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    Vitamin C

    Vitamin C (ascorbic acid) is a water-soluble essential nutrient that humans cannot produce internally due to a genetic mutation shared by all primates. Found abundantly in citrus fruits, bell peppers, and cruciferous vegetables, it serves as one of the body's primary antioxidants and is required for collagen synthesis, neurotransmitter production, and proper immune cell function.

    Research Evidence
    Reduces duration and severity of the common cold
    Strong
    May improve sperm quality parameters in infertile men
    Limited
    Essential cofactor for collagen biosynthesis
    Strong
    Enhances non-heme iron absorption from food
    Strong
    Supports exercise recovery and reduces oxidative stress in athletes
    Moderate
    Lowers C-reactive protein in individuals with elevated baseline inflammation
    Moderate

    Expert Evidence

    76 references from 5 experts

    “Just because I take a supplement does not in any way mean that you should as well.”

    Stop These "Longevity" Supplements

    7:36
    Safety & Cautions

    Side Effects

    • Diarrhea or loose stools at high doses
    • Nausea or stomach cramps
    • Increased oxalate excretion (relevant for kidney stone risk)
    • Possible interference with certain lab tests
    Vitamin C is generally very well tolerated at doses up to 2,000 mg per day. Individuals with a history of kidney stones or iron overload conditions (hemochromatosis) should consult a physician before supplementing at higher doses.
    Pairs Well With
    Price Comparison
    From $0.06/ct
    N
    NOW Foods
    4.8
    250 ct

    $0.08/ct

    $19.59 total

    N
    NutricostBest Value
    4.7
    240 ct

    $0.06/ct

    $13.95 total

    N
    Nature Made
    4.8
    100 ct

    $0.08/ct

    $8.07 total

    N
    NutriFlair
    4.7
    180 ct

    $0.12/ct

    $20.99 total

    N
    Nature's Way
    4.6
    100 ct

    $0.14/ct

    $13.99 total

    V
    Vital Nutrients
    4.7
    100 ct

    $0.25/ct

    $24.99 total

    F
    FIQ
    4.4
    90 ct

    $0.48/ct

    $43.00 total

    O
    Opti + Life MD
    4.7
    100 ct

    $0.45/ct

    $45.00 total

    F
    FlavCity
    4.7
    60 ct

    $0.50/ct

    $29.99 total