CAS Number 77-92-9
INCI Name Citric acid
Citric Acid has become a popular ingredient in cosmetic and skincare products for good reason. It offers multiple benefits, from enhancing product longevity to improving skin health. This naturally occurring compound deeply cleanses the skin while providing anti-aging effects. Citric Acid acts as a preservative, extending the shelf life of formulations. In essence,it is a powerful ingredient that elevates skincare formulations. Its chemical formula is C₆H₈O₇.
Purpose
Citric acid has multiple uses in a formulation. It works as a chelating agent, helping to prevent metal ions like calcium and magnesium from affecting the product’s stability. It also acts as a masking agent, reducing unwanted smells or tastes to improve the product’s overall feel. Additionally, it functions as a preservative, lowering the pH to stop bacteria from growing and keeping the product fresh for longer. These benefits make citric acid a valuable ingredient in skincare and cosmetic products.
Origin
Citric acid is a naturally occurring alpha-hydroxy acid (AHA) derived from citrus fruits such as oranges, lemons, and grapefruits. While it is found in nature, most commercial this is produced through fermentation using Aspergillus niger, a type of fungus that converts sugar-based substrates like molasses or corn starch into citric acid. This method ensures large-scale production for use in food, cosmetics, and pharmaceuticals.
| Feature | Description |
| Name | Citric Acid |
| Type | Organic acid |
| Source | Naturally derived from citrus fruits |
| Function | pH adjuster |
| PH | 2-3 |
| Odor | Odorless or slightly sour |
| Color | White |
| Viscosity | 6.5 cP |
| Boiling Point | 310°C |
| Physical Form | Crystalline powder or granular form |
| Concentration | 0.1-2% |
| Solubility | Soluble in water |
Natural Occurrence
Citric acid is a naturally occurring organic acid primarily found in citrus fruits like lemons, oranges, and grapefruits. It contributes to the sour taste of these fruits, making it one of the most widely recognized acids in nature. While it’s present in smaller amounts in various other fruits and vegetables, citrus fruits remain the richest natural source.
Acidic Nature
Citric acid is highly acidic, with a pH typically ranging from 2 to 3 when dissolved in water. This low pH makes it an excellent agent for regulating and adjusting the acidity in cosmetic and skincare formulations, as well as in food products. Its acidic nature is responsible for its exfoliating properties and its ability to act as a preservative by lowering pH and preventing microbial growth.
Water Solubility
One of citric acid’s key characteristics is its high solubility in water. This makes it easy to incorporate into various formulations, particularly in skincare products that are water-based, such as toners, serums, and lotions. Its solubility ensures that it can be evenly distributed in the product, providing consistent performance and effectiveness.
Alpha-Hydroxy Acid (AHA)
Citric acid belongs to the family of alpha-hydroxy acids (AHAs), which are commonly used in skincare for their exfoliating properties. AHAs work by gently dissolving the bonds between dead skin cells, allowing for smoother, brighter skin. Citric acid’s gentle exfoliating action helps to remove dead skin, promoting a fresh appearance and enhancing the skin’s ability to absorb other active ingredients.
Preservative Properties
As a natural preservative, it helps to extend the shelf life of products by creating an acidic environment that inhibits the growth of bacteria, mold, and yeast. In cosmetic and skincare formulations, this is especially important, as it helps prevent the contamination of products, keeping them safe for use over time without the need for harsh synthetic preservatives.
Chelating Agent
Citric acid is also known for its chelating properties. It binds to metal ions, such as calcium, magnesium, and iron, that may be present in water or formulations. These metal ions can destabilize products, leading to discoloration or loss of efficacy. By binding to these metals, citric acid prevents such destabilizing effects, ensuring the integrity and effectiveness of the final product.
Antioxidant
Another beneficial property of citric acid is its antioxidant capacity. It helps to neutralize free radicals, which are highly reactive molecules that can cause oxidative stress and damage to skin cells. By reducing oxidative damage, citric acid supports the skin’s natural defenses against environmental factors like pollution, UV rays, and stress, contributing to a healthier, more youthful appearance.
Non-Toxic and Biodegradable
Citric acid is considered non-toxic and biodegradable, which makes it environmentally friendly and safe for use in a wide variety of consumer products. Its natural origin and gentle nature mean it can be used in formulations without causing harm to human health or the environment, which is especially important in the beauty industry, where sustainability and safety are top priorities.
Cleansing Agent
In addition to its exfoliating and pH-regulating properties, citric acid serves as an effective cleansing agent. It helps to break down oils, dirt, and other impurities on the skin, making it a popular ingredient in facial cleansers, shampoos, and body washes. Its ability to dissolve oil without stripping the skin of moisture makes it a gentle yet effective cleansing agent, suitable for a variety of skin types.
Mild Irritant
Despite its many benefits, citric acid can be a mild irritant to the skin, especially when used in high concentrations or on sensitive skin. The acid can cause a tingling or burning sensation, and in some cases, redness or irritation. However, this is usually only a concern when used excessively, which is why formulations are carefully balanced to avoid overuse. For most individuals, citric acid is safe and well-tolerated when used in appropriate concentrations.
Safety Profile
Citric acid is generally regarded as safe for use, as it is milder and gentler compared to many other acids. However, it may cause redness or irritation on highly sensitive skin, so performing a patch test is advised. Because citric acid exfoliates the skin, it can increase sensitivity to the sun’s harmful rays. To protect the skin, it is recommended to apply as a sunscreen with a good SPF after using products containing citric acid.
Shelf Life and Storage
Citric acid has a shelf life of 2-3 years when stored properly in a cool, dry place. It should be kept in an airtight container to prevent moisture and air exposure, which can affect its effectiveness. Avoid storing it in extreme temperatures or direct sunlight.
Applications of Citric Acid
Chelating Agent
Citric acid serves as a chelating agent, meaning it binds to metal ions like calcium, magnesium, and iron that may be present in formulations. This prevents these metals from destabilizing the product, ensuring that the formulation remains stable and effective over time. It also prevents discoloration and degradation of other ingredients, making citric acid essential for the consistency and longevity of skin and hair care products.
Skin Exfoliation
Citric acid is a natural exfoliating agent, helping to slough off dead skin cells from the surface. By dissolving the bonds between skin cells, it promotes the shedding of old, dull skin and reveals a smoother, fresher layer. This exfoliating action helps reduce the appearance of fine lines and promotes a more radiant, youthful complexion, making it a popular choice in facial cleansers, toners, and masks.
Unclogs Pores
Regular use of citric acid can help unclog pores by breaking down the oils, dirt, and dead skin cells that accumulate in the pores. This helps prevent blackheads and acne breakouts, promoting clearer skin. Citric acid’s mild exfoliating properties allow it to gently clean out pores without being too harsh on the skin, which is especially beneficial for oily or acne-prone skin types.
Astringent Properties
One of the notable characteristics of citric acid is its astringent properties, which help to tighten and tone the skin. By removing excess oils and tightening the skin, citric acid leaves the skin feeling clean and refreshed. It’s particularly effective for those with oily or combination skin, as it helps control shine and balance the skin’s oil production, creating a matte finish without causing dryness.
Youthful Skin
Citric acid’s exfoliating and astringent properties work together to keep the skin looking youthful and healthy. By removing dead skin cells, it allows fresh, new skin to surface, improving the skin’s texture and tone. The reduction in clogged pores and oil buildup also minimizes the chances of breakouts, contributing to a smoother, clearer complexion that has a more youthful glow.
