Vitamin C
Also known as: Ascorbic Acid, Ascorbate, Sodium Ascorbate
A potent antioxidant and immune-supporting vitamin — essential for collagen synthesis and iron absorption.
What it is
Vitamin C (ascorbic acid) is a water-soluble antioxidant and enzyme cofactor that humans cannot synthesize internally — making dietary and supplemental intake essential. It is one of the most well-studied vitamins, with clear evidence supporting its roles in immune function, collagen synthesis, non-heme iron absorption, and antioxidant defense.
How it works
Vitamin C is required for the hydroxylation of proline and lysine in collagen synthesis — without it, collagen is structurally unstable (the mechanism behind scurvy). It regenerates vitamin E from its oxidized form, enhancing the body's overall antioxidant network. In the immune system, it accumulates in phagocytes and lymphocytes, enhancing their function during infection. It also converts dietary non-heme iron to the ferrous form needed for absorption.
Clinical dose range
500–2,000 mg/day
RDA is 75 mg (women) to 90 mg (men). However, absorption becomes increasingly inefficient above 1,000 mg/day. Divided dosing (e.g., 500 mg twice daily) improves plasma saturation. Higher doses used in therapeutic contexts (cancer support, IV vitamin C) require medical supervision.
Forms comparison
What to look for on the label
- Ascorbic acid or sodium ascorbate as the primary form
- Dose 500–1,000 mg per serving for typical use
- Third-party tested for potency and contaminants
- Avoid products with unnecessary added sugars in 'vitamin C gummies'
Health goals supported
Safety & dosing notes
UL: 2,000 mg/day. Doses above 1,000 mg/day commonly cause GI discomfort and loose stools (osmotic diarrhea). High doses may slightly increase oxalate excretion — a consideration for kidney stone formers. Generally extremely safe within the UL.
SuppsBuddy validates ascorbic acid or sodium ascorbate as the primary form and checks that dose sits within absorption-efficient ranges. Gummy formulations receive a lower score if they contain significant added sugars. Liposomal claims are flagged for third-party bioavailability verification.
Frequently asked questions
What is Vitamin C?
Vitamin C (ascorbic acid) is a water-soluble antioxidant and enzyme cofactor that humans cannot synthesize internally — making dietary and supplemental intake essential. It is one of the most well-studied vitamins, with clear evidence supporting its roles in immune function, collagen synthesis, non-heme iron absorption, and antioxidant defense.
How does Vitamin C work?
Vitamin C is required for the hydroxylation of proline and lysine in collagen synthesis — without it, collagen is structurally unstable (the mechanism behind scurvy). It regenerates vitamin E from its oxidized form, enhancing the body's overall antioxidant network. In the immune system, it accumulates in phagocytes and lymphocytes, enhancing their function during infection. It also converts dietary non-heme iron to the ferrous form needed for absorption.
What is the typical clinical dose range for Vitamin C?
500–2,000 mg/day. RDA is 75 mg (women) to 90 mg (men). However, absorption becomes increasingly inefficient above 1,000 mg/day. Divided dosing (e.g., 500 mg twice daily) improves plasma saturation. Higher doses used in therapeutic contexts (cancer support, IV vitamin C) require medical supervision.
What forms of Vitamin C should I look for?
Ascorbic Acid: Most studied, most bioavailable; identical to the vitamin C in food | Sodium Ascorbate: Buffered form; less acidic, better tolerated at high doses | Ascorbyl Palmitate: Fat-soluble form used as a preservative and supplement; lower vitamin C activity | Calcium Ascorbate (Ester-C): Buffered, somewhat gentler on digestion; similar efficacy to ascorbic acid
Is Vitamin C safe?
UL: 2,000 mg/day. Doses above 1,000 mg/day commonly cause GI discomfort and loose stools (osmotic diarrhea). High doses may slightly increase oxalate excretion — a consideration for kidney stone formers. Generally extremely safe within the UL. This information is educational and is not medical advice.
How does SuppsBuddy evaluate Vitamin C?
SuppsBuddy validates ascorbic acid or sodium ascorbate as the primary form and checks that dose sits within absorption-efficient ranges. Gummy formulations receive a lower score if they contain significant added sugars. Liposomal claims are flagged for third-party bioavailability verification.
Related ingredients
This page is for educational purposes only. These statements have not been evaluated by the FDA. This information is not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before starting any supplement.