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Vitamin C is a big cosmetic chemistry challenge. Many skin care enthusiasts have been let down by their vitamin C in one way or another. They oxidize, they sensitize, they smell funny, and they just don’t produce results. We want to help you C through the BS!

What is vitamin C?

Vitamin C is an essential vitamin, antioxidant and cofactor for energy production in the body. Also known as L-ascorbic acid, this micronutrient is a skin care powerhouse ingredient.

What does vitamin C do for the skin?

When applied topically, vitamin C has been shown to brighten the complexion by decreasing the maturing process of pigment-producing cells [1]. In turn, this decreases the appearance of dark spots and uneven skin tone.

There is also compelling cell culture and human skin studies that show topical vitamin C can increase collagen production, decreasing fine lines and wrinkles and boosting elasticity [2, 3, 4].

Finally, vitamin C’s role as an antioxidant helps to prevent oxidative damage caused by external stressors like ultraviolet light and pollution [5, 6]. Over time this may help prevent cellular and DNA damage that compromises the look and function of skin and keep it visibly healthy [6].

Why is vitamin C a difficult ingredient with which to formulate skin care?

The purest form of vitamin C, L-ascorbic acid, is also the most volatile. It’s organic state is a powder that dissolves easily in water. Unfortunately, once in contact with water it begins to oxidize, a process that changes the chemical structure to form new molecules. These molecules don’t exhibit the same skin benefits as L-ascorbic acid and can also cause skin care products to rapidly change colour, and produce an unpleasant odour [7]. The rate of oxidation also increases when the exposed to air, higher temperatures, or is in a formula with a less-acid pH (higher than ~4) [7]. Since L-ascorbic acid also oxidizes rapidly in a neutral or basic pH environment, most vitamin C products are quite acidic (pH 3.5) and often result in skin irritation, redness, or peeling. Trying to make a skin care formula where L-ascorbic acid remains in it’s active form long-term is nearly impossible.

How have companies tried to formulate with vitamin C?

Vitamin C serums are everywhere on the market in a variety of forms and formulations. Some companies try adding other antioxidants like vitamin E or green tea to the formula to slow the rate of oxidation, while others opt for chemical preservatives and synthetic stabilizers. Some formulas are made without water and instead suspend L-ascorbic acid in liquid silicon. Unfortunately, there is mixed information as to how effectively the active ingredients like vitamin C can penetrate into the skin while complexed with silicon. Skin care companies have tried to combat this by patenting micro-encapsulation technologies but again, the ability for these large particles to make their way into the skin is highly debated. 

How is the Consonant Vitamin C + Licorice Serum different?

After years of research and development and numerous mixtures and methods, we’ve cracked the code on vitamin C. Consonant Vitamin C + Licorice Serum is stabilized, pH balanced, non-sensitizing, and is pure unscented. We achieved this by formulating our serum with two clinically-proven forms of vitamin C derivatives, complexed with pure licorice extract. Let’s take a closer look at the stats and science for each ingredient!

Sodium Ascorbyl Phosphate (SAP)

This is a water-soluble, naturally-occurring vitamin C derivative. Its chemical structure includes L-ascorbic acid with the addition of sodium and phosphorus molecules. These molecules are what allows this ingredient to resist oxidation, remain active in a higher pH solution, yet remain bioavailable to the skin [8, 9].

It also acts as an antioxidant that reduces oxidative stress by neutralizing free radicals, effectively slowing down the aging process and formation of fine lines and wrinkles [9]. It has also been shown to act as a treatment for hyperpigmentation by inhibiting melanin overproduction [10].

In human studies SAP was also an effective treatment for acne – brightening the complexion [11]. We chose it over any other vitamin C derivative for its ability to better penetrate the skin’s outer layer and yield higher levels of active vitamin C in the skin [9].     


Aminopropyl Ascorbyl Phosphate (AAP)

This cutting-edge form of vitamin C whose molecular structure was discovered in Korea, has been shown to provide potent brightening and collagen-synthesizing activity.

A human trial with 33 participants and found that just 0.5% of AAP (the Consonant Vitamin C + Licorice contains 0.7%), significantly reduced age spots after 8 weeks. They also measured a dramatic decrease in the total number of wrinkles, after 8 weeks. Similar to SAP, AAP is stable, resists oxidation and does not cause skin irritation.

Licorice Extract

Licorice root extract is a traditional natural health product used in the treatment of skin irritation and discolouration. In clinical trials it has been shown to promote skin brightening by inhibiting the production of the enzyme tyrosine which is needed in the production of excess pigment in the skin [12]. This helps remove excess melanin and provides anti-inflammatory benefits [12]. Formulated in combination with vitamin C ingredients, it can provide superior brightening and dark spot reduction.

Who is Vitamin C + Licorice good for?

This serum was formulated to be tolerated by all skin types especially sensitive skin. It is excellent for anyone looking to combat dullness, discolouration, visible signs of ageing, and uneven tone.

In a panel study of 29 women aged 35-70 over the course of 28 days:

100% saw improvements in their skin compared to before starting the study.
100% experienced no irritation.
100% said the serum absorbed quickly into the skin.
90% said they would buy this serum.

How can it help my skin?

Vitamin C + Licorice Serum is expertly formulated to bring your skin brightness. The active ingredients are at the optimal concentrations to help illuminate your complexion, smooth the appearance of fine lines, even tone, and minimize the look of dark spots.

Additionally, this serum is a delight to apply. It's lightweight, buildable, layers well with other products, and leaves the skin immediately glowing.

How do I add it to my regimen?

Vitamin C + Licorice does its best work when applied in the morning after cleansing, before moisturizer and sunscreen. Pairing Vitamin C + Licorice with The Perfect Sunscreen is the holy grail of keeping skin bright, radiant, and protected.

Due to the nature of our stabilized vitamin C ingredients this serum can also be paired with other actives without irritation. A general best practice is to apply water-based serums thinnest to thickest, then oil-based serums followed by moisturizer and SPF. Click HERE for our complete product layering guide.
No matter how your vitamin C serums have let you down in the past, here’s to brighting your outlook…and your skin! Shop the Consonant Vitamin C + Licorice now and C through the BS!
[1] Ando, H., Kondoh, H., Ichihashi, M., & Hearing, V. J. (2007). Approaches to identify inhibitors of melanin biosynthesis via the quality control of tyrosinase. Journal of Investigative Dermatology127(4), 751-761.
[2] Protective effects of a topical antioxidant mixture containing vitamin C, ferulic acid, and phloretin against ultraviolet-induced photodamage in human skin. Oresajo C, Stephens T, Hino PD, Law RM, Yatskayer M, Foltis P, Pillai S, Pinnell SRJ Cosmet Dermat
[3] The role of antioxidants in photoprotection: a critical review. Chen L, Hu JY, Wang SQJ Am Acad Dermatol. 2012 Nov; 67(5):1013-24.
[4] UV photoprotection by combination topical antioxidants vitamin C and vitamin E. Lin JY, Selim MA, Shea CR, Grichnik JM, Omar MM, Monteiro-Riviere NA, Pinnell SRJ Am Acad Dermatol. 2003 Jun; 48(6):866-74.
[5] Farris PK. Cosmetical vitamins: vitamin C. In: Draelos ZD, Dover JS, Alam M,editors. Cosmoceuticals. Procedures in Cosmetic Dermatology. 2nd ed. New York: Saunders Elsevier; 2009. pp. 51–56.
[6] Solar ultraviolet A radiation: an oxidizing skin carcinogen that activates heme oxygenase-1. Tyrrell RM Antioxid Redox Signal. 2004 Oct; 6(5):835-40.
[7] Smaoui, S. L. I. M., & Hilima, H. B. (2013). Application of l-ascorbic acid and its derivatives (sodium ascorbyl phosphate and magnesium ascorbyl phosphate) in topical cosmetic formulations: stability studies. Journal of the chemical society of Pakistan, 35(4), 1096-1102.
[8] Ravetti, S., Clemente, C., Brignone, S., Hergert, L., Allemandi, D., & Palma, S. (2019). Ascorbic acid in skin health. Cosmetics6(4), 58.
[9] Špiclin, P., Homar, M., Zupančič-Valant, A., & Gašperlin, M. (2003). Sodium ascorbyl phosphate in topical microemulsions. International journal of pharmaceutics256(1-2), 65-73.
[10] Fočo, A., Gašperlin, M., & Kristl, J. (2005). Investigation of liposomes as carriers of sodium ascorbyl phosphate for cutaneous photoprotection. International journal of pharmaceutics291(1-2), 21-29.
[11] Klock, J., Ikeno, H., Ohmori, K., Nishikawa, T., Vollhardt, J., & Schehlmann, V. (2005). Sodium ascorbyl phosphate shows in vitro and in vivo efficacy in the prevention and treatment of acne vulgaris. International journal of cosmetic science27(3), 171-176.
[12] Frattaruolo, L., Carullo, G., Brindisi, M., Mazzotta, S., Bellissimo, L., Rago, V., ... & Cappello, A. R. (2019). Antioxidant and anti-inflammatory activities of flavanones from Glycyrrhiza glabra L.(licorice) leaf phytocomplexes: Identification of licoflavanone as a modulator of NF-kB/MAPK pathway. Antioxidants8(6), 186.

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