NOW Foods L Carnitine, Triple Strength Liquid 16 fl. oz. Acetyl L Carnitine HCl 300 mg Capsules Supports Brain Health Bayview Pharmacy ONLY NATURAL PET Thyroid Support Supplement for Cats Multivitamin with L Carnitine & Lemon Balm Vet Are these Supplements Hurting your Thyroid? L carnitine reduces hyperthyroidism symptoms If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy.