Ch.01, Vitamin C
By now you have probably heard about the transformative effects of Vitamin C - a more glowy, dewy, plump and youthful skin.
Hmm does it really do all this? You think to yourself. Short answer is: yes it can! There are a couple of important precautions though, so lets dive into them.
The Benefits
First of all, what is Vitamin C and what does it do exactly?
It is a nutrient found in citrus fruits and vegetables that your body needs to properly grow, repair and function.
When it comes to our skin, numerous scientific studies show that vitamin C can:
✓ promote collagen synthesis
✓ protect against sun damage
✓ fight inflammation
✓ lighten pigmentation
In other words, this skincare hero can help brighten your complexion and add firmness for a more healthy, youthful-looking skin.
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🧬 Promotes Collagen Synthesis: Vitamin C is an essential co-factor for a number of key enzymes, prolyl hydroxylase and lysyl hydroxylase, that cross-link and stabilize collagen fibers. In other words, vitamin C can 'reweave' the skin fibers by binding and strengthening them. As a result, it can help promote more plump and smooth skin (2). In clinical research applying vitamin C to photaged skin demonstrated a statistically significant improvement in skin quality parameters including a decrease in wrinkles (17, 20, 13, 18, 9, 14), improved skin smoothness (14, 9, 13) and increase in collagen formation (18, 20).
⛅ Protects against sun damage: Although vitamin C does not absorb or block UV light like traditional sunscreens, it protects the skin against UV-induced damage. It does so, by giving up some of its electrons to neutralize free radicals which are molecules that induce cellular damage (4). Vitamin C’s ability to prevent oxidative damage from free radicals is also why it is called an antioxidant. Under laboratory conditions, vitamin c was shown to reduce sunburn cell formation by 40-60% (3), decrease UVB-induced eythema by 52% (3) and protect against thymine dimer formation known to potentially cause skin cancer (11,15).
✨ Lightens pigmentation: Due to its ability to suppress melanin production, vitamin C has been linked to skin lightening effects. Specifically, it indirectly inhibits the activity of the main enzyme, tyrosinase, which catalyzes the production of melanin. In-vitro data and several clinical studies shows that vitamin C can lead to an increase in skin radiance (9), and a measurable reduction in melanin index (21, 9, 14) as well as a decrease in UV-induced pigmentation (16).
🧊 Fights Inflammation: Vitamin C works as an anti-inflammatory agent through its capacity to inhibit something called NFkB. Latter is a family of transcription factors which are proteins that mediate and regulate cellular behaviors that includes inflammatory responses. Consequently, vitamin C has been shown to promote wound healing and prevent post-inflammatory hyperpigmentation (4).
What to look for
To obtain the benefits of vitamin C there is a caveat! Actually there are 3 of them.
Lets go through them:
1. Choose the right type of Vitamin C
Not all vitamin c's are created equal. There are several derivatives (e.g. copycats) of vitamin C used in cosmetic creams today. Nevertheless, L-ascorbic acid - which is the scientific name for vitamin C in its purest form - has long been referred to as the golden standard since it is the most researched and potent form.
Moreover, synthetic derivatives are considered limited in their ability to actually penetrate and increase vitamin C levels in skin. You can read more about it here.
2. Check for freshness
Pure vitamin C e.g. L-Ascorbic acid is highly sensitive to air, light and water and therefore easily oxidise in water-based solutions. In its unstable form, its potency is drastically reduced and it becomes a source of free radicals which are harmful to the skin. As a result, many products touting vitamin C are more or less inactive before they even hit the shelves.
To avoid this, look for vitamin C that can be freshly mixed or is formulated with supporting ingredients like vitamin E and ferulic acid which studies have shown can greatly enhance vitamin C stability and efficacy. You can also check the color of the formula as vitamin C gradually darkens from a pale yellow into a brown color when it goes bad. Some producers color their serums orange to hide this.
3. Ensure pH value & concentration levels are correct
To actually penetrate the skin and deliver any benefits, it is critical that vitamin C formulations are formulated at pH levels that are less than 3.5 and at concentration levels that exceed 5%.
There is such a thing as too much though! Anything above 20% greatly increases chances of irritation without delivering additional benefits.
How to use Vitamin C
Including Vitamin C in your skincare routine can be a little tricky, so here are some tips on how to use it correctly:
Use after cleanser on damp skin
After cleansing your face, apply a few drops of your vitamin C serum to your face and neck as the first serum treatment. For enhanced absorption, consider applying the serum on slightly damp skin. Allow the serum to fully absorb into your skin before proceeding to the next step. Follow up with a suitable moisturizer to lock in the benefits and provide hydration. As the final step, apply a broad-spectrum sunscreen to protect your skin from harmful UV rays.
Incorporate into daytime skincare
Vitamin C can be used in your day or nighttime routine, but using it during the day is especially beneficial. This is because Vitamin C is a potent antioxidant that fight the oxidative stress caused by the sun and environmental pollutants.
Optimize absorption with hydroxy acids
The absorption of Vitamin C can be greatly affected by the pH of the skin (8). Cleansers with hydroxy acids like glycolic acid, salicylic acid, or lactic acid can lower the pH of the skin temporarily, creating a more acidic environment which can enhance the absorption of vitamin C when applied topically.
Gradually increase frequency
If it’s your first-time using Vitamin C, you may experience a mild tingling sensation initially, which should subside as the skin adjusts. It is advised to gradually introduce vitamin C into the routine, starting with every other day application and increasing the frequency to daily use. Regular application of vitamin C can replenish the skin's antioxidant reserve, and a significant amount of absorbed vitamin C can remain in the skin for several days (8).
How to layer Vitamin C
Vitamin Cs besties
Antioxidants: Studies have shown that pairing Vitamin C with other antioxidant ingredients such as ferulic acid and vitamin E (tocopherol), increase the stability and efficacy of the vitamin, helping it to remain active for longer periods and providing better protection against oxidative stress (11, 27).
Niacinamide: Yes, you can combine Vitamin C with Niacinamide to boost the brightening and antioxidant effect of your serum. It was believed, that combining these ingredients can form niacin, a molecule that can cause redness and flushing on your skin. However, the conversion of niacinamide to niacin needs really high temperatures for a long time (90°C, 75 hours) and those conditions won’t occur on your skin (26).
Sunscreen: This is a must! Vitamin C is capable of increasing protection against UVB radiation when combined with sunscreen (27). However, keep in mind that Vitamin C does not replace sunscreen or physical protection from the sun. Always use broad-spectrum sunscreen and try to limit sun exposure.
Vitamin Cs enemies
Retinoids: Layering these retinoids and Vitamin C simultaneously can be overwhelming for your skin and may lead to irritation. It is therefore advisable to use these two potent ingredients at alternate times. A clinical study conducted on women with mild to moderate hyperpigmented and photodamaged skin revealed promising findings. Participants who incorporated vitamin C into their morning routine and used retinol every other night witnessed improvements in fine lines and skin tone in just four weeks (28). However, it is crucial to ensure that your skin is fully acclimated to either retinoids or vitamin C before introducing both into your skincare routine. A gradual approach allows your skin to adjust and minimizes the risk of irritation.
Exfoliating acids: similar to retinoids, layering exfoliating acids, such as toners and serums, with Vitamin C can be a bit too harsh for your skin and increase risk of irritation. If you want to include both of them in your skincare routine, we recommend using Vitamin C in the morning and exfoliating acids 1-2 nights per week. Also, make sure your skin is fully used to Vitamin C before including exfoliating acids in your routine.
CHEAT SHEET
Vitamin C (in its pure form as ascorbic acid) can promote collagen synthesis, protect against sun damage, fight inflammation, and lighten pigmentation in the skin.
Synthetic derivatives of vitamin C are considered limited in their ability to actually penetrate and increase vitamin C levels in the skin.
When purchasing Vitamin C serums, it's important to ensure that the concentration of Vitamin C is above 5% and the pH value is below 3.5. These factors contribute to optimal absorption and efficacy.
Vitamin C is notorious for its instability. To counteract oxidation, it's advisable to choose products that either allow for fresh mixing or are formulated with stabilizing ingredients like vitamin E and ferulic acid.
For optimal results, incorporate Vitamin C into your daytime skincare routine by applying a few drops to your face and neck immediately after cleansing. Follow up with a moisturizer and sunscreen to protect your skin throughout the day.
Questions & Answers
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Topical application provides the most efficient and direct route of administration as it allows for high concentrations of vitamin C to penetrate the skin. Oral supplementation, on the other hand, results in limited skin absorption since our bodies excrete excess amounts of the vitamin via the kidneys.
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No, lemon or orange juice contains approximately 0.04 % ascorbic acid, so for starters, this is a very low concentration to deliver any benefit to your skin. But most importantly, citrus fruits juices also contain a type of molecules (furanocoumarins and psoralens) that can cause phytophotodermatitis (blisters and inflamed lesions caused by skin exposure to different plant juices, followed by UV light exposure (28, 29).
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Applying vitamin C on slightly damp skin can help facilitate its absorption, as the moisture helps the ingredients penetrate the skin more efficiently. Thus, gently pat dry your skin after cleansing, but don’t wait until your skin is completely dry, and apply your Vitamin C.
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Vitamin C derivatives (magnesium ascorbyl phosphate, ascorbyl-6-palmitate, dehydroascorbic acid, etc) are commonly used in skin care products since they have better stability in the formulation. However, none of them are as efficient as ascorbic acid (the pure form of Vitamin C). One study that tested the absorption of vitamin C into the skin, showed that most vitamin C derivatives did not increase skin levels of ascorbic acid. Thus, there are few to no studies proving their efficacy (8).
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After applying vitamin C to your skin, it is generally recommended to wait for a few minutes before applying your moisturizer. This allows sufficient time for the vitamin C product to absorb into the skin and work effectively.
The exact waiting time can vary depending on the specific vitamin C formulation and the individual's skin type.
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The time it takes for a vitamin C serum to show visible results can vary depending on various factors, including the individual's skin type, the concentration and formulation of the serum, and the frequency of use. Generally, it may take several weeks of consistent use to start noticing the effects of a vitamin C serum on your skin. This is because vitamin C works gradually to improve the overall health and appearance of the skin.
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1. Michels, Vitamin C and Skin Health, Oregan State University. 2011
2. Sheldon R. Pinnell, MD , Doren L. Madey, PhD, Topical Vitamin C in Skin Care, Aesthetic Surgery Journal, Volume 18, Issue 6. 1998
3. Al-Niaimi F, Chiang NYZ. Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. J Clin Aesthet Dermatol. 2017
4. Telang PS. Vitamin C in dermatology. Indian Dermatol Online J. 2013
5. Farris PK, Krol Y. Under Persistent Assault: Understanding the Factors that Deteriorate Human Skin and Clinical Efficacy of Topical Antioxidants in Treating Aging Skin. Cosmetics. 2015
6. Ravetti S, Clemente C, Brignone S, Hergert L, Allemandi D, Palma S. Ascorbic Acid in Skin Health. Cosmetics. 2019
7. Helfrich YR, Sachs DL, Voorhees JJ. Overview of skin aging and photoaging. Dermatol Nurs. 2008
8. Pinnell SR, Yang H, Omar M, et al. Topical L-ascorbic acid: percutaneous absorption studies. Dermatol Surg. 2001
9. Rattanawiwatpong P, Wanitphakdeedecha R, Bumrungpert A, Maiprasert M. Anti-aging and brightening effects of a topical treatment containing vitamin C, vitamin E, and raspberry leaf cell culture extract: A split-face, randomized controlled trial. J Cosmet Dermatol. 2020
10. Lin FH, Lin JY, Gupta RD, et al. Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin. J Invest Dermatol. 2005
11. Murray JC, Burch JA, Streilein RD, Iannacchione MA, Hall RP, Pinnell SR. A topical antioxidant solution containing vitamins C and E stabilized by ferulic acid provides protection for human skin against damage caused by ultraviolet irradiation. J Am Acad Dermatol. 2008
12. Campos PM, Gonçalves GM, Gaspar LR. In vitro antioxidant activity and in vivo efficacy of topical formulations containing vitamin C and its derivatives studied by non-invasive methods. Skin Res Technol. 2008
13. Traikovich SS. Use of topical ascorbic acid and its effects on photodamaged skin topography. Arch Otolaryngol Head Neck Surg. 1999
14. Xu TH, Chen JZ, Li YH, et al. Split-face study of topical 23.8% L-ascorbic acid serum in treating photo-aged skin. J Drugs Dermatol. 2012
15. Lin JY, Selim MA, Shea CR, et al. UV photoprotection by combination topical antioxidants vitamin C and vitamin E. J Am Acad Dermatol. 2003
16. De Dormael R, Bastien P, Sextius P, et al. Vitamin C Prevents Ultraviolet-induced Pigmentation in Healthy Volunteers: Bayesian Meta-analysis Results from 31 Randomized Controlled versus Vehicle Clinical Studies. J Clin Aesthet Dermatol. 2019
17. Raschke T, Koop U, Düsing HJ, et al. Topical activity of ascorbic acid: from in vitro optimization to in vivo efficacy. Skin Pharmacol Physiol. 2004
18. Humbert PG, Haftek M, Creidi P, et al. Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double-blind study vs. placebo. Exp Dermatol. 2003
19. Kameyama K, Sakai C, Kondoh S, et al. Inhibitory effect of magnesium L-ascorbyl-2-phosphate (VC-PMG) on melanogenesis in vitro and in vivo. J Am Acad Dermatol. 1996
20. Fitzpatrick RE, Rostan EF. Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage. Dermatol Surg. 2002
21. Espinal-Perez LE, Moncada B, Castanedo-Cazares JP. A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma. Int J Dermatol. 2004
22. Al-Niaimi F, Chiang NYZ. Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. J Clin Aesthet Dermatol. 2017
23. Khan, Hira & Akhtar, Naheed & Ali, Atif., Fortification of facial skin collagen efficacy by combined ascorbyl palmitate and sodium ascorbyl phosphate. Acta Poloniae Pharmaceutica. 2018
24. Stamford NP. Stability, transdermal penetration, and cutaneous effects of ascorbic acid and its derivatives. J Cosmet Dermatol. 2012
25. Geesin JC, Gordon JS, Berg RA. Regulation of collagen synthesis in human dermal fibroblasts by the sodium and magnesium salts of ascorbyl-2-phosphate. Skin Pharmacol. 1993
26. Higuchi, T. & Finholt, P. Rate Studies on the Hydrolysis of Niacinamide. 1962
27. Darr, D., Dunston, S., Faust, H. & Pinnell, S. Effectiveness of antioxidants (Vitamin C and E) with and without sunscreens as topical photoprotectants. Acta Derm Verereol 264–268. 1996
28. Herndon Jr, J. H., Jiang, L. I., Kononov MBA, T. B. & Fox Thomas J Stephens, T. B. An Open Label Clinical Trial to Evaluate the Efficacy and Tolerance of a Retinol and Vitamin C Facial Regimen in Women With Mild-to-Moderate Hyperpigmentation and Photodamaged Facial Skin. J Drugs Dermatol vol. 15. 2016
29. Mioduszewski, M. & Beecker, J. Phytophotodermatitis from making sangria: a phototoxic reaction to lime and lemon juice. CMAJ 187. 2015
30. Safran, T. et al. Blistering phytophotodermatitis of the hands after contact with lime juice. Contact Dermatitis 77, 53–54. 2017