Vitamin C in a sustained release form (to maintain useful levels over time) is highly recommended for daily use by NYBC. Here’s an excerpt from the website description:
Vitamin C Overview: Vitamin C is another critical nutrient, an antioxidant and highly efficient free radical scavenger, antiviral, antibacterial and antifungal which should be in any HIV protocol. Vitamin C is responsible for the reactivation of key antioxidants, particularly vitamin E, beta-carotene, and glutathione, after they have been oxidized by donating electrons to neutralize a free radical (known as the redox process). Vitamin C and certain sulfur amino acids are the only water-soluble nutrients which can be taken in sufficiently large, yet safe, quantities to effectively conduct this redox process.
For more details, see the complete NYBC entry: