Ingredient Spotlight: Ascorbic Acid

antioxidant antioxidants Ascorbic Acid Boost collagen brightens Collagen Ferulic Acid oxidation smoothing Vitamin C Vitamin E

Topical Vitamin C (L-Ascorbic Acid)

Vitamin C is a water-soluble vitamin essential for the synthesis/maintenance of collagen. The human body is incapable of synthesizing or storing Vitamin C, relying instead on dietary and/or supplemental replenishment. Also known as Ascorbic Acid (Synthetic), L-Ascorbic Acid (Natural), or AA.

Skin Benefits:

  • Brightens: Fades pigmentation/discoloration.  Diminished dark spots by 62.5% in 16 weeks with 5% ascorbic acid applied daily. 
  • Firms: Supports Collagen Production. Improved collagen production by 800% (in vitro).
  • Protects: Antioxidant function defends against environmental aggressors (UVA/UVB, pollution, et. al.)
  • Smooths: Decreases Roughness. In 3-month blind study (in vivo) of 10% ascorbic acid applied daily:
    • Improved smoothness and tone by 57.9% based on photographic assessment.
    • Improved smoothness and tone by 84.2% based on self-assessment from participants receiving active treatment. 


  • Effective in topical applications ranging between 5-20% concentrations.
  • Combinations with Vitamin E (Tocopherol) and Ferulic Acid help to boost photoprotective capabilities.
  • Ascorbic Acid degrades quickly with exposure to light, heat, and alkalinity, so choose airless/opaque containers and acidic formulations (4.0 ph or lower).
  • Avoid any vitamin C skincare that has an orange tint. As ascorbic acid oxidizes, it takes on an orange to brown tint. 
    • Whether pigmented from oxidation, dyes, or additional ingredients, it is best to stick with vitamin c skincare that is clear or colorless.
    • If you notice a change in color, discard the skincare. 
  • Sensitive skin may better tolerate lower concentrations, especially naturally sourced extracts or seed oils, or alternative Vitamin C derivatives. 
  • Power Combinations include Alpha Lipoic Acid, Ferulic Acid, Glutathione, Green Tea, L-Arginine,  Peptides, and Vitamin E.
  • Don't mix Ascorbic Acid with:


    • Synthetic
    • Algae, Blackberry, Broccoli, Cranberry, Goji Berry, Grape, Hibiscus, Honeydew, Kelp, Pomegranate, Red Raspberry, Seabuckthorn, Watermelon


         Vitamin C Trivia    


        • Journal of the America Academy of Dermatology, November 2012, pages 1103–1024.
        • International Journal of Dermatology, 2004 Aug, 43(8):604-607, A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma.
        • Archives of Otolaryngology – Head and Neck Surgery, 1999 Oct 5:125(10):1091-1098, Use of topical ascorbic acid and its effects on photodamaged skin topography.
        • Proceeding of the National Academy of Sciences of the United States of America, 1981 May; 78(5): 2879-2882, Regulation of Collagen Synthesis by Ascorbic Acid.
        • Journal of Cosmetic Dermatology, Vol. 11 (4) – Dec 1, 2012, Stability, Transdermal Penetration, and Cutaneous Effects of Ascorbic Acid and its Derivatives.
        • Journal of Cosmetic Dermatology, Vol. 4 (1) – Jan 1, 2005, Relevance of Vitamins C and E in Cutaneous Photoprotection.
        • The Journal of Investigative Dermatology, 2005 Oct, 125(4), Ferulic Acid Stabilizes a Solution of Vitamins C and E and Doubles its Photoprotection of Skin.
        • Experimental Dermatology, 2003 Jun, 12(3), Topical Ascorbic Acid on Photoaged Skin.
        • BMC Dermatology 2004;4:13, Topically Applied Vitamin C Increases the Density of Dermal Papillae in Aged Human Skin.
        • Clin Nutr 2005;24:979-987, Treatment with supplementary arginine, vitamin C and zinc in patients with pressure ulcers.
        • Journal of Clinical and Aesthetic Dermatology, 2017 Jul, 10(7).

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          • Glory on

            Thank you so much.. Your website has been really helpful. Am always here reading. Thanks alot

          • Luna Medici on

            love ctherapy! thanks for keeping it clean!

          • Tati on

            tried them all, yours is the best small batch c serum. I never buy vitamin c that has sat on a retail shelf.

          • about-face essentials on

            Thanks, Ashlee – it’s one of our favorites, too!

          • AshleeB on

            Nice to learn why c+therapy works for my skin. Never need to follow with a moisturizer like most serums. Never change it please?

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