Side Effects of Vitamin C: Separating Facts from Myths

Side Effects of Vitamin C

Side Effects of Vitamin C

Side Effects of Vitamin C. Vitamin C, also known as ascorbic acid, is renowned for its immune-boosting and antioxidant properties. However, like any supplement, it’s important to understand the potential side effects that may arise from its consumption. This article aims to shed light on the possible adverse effects of taking Vitamin C, backed by scientific evidence.

1. Gastrointestinal Distress:

One of the most commonly reported side effects of excessive Vitamin C intake is gastrointestinal discomfort. This can include symptoms like nausea, diarrhea, and stomach cramps. These effects are often dose-dependent, meaning they become more likely with higher doses of Vitamin C.

2. Kidney Stones:

There has been some concern about the connection between high-dose Vitamin C supplementation and the formation of kidney stones. While this risk appears to be more relevant to individuals with a history of kidney stones or preexisting kidney conditions, it’s advisable to exercise caution, especially when taking large doses of Vitamin C.

3. Interference with Medical Tests:

It’s worth noting that Vitamin C can interfere with certain medical tests, like blood sugar monitoring for individuals with diabetes. High doses of Vitamin C might affect the accuracy of these tests, potentially leading to incorrect results.

4. Iron Absorption:

Vitamin C enhances the absorption of non-heme iron (the type of iron found in plant-based foods). While this is generally considered a positive effect, individuals with iron overload disorders should be cautious, as increased iron absorption could exacerbate their condition.

5. Allergic Reactions:

Though rare, some individuals might experience allergic reactions to Vitamin C supplements. Symptoms can range from skin rashes and itching to more severe reactions like difficulty breathing. If you suspect an allergic reaction, seek medical attention promptly.


It’s crucial to emphasize that Vitamin C is generally considered safe when consumed within the recommended daily allowances. The potential side effects are more likely to occur with excessive intake, often from high-dose supplements. As always, consulting with a healthcare professional before making any significant changes to your supplement regimen is advisable.


1. Carr AC, et al. (2013). Vitamin C and Immune Function. DOI: 10.3390/nu5031293

2. NIH Office of Dietary Supplements – Vitamin C. (

3. Jacob RA, et al. (1990). Long-term effects of vitamin C supplementation on the human serum erythropoietin concentration: implications for vitamin C in erythropoiesis. DOI: 10.1093/ajcn/52.4.717

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