Understanding Syringe Volume

Insulin syringes come in three standard volumes:

  • 0.3ml (30 units) — for very small doses, typically insulin microdosing.
  • 0.5ml (50 units) — the most popular for GLP-1 medications and peptides. Finer marks for accurate small doses.
  • 1ml (100 units) — for larger-volume medications. Commonly used for TRT, higher-dose peptides, and insulin.

The "unit" markings are based on the U-100 insulin standard. For non-insulin medications like semaglutide, measure in mL rather than units.

Needle Gauge — What the Numbers Mean

Gauge (G) measures needle thickness. Higher numbers mean thinner needles:

  • 18G — thick, used only for drawing medication from vials (never for injection).
  • 25G — medium, used for intramuscular injections.
  • 29G — fine, suitable for subcutaneous injection.
  • 31G — ultra-fine (0.25mm), the standard for subcutaneous self-injection. Virtually painless.

Needle Length

  • 6mm — ideal for subcutaneous injection in most people. Short enough to stay in the fat layer.
  • 8mm — may require a 45-degree angle in lean individuals.
  • 12.7mm — typically for intramuscular injections.

Our syringes use 6mm needles, the most widely recommended length for subcutaneous self-injection.

Which Syringe for Your Medication?

GLP-1 Medications (Semaglutide, Tirzepatide)

Recommended: 0.5ml, 31G, 6mm. GLP-1 doses are typically small, so finer graduations help with accurate measurement.

Peptides (BPC-157, TB-500, etc.)

Recommended: 0.5ml or 1ml, 31G, 6mm. Choose based on your dose volume — 0.5ml for doses under 0.5ml, 1ml for larger doses.

Testosterone Replacement Therapy

For subcutaneous TRT: 1ml, 31G, 6mm for injection, plus a 10mL syringe with 18G needle for drawing from the vial.

Key Takeaways

  • For subcutaneous self-injections, 31G, 6mm is the standard.
  • Choose 0.5ml for small doses or 1ml for larger doses.
  • Use a separate draw needle (18G) when drawing from vials.
  • All our syringes are individually wrapped and sterile. Never reuse a syringe.