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
StrongMay improve sperm quality parameters in infertile men
LimitedEssential cofactor for collagen biosynthesis
StrongEnhances non-heme iron absorption from food
StrongSupports exercise recovery and reduces oxidative stress in athletes
ModerateLowers C-reactive protein in individuals with elevated baseline inflammation
ModerateExpert Evidence
84 references from 6 experts
“Just because I take a supplement does not in any way mean that you should as well.”
Stop These "Longevity" Supplements
7:3637 references in 13 episodes from 2021–2025
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
NutricostBest Value
4.8
•240 ct$0.06/ct
$13.95 total
N
NOW Foods
4.8
•250 ct$0.07/ct
$18.50 total
N
Nature Made
4.8
•100 ct$0.29/ct
$29.19 total
N
NutriFlair
4.8
•180 ct$0.12/ct
$21.99 total
N
Nature's Way
4.7
•100 ct$0.14/ct
$14.45 total
V
Vital Nutrients
4.6
•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