How to Inject L Carnitine for Weight Loss Safely 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 The mechanism of acetyl L carnitine on colorectal cancer and its metabolomic study ScienceDirect The How matters just as much as the What. We put together this step by step guide so you never have to guess what you need,where to inject and the mistakes to avoid.