Subcutaneous Injection: What It Is and How to Give One Know About L Carnitine Injections for Weight Loss L Carnitine injection is recommended at 1 ampule every 2 3 days for best results. The L Carnitine is taken intravenously either by normal injection or using a butterfly needle. After taking this L Carnitine, you Issue 13: IMCAS 2025 RESEARCH POSTER: L Carnitine Subcutaneous Injection After HIFU for Local Fat Reduction: a Case Study Suisselle Compounded Carnitine (L) Injection Empower Pharmacy Subcutaneous Injection Sites and Instructions for Safe Self Administration