What Size Needle for Peptide Injections (BPC-157, TB-500, Ipamorelin)?
The quick answer
| Step | Syringe | Needle |
|---|---|---|
| Reconstituting, option A: adding the diluent to the powder | Sterile luer syringe sized to the volume | Sterile 18G blunt fill or other drawing-up needle specified for the vial |
| Reconstituting, option B: small one-way transfers | A new fixed-needle insulin syringe for each pass | Built-in insulin needle; no separate draw needle |
| Subcutaneous injection, as prescribed | 0.5mL insulin syringe for small volumes, or 1mL when the volume needs it | Built-in 31G, 6mm is common for small volumes; other sizes may suit |
Many prescribed peptides arrive as a freeze-dried powder. Reconstitution means adding the sterile diluent your prescriber, pharmacist or instructions specify. Your syringe and needle must still match your label, route, volume, site and build.
The draw needle (18G) for reconstitution
A 10mL syringe with an 18G draw needle moves larger diluent volumes in a single pass. That's quicker and means fewer stopper punctures than several small transfers. Use it for transfer only, and ask your pharmacist if small vials or repeated access need a different device.
It's a convenience, not a requirement. If you reconstitute with fixed-needle insulin syringes, use a new sterile syringe for each pass. Never put a syringe that has touched the peptide vial back into the diluent vial. A blunt, reused needle can also shear rubber fragments off the stopper into the vial (coring).
You never inject with the 18G needle. For the full method, see our reconstitution guide and bacteriostatic water needle guide.
The injection syringe (31G, 6mm insulin)
For subcutaneous peptides, a 31G, 6mm insulin syringe is a common choice for small volumes. Use a new sterile syringe for each injection. Never re-enter a vial after the needle has touched skin, or draw from more than one vial with the same syringe.
Peptide volumes are often small, so the 0.5mL insulin syringe is usually easier to read than a 1mL barrel. Use the 1mL insulin syringe when your volume needs it. A 31G needle is very fine and often chosen for comfort, though how it feels varies.
Matching units to your dose
How many units you draw depends on the concentration. Use the dose volume or units your prescriber or pharmacy gives you in writing for your vial, and don't work it out from online examples. On a U-100 insulin syringe, 100 units = 1mL.
Our reconstitution guide covers the mixing steps. For BPC-157 and TB-500 vials, see our BPC-157 and TB-500 reconstitution supplies guide.
Supplies for peptide injections
- 10mL draw syringe with 18G needle: for one-way transfers when your instructions allow 18G. Not for injecting or drawing doses.
- 10mL bacteriostatic water vial: only when your instructions specify it. The mixed product's storage and discard date come from your pharmacy, not the water vial.
- 0.5mL insulin syringes (31G, 6mm): easier to read for small volumes.
- 1mL insulin syringes (31G, 6mm): for larger doses.
- 70% isopropyl alcohol wipes (100-pack): wipe every stopper and site and let it air-dry before puncturing.
- 0.6L Sharpsafe container: a small locking sharps bin. Pick a size and disposal route that suit your use and local rules.
Or browse the full injection supplies collection.
When to call your prescriber
Stop and contact your prescriber for:
- Redness, warmth, swelling or pus at the site over the next 24 to 72 hours, which may be infection
- A lump that is hot, tender or doesn't settle after a week
- Fever, chills or feeling unwell after an injection
- A rash, hives or itching at or beyond the site (possible allergic reaction)
Don't inject, and contact your prescriber or pharmacist, if the solution is cloudy or has particles after the expected dissolving time, or looks different from the instructions. The same applies to the wrong diluent or volume, an unknown concentration, a storage breach or any suspected dose error.
Signs of a severe allergic reaction - swelling of the face or throat, or trouble breathing - call 000 immediately.
Frequently asked questions
What gauge needle do you use to inject peptides?
A 31G, 6mm insulin syringe is a common choice for small subcutaneous volumes. The 18G draw needle is only for moving diluent. You don't inject with it.
Do I need a separate draw needle?
It's convenient, not essential. You can reconstitute with 1mL insulin syringes in a few passes, using a new sterile syringe each time. Never return a syringe that touched the peptide vial to the diluent vial.
0.5mL or 1mL insulin syringe for peptides?
Usually 0.5mL, because its finer marks are easier to read for small doses. Use 1mL if your concentration gives a larger volume. Either way, convert the microgram dose to mL using your prescribed concentration.
How many units is my dose?
Units = dose volume in mL x 100 on a U-100 syringe. Use your prescription label or pharmacy instructions rather than guessing.
