant reconstitution math, syringe units, cycle cost, and stack planning for 40+ peptides.
The single most common peptide mistake is miscalculating concentration and drawing the wrong syringe volume. If your vial contains 5 mg of BPC-157 and you add 2 mL of bacteriostatic water, your concentration is exactly 2,500 mcg/mL. A 250 mcg dose at that concentration = 0.10 mL = 10 units on a standard 100-unit insulin syringe. Getting this wrong by even a factor of 2 means consistently under- or overdosing. Always calculate from first principles every time you reconstitute a new vial, never assume from memory. A second critical rule: always use bacteriostatic water (0.9% benzyl alcohol), never regular sterile water or saline. BAC water's preservative allows safe multi-dose use of the same vial for 4–6 weeks refrigerated. Regular water has no preservative and goes bacterial within 24 hours of opening. Store reconstituted peptides at 34–40°F, refrigerator, not freezer. Ice crystal formation permanently denatures (destroys) the peptide structure. For GH-releasing peptides like CJC-1295 and Ipamorelin, timing is everything: inject on a completely empty stomach (2+ hours after last meal) and wait 30–60 minutes before eating. Dietary carbohydrates and fats acutely suppress GH release and will blunt the pulse even if your reconstitution math is perfect. Most people lose 30–50% of their GH peptide benefit simply by poor injection timing.
Peptides are typically supplied as lyophilized (freeze-dried) powder in sealed vials. Before injecting, you must dissolve the powder in bacteriostatic water (BAC water): sterile water containing 0.9% benzyl alcohol as a preservative that allows multi-use of the vial. The amount of water you add determines the concentration of your solution.
The key formula is simple: Concentration (mg/mL) = Vial Size (mg) ÷ BAC Water Added (mL). If you have a 5 mg vial and add 2 mL of BAC water, your concentration is 2.5 mg/mL or 2,500 mcg/mL. All the dosing math flows from this single number.
Peptides are injected subcutaneously (under the skin, typically on the abdomen or thigh) using insulin syringes. The most common size is a 100-unit syringe, where 100 units = 1.0 mL. So if you need 0.10 mL, you draw to the 10-unit line. This calculator converts your dose into units automatically based on your concentration.
| Vial Size | BAC Water | Concentration | 200 mcg dose = | 250 mcg dose = |
|---|---|---|---|---|
| 5 mg | 1 mL | 5,000 mcg/mL | 4 units | 5 units |
| 5 mg | 2 mL | 2,500 mcg/mL | 8 units | 10 units |
| 5 mg | 5 mL | 1,000 mcg/mL | 20 units | 25 units |
| 10 mg | 2 mL | 5,000 mcg/mL | 4 units | 5 units |
| 10 mg | 5 mL | 2,000 mcg/mL | 10 units | 12.5 units |
Always inject BAC water slowly down the side of the vial: never directly onto the peptide powder, as force can denature (destroy) the peptide. Swirl gently rather than shaking. Once reconstituted, store in the refrigerator (not frozen) and use within 4–6 weeks for most peptides. The benzyl alcohol in BAC water keeps it sterile through multiple uses.
This is where most people get confused. Here's the complete conversion chain: 1 mg = 1,000 mcg. On an insulin syringe: 1 unit = 0.01 mL, so 100 units = 1.0 mL. When you see a dose like "250 mcg of BPC-157," you convert that to a volume based on your concentration, then convert that volume to syringe units. Our calculator handles all three steps simultaneously.
The standard syringe for sub-Q peptide injections, 31-gauge causes minimal pain and the 1 mL barrel matches the 100-unit scale this calculator uses.
View on Amazon →Required for reconstituting lyophilized peptide powder, benzyl alcohol preservative allows safe 4–6 week multi-dose use from the same vial.
View on Amazon →Safe, puncture-resistant disposal of used syringes and needles, required for responsible and legal sharps disposal.
View on Amazon →CJC-1295 and Ipamorelin are the classic "GH peptide stack", one stimulates the release signal (GHRH analog), the other amplifies the pulse (GHRP). Together they produce significantly more GH output than either alone. Standard protocol: 100–200 mcg CJC-1295 (no DAC) + 200 mcg Ipamorelin, injected together 2–3 times daily on an empty stomach. A 12-week cycle with a 4-week off period is typical. CJC-1295 with DAC has a multi-day half-life, so it's dosed once weekly at 1,000–2,000 mcg instead.
Tirzepatide, Semaglutide, and Retatrutide are the blockbuster weight loss peptides. These are long-acting and injected once weekly. Dosing always starts low and escalates slowly over months to allow the body to adapt and minimize GI side effects. Tirzepatide typically starts at 2.5 mg weekly and increases by 2.5 mg every 4 weeks up to 15 mg. Retatrutide is triple-agonist (GIP/GLP-1/glucagon receptor), the most potent of the class and dosed even more conservatively, starting at 2 mg weekly.
BPC-157 (Body Protection Compound) is derived from a gastric protein and shows remarkable healing properties across tendon, ligament, muscle, gut, and neurological tissue in research. It can be injected subcutaneously or directly at/near an injury site. TB-500 (Thymosin Beta-4) promotes cell migration and differentiation, often stacked with BPC-157 for synergistic healing. The newer Pentadeca Arginate (PDA) offers similar benefits to BPC-157 with potentially improved stability.
| Peptide | Category | Typical Dose | Frequency | Half-Life |
|---|---|---|---|---|
| BPC-157 | Healing | 200–500 mcg | 1–2x daily | ~4 hours |
| TB-500 | Healing | 2–5 mg | 2x/week (loading) | ~4–5 days |
| CJC-1295 (no DAC) | GH Peptide | 100–200 mcg | 2–3x daily | ~30 min |
| Ipamorelin | GH Peptide | 100–300 mcg | 2–3x daily | ~2 hours |
| CJC-1295 (w/ DAC) | GH Peptide | 1,000–2,000 mcg | Once weekly | ~7–8 days |
| Semaglutide | GLP-1 | 0.25–2.4 mg | Once weekly | ~7 days |
| Tirzepatide | GLP-1/GIP | 2.5–15 mg | Once weekly | ~5 days |
| Retatrutide | Triple Agonist | 2–12 mg | Once weekly | ~6 days |
| Sermorelin | GH Peptide | 200–500 mcg | Daily (bedtime) | ~10 min |
| PT-141 | Sexual Health | 0.5–2 mg | As needed (pre) | ~6–12 hours |