Vitamin Cit may be one of the most talked about ingredients in skin care, but it’s also one of the most misunderstood. Between percentage disputes, fear of oxidation, and layered confusion, the science is often buried under the hype.
Chemical and inventorMarie Veronique Nadeauthe discussion starts with biology.Vitamin C iimportant for collagen production, cellular repair, and long-term skin firmness. There is no Vitamin C equivalent to collagen. The real question is not whether you should use it, but what form your skin can tolerate and benefit from.
For his productMarie Veronique,has come up with two different approaches to Vitamin C: the antioxidant-driven Vitamin C+E+Ferulic Serum, and the gentle-based C+ Therapy Serum designed for sensitive or reactive skin types. Both reflect his first philosophy of longevity and his faith in smart design over trend chasing.
We sat down with Marie to decide whatVitamin Cwhat it’s really doing to your skin, how to choose the right version, what to avoid, and why pairing it systematically with retinol may be one of the most powerful steps you can take in long-term skin health.
You can read our previous Living Well Interview with Marie Veronique Nadeau here.
In an interview with Marie Marie Veronique Nadeau
How should one include Vitamin C in their morning and/or evening regimen?Ascorbic acid is still pretty much the gold standard in skin care. For most people a serum containing stable ascorbic acid in the anhydrous system with a pH of 4 to 4.5 will be their first choice, especially one that is also fortified with Vitamin E and ferulic acid. It can be used in the morning under sunscreen for extra anti-oxidant protection. It can be used at night to aid in regeneration processes such as collagen production. Ascorbic acid hydroxylates proline, and is one of the first steps in collagen biosynthesis- no Vitamin C, no collagen.
People who have trouble tolerating low pH, that is, with sensitive or sensitive skin or inflammatory conditions like rosacea, should look for Vitamin C derivatives in their serum. No one should attempt to applyVitamin Cdirectly on their skin—this can be very dangerous.
Can you use Vitamin C and retinol?Yes, absolutely, and anyone interested in skin longevity will want to. You can use them together (layered) or separate them into morning and evening use. Use itvitamin Cduring the day due to its antioxidant properties and retinol at night, when you get the best benefit from its signaling properties that send instructions to fibroblasts to make more collagen. You get great synergy by using both—Vitamin Cprovides a necessary step in the production of collagen, while retinol converts to retinoic acid in the cell, where it binds to receptors that act as chemical messengers that inform processes such as the regulation of collagen production and cell transformation and the reduction of melanin production (light skin).
What should people look for (and avoid) when choosing a Vitamin C product?First, avoid AA (ascorbic acid) powders that can give you heartburn.
People looking for the benefits of immunity and longevity should look for a serum with Vitamin C such as ascorbic acid combined with a helping of antioxidants such asVitamin E and ferulic acid.
For people with sensitive or sensitive skin, look for Vitamin C derivatives. You can refine your search to find derivatives that suit your special needs.For example, people looking for skin lightening results should look for ingredients like glyceryl ascorbate and tetrahexyldecyl ascorbate. People with acne problems should look to SAP (sodium ascorbyl phosphate) to reduce sebum oxidation in clogged pores, the main cause of acne. And then sensitive, challenging skin in that age group where collagen production is important should seek THA (tetrahexyldecyl ascorbate) and MAP (magnesium ascorbyl phosphate); both have good performance records for fibroblast penetration to hydroxylate proline. The cell secretes hydroxyproline, a necessary component of collagen, and the hard and fast rule is: no Vitamin C = no collagen!
How does Vitamin C interact with other active ingredients such as retinoids, AHAs/BHAs, and peptides?
- Vitamin C + retinol has an important synergistic interaction, with signaling from retinol and hydroxyproline from Vitamin C providing benefits in both age delay and skin lightening fields. In addition to promoting collagen production, the two also interact using epigenetic mechanisms to promote epidermal thickening.
- The combination of AHAs and BHAs can increase skin sensitivity as they are acids. Vitamin C has great benefits and can be used daily, while the AHA extract can be used once a week, separately from Vitamin C. I recommend lactic acid for exfoliation treatment, as it has, in addition to being gentle, a great profile for the longevity of the skin-including increasing collagen production and dermal firmness. It also acts as a signaling molecule to regulate autophagy.
- Vitamin C and peptides: It is probably best to use Vitamin C and peptides separately, because of the possible pH conflict when the results are neutral (especially in the case of copper peptides). Use vitamin C in the morning for antioxidant benefits and peptides at night for repair purposes.
Your brand offers Vitamins C+E+Ferulic Serum and C-Therapy Serum, at a high level, what are the main differences in purpose and effectiveness between the two?Vitamins C+E+Ferulic Serumit combines powerful antioxidants to bring increased antioxidant protection, and Vitamin C as ascorbic acid promotes collagen production. It is designed for people with normal skin who need protection and want the age-delaying benefits of Vitamin C delivered in a highly effective way.
Everyone needsVitamin C,but not everyone can use ascorbic acid. That’s why we developedIC-Therapy Serumfor those people on the spectrum with Vitamin C sensitivity or other problems.Vitamin C productsthey are stable and deliver ascorbic acid to the skin without causing problems with sensitivity. In addition, each derivative in C-Therapy Serum performs a unique range of functions. Medical research shows that: sodium ascorbyl phosphate prevents the oxidation of waste in clogged pores to clear the exit, glyceryl ascrobate softens and improves barrier function, and magnesium ascorbyl phosphate and tetrahexyldecyl ascorbate prevent hyperpigmentation processes and increase collagen levels. The formulation is combined with alpha-lipoic acid – a universal antioxidant that helps prevent mitochondrial DNA damage.
Are there any ingredients you should avoid pairing with any serum?They are designed to work with most ingredients but remember the rules—you don’t want to avoid lowering the pH so be careful when combining with AHAs, BHAs, and another rule: Protect during the day and repair at night—so use antioxidants during the day and retinol and other signal peptides to repair at night.
How can you tell if your Vitamin C serum has oxidized and is no longer effective?The color should remain the same as when you first use it, if it starts to turn black that is a sign that it may be oxidizing.
How is your formula different from other C+E+Ferulic serums on the market?We pay attention to synergy, both within the formulation, where we want to increase the antioxidant power of the serum, but within the wider context of howVitamin Cworks with other protective and rejuvenating products, especially sunscreen and retinol serums.
We combine advanced technology in a lightweight serum that can be layered with sunscreen during the day to deliver antioxidant protection, or with a retinoid product at night to ensure that enough ascorbic acid is in the skin tissue to respond to retinoic acid signaling to make collagen.
Vitamin Cmust be present to hydroxylate proline to form a stable collagen triple helix. To fully optimize skin health and longevity, we recommend combining oral, daily, and topical supplementsVitamins C+E+Ferulic SerumorIC-Therapy Serumand should be used daily.
Is there an emerging ingredient or new research direction in antioxidant science that you’re most excited about in skin care?Well, there are new studies that show thatVitamin Cit plays a role in rejuvenating the skin with epidermal thickening-which greatly increases its longevity profile, as it tackles the problem of crepey skin that is a major concern of aging skin. Acting through an epigenetic process called DNA demethylation, Vitamin C activates TET enzymes to activate genes that promote keratinocyte proliferation and increase epidermal thickness.
Synergy is some interesting news; the use of retinol and Vitamin C together improves the skin’s thickening process-retinol acts as a signaling molecule to regulate and increase TET enzymes within the cell, while Vitamin C acts as a cofactor to recharge the enzymes. Using the two vitamins together influences the epigenome and improves the longevity of the skin.