Is there citric acid in vitamin C supplements? Unpacking the Ingredients

November 1, 2025 •

4 min read

While many people confuse them, Vitamin C is actually known as ascorbic acid and is a different compound from citric acid. The presence of citric acid in vitamin C supplements is common, but it is important to understand why it might be included and what it means for your diet.

Quick Summary

Many vitamin C supplements contain citric acid as a preservative or flavoring agent, a compound chemically distinct from vitamin C (ascorbic acid). The manufactured version is often produced using a fungus, which can be an issue for those with sensitivities. Buffered supplements offer alternatives free of citric acid.

Key Points

Distinct Compounds: Vitamin C is ascorbic acid, an essential nutrient, while citric acid is a different organic acid, though often found together in nature.
Common Additive: Manufactured citric acid is frequently added to vitamin C supplements as a preservative and to enhance flavor, especially in chewable or effervescent forms.
Manufactured from Mold: Most commercial citric acid is produced through the fermentation of the fungus Aspergillus niger, which can be an issue for people with mold allergies.
Buffered Alternatives: For those with sensitivities, buffered vitamin C supplements (using sodium or calcium ascorbate) are available and are much gentler on the stomach.
Check the Label: To avoid citric acid, check supplement labels for the presence of the additive and seek out products specifically marketed as buffered or citric-acid-free.
Consider Sensitivities: People with acid reflux, dental issues, or known mold allergies should be especially mindful of supplements containing citric acid.

The Difference Between Vitamin C (Ascorbic Acid) and Citric Acid

Although they are often found together in citrus fruits and share a similar sour taste, Vitamin C and citric acid are fundamentally different compounds.

Vitamin C (Ascorbic Acid):

An essential water-soluble vitamin that the human body cannot produce on its own.
Plays a crucial role in immune function, collagen production, and acts as a powerful antioxidant protecting cells from oxidative stress.
Chemical formula is $C_6H_8O_6$.

Citric Acid:

An organic acid that is not an essential nutrient.
Plays a metabolic role in the Krebs cycle for energy production but is not required from an external dietary source.
Primarily used in the food industry as a preservative, flavor enhancer, and pH regulator.
Chemical formula is $C_6H_8O_7$.

Why Citric Acid Appears in Vitamin C Supplements

The inclusion of citric acid in many vitamin C supplements serves several functional purposes for manufacturers.

Preservative: Citric acid helps increase the shelf life of supplements by inhibiting the growth of microbes.
Flavoring Agent: It is commonly used to add a tangy or tart flavor, especially in chewable tablets, gummies, and effervescent drink mixes. The tartness can also mask the taste of other ingredients.
Enhances Mineral Absorption: In certain formulations, citric acid (in the form of citrate) is bonded with minerals like magnesium or calcium to create highly absorbable compounds (e.g., magnesium citrate, calcium citrate).

The Source of Manufactured Citric Acid

The citric acid used as a common food additive is not extracted from citrus fruits. Instead, it is mass-produced via a fermentation process involving a common fungus called Aspergillus niger (black mold). This manufactured citric acid can sometimes contain residues from the fermentation process. For individuals with mold allergies or sensitivities, this can be a concern, potentially triggering adverse reactions.

Finding a Vitamin C Supplement Without Citric Acid

For those with sensitivities or a desire to avoid manufactured additives, there are many vitamin C alternatives available. When checking product labels, you should look for specific ingredients or product descriptions.

Buffered Vitamin C: Supplements labeled as "buffered" are a great option for those with sensitive stomachs or citric acid concerns. These formulations use mineral ascorbates, such as sodium ascorbate or calcium ascorbate, which are non-acidic and gentle on the digestive system.
Alternative Forms: Look for options like liposomal vitamin C, which offers enhanced absorption and is less likely to contain added citric acid, or supplements that contain only L-ascorbic acid and clearly state they are free of citric acid.
Natural Sources: While supplements offer convenience, obtaining your vitamin C from whole foods like bell peppers, broccoli, and kiwi is the most natural way and avoids all additives.

Ascorbic Acid vs. Citric Acid: A Comparison Table


Feature	Ascorbic Acid (Vitamin C)	Citric Acid
Nutritional Status	Essential Vitamin	Non-Essential Compound
Body Production	Cannot be produced by humans; must be obtained from diet or supplements.	Produced naturally by the body in small amounts as part of metabolism.
Function in Supplements	The active ingredient that provides the vitamin C benefit.	Added as a preservative, flavoring, or to enhance mineral absorption.
Typical Source	Found in a wide variety of fruits and vegetables (e.g., oranges, strawberries, bell peppers).	Naturally found in citrus fruits; commercially produced from black mold (Aspergillus niger).
Acidity	Less acidic compared to citric acid.	More acidic compared to ascorbic acid, contributing to its tartness.

Who Should Be Mindful of Citric Acid?

While generally recognized as safe, manufactured citric acid can pose issues for certain individuals:

Individuals with mold allergies: As manufactured citric acid is derived from a fungus, those with mold sensitivities may experience an allergic reaction.
People with sensitive stomachs: The acidity of citric acid can cause gastrointestinal distress, such as nausea or an upset stomach, particularly at high doses.
Those with tooth enamel concerns: The high acidity of citric acid can contribute to the erosion of tooth enamel over time, especially from chewable supplements or effervescent drinks.

Conclusion

In summary, Vitamin C supplements do not inherently contain citric acid, but it is a very common additive for preservation and flavor. The key takeaway for consumers is to differentiate between the active ingredient, L-ascorbic acid, and the additive, citric acid. By checking ingredient labels for terms like "citric acid" or "buffered C" and being aware of the manufacturing process, individuals with sensitivities can make an informed choice. For those with mold allergies, severe acid reflux, or dental concerns, buffered vitamin C or a supplement specifically labeled citric-acid-free is likely a safer option. As with any dietary change, it is always recommended to consult a healthcare professional for personalized advice.

Source for buffered vs. traditional Vitamin C information: Bronson Vitamins - Sodium Ascorbate

Frequently Asked Questions

No, they are two different compounds. Vitamin C is an essential vitamin also known as ascorbic acid ($C_6H_8O_6$), while citric acid ($C_6H_8O_7$) is a non-essential organic acid used primarily as a food additive.

Manufacturers use citric acid as a preservative to extend the product's shelf life, as a flavoring agent to provide a tart taste, and sometimes to enhance the absorption of other minerals in the supplement.

For some people, especially those with mold allergies, the manufacturing process of citric acid (which uses Aspergillus niger, a black mold) can result in residues that trigger an allergic reaction or sensitivity.

Buffered vitamin C is a non-acidic form of vitamin C, typically mineral ascorbates like sodium or calcium ascorbate. These are gentle on the stomach and often do not contain added citric acid. It is always best to verify the ingredients on the specific product label.

Yes, high levels of acid, including citric acid, can wear away your tooth enamel over time. This can increase tooth sensitivity and the risk of cavities, so it is recommended to consume high-acidity products in moderation.

Unlike the naturally occurring citric acid in citrus fruits, the manufactured version is produced through the fermentation of a fungus, Aspergillus niger, which feeds on a carbohydrate source like corn syrup.

While generally recognized as safe, consuming too much citric acid can cause side effects like an upset stomach, nausea, or irritation for those with sensitivities. People with mold allergies may have a more serious reaction.