Recommended Injection Sites for Mounjaro (Tirzepatide)
Mounjaro should be injected subcutaneously into the abdomen, thigh, or upper arm, with the abdomen providing the fastest and most consistent absorption. 1
Specific Anatomical Sites
The American Diabetes Association guidelines for subcutaneous injections, which apply to tirzepatide as a subcutaneously administered peptide, specify the following injection locations: 2, 1
- Abdomen: Inject at least 2 adult fingerbreadths (approximately 1 cm) away from the umbilicus, using the anterior abdominal wall 1
- Thigh: Use the upper third anterior lateral aspect of both thighs 1
- Upper arm: Use the middle third posterior aspect of the upper arm 1
- Buttocks: The posterior lateral aspect of both upper buttocks may also be used 2, 1
Optimal Site Selection
The abdomen is the preferred first-choice injection site because it provides the fastest and most consistent absorption of subcutaneously administered peptides. 1 For peptides and small proteins like tirzepatide (molecular weight <16 kDa), regional differences in subcutaneous blood flow and pre-systemic metabolism can affect absorption rates between injection sites. 3
Critical Injection Technique
- Use a 90-degree angle for subcutaneous injection with appropriate needle length 2, 1
- Inject at room temperature: Allow Mounjaro to reach room temperature before injection to reduce pain and prevent lipodystrophy 1
- Keep the needle embedded in skin for at least 5-6 seconds after complete delivery, particularly with pen devices 1
- Use 4-mm pen needles inserted at 90° for all adults regardless of BMI 1
Site Rotation Protocol
Systematic rotation within and between injection sites is mandatory to prevent lipohypertrophy. 2, 1
- Divide each injection area into quadrants or halves and rotate systematically within one area before moving to another 1
- Inject at least 1 cm from previous injection sites, rotating in a consistent direction 1
- Never inject into the same exact site repeatedly 1
Critical Pitfalls to Avoid
- Never inject into areas with lipohypertrophy (lumpy, raised tissue), as this causes unpredictable absorption and increased glucose variability 2, 1
- Avoid intramuscular injection: Inadvertent IM injection leads to unpredictable absorption and frequent unexplained hypoglycemia 2
- Do not inject into scars or damaged tissue, as absorption will be unpredictable 1
- Inspect all injection sites at every visit to identify lipohypertrophy early 1
Special Populations
For lean patients (BMI <19 kg/m²), the risk of unintentional intramuscular injection is especially high. 2 These patients should use a 4-mm pen needle perpendicularly into a properly lifted skinfold to ensure subcutaneous delivery. 2