Z-stack is an Immune System Formula Developed by Dr. Vladimir (Zev) Zelenko OBM to Prevent Treat Viruses and Maximize Your Immune Function Immune Support | Kosher Certified | Dietary Supplement Developed by the late Dr. Vladimir Zelenko, this Kosher-certified formula is designed to support your immune system using science-backed ingredients in precise, doctor-formulated ratios. Trusted by thousands, this supplement combines key vitamins and minerals to help your body defend itself naturally. Key Benefits: Supports a Healthy Immune System Formulated by a Board-Certified Physician Kosher Certified Made in the USA Non-GMO, Gluten-Free, No Artificial Fillers Core Ingredients (Varies by Version): Vitamin C – Powerful antioxidant and immune booster Vitamin D3 – Supports immune cell function and mood Zinc – Essential mineral for immune strength Quercetin – Plant-based flavonoid that aids zinc absorption into cells Some formulations may also include NAC, EGCG, or other immune-enhancing compounds.