Calcium Carbonate in Personal Care Products

Calcium carbonate is a white mineral that serves as an opacifying agent, colorant, bulking agent, abrasive, buffering agent, and filler in personal care products.
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Calcium carbonate is a natural mineral found in rocks such as calcite, vaterite, and aragonite. It is also found in marine organism shells, pearls, and eggshells. In its pure form, it appears as a white, odorless powder. It is a versatile compound with various applications in the personal care industry. 

What is Calcium Carbonate?

The chemical formula of calcium carbonate is CaCO3, which is comprised of [Ca]2+ and [CO3]2- ions. The carbonate ion has a triangular planar structure. The molecular structure of calcium carbonate is given below. 

Calcium Carbonate Chemical Structure

Calcium Carbonate Chemical Structure. Source: Wikipedia

How is Calcium Carbonate Produced?

Calcium carbonate is an abundant mineral in the Earth’s crust and can be found in various forms, such as limestone, marble, calcite, and aragonite. It is commonly extracted from mining or quarrying marble stones for mass production. Additionally, calcium carbonate occurs naturally in the shells of shellfish, snails, and eggshells. Approximately 95% of dry eggshells and seashells consist of calcium carbonate. 

Calcium carbonate can also be synthetically produced. One method combines calcium oxide (quicklime) with carbon dioxide to form calcium carbonate. This can be done through a chemical reaction where calcium oxide reacts with carbon dioxide in the presence of water to produce calcium carbonate. Another method involves using calcium chloride and sodium carbonate to precipitate calcium carbonate from the solution. These methods allow calcium carbonate creation in a controlled environment, ensuring its purity and quality for various industrial and commercial applications.

Applications in Personal Care

AbrasiveCalcium carbonate is used as an abrasive in personal care products to help remove dirt, oil, and dead skin cells from the skin’s surface.
Buffering AgentCalcium carbonate acts as a buffer in formulations to help maintain the pH level of the product.
Bulking AgentCalcium carbonate is a bulking agent to increase a product’s volume and density while providing a smooth texture.
OpacifyingCalcium carbonate is an opacifying agent that adds opacity to products such as lotions and creams, giving them a more luxurious appearance.
FillerCalcium carbonate is used as filler in multiple cosmetic applications. 
Oral CareIn oral care products, calcium carbonate, with its mild abrasive properties, helps strengthen tooth enamel, prevent cavities, and freshen breath.

Product Examples

SkincareFace scrubs, body wash, body powders
Oral CareToothpaste
Hair CareShampoos, conditioners
CosmeticsFace powders, foundations
Baby CareDiaper cream, diaper powders
Men’s GroomingShaving cream

Properties of Calcium Carbonate

Physical FormSolid
Shelf Life~60 months (when stored at prescribed conditions)
Storage Temperature & ConditionsStore at +5°C to +30°C
AppearanceFine white powder
Density2.711 g/cm3
Molar Mass100.0869 g/mol
Refractive Index1.6583
Melting Point825°C
Solubility15 mg/L at 25°C in water

Typical Formulations


Here is an example of a toothpaste formulation table along with the % weight of ingredients: 

Ingredient% Composition
Sorbitol (70wt% aqueous solution)21
Guar gum0.1
Sodium saccharin0.27
Sodium monofluorophosphate1.1
Sodium bicarbonate0.1
Sodium carbonate0.4
Calcium carbonate42
Titanium dioxide0.1
Sodium la2
Deionized water28.8033
CI Pigment Green 70.0067

Source: Google Patents 

Pressed Face Powder

Here is an example of a face powder formulation table along with the % weight of ingredients: 

Ingredient% Composition
Ground rice hulls74.875
Titanium dioxide3.75
Zinc stearate7.50
Zinc oxide0.2
Calcium carbonate7.5
20% Iron oxide in talc0.025
20% D&C Red in talc0.25
20% D&C Orange in talc0.15

Source: Google Patents 

Calcium Carbonate Formulation Considerations

Physical FormsPowder or crystals. Calcium carbonate crystallizes in three anhydrous polymorphs as follows:

– Calcite: White hexagonal crystals
– Aragonite: White orthorhombic crystals
– Vaterite: Colorless hexagonal crystals.
Stability– Oxidation: Stable
– Heat: Decomposes around ~750 °C (Stability Calcite > Aragonite > Vaterite)
– pH: Highly reactive with strong acids
Sensory AttributesOdorless with a slightly chalky taste
Dosage0.5-2% (varies as per product and formulation)
Interaction with Other ComponentsIncompatible with strong oxidizers and strong acids. May engage in violent explosive reactions with some acids due to higher reactivity.

Effect on Properties of Product Applications

OpacityCalcium carbonate can provide opacity to cosmetics formulations. According to a study, it can help attain a 45% contrast ratio. It can be a safe alternative to controversial whitening agents used in solid cosmetics. Its high purity, consistent particle size, and morphology make it the opacity agent of choice.
TextureCalcium carbonate can control sheen to a certain extent by absorbing/adsorbing sebum, providing a matte gloss. It acts as a mild abrasive agent. It also improves the feel of the product by increasing its smoothness and modifying the texture to provide a silky feel. 
ConsistencyCalcium carbonate is a thickener that produces viscous dispersions and imparts body, improves consistency, or stabilizes emulsions.
ColorCalcium carbonate is white in color and can be used as a whitening agent in cosmetic formulations. 

Safety and Regulatory Considerations

FDA InformationCalcium carbonate is generally recognized as safe (GRAS) by the US FDA. It is approved as an active ingredient in over-the-counter (OTC) products. Calcium carbonate falls under the category of color additives and is exempt from batch certification. It is important to note that color additives listed for use in drugs or cosmetics are not allowed in products intended for the eye area, injected products, or surgical sutures unless stated explicitly in the regulation for the color additive.
EU Information – Calcium carbonate is allowed to be used as a colorant in cosmetics products.
– Approved to be used as a food additive as E170 with a specific maximum level of quantum satis.

Safety & Toxicity of Calcium Carbonate

The safety and toxicity of calcium carbonate in cosmetic products have been extensively evaluated. Calcium carbonate is considered safe for use in cosmetics. Studies have shown that calcium carbonate is non-toxic and safe for cosmetics when formulated as non-irritating. The Cosmetic Ingredient Review (CIR) Expert Panel concludes that it is safe for use in cosmetics at present practices of use and concentration. 

Identification Numbers

Chemical NameCalcium carbonate
CAS Number471-34-1
EC Number207-439-9

Acceptable Limits or Maximum Usage

The usage of calcium carbonate in cosmetic products varies depending on the specific product type. In eye area cosmetics, calcium carbonate can be used at concentrations up to 35%, while in dentifrices (toothpaste), the maximum allowable concentration is up to 10%.

Fun Facts About Calcium Carbonate 

  • While calcium carbonate is a naturally occurring substance, mining and processing can have environmental impacts, including habitat disruption and carbon emissions. For this reason, some companies are exploring sustainable sourcing and production methods to mitigate these effects.
  • In toothpaste, calcium carbonate is an abrasive agent that helps remove plaque and surface stains from teeth. It’s an effective alternative to more abrasive compounds like silica, which can be harsh on enamel.