Ingredient Education · Feb 16, 2026

Citric Acid

Citric acid tends to spark strong reactions in ingredient discussions. It is often described as “derived from mold” or framed as inherently problematic because of how it is produced. As with many ingredients, the reality is more nuanced than the headline version.

Citric acid is a naturally occurring organic acid found in citrus fruits. It is also produced in small amounts within the human body as part of the citric acid cycle, a core metabolic pathway involved in converting food into usable energy. Chemically speaking, citric acid is citric acid. The molecule does not change based on whether it originated in a lemon or through fermentation.

Today, most commercial citric acid is produced through controlled fermentation using a microorganism called Aspergillus niger. This is where much of the concern originates, because A. niger is classified as a mold species. Understanding the manufacturing process helps clarify what that actually means.

During production, Aspergillus niger is used in a contained fermentation system to convert sugars into citric acid. Once fermentation is complete, the microbial biomass is separated from the liquid medium. The citric acid is then purified, filtered, precipitated, and crystallized to isolate the compound. The finished product is purified citric acid, not mold culture or mold spores. Fermentation-derived does not mean mold remains present in the final crystalline ingredient. It reflects the use of microorganisms during manufacturing, followed by purification steps designed to remove microbial material and impurities.

Fermentation as a production method is not unique to citric acid. Certain cheeses, such as Brie, Camembert, and Roquefort, are intentionally made using mold cultures. Traditional soy sauce and miso rely on mold species such as Aspergillus oryzae during fermentation. More broadly, foods like yogurt and sourdough also rely on microbial fermentation before further processing. In each case, microorganisms are used in a controlled environment to generate a desired result. Their use during production does not mean the finished ingredient contains that organism. It reflects a biological manufacturing process followed by refinement.

From a regulatory standpoint, citric acid is widely recognized as safe for use in food and cosmetics. In cosmetic formulations, it is typically used in very small amounts as a pH adjuster. That function matters. Skin maintains a slightly acidic pH, and keeping formulations within an appropriate range supports barrier integrity and overall stability. In many cases, citric acid is included at fractions of a percent simply to bring a product into a skin-compatible pH range.

Some individuals report sensitivity to added citric acid while tolerating whole citrus fruit. This distinction may relate to concentration, frequency of exposure, individual digestive differences, or the absence of the whole-food matrix that naturally accompanies citric acid in fruit. Isolated compounds behave differently from whole foods because they are concentrated and not packaged with fiber, enzymes, and phytonutrients. That difference does not automatically indicate toxicity, but it can help explain variations in tolerance.

Concerns are sometimes raised about residual mold or contamination. In properly manufactured, food-grade citric acid, purification steps are designed to remove microbial material and impurities. Food-grade material must meet defined purity specifications and contaminant limits. While no ingredient exists in a theoretical vacuum, regulatory standards and supplier documentation provide guardrails around acceptable levels. I choose food-grade, non-GMO citric acid from established suppliers and rely on those standards rather than assuming contamination in the absence of evidence.

I do not view citric acid as inherently harmful. At the same time, I do not believe that every industrial ingredient deserves unquestioned trust. My approach remains consistent across the board: evaluate how it is made, how it functions, the concentration at which it is used, and whether it serves a meaningful purpose in a formulation.

In the case of citric acid, when used appropriately and sourced responsibly, it serves a clear functional role. For that reason, it is an ingredient I am comfortable using for pH balancing in certain formulations.

Low-tox living is not about labeling every laboratory-produced ingredient as problematic. It is about discernment. Some ingredients warrant caution due to unresolved long-term concerns or unnecessary exposure. Others, when understood in context and used appropriately, have a reasonable and well-documented place in formulation.

Citric acid falls into the latter category for me.

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