Ester-C Plus is exclusively formulated by Solgar and provides a patented method of supplementing pH neutral (non-acidic) vitamin C to prevent stomach irritation. In addition, Ester-C Plus includes the vitamin C metabolites, L- hreonic acid, L-lyxonic acid and L-ylonic acid, that occur along with vitamin C in nature. A special manufacturing process is employed to form a unique calcium ascorbate metabolite complex.