Top 10 Best Vitamin B1 (Thiamine) Supplements 1. Suntheanine® L-Theanine 200mg (Double-Strength) in Cold-Pressed Organic Coconut Oil; Non-GMO & Gluten Free – 60 Liquid Softgel, Made in USA 2. Nature Made Vitamin B1, 100mg, 100 Tablet 3. Solgar – Vitamin…