Acetyl L Carnitine Dosage for Erectile Dysfunction 5 Worthy Holistic Reasons to Use Propionyl L Carnitine Acetyl l carnitine plus propionyl l carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve sparing radical retropubic prostatectomy ScienceDirect Serum l carnitine and vitamin D levels may be low among oral sildenafil citrate non responders International Journal of Impotence Research Propionyl L Carnitine Erectile Dysfunction: What the Evidence Shows and How It Fits Into Daily Use