Lecture Notes: Testosterone Replacement Therapy (TRT) Injection Techniques

Speaker: Gil Tebak

Key Topics Covered:

• Injection Sites: Intramuscular vs. Subcutaneous
• Needle Sizes
• Pharmacokinetics and Pharmacodynamics
• Practical Tips for Injections

Introduction

• Focus: Injection techniques for Testosterone Replacement Therapy (TRT).
• Comparison of intramuscular and subcutaneous injection methods.

Intramuscular vs. Subcutaneous Injections

• Intramuscular (IM) Injections:

  • Generally recommended for oil-based medications.
  • Offers advantages in terms of pharmacokinetics (absorption, distribution, metabolism, excretion).
  • More consistent blood flow due to muscle contractions.
  • Contains fewer pain receptors compared to subcutaneous tissue.
  • Hydrophilic (water-loving), absorbs oil-based medication better.

• Subcutaneous (Sub-Q) Injections:

  • Sometimes used for daily injections to reduce scar tissue.
  • Better suited for water-based medications (e.g., insulin).
  • Adipose tissue (fatty layer) is hydrophobic (repels water) and absorbs oil, affecting release into bloodstream.
  • Contains more sensory nerves, can lead to more irritation.

Injection Techniques

• For daily microdosing with oil-based medications: subcutaneous may be used to reduce long-term scar tissue.
• Intramuscular recommended especially for bi-weekly or tri-weekly dosing with long esters.

Pharmacokinetics and Dynamics

• Pharmacokinetics (ADME):
  • Absorption: Entry into bloodstream.
  • Distribution: Transport to target tissues.
  • Metabolism: Primarily by liver; may activate or deactivate drugs.
  • Excretion: Removal from the body.
• Pharmacodynamics:
  • Half-life considerations: Important for dosing frequency.
  • Intramuscular injections offer a stable half-life, better for TRT.

Needle Sizes and Injection Sites

• Preferred Injection Sites:
  • Lateral deltoid (shoulder): Lean area, good for smaller volumes.
  • Ventral glute: Side of the hip, suitable for larger needles if necessary.
• Needle Sizes:
  • Intramuscular injections: 27-29 gauge, half-inch needles.
  • Subcutaneous injections (for water-based): 31 gauge.

Practical Tips

• Use an insulin syringe for drawing and injecting medication.
• Ensure vial is properly pressurized to ease drawing medication.
• Avoid areas like quads due to high nerve density and potential for scar tissue development over time.

Considerations for European TRT Patients

• Many European patients receive testosterone in glass ampules.
• Tips for storing and managing dosages from ampules:
  • Pre-fill syringes for short-term use.
  • Transfer ampule contents to sterile vials for longer-term storage.

Conclusion

• Emphasis on using appropriate injection techniques for specific medication types.
• Encouragement to use intramuscular methods for oil-based TRT medications unless otherwise required.

Contact Information

• Gil Tebak offers coaching and consultations via Next Level Dietetics.
• Active in TRT and hormone optimization communities for further inquiries.