What Is Citric Acid?

Medically reviewed by Suzanne Fisher, RD

Citric acid is a compound found naturally in citrus fruits like lemons, limes, and oranges. It’s what gives these fruits their distinct acidic flavors. This natural form of citric acid is a known antioxidant that helps counter inflammation and oxidative damage to cells.

Synthetic or manufactured versions of citric acid are commonly added to packaged foods and beverages because it helps extend their shelf life and give them an acidic flavor. Citric acid is also added to supplements, cosmetics, and cleaning products as a preservative, pH balancer, and water softener.

Natural Sources of Citric Acid

You can find citric acid naturally in citrus fruits and a few other types of fruit. The juices of these fruits are also good sources of citric acid. Natural sources of citric acid include:

• Lemons

• Limes

• Blackberries

• Grapefruits

• Oranges

• Raspberries

• Strawberries

Related: 9 Health Benefits of Citrus Fruits

Synthetic Sources of Citric Acid

Scientists often produce citric acid by fermenting the fungi Aspergillus niger and the yeast Yarrowia lipolytica. This is considered a manufactured form of citric acid since it doesn’t occur naturally.

You can find synthetic forms of citric acid in prepared foods, beverages, medications, supplements, cosmetics, and cleaning products.

Food and Beverages

There are a few reasons why manufacturers add citric acid to food and drinks. It can add an acidic flavor or a brighter color to foods or beverages, act as a preservative, and help control the pH (acidity) of the product. Increasing the acidity of foods or drinks in this way helps prevent the growth of mold, fungus, mildew, and bacteria that could cause illness if ingested.

Supplements and Medications

Synthetic citric acid is used in certain supplements to enhance their absorption and to preserve the vitamins and minerals. It also enhances the flavor of supplements or medications so that they’re more acidic and potentially more palatable.

Citric acid is also often used in combination with sodium bicarbonate (baking soda) to create effervescent (fizzy) tablets or powders. Effervescence can make certain compounds taste better—especially when made with citric acid, which gives off a citrus flavor—and these fizzy tablets tend to dissolve and work quickly in the body.

Cosmetics

Citric acid is used in many beauty products like shampoo, body soap, face wash, lotion, conditioner, and more. It helps balance the pH of a product and stabilize it for a longer shelf-life. Citric acid also has antioxidant properties and other properties that support skin health, making it a common additive to many skin products.

Cleaning Products

You can find citric acid in several cleaning products like detergents, disinfectants, and sanitizers. It’s also used to clean food equipment to eliminate lingering flavors. The acid helps to kill bacteria, mildew, fungi, and some viruses as well as eliminate dirt, rust, slime, and calcium deposits.

Health Benefits of Citric Acid

Citric acid offers several health benefits, both in its natural and manufactured form.

Promotes Skin Health

You can find citric acid in skincare products like face wash and body soap—and not just because it's a preservative. Citric acid is a type of alpha-hydroxy acid (AHA) that can help counter inflammation and signs of aging. It does so by peeling off dead skin cells, which promotes a new generation of skin cells, and in turn, improves skin elasticity.

However, high doses of or prolonged exposure to citric acid could be harmful, causing skin irritation and a greater risk of skin damage from UV rays.

Related: The 13 Best Foods For Glowing Skin

Enhances Nutrient Absorption

Citric acid is added to many mineral supplements to preserve them, balance the pH, and also to enhance their absorption. A few examples include magnesium citrate, calcium citrate, and potassium citrate.

Calcium citrate is one of the most bioavailable forms of calcium, meaning our bodies can absorb it easily. This is helpful for raising calcium levels—a nutrient that many Americans don’t eat enough.

Another example is magnesium citrate, which studies have shown is more effective at raising our magnesium levels than magnesium oxide. This form of magnesium is commonly used as a laxative for people struggling with constipation or preparing for a colonoscopy.

Related: Which Type of Magnesium Is Best?

May Prevent Kidney Stones

Citric acid may help prevent kidney stones. In people with low urine citrate levels, increasing urinary citrate levels can help prevent stone formation. This can be achieved by eating more fruits rich in citric acid and low in oxalates—such as lemons and limes—and by taking alkaline-citrate salts like potassium citrate.

The citrate binds with calcium in your urine to help prevent oversaturated urine. It can also bind calcium oxalate crystals to prevent them from growing and becoming painful kidney stones.

Related: What Causes Kidney Stones?

Acts as an Antioxidant

The natural form of citric acid is a known antioxidant. Antioxidants are important because they help reduce oxidative damage to cells, which is linked to cancer, cardiovascular disease, neurological disease, and more. They also counter inflammation in a way that could help support immune health and benefit the brain and liver.

Can Citric Acid Be Bad For You?

Citric acid is generally recognized as safe (GRAS) by the FDA, so consuming it as an additive in foods and drinks is typically not a concern. The amounts used in food and beverages are within safe limits.

However, synthetic citric acid may pose an allergen risk to some people. A series of four case reports found that Aspergillus niger—the fungi used to create manufactured citric acid—could be an allergen. If you have a mold allergy, you may be allergic to this compound as well.

It's also possible to be allergic to citrus fruits and other fruits containing citric acid. If you have a known citrus or fruit allergy, you may want to avoid or take precautions when trying natural food sources of citric acid.

The researchers from the above case report series also note that the manufactured form of citric acid could contribute to chronic inflammation, leading to inflammation-related chronic conditions like asthma, autism spectrum disorder, irritable bowel syndrome, and fibromyalgia. However, this study just observed associations, meaning it can't confirm if citric acid has a direct impact on any of these conditions.

Lastly, if you’re using citric acid on your skin, it could cause irritation depending on how much you use and your skin’s sensitivity to it. Make sure to test patch new skincare products before using them fully, and stop using a product if it causes pain or irritation.

A Quick Review

Citric acid is naturally present in citrus fruits and some other fruits, like berries. You can also find manufactured forms of citric acid in several food, pharmaceutical, personal care, and cleaning products. Citric acid is a popular additive as it acts as a preservative and antioxidant, adds acidity, alters the pH, and enhances mineral absorption.

Most people can consume and use regular amounts of citric acid safely without concern, but people with mold allergies may be allergic to compounds in the synthetic versions of citric acid.

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