For daily immune and antioxidant support, two capsules give you 1,000 mg of **Vitamin C** — right in the middle of the clinical range (250–2,000 mg) and a well-supported dose. You can also take just one capsule on lighter days and still get 500 mg, which is above the clinical minimum. Each capsule adds 200 mg of **citrus bioflavonoids** as a modest complement.
Ester-C is positioned as a premium, stomach-friendly form of vitamin C, but the clinical evidence supporting meaningful absorption advantages is thin. It works fine as a vitamin C source, but you shouldn't expect a significant edge from the form itself.
At the full two-capsule dose, you're well under the 2,000 mg tolerable upper limit, which gives you room if you get vitamin C from other sources too. The capsules are gelatin-based, so they're not suitable for vegetarian or vegan diets.
BioStacks
Other Ingredients (4)
GelatinCapsule
Protein derived from collagen, used in traditional capsule shells
Microcrystalline CelluloseBinder
Plant-derived cellulose used as a binder and filler in supplements
Microcrystalline CelluloseBinder
Plant-derived cellulose used as a binder and filler in supplements
Stearic AcidLubricant
Saturated fatty acid used as tablet lubricant
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Sources & Scoring
Nutrient data (RDA, UL, and safety thresholds) sourced from: NIH Office of Dietary Supplements and National Academies Dietary Reference Intakes (DRI).
This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.
The score analyzes what's on the label: ingredient doses vs. clinical ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.