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Vitamin

Vitamin C

Also known as: Ascorbic acid, L-ascorbic acid, Ascorbate, Sodium ascorbate

A
Evidence

Vitamin C is an essential water-soluble antioxidant required for collagen synthesis, immune function, and iron absorption. Calcium ascorbate is a buffered form that reduces gastric irritation.

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Daily target & upper limit

90 mg / day · UL 2000 mg

Vitamin C has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:

Vitamin C dosage reference →

Primary uses

  • Immune support
  • Antioxidant
  • Collagen synthesis
  • Iron absorption
  • Enhanced immune support
  • High-dose C therapy
  • Antioxidant protection
  • Cortisol reduction
  • Exercise recovery
  • Adrenal support
  • Cortisol production
  • Stress resilience

How it works

  • Collagen hydroxylation cofactor
  • Electron donor antioxidant
  • Immune cell support
  • Enhances iron absorption

Dosage

Typical range
500-2000mg daily
Timing
Divided doses
With food
Optional
Duration
Safe long-term
Special populations
Higher needs when sick

Forms

  • Ascorbic acid powder
  • Sodium ascorbate
  • Liposomal
  • Liquid gel
  • Capsules
  • Ascorbic acid
  • Buffered/Ester-C
  • Buffered C
  • Liposomal C
  • Buffered
  • Liposomal vitamin C
  • Ester-C
  • Powder
  • Buffered (sodium ascorbate)
  • Calcium ascorbate· 70/100

Safety

Common side effects

  • GI upset at high doses
  • Diarrhea

Contraindications

  • Hemochromatosis
  • G6PD deficiency (IV)

Products containing Vitamin C

Top-scoring supplements in our catalog that list Vitamin C on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Thorne
MediClear-SGS™ - Vanilla
95
Thorne
Vitamin C 1,000 mg (formerly Ascorbic Acid)
95
Thorne
Thyroid Health Complex (formerly Thyrocsin)
94
Thorne
Basic Nutrients 2/Day
93
See all products →

Known interactions

Evidence notes

Essential vitamin with extensive research

Grade A: Multiple well-designed human trials support the main claims.

Cited research for Vitamin C

Clinical studies referenced across Formulate guides that mention vitamin c. Each links to the full study page with PubMed source + the guides that cite it.

Vitamin C compared head-to-head

Related in Vitamin

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.