The 5 Essential Vitamins™. VO5 has a unique formula with 5 Essential Vitamins that help nourish, moisturize and hydrate your hair leaving it looking and feeling thicker, fuller and simply beautiful. That's the secret of VO5. Vitamin E, Vitamin H, Vitamin C, Vitamin B5, Vitamin B3. Protects Against Breakage Long-Lasting Fragrance 5 Essential Vitamins™ for Healthy, Beautiful Hair