The quick answer

Step Syringe Needle
Reconstituting option A (adding the specified sterile diluent to the powder) Sterile luer syringe sized to the specified volume Sterile 18G blunt fill or other drawing-up needle specified for the vial
Reconstituting option B for small one-way transfer passes New fixed-needle insulin syringe for each transfer pass Integrated insulin needle; no separate draw needle attaches
Prescriber-directed subcutaneous administration 0.5mL insulin syringe is often easier for small prescribed volumes; use 1mL when the dose volume requires it or when its markings still allow accurate measurement under prescriber or pharmacist guidance Integrated 31G, 6mm is a common option for small prescribed subcutaneous volumes when it matches the label and prescriber or pharmacist instructions; other sizes may be appropriate

Some prescribed peptide products arrive as a freeze-dried powder. Reconstitution means adding the sterile diluent specified by the prescriber, pharmacist or product instructions. If the product is later administered subcutaneously, the syringe and needle choice still needs to match the prescription label, route, volume, site and patient factors.

Peptide injection supplies: a 10mL bacteriostatic water vial, a 1mL insulin syringe and an 18G draw needle
Peptide injection supplies: a 10mL bacteriostatic water vial, a 1mL insulin syringe and an 18G draw needle.

The draw needle (18G) - for reconstitution

To reconstitute, you transfer the specified sterile diluent into the peptide vial. A 10mL syringe with an 18G draw/fill needle can move larger instructed diluent volumes in a single pass - quicker and with fewer stopper punctures than several small transfers, provided sterile single-use equipment and aseptic technique are used. Use it for draw/transfer only, keep punctures to a minimum, and ask your pharmacist if a different transfer device is required for small vials or repeated access.

The draw needle is a convenience, not a requirement. If using fixed-needle insulin syringes for reconstitution, use a completely new sterile syringe for each draw-transfer pass. Never reinsert a syringe that has touched the peptide vial back into the bacteriostatic water or diluent vial. A blunt, re-used needle also increases the risk of coring (shearing tiny rubber fragments from the stopper into the vial).

You do not inject with the 18G needle. It is for filling only; the injection is done with the fine insulin syringe below. For the full method, see our reconstitution guide and the bacteriostatic water needle guide.

The injection syringe (31G, 6mm insulin)

For peptides that your prescriber has specifically directed you to administer subcutaneously, a fine 31G, 6mm insulin syringe is a common option for small volumes when it matches the label and technique instructions. Use one new sterile insulin syringe for each injection. Do not re-enter any vial after the needle has touched skin, and do not use the same syringe or syringe/needle assembly to draw from multiple stock vials.

Because prescribed peptide volumes can be small, the 0.5mL insulin syringe is often easier to read accurately than a 1mL barrel. Use the 1mL insulin syringe when the dose volume requires it or when its markings still allow accurate measurement under prescriber or pharmacist guidance. A 31G needle is very fine and is commonly chosen to minimise discomfort for prescribed subcutaneous injections, though discomfort varies by person, site, technique and solution.

Matching units to your dose

How many units you draw depends on how you reconstituted the vial. The concentration sets the maths:

Concentration (mg/mL) = peptide amount (mg) divided by final solution volume (mL). Use the final volume or concentration stated by the prescriber or pharmacy. Do not assume final volume equals diluent added unless those instructions explicitly say to use that approximation.

For example, a 5mg vial reconstituted under instructions that define the final volume as 2mL gives 2.5mg/mL. If your prescription says to draw 0.25mg from that concentration, the volume is 0.1mL, which is 10 units on a U-100 insulin syringe (100 units = 1mL). Our reconstitution guide has the full concentration tables, and for BPC-157 and TB-500 specifically see the prescriber-directed concentration examples for BPC-157/TB-500 products.

Supplies for peptide injections

  • 10mL draw syringe + 18G draw/fill needle - draw/transfer equipment for larger one-way transfer volumes when written instructions allow that gauge; not for injection or routine dose withdrawal.
  • 10mL bacteriostatic water vial - use only when specified by the prescriber, pharmacist or product instructions. Bacteriostatic water may be supplied as a multi-dose diluent, but the reconstituted product's storage, beyond-use date and discard limit must come from the pharmacy or product instructions, not from the diluent vial alone.
  • 0.5mL insulin syringes (31G, 6mm) - can help measure small prescribed volumes more readably when appropriate for the prescribed concentration and instructions.
  • 1mL insulin syringes (31G, 6mm) - for larger per-dose volumes.
  • Alcohol wipes (200-pack) - swab every stopper and site, then let it air-dry before puncturing.
  • 0.6L Sharpsafe container - a small locking sharps bin for used syringes and needles; choose a size and disposal pathway that matches your use and local requirements.

Or browse the full injection supplies collection.

When to call your prescriber

Subcutaneous injections can cause bleeding, bruising, pain, irritation, infection, allergic reaction, or dosing errors. Follow your prescriber's instructions and seek advice if anything seems wrong. Stop and contact your prescriber if you notice any of these:

  • Redness, warmth, swelling or pus at the injection site over the next 24 to 72 hours (possible infection).
  • A lump that is hot, tender, or does not settle after a week.
  • Fever, chills or feeling generally unwell after an injection.
  • A rash, hives or itching at or beyond the site (possible allergic reaction).
  • Signs of a severe allergic reaction - swelling of the face or throat, or trouble breathing - call 000 immediately.
  • Cloudy solution or visible particles after the expected full dissolution time, or any appearance that conflicts with the product instructions - do not inject it.
  • Wrong diluent, wrong volume, unknown or uncertain concentration, storage breach, or any suspected dose error - do not inject; contact your prescriber or pharmacist before continuing.

Frequently asked questions

What gauge needle do you use to inject peptides?

A fine 31G, 6mm insulin syringe is a common subcutaneous option when the prescription label and prescriber instructions specify a small subcutaneous volume. The wider 18G draw needle is only for moving diluent during reconstitution - you do not inject with it.

Do I need a separate draw needle?

It is convenient but not essential. An 18G draw needle can transfer larger diluent volumes in one pass. You can also reconstitute with a 1mL insulin syringe in a few passes, but use a completely new sterile syringe for each pass and never return a syringe that touched the peptide vial to the diluent vial.

0.5mL or 1mL insulin syringe for peptides?

Often 0.5mL for small prescribed dose volumes, because the 0.5mL barrel's finer graduations are easier to read. The microgram dose still has to be converted to mL using the prescribed concentration. Use 1mL if your reconstitution gives a larger per-dose volume.

How many units is my dose?

It depends on your concentration. On a U-100 insulin syringe, units = dose volume in mL times 100. Reconstitute only as instructed and use your prescription label, pharmacy instructions or the concentration tables in our reconstitution guide rather than guessing.