D
Body Fat
No effect
941 participants
none
?
Weight
941 participants
↓Improves
Vitamin C
Vitamin C, or ascorbic acid, is an essential vitamin and a very popular supplement due to its antioxidant properties, safety profile, and low price. Many people supplement with vitamin C because it is believed to reduce symptoms of the common cold.
Quick Answer
What it is
Vitamin C, or ascorbic acid, is an essential vitamin and a very popular supplement due to its antioxidant properties, safety profile, and low price. Many people supplement with vitamin C because it is believed to reduce symptoms of the common cold.
Key findings
- Grade B: Blood Flow
- Grade C: Blood glucose (High Cholesterol)
- Grade C: Anti-Oxidant Enzyme Profile (Bone Health)
Safety
No specific caution or interaction language was detected in the current summary/outcome notes.
ℹ️ Quick Facts: Vitamin C
Quick Facts: Vitamin C
- Best Evidence:Grade C
- Conditions Studied:41
- Research Outcomes:262
- Grade B Findings:1
- Key Effect:Immune Health
Outcomes by grade:
A0
B1
C8
D19
41 conditions · 262 outcomes
Detailed Outcomes
Grade:
Effect:
Size:
Sort:
|
B
Blood Flow
Small Increase
83 participants
small↑Improves
?
Protection from Smoking
83 participants
↑Improves
?
LDL Oxidation
2 studies64 participants
↓Improves
?
Oxidative Stress Biomarkers
56 participants
↓Improves
?
Plasma Vitamin C
19 participants
↑Improves
?
Vascular Function
2 studies19 participants
↑Improves
?
Blood glucose
10 participants
↓Improves
?
Blood Pressure
1 study9 participants
↓Improves
?
Heart Rate
9 participants
↓Improves
?
Insulin
1 study10 participants
↑Worsens
?
Pre-Eclampsia Risk
50 participants
↑Worsens
C
Blood glucose
Small Improvement
216 participants
small↓Improves
?
Total cholesterol
1157 participants
↓Improves
?
HbA1c
216 participants
↓Improves
?
Triglycerides
216 participants
↓Improves
?
High-density lipoprotein (HDL)
3 studies166 participants
↑Improves
?
Low-density lipoprotein (LDL)
3 studies166 participants
↓Improves
?
Blood Pressure
2 studies99 participants
↓Improves
?
Creatinine
1 study65 participants
↑Improves
?
Inflammation
941 participants
↓Improves
?
Plasma Vitamin C
50 participants
↑Improves
?
Urea
1 study65 participants
↑Improves
C
Blood glucose
Small Improvement
28 participants
small↓Improves
?
Upper Respiratory Tract Infection Risk
1159 participants
↑Worsens
?
Cortisol
93 participants
↓Improves
?
Exercise-Induced Immune Suppression
5 studies93 participants
↑Improves
?
Heart Rate
40 participants
↓Improves
?
Inflammation
30 participants
↓Improves
?
Muscle Damage
30 participants
↑Worsens
?
Oxidative Stress Biomarkers
56 participants
↓Improves
?
Plasma Vitamin C
56 participants
↑Improves
?
Upper Respiratory Tract Infection Symptoms
474 participants
↓Improves
?
Exercise-Induced Oxidation
16 participants
↑Worsens
?
IL-1Ra
1 study28 participants
↓Improves
?
Insulin
1 study28 participants
↑Worsens
?
Interferon Gamma
28 participants
↑Improves
?
Interleukin 10
1 study28 participants
↑Improves
?
Interleukin 2
1 study28 participants
↑Improves
?
Interleukin 6
1 study28 participants
↓Improves
?
Interleukin 8
1 study28 participants
↑Worsens
?
Lymphocyte Count
1 study28 participants
↑Improves
?
Monocyte Count
1 study28 participants
↑Improves
?
Natural Killer Cell Content
1 study28 participants
↑Improves
?
Neutrophil Count
1 study28 participants
↑Improves
?
Uric Acid
28 participants
↓Improves
C
Blood Flow
Small Increase
37 participants
small↑Improves
?
Blood glucose
174 participants
↓Improves
?
Total cholesterol
1078 participants
↓Improves
?
Triglycerides
137 participants
↓Improves
?
Blood Pressure
2 studies65 participants
↓Improves
?
HbA1c
65 participants
↓Improves
?
High-density lipoprotein (HDL)
2 studies65 participants
↑Improves
?
Insulin
2 studies68 participants
↑Worsens
?
Low-density lipoprotein (LDL)
2 studies65 participants
↓Improves
?
Body Fat
31 participants
↓Improves
?
C-Reactive Protein (CRP)
72 participants
↓Improves
?
Glycemic Control
37 participants
↑Improves
?
Inflammation
941 participants
↓Improves
?
Interleukin 6
1 study72 participants
↓Improves
?
Kidney Function
1 study31 participants
↑Improves
?
Liver Enzymes
1 study31 participants
↑Worsens
?
Plasma Vitamin C
37 participants
↑Improves
?
Weight
31 participants
↓Improves
C
Blood glucose
Small Improvement
72 participants
small↓Improves
?
C-Reactive Protein (CRP)
72 participants
↓Improves
?
Fat Oxidation
1 study20 participants
↑Improves
?
Fatigue Symptoms
1 study20 participants
↓Improves
?
Heart Rate
20 participants
↓Improves
?
Interleukin 6
1 study72 participants
↓Improves
?
Total cholesterol
72 participants
↓Improves
?
Triglycerides
72 participants
↓Improves
?
Weight
20 participants
↓Improves
C
Anti-Oxidant Enzyme Profile
Small Increase
90 participants
small↑Improves
?
Bone Mineral Density
124 participants
↑Improves
C
Seminal Motility
Moderate Improvement
1 study120 participants
moderate↑Improves
?
Sperm Quality
120 participants
↑Improves
C
Blood Flow
Small Increase
19 participants
small↑Improves
?
Microcirculation
19 participants
↑Improves
C
Depression Symptoms
Small Improvement
81 participants
small↓Improves
?
Frequency of Intercourse
1 study81 participants
↑Improves
?
Plasma Vitamin C
81 participants
↑Improves
D
Upper Respiratory Tract Infection Risk
No effect
21620 participants
none
D
Common Cold Symptoms
No effect
3001 participants
none
?
Upper Respiratory Tract Infection Symptoms
14426 participants
↓Improves
D
All-Cause Mortality
No effect
366 participants
none
?
Length of hospitalization
3 studies366 participants
↓Improves
?
Need for mechanical ventilation
2 studies366 participants
↑Worsens
D
Aerobic Exercise Metrics
No effect
68 participants
none
?
Oxidative Stress Biomarkers
35 participants
↓Improves
?
Blood glucose
28 participants
↓Improves
?
Cortisol
28 participants
↓Improves
?
Exercise Adaptations
15 participants
↑Improves
?
Exercise-Induced Immune Suppression
1 study28 participants
↑Improves
?
Exercise-Induced Oxidation
7 participants
↑Worsens
?
Glycemic Control
21 participants
↑Improves
?
Heart Rate
28 participants
↓Improves
?
Insulin
1 study28 participants
↑Worsens
?
Interferon Gamma
28 participants
↑Improves
?
Interleukin 10
1 study28 participants
↑Improves
?
Interleukin 2
1 study28 participants
↑Improves
?
Interleukin 6
1 study28 participants
↓Improves
?
Interleukin 8
1 study28 participants
↑Worsens
?
Lymphocyte Count
1 study28 participants
↑Improves
?
Monocyte Count
1 study28 participants
↑Improves
?
Natural Killer Cell Content
1 study28 participants
↑Improves
?
Neutrophil Count
1 study28 participants
↑Improves
?
Oxygen Uptake
1 study15 participants
↑Improves
?
Plasma Vitamin C
28 participants
↑Improves
?
Rating of Perceived Exertion
1 study28 participants
↑Improves
?
Uric Acid
28 participants
↓Improves
D
Common Cold Symptoms
No effect
1731 participants
none
?
Upper Respiratory Tract Infection Risk
8012 participants
↑Worsens
?
Upper Respiratory Tract Infection Symptoms
4935 participants
↓Improves
D
High-density lipoprotein (HDL)
No effect
3 studies112 participants
none
?
Low-density lipoprotein (LDL)
3 studies112 participants
↓Improves
?
Total cholesterol
112 participants
↓Improves
?
Triglycerides
112 participants
↓Improves
?
Inflammation
941 participants
↓Improves
D
Upper Respiratory Tract Infection Risk
No effect
1332 participants
none
?
Upper Respiratory Tract Infection Symptoms
666 participants
↓Improves
D
Aerobic Exercise Metrics
No effect
7 participants
none
?
Blood glucose
875 participants
↓Improves
?
HbA1c
488 participants
↓Improves
?
Insulin
9 studies233 participants
↑Worsens
?
Oxidative Stress Biomarkers
112 participants
↓Improves
?
Cortisol
31 participants
↓Improves
?
Exercise-Induced Immune Suppression
3 studies31 participants
↑Improves
?
C-Reactive Protein (CRP)
476 participants
↓Improves
?
DNA Damage
73 participants
↑Worsens
?
Exercise-Induced Oxidation
23 participants
↑Worsens
?
Plasma Vitamin C
89 participants
↑Improves
?
Blood Flow
34 participants
↑Improves
?
Exercise Adaptations
39 participants
↑Improves
?
Glycemic Control
21 participants
↑Improves
?
High-density lipoprotein (HDL)
1 study80 participants
↑Improves
?
Inflammation
16 participants
↓Improves
?
Interleukin 6
1 study6 participants
↓Improves
?
LDL Oxidation
1 study30 participants
↓Improves
?
Mineral Bioaccumulation
45 participants
↑Improves
?
Muscle Damage
16 participants
↑Worsens
?
Plasma Vitamin E
1 study80 participants
↑Improves
?
Protection from Smoking
30 participants
↑Improves
?
Resistin
80 participants
↑Improves
?
Total cholesterol
80 participants
↓Improves
?
Triglycerides
80 participants
↓Improves
D
Adiponectin
No effect
1 study8 participants
none
?
Blood glucose
537 participants
↓Improves
?
Total cholesterol
406 participants
↓Improves
?
Triglycerides
396 participants
↓Improves
?
HbA1c
354 participants
↓Improves
?
High-density lipoprotein (HDL)
8 studies284 participants
↑Improves
?
Low-density lipoprotein (LDL)
8 studies284 participants
↓Improves
?
Insulin
5 studies129 participants
↑Worsens
?
Blood Pressure
4 studies154 participants
↓Improves
?
C-Reactive Protein (CRP)
106 participants
↓Improves
?
Glycemic Control
80 participants
↑Improves
?
Plasma Vitamin C
157 participants
↑Improves
?
Blood Flow
63 participants
↑Improves
?
Body Fat
44 participants
↓Improves
?
Interleukin 6
2 studies98 participants
↓Improves
?
Kidney Function
2 studies55 participants
↑Improves
?
Oxidative Stress Biomarkers
43 participants
↓Improves
?
Weight
44 participants
↓Improves
?
Anti-Oxidant Enzyme Profile
13 participants
↑Improves
?
Creatinine
1 study65 participants
↑Improves
?
Fat Oxidation
1 study13 participants
↑Improves
?
Fructosamine
1 study13 participants
↑Worsens
?
Inflammation
8 participants
↓Improves
?
LDL Oxidation
1 study8 participants
↓Improves
?
Liver Enzymes
1 study31 participants
↑Worsens
?
Muscle Mass
1 study13 participants
↑Improves
?
TNF-Alpha
1 study26 participants
↓Improves
?
Urea
1 study65 participants
↑Improves
?
Uric Acid
13 participants
↓Improves
?
Vascular Function
1 study26 participants
↑Improves
D
Aerobic Exercise Metrics
No effect
28 participants
none
?
Muscle Damage
76 participants
↑Worsens
?
Cortisol
44 participants
↓Improves
?
Exercise-Induced Immune Suppression
2 studies44 participants
↑Improves
?
Inflammation
30 participants
↓Improves
?
Blood glucose
28 participants
↓Improves
?
Exercise-Induced Oxidation
16 participants
↑Worsens
?
Heart Rate
28 participants
↓Improves
?
IL-1Ra
1 study28 participants
↓Improves
?
Insulin
1 study28 participants
↑Worsens
?
Interferon Gamma
28 participants
↑Improves
?
Interleukin 10
1 study28 participants
↑Improves
?
Interleukin 2
1 study28 participants
↑Improves
?
Interleukin 6
1 study28 participants
↓Improves
?
Interleukin 8
1 study28 participants
↑Worsens
?
Lymphocyte Count
1 study28 participants
↑Improves
?
Monocyte Count
1 study28 participants
↑Improves
?
Muscle Soreness
1 study18 participants
↓Improves
?
Natural Killer Cell Content
1 study28 participants
↑Improves
?
Neutrophil Count
1 study28 participants
↑Improves
?
Oxidative Stress Biomarkers
28 participants
↓Improves
?
Plasma Vitamin C
28 participants
↑Improves
?
Rating of Perceived Exertion
1 study28 participants
↑Improves
?
Uric Acid
28 participants
↓Improves
D
Glycemic Control
No effect
21 participants
none
?
Muscle Damage
60 participants
↑Worsens
?
Inflammation
14 participants
↓Improves
?
Muscle Soreness
1 study18 participants
↓Improves
D
Aerobic Exercise Metrics
No effect
26 participants
none
?
Blood glucose
100 participants
↓Improves
?
HbA1c
74 participants
↓Improves
?
Plasma Vitamin C
76 participants
↑Improves
?
Blood Pressure
1 study24 participants
↓Improves
?
Heart Rate
26 participants
↓Improves
?
Kidney Function
1 study24 participants
↑Improves
?
Oxidative Stress Biomarkers
26 participants
↓Improves
?
Total cholesterol
50 participants
↓Improves
?
Triglycerides
50 participants
↓Improves
D
Adrenocorticotropic Hormone
No effect
1 study22 participants
none
?
Blood Flow
21 participants
↑Improves
?
Blood glucose
22 participants
↓Improves
?
Cortisol
22 participants
↓Improves
?
Insulin
1 study22 participants
↑Worsens
?
Osteocalcin
1 study22 participants
↑Improves
D
Aerobic Exercise Metrics
No effect
15 participants
none
?
Cortisol
28 participants
↓Improves
?
Exercise Adaptations
15 participants
↑Improves
?
Exercise-Induced Immune Suppression
1 study28 participants
↑Improves
?
Oxidative Stress Biomarkers
28 participants
↓Improves
?
Oxygen Uptake
1 study15 participants
↑Improves
?
Plasma Vitamin C
28 participants
↑Improves
D
Adiponectin
No effect
1 study8 participants
none
?
Blood glucose
8 participants
↓Improves
?
C-Reactive Protein (CRP)
8 participants
↓Improves
?
High-density lipoprotein (HDL)
1 study8 participants
↑Improves
?
Inflammation
8 participants
↓Improves
?
Insulin
1 study8 participants
↑Worsens
?
LDL Oxidation
1 study8 participants
↓Improves
?
Low-density lipoprotein (LDL)
1 study8 participants
↓Improves
?
Total cholesterol
8 participants
↓Improves
?
Triglycerides
8 participants
↓Improves
D
Aerobic Exercise Metrics
No effect
7 participants
none
?
Exercise-Induced Oxidation
7 participants
↑Worsens
?
Oxidative Stress Biomarkers
7 participants
↓Improves
D
High-density lipoprotein (HDL)
No effect
1 study439 participants
none
?
Low-density lipoprotein (LDL)
1 study439 participants
↓Improves
?
Total cholesterol
439 participants
↓Improves
?
Triglycerides
439 participants
↓Improves
D
Body Fat
No effect
941 participants
none
?
Weight
941 participants
↓Improves
?
Uric Acid
1013 participants
↓Improves
?
COVID-19 Severity
274 participants
↓Improves
?
Gout Symptoms
14641 participants
↓Improves
?
Oxidative Stress Biomarkers
60 participants
↓Improves
?
Bacterial Vaginosis Symptoms
277 participants
↓Improves
?
Inflammation
24 participants
↓Improves
?
Cataract Risk
11545 participants
↑Worsens
?
Charcot Marie Tooth Disease Symptoms
271 participants
↓Improves
?
Aerobic Exercise Metrics
18 participants
↑Improves
?
Heart Rate
11 participants
↓Improves
?
Uric Acid
184 participants
↓Improves
?
Upper Respiratory Tract Infection Symptoms
57 participants
↓Improves
?
Subjective Well-Being
55 participants
↑Improves
?
Preterm Birth Risk
9968 participants
↑Worsens
?
Upper Respiratory Tract Infection Symptoms
252 participants
↓Improves
Evidence by Condition
Best grade per condition (each condition may have multiple outcomes)
Research Citations (100)
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18 shared conditions · 433 outcomes
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17 shared conditions · 502 outcomes
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