Vitamin C New Studies 03.2026

Vitamin C is typically not tested in human studies as an “all-purpose remedy,” but in specific situations with clearly measurable endpoints.

In more recent research, the following has been observed:

Respiratory tract: add-on in hospitalized pneumonia

In a randomized study in children, vitamin C was given in addition to standard treatment and compared with placebo.Symptoms improved more after two to three days in the vitamin C groups than under placebo.

Respiratory tract: blood vitamin C level and its link to infections

An analysis in children and adolescents related measured blood vitamin C levels to self-reported respiratory infections in the past 30 days.Higher vitamin C levels were statistically associated with a lower risk of a recently reported respiratory infection.

Type 2 diabetes: blood sugar, blood pressure, and blood lipids

A systematic review with meta-analysis (a statistical synthesis of multiple studies) evaluated randomized trials in which vitamin C, vitamin E, or their combination was investigated.

Typical lab and cardiovascular measures were included, such as HbA1c (long-term blood glucose), fasting glucose, blood pressure, and blood lipids.

HbA1c decreased after vitamin C or vitamin E supplementation; in the analysis, HbA1c dropped under vitamin C or vitamin E, while the combination of vitamin C + E did not show this decrease.

For blood pressure, a significant reduction was reported only for vitamin C and for the combination C + E. An increase in HDL was described in this paper only for the combination of vitamin C + E.

Iron deficiency anemia: plant-based iron with or without vitamin C

In a randomized, double-blind study in adults with iron deficiency anemia (anemia caused by iron deficiency), three groups were compared:

• plant-based iron plus vitamin C,

• plant-based iron alone, and

• placebo.

Blood markers such as hemoglobin (the red pigment in red blood cells) and other measures of iron status were assessed.Both iron groups improved hemoglobin compared with the placebo group, and the combination of iron plus vitamin C showed the stronger improvement.Serum iron (iron measured in the blood) and ferritin (the main iron storage protein in the body) increased, but these changes were not statistically significant in this study.

Skin: vitamin C protective serum after microneedling

In a study, after microneedling (a treatment with fine needles intended to stimulate skin renewal), a protective serum containing vitamin C, vitamin E, and ferulic acid (a plant-derived antioxidant compound) was tested. For comparison, a placebo (without active ingredients) was used on the other half of the face. Visible signs of sun-damaged skin (photoaging) and other measurable skin parameters were assessed.

After twelve weeks, the side treated with microneedling plus the protective serum performed clearly better than microneedling plus placebo. Improvements were stronger in photoaging ratings, the pigment score, and skin elasticity. The overall assessment of improvement (GAIS) was also clearly better on the serum side.

Wound healing: vitamin C level before surgery in diabetic foot disease

An investigation examined whether the vitamin C level before surgery for diabetic foot wounds was associated with healing time. The outcome was the time until complete wound healing.

People with higher vitamin C levels before surgery had faster wound healing on average. According to the report, the albumin level (an important transport protein in blood plasma) and the wound location on the foot also played a role.

Oxidative stress after a viral infection: vitamin C as a comparator

A study examined people recovering after a moderate COVID course. One group received a single dose of vitamin C, while the other received a plant-based blend. The researchers measured blood markers for “cell stress” related to reactive oxygen species and a blood value linked to NO availability.

After a single dose of vitamin C, certain stress signals were lower. Other measured values were not improved by vitamin C in this study. Compared with the plant-based blend, the paper describes vitamin C as having a more limited effect.

07.03.2026

Written by: Alireza Mohtashami

Sources

1. Phuaksaman C, Jampachaisri K, Srisingh K. Effect of vitamin C supplement in treatment of childhood pneumonia requiring hospitalization: a randomized controlled trial. Clin Exp Pediatr. 2025. https://pubmed.ncbi.nlm.nih.gov/40211857/ 

   
   

2. Li C, Zhu Z, Jiang S, et al. The association between serum vitamin C levels and respiratory infections in children and adolescents. Frontiers in Nutrition. 2025. https://www.frontiersin.org/articles/10.3389/fnut.2025.1601218 

   
   

3. Aragón-Vela J, et al. Effects of Vitamin C and/or E Supplementation on Glycemic Control and Cardiovascular Risk Factors in Type 2 Diabetes: A Systematic Review and Subgroup Meta-analysis. Nutrition Reviews. 2025/2026 (PMC-Volltext). https://pmc.ncbi.nlm.nih.gov/articles/PMC12793614/ 

   
   

4. Patel MN, et al. Efficacy of Plant-Based Iron and Vitamin C in Adults With Iron Deficiency Anemia: A Randomized, Double-Blind Clinical Study. 2025. https://pubmed.ncbi.nlm.nih.gov/41287676/ 

   
   

5. Liu C, et al. A Double-Blinded, Split-Face Clinical Trial Evaluating the Effects of a Vitamin C, E, and Ferulic Acid Serum Combined with Microneedling on Facial Photoaging. 2026 (PMC-Volltext). https://pmc.ncbi.nlm.nih.gov/articles/PMC12912124/ 

   
   

6. Kancherla K, et al. The Role of Vitamin C in Wound Healing in Surgically Managed Diabetic Foot Disease. Diabetology (MDPI). 2025. https://www.mdpi.com/2673-4540/6/2/9 

   
   

7. Fink B, et al. A Plant-Based Dietary Supplement Exhibits Significant Effects on Markers of Oxidative Stress, Inflammation, and Immune Response in Subjects Recovering from Respiratory Viral Infection: A Randomized, Double-Blind Clinical Study Using Vitamin C as a Positive Control. Int J Mol Sci. 2025 (PMC-Volltext). https://pmc.ncbi.nlm.nih.gov/articles/PMC12153994/