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04 / Injection

Administration procedures

Practitioner-facing reference compiled from peptide handling and pharmacology literature.

Subcutaneous injection

  1. The vial surface is cleaned with alcohol prep.
  2. The plunger and needle are uncapped.
  3. The needle is inserted into the center ring, the vial inverted, and the dose drawn (air is injected first if flow is slow).
  4. The needle is recapped, or left uncapped on a sanitized surface.
  5. The skin site is cleaned; subcutaneous fat is pinched and lifted away from the body where possible.
  6. The needle is inserted fully and the plunger depressed completely.
  7. After a few seconds the needle is removed, capped, and disposed of.
  8. The site is massaged through clothing for about one minute to aid absorption.
  9. The peptide is returned to refrigeration.

Intramuscular injection

  1. The vial surface is cleaned.
  2. The needle and plunger are uncapped.
  3. The bottle is inverted and the indicated dose drawn.
  4. The needle is recapped if the surface is not sanitized.
  5. The skin surface is cleaned.
  6. The needle is inserted through the skin into the muscle.
  7. The plunger is depressed completely, then the needle is removed after a brief pause.
  8. The site is massaged through clothing for about one minute, and the peptide is returned to refrigeration.

Frequently asked questions

What is the difference between subcutaneous (SQ) and intramuscular (IM) peptide injection?

Subcutaneous administration deposits into the fatty layer just under the skin, giving slower and more sustained absorption; intramuscular deposits deeper into muscle tissue, giving faster onset. Most peptide research dosing is reported as subcutaneous, with intramuscular reported where faster systemic uptake is the stated objective.

Which sites are reported for subcutaneous administration?

The sites reported are the abdomen, avoiding the navel, the upper outer thigh, and the upper outer arm. Descriptions of the technique note that the subcutaneous layer is drawn away from the body before insertion, and that sites are rotated to reduce local irritation. Reported for reference only; consult a qualified clinician before any human use.

How painful is subcutaneous administration reported to be?

Small volumes administered through a 29-31 gauge needle are typically described as minimally painful. Larger-gauge needles, used for the reconstitution draw rather than for administration, are noticeably sharper. Reports note that cleaning the site and inserting briskly reduces discomfort.

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