Cosmedix Pure C Review - The Dermatology Review

Cosmedix Pure C Review



Cosmedix is a line of skin care products for both at-home and professional use. The brand offers cleansers, toners, masks and balms, serums, eye care, lip care, exfoliators, body care, and so much more. In this review, we’ll discuss the Cosmedix Pure C Vitamin C Mixing Crystals so you’ll know what this product is, who it’s for, key formulation insights, how to use it, and what customers are saying about this product. 

What is it?

Cosmedix Pure C Vitamin C Mixing Crystals is a mixing powder consisting of pure vitamin C (L-ascorbic acid) crystal. This product is claimed to help firm skin and smooth wrinkles, as well as even skin tone by reducing the look of acne scars, dark spots, and hyperpigmentation. The powder can be mixed with your favorite nighttime serum or moisturizer to boost results. 

Who is it for?

Cosmedix Pure C can be used by all skin types, and is best for those with acne scars and/or hyperpigmentation, as well as those who want to prevent signs of aging. You can also use Cosmedix Pure C if you want to achieve a bright, glowing, smooth complexion. The form of this product is especially beneficial if you already have a favorite serum or moisturizer but you want to reap all of the benefits of vitamin C. 

Formulation insight

As mentioned above, Cosmedix Pure C contains only one ingredient, L-ascorbic acid, which is the biologically active form of vitamin C. Vitamin C is a very popular skin care ingredient because it provides numerous benefits to the skin. Also, the skin does not receiving nearly enough vitamin C, even when we consume foods rich in this nutrient. This is because the absorption in the gut is limited by an active transport mechanism after oral intake. So no matter how much vitamin C you ingest only a finite amount can be absorbed. Furthermore, bioavailability of ascorbic acid in the skin is inadequate when it is administered orally. Therefore, the use of topical products that contain vitamin C, like Cosmedix Pure C, can provide your skin with all the benefits this ingredient has to offer. 

L-ascorbic acid exerts potent antioxidant activity. Specifically, L-ascorbic acid donates electrons to neutralize reactive oxygen species (ROS) such as the superoxide ion and peroxide that are generated when the skin is exposed to UV light. This is important because the harmful effects of ROS occur as direct chemical alterations of the cellular DNA, the cell membrane, and cellular proteins, including collagen. Damaged collagen manifests as signs of premature skin aging, including wrinkles, lines, and sagging skin. L-ascorbic acid’s protective effect on collagen makes this ingredient an excellent addition to an anti-aging skin care routine. 

Another way that L-ascorbic acid helps to reduce signs of aging is through collagen synthesis. Specifically, L-ascorbic acid serves as a cofactor for the enzymes prolysyl and lysyl hydroxylase, the enzymes that are responsible for stabilizing and cross-linking the collagen molecules. Clinical studies have shown that the topical use of L-ascorbic acid increases collagen production in both young and aged human skin. Once again, by increasing the amount of collagen in the skin, signs of aging will be diminished and the skin will appear more firm. 

In addition to its anti-aging properties, L-ascorbic acid has the ability to reduce the appearance of dark spots and improve uneven skin tone. This is accomplished through inhibition of melanin synthesis. Melanin is a pigment that gives our skin color, but too much of this pigment can lead to undesirable dark spots called hyperpigmentation. L-ascorbic acid decreases melanin formation by inhibiting tyrosinase, an enzyme that is required for melanin synthesis. The result is skin that appears brighter with less dark spots and a more even skin tone. 

Since L-ascorbic acid is an acidic ingredient, some people may experience sensitivity, redness, or stinging after using products with this ingredient. These side effects typically occur when high concentrations of ascorbic acid are used, or when ascorbic acid is combined with other ingredients that exfoliate the skin (i.e. retinol, AHAs, BHAs, etc.). If you notice these effects when using Cosmedix Pure C, you may want to decrease how often you use the product. 

While L-ascorbic acid is very beneficial to the skin, it is notoriously difficult to stabilize in cosmetic formulations. This is because it is such an excellent antioxidant, which means that it will readily donate electrons to the oxygen content in air. After becoming oxidized, the L-ascorbic acid molecule is ineffective and cannot provide skin benefits. Therefore, a product that contains ascorbic acid needs to be packaged to prevent oxidation. Fortunately, Cosmedix Pure C is packaged in an opaque container that protects the L-ascorbic acid crystals from light and air. However, you should still store this product in a cool, dry place. 

How to use

At night, mix a few shakes of Cosmedix Pure C Mixing Crystals with a serum or moisturizer and apply to cleansed and toned skin. The brand recommends using this product with their Simply Brilliant 24/7 Brightening Serum. It is not recommended to apply this product during the daytime because prolonged sun exposure can make skin more sensitive to the sun.


Cosmedix Pure C reviews are overall very positive, with the product receiving an average of 4.8 out of 5 stars after 57 customer reviews on the brand’s website. Many reviews mention that it’s easy to mix the Cosmedix Pure C Mixing Crystals with a serum, and that using vitamin C has helped skin to glow. It is also said to help fade sun spots, minimize the appearance of pores, and make skin look brighter and healthier. 

References: Indian Dermatol Online J 2013 Apr-Jun; 4(2): 143–146





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