What Is Magnesium Carbonate?
Magnesium carbonate, labeled on cosmetic ingredient lists as CI 77713, is a naturally occurring mineral salt made of magnesium, carbon and oxygen. It is most often sourced from magnesite rock deposits or harvested from seawater brines rich in magnesium. Once collected the raw material is purified, reacted with carbon dioxide and then dried to create a fine white powder suitable for cosmetic use. Historically the compound was valued for its ability to absorb moisture and oil which led to its early adoption in chalk, face powders and theater makeup during the late 1800s. As formulation science advanced manufacturers refined the particle size for smoother textures and discovered that its bright white color could help adjust product opacity. Today magnesium carbonate appears in a wide range of products such as pressed and loose powders, mattifying primers, clay masks, dry shampoos, deodorants, toothpastes and even some cream foundations where it helps control shine and improve feel.
Magnesium Carbonate’s Cosmetic Benefits/Uses
Formulators turn to magnesium carbonate for several practical reasons linked to the properties listed below.
- Absorbent: Soaks up excess oil and sweat on the skin or scalp which supports a matte finish and longer lasting makeup wear
- Binding: Helps pressed powders hold together in the pan reducing crumbling and fallout while still allowing a smooth pickup on the brush or puff
- Bulking: Adds safe, inert volume to formulations letting chemists achieve the desired feel or weight without altering active ingredient levels
- Colorant: Provides a clean white hue that can lighten or neutralize other pigments ensuring a consistent shade across production batches
- Opacifying: Increases opacity so products like sunscreen sticks, concealers and toothpaste look uniformly opaque rather than translucent
Who Can Use Magnesium Carbonate
Thanks to its gentle, inert nature magnesium carbonate suits most skin types including normal, oily, combination and even sensitive skin because it does not penetrate deeply or disrupt the skin barrier. Very dry or mature skin may find heavy use in loose powders or clay masks a bit dehydrating since the powder is highly absorbent, so layering with hydrating products can help balance that effect.
The mineral is sourced from rock or seawater and contains no animal derived components which makes it acceptable for vegans and vegetarians. Its simple mineral origin also aligns with many clean and cruelty free standards.
Current research shows no specific risks linked to topical magnesium carbonate use during pregnancy or while breastfeeding. That said this is not medical advice and anyone who is pregnant or nursing should review all skincare products with a qualified healthcare professional to be safe.
Magnesium carbonate is not known to cause photosensitivity so it will not make skin more prone to sunburn. It is also fragrance free, gluten free and non reactive with common actives like retinol or vitamin C which makes it easy to fit into most routines.
Potential Side Effects/Adverse Reactions
Responses to topical magnesium carbonate can differ from person to person. The following are potential side effects yet they are uncommon when the ingredient is used properly in a finished cosmetic.
- Dryness or tight feeling: excessive oil absorption can leave the skin feeling parched especially on already dry areas
- Mild irritation: very sensitive individuals may notice temporary redness or a stinging sensation if the powder is applied to broken or compromised skin
- Respiratory discomfort on inhalation: loose powders that become airborne could cause coughing or throat irritation if inhaled repeatedly during application
- Clogged pores when mixed with heavy oils: in rare cases magnesium carbonate incorporated into very occlusive formulations may trap debris against the skin leading to bumps
If any irritation or discomfort occurs discontinue use and consult a medical professional for guidance.
Comedogenic Rating
Rating: 1/5
Magnesium carbonate is an inert, mineral powder that sits on the surface of the skin and does not melt into pore-clogging oils. Its porous structure absorbs sebum rather than blocking follicles, which keeps its score low. Occasional clogging can happen only if the mineral is packed into a very heavy, oily base that already has a higher comedogenic load. Overall it is generally suitable for people who are prone to acne or breakouts.
Because it can be drying, extremely oily skin might overcompensate by producing more sebum, which is something users can monitor when trying a new formula that contains this powder.
Summary
Magnesium carbonate mainly acts as an absorbent, binder, bulking agent, white colorant and opacifier. Its tiny, porous particles soak up oil and moisture, help powders press together, add lightweight volume, lighten pigment mixes and make products look uniformly opaque. These straightforward functions rely on the mineral’s natural ability to hold liquids and reflect light while staying chemically inactive.
The ingredient is a workhorse in cosmetics such as setting powders, primers, deodorants and dry shampoos, yet it rarely gets spotlighted on marketing labels. Formulators like it because it is inexpensive, stable and easy to source, even if consumers may not recognize the name.
Current data shows it is low risk for skin irritation or sensitization, though inhaling large amounts of airborne powder should be avoided. As with any new product, doing a quick patch test is a smart precaution before full application.