A Complete Guide: Vitamin C in Skin Health

In this complete guide, I will discuss the role of vitamin C when it comes to our skin health. The skins job is to act as a barrier against insults from the environment. It is composed of two layers: the epidermal outer layer which is highly cellular and functions as a strong barrier, and the inner dermal layer which ensures strength and elasticity and gives nutritional support to the epidermis. The skin contains high concentrations of vitamin C, stimulating collagen synthesis and assisting in antioxidant protection against UV-induced photodamage. 

Because humans are unable to synthesize their own Vitamin C they are particularly vulnerable to Vitamin C deficiency. 

Since blood is the vehicle for vitamin C transport through the body, plasma concentration is a good indicator of adequate supply.  Therefore, the plasma level of the individual is the most pertinent issue for the efficacy of topical application: if plasma levels are high (saturated, full, adequate), then topical application renders ineffective (not increasing skin vitamin C content).   Vitamin C, as a water-soluble and charged molecule, is repelled by the physical barrier of the terminally differentiated epidermal cells. It is only when pH levels are below 4 and vitamin C is present as ascorbic acid that penetration occurs.

Find out how to make your own topical serum of Vitamin C at the end of this post 🙂

It is accepted that nutritional status with respect to both macro and micronutrients is important for skin health and appearance. Evidence is provided by the many vitamin deficiency diseases that result in significant disorders of the skin.

Table 1. Vitamin C content of human skin and a comparison with other tissues.

Tissue	Vitamin C Content (mg/100 g Wet Weight)	References
Adrenal glands	30–40	[28]
Pituitary glands	40–50	[29]
Liver	10–16	[28,30]
Spleen	10–15	[28,31]
Lungs	7	[28]
Kidneys	5–15	[30]
Heart muscle	5–15	[28,29,31]
Skeletal muscle	3–4	[29,32]
Brain	13–15	[28]
Skin-epidermis	6–64	[25, 27]
Skin-dermis	3–13	[25, 27]

BEST FORM OF VITAMIN C FOR SKIN HEALTH

L- Ascorbic Acid (LAA)

She’s the real deal, completely genuine, and no one’s second choice. This is vitamin C in its purest, unadulterated form, the ultimate standard of vitamin C. Ascorbic acid boasts the highest biological activity among all its counterparts, making it a powerhouse in terms of antioxidants, fading pigmentation, and improving collagen production. Being it’s active form, it doesn’t need any extra steps to kick into action once applied. The sweet spot for its effectiveness lies between 8-20%, but remember, a higher concentration doesn’t necessarily mean better results; it could even lead to more irritation.

Caveat – this form is temperamental, prone to oxidation (you can spot this through its color, a deep amber hue signals oxidation). This can occur due to exposure to high temperatures, light, or air. Once oxidized, it loses its antioxidant properties and renders useless. This is why the recommendation often stands: once you open a serum with L-AA, it’s best to use it daily before it turns amber. Storing it in the fridge can also buy you some extra time.

Tetrahexyldecyl Ascorbate (THD)

A favorite in the skincare industry. Its stable, easy to formulate and a joy to work with for cosmetic chemists.  It is oil soluble with great skin penetration (that is usually integral when looking at anti-aging properties).  There is also in-vitro (work performed with cells, tissues, etc.) data showing that it converts to AA in the skin. Tetrahexyldecyl Ascorbate mentioned only in one published in-vivo (work performed on living subjects; animals, humans, etc) study that examined the anti-aging properties of a silicone formula containing 10% AA and 7% THDA. The study was a small (10 patients), double-blind experiment, and the formula did show some measurable anti-aging results. However, it is hard to know how much pure vitamin C or THDA can be thanked.

 A really promising, but not well-proven vitamin C derivative that can be worth a try especially if you like experimenting (but if you like the tried and true, pure vitamin C will be your best bet).

Sample Product: Rose-E + C Anti-Aging Cream – 1 oz Glass Jar – Now with EMU oil – Fancy Farm Skincare

Sodium Ascorbyl Phosphate (SAP)

This derivative is especially best for those with acne prone skin, as it has been proven to fight acne, and suppress the bacteria that causes acne (it’s an antimicrobial derivative).  According to this study, the stability, antimicrobial properties, reduced irritation and brightening effects make it a optimistic option when addressing the skin benefits. However, it is proven to be less potent, have a lower absorbion and overall limited in its research on its effectiveness of boosting collagen production, combating free radicals, and reducing signs of aging.

Ultimately, the choice between SAP and l-ascorbic acid depends on individual preferences, skin type, and desired outcomes. While SAP offers stability and gentleness, l-ascorbic acid’s potency and proven effectiveness make it a favored choice for many seeking rapid and potent skin benefits.

Magnesium Ascorbyl Phosphate

MAP is one of the most stable derivatives of Vitamin C.  Research has proven MAP to boost collagen production and help with pigmentation.  It also has a reduced potential for inducing skin irritation when contrasted with l-ascorbic acid, making it particularly suitable for individuals with sensitive skin. However, its antioxidant capabilities are still questionable, and it is poorly absorbed.  Some scientific studies also propose that l-ascorbic acid may exert a more robust influence on collagen production, a key determinant in skin health and rejuvenation.

Ascorbyl Glucoside

This is the least stable among the derivatives. While its collagen boosting effects are similar to L-AA, more studies are still needed to confirm whether it boasts other similar benefits to Ascorbic Acid, and how effective it is. It converts to sugar and L-AA when applied on the skin.

Ethylated L-Ascorbic Acid

Ethyl Ascorbic Acid or EAC for short is an “etherified derivative of ascorbic acid” that consists of vitamin C and an ethyl group bound to the third carbon position. This makes Vitamin C very stable and soluble in both water and oil.  It does not require conversion into L-AA when applied. The skin recognizes this ethylated form as ascorbic acid, but more stable form that is less likely to oxidize and remains more effective over a longer period of time (as compared to L-AA). Because this derivative is very similar to L-AA (aside from the extra ethyl group that makes it stable), it is still just as strong and provides identical benefits.

Pros are: longer shelf life, stability to the elements, gentler on skin, proven antioxidant effects and enhanced lipid solubility, facilitating better penetration into the skin. This leads to improved absorption and bioavailability. 

Cons are: Potency variation – while more stable, ethylated forms of L-Ascorbic Acid might not be as potent as the unmodified version in terms of antioxidant and skin-brightening effects, Effect on Collagen Production – studies suggest that ethylated forms might have a somewhat reduced impact on collagen synthesis compared to unmodified L-Ascorbic Acid, Formulation Challenges – The alteration of the molecular structure in ethylated derivatives might introduce formulation complexities. Formulators need to consider pH compatibility and stability when creating products, and Cost: Ethylated L-Ascorbic Acid might be costlier to produce due to the additional steps involved in its synthesis.

Vitamin C : L-Ascorbic Acid vs its derivitaves?

To be honest, the answer was evident early on in my research that ascorbic acid was the preferred method of topical application (on the skin) to any of its derivatives.  L-Ascorbic Acid is the active form of vitamin C. It has the highest antioxidant capacity of all forms of Vitamin C. It is the most researched and therefore the most proven of elite benefits when it comes to addressing issues of depigmentation and fine lines and wrinkles as well as improving collagen synthesis and protecting / reversing skin damage from UV.  However, LAA is notoriously hard to formulate with because of its inherent instability as a molecule when mixed with water.  Not to mention it easily breaks down by oxygen and light making it fairly difficult to incorporate into skincare. After just 1 week LAA loses 50% of its antioxidant properties and 2 weeks nearly all benefits are lost.

You can stabilize L-ascorbic acid by combining it with some other nutrients like vitamin e – alpha tocopheryl acetate or Feurlic acid. Brands like Skin Ceuticals and Paula’s Choice do this method.  If you are doing this at home; Vitamin E does not suspend well in water – that means you will have to use an emulser that will help suspend it well with your water-based Vitamin C. I do not like emulsers as they are semi-synthetic and synthetic varieties not naturally derived.

If you want to skip the nuance of making your own whole, raw Vitamin C formula you can use a derivative eg. Tetrahexyldecyl Ascorbate (THD). These are precursors to L-Ascorbic Acid. They end to be lipophilic (fat loving) and penetrate well into the skin. This route tends to be a titch more expensive. Plus in general it is not well established how well these convert back into L-ascorbic acid in your skin.  

Frankly, in my universe it is not really a debate. The preferred method of topical administration for vitamin c is L-Ascorbic Acid, if only it was just more stable of a molecule. Being as unstable as it is, the downfall is the effective shelf life.

FUNCTIONS OF VITAMIN C IN THE SKIN

Promoter of Collagen Formation

Vitamin C present in the fibroblasts supporting the synthesis of the collagen fibres.

Scavenger of Free Radicals and Disposer of Toxic Oxidants

Vitamin C is a potent antioxidant that can neutralize and remove oxidants, such as those found in environmental pollutants and after exposure to ultraviolet radiation.

However, vitamin C is only one player in the antioxidant arsenal that includes enzymatic defenses (catalase, glutathione peroxidase and superoxide dismutase) as well as other non-enzymatic defenses (vitamin E, glutathione, uric acid and other putative antioxidants such as carotenoids)

Inhibitor of Melanogenesis

The inhibition in melanin production by vitamin C is thought to be due to the vitamin’s ability to reduce the ortho-quinones generated by tyrosinase, although other mechanisms are also possible. Agents that decrease melanogenesis are used to treat skin hyperpigmentation in conditions such as melisma or age spots.

Interacts with Cell Signaling Pathways

In vitro studies clearly show that vitamin C can play a role in the differentiation of keratinocytes. In addition to vitamin C’s ability to promote collagen synthesis [73,79], there is evidence to suggest that vitamin C increases proliferation and migration of dermal fibroblasts [78,82], functions vital for effective wound healing [78]. Through the stimulation of regulatory hydroxylases, vitamin C also regulates the stabilization and activation of the hypoxia-inducible factor (HIF)-1, a metabolic sensor that controls the expression of hundreds of genes involved with cell survival and tissue remodeling, including collagenases [103, 105]. Vitamin C has been shown to both stimulate [69] and inhibit elastin synthesis in cultured fibroblasts [81]. Glycosaminoglycan synthesis as part of extracellular matrix formation is also increased by vitamin C treatment [106], and it may also influence gene expression of antioxidant enzymes, including those involved in DNA repair [78]. As such, vitamin C has been shown to increase the repair of oxidatively damaged bases. [78]. The modulation of gene expression may be important for its ability to protect during UV exposure via its inhibition of pro-inflammatory cytokine secretion and apoptosis.

EVERDAY CHALLENGES TO SKIN HEALTH

During the course of a normal lifetime, the skin is exposed to a number of threats that affect it’s structure, function and appearance, including:

• Deterioration due to normal aging; ie. loss of elasticity and wrinkle formation.
• Exposure to the elements, leading to discoloration, dryness and accelerated wrinkling.
• Chemical insults; ie. exposure to oxidizing skin products (hair dyes, soaps, detergents, bleaches).
• Direct injury; ie. wounding and burning.

As we age it is shown that your vitamin C content in both the epidermis and dermis declines. Aging of skin can be thought of as two distinct processes—natural or ‘intrinsic’ aging, caused simply by the passage of time, and environmental aging.

Environmental Aging includes lifestyle factors such as smoking and exposure to pollutants. This increases the rate of environmental aging and can have a marked impact on the function and appearance of skin.

Intrinsic aging is a slow process, and, in the absence of environmental aging, changes are not usually apparent until advanced age, when smooth skin with fine wrinkles, pale skin tone, reduced elasticity, and occasional exaggerated expression lines are evident.  There is a reduction in the thickness of the dermal layer, along with fewer fibroblasts and mast cells, less collagen production and reduced vascularization. Specifically, during intrinsic aging there is gradual degradation of the extracellular matrix components, particularly elastin and collagen. The loss of elastin results in the reduction in elasticity and capacity for recoil that is observed in aging skin.

Intrinsic aging is largely unavoidable and may be largely dependent on our genetic background and other factors [129,130]. Some mitigation of these effects may be achieved by:

• Limiting exposure to environmental risk factors such as smoking, poor nutrition and chronic exposure to sunlight, which cause premature skin aging.
• Using treatments to potentially reverse skin damage, including topical or systemic treatments that help regenerate the elastic fiber system and collagen.

Fermented Papaya Extract Study

A double-blind nutrition intervention study has evaluated the effects of dietary supplementation with a fermented papaya extract [135] and an antioxidant cocktail in a population of healthy individuals aged between 40 and 65, all with visible signs of skin aging. Notably, the intervention resulted in a measurable improvement in skin physical parameters, with a generally enhanced response from the fermented papaya extract compared with the antioxidant cocktail. This is an interesting study and suggests that antioxidant supplementation, including vitamin C, could benefit skin health generally.

UV radiation damages skin through the production of reactive oxygen species, which can damage the extracellular matrix components and affect both the structure and function of cells. IN EXCESSIVE AMOUNTS.  Acute exposure of skin to UV radiation can cause sunburn, resulting in a large inflammatory response causing characteristic redness, swelling and heat. Termed photoaging, the most obvious features are wrinkles, hyperpigmentation and marked changes in skin elasticity that cause skin sagging, with the skin also becoming sallow and rougher with age. Photoaged skin is most likely to be found on the face, chest and upper surface of the arms.

Vitamin C is not a “sunscreen” because it does not absorb light in the UVA or UVB spectrum. Rather, the antioxidant activity of vitamin C protects against UV-induced damage caused by free radicals. Vitamin C transport proteins are increased in keratinocytes in response to UV light, suggesting an increased need for vitamin C uptake for adequate protection. UV light decreases vitamin C content of skin, an effect that is dependent on the intensity and duration of UV exposure.

Topical application of vitamin C, in combination with vitamin E and other compounds, has also been shown to reduce injury due to UV irradiation. One study suggests that when health status is already optimal there is no absorption of vitamin C following topical application. Hence, “beauty from the inside”, via nutrition, may be more effective than topical application [132]. Topically applied combinations of vitamin C and vitamin E are more effective in preventing photodamage than either vitamin alone.

See my post on Sunlight for additional information on UV Radiation + Photoaging..

Wrinkles are formed during chronological aging; accelerated by exposure to UV radiation or smoking. The formation of wrinkles is thought to be due to changes in the lower, dermal layer of the skin.  Loss of collagen, deterioration of collagen and elastic fibers and changes to the dermal–epidermal junction contribute. UV light induces cytokine production, which triggers fibroblast elastase expression causing degradation of elastic fibers, loss of elasticity and consequent wrinkle formation.

Human studies often assess skin health by changes in depth or number of wrinkles and by the individual’s perception of skin health. Two observational studies found that higher intakes of vitamin C from the diet were associated with better skin appearance, with notable decreases in skin wrinkling (51, 52).

Reversal of Wrinkles

Vitamin C can protect against wrinkle formation through improved collagen synthesis proven in measured differences in wound healing and collagen synthesis in smokers, abstinent smokers and non-smokers with associated variances in plasma vitamin C status. Smokers had depleted vitamin C levels compared with non-smokers; these levels improve by smoking cessation, with an associated improvement in wound healing and collagen formation.

Wound healing is a complex process with three main consecutive and overlapping stages, inflammation, new tissue formation and remodeling. Following vasoconstriction and fibrin clot formation to stem bleeding, inflammatory cells are recruited to the wound site. The first of these cells is the neutrophil, which clears the wound of any damaged tissue and infectious material and signals the recruitment of tissue macrophages. Macrophages continue clearing damaged material and bacteria, including spent neutrophils. Crucially, they are involved in orchestrating the healing process, signaling fibroblasts to remodel tissue at the wound site and providing vital signals for re-epithelialization and dermal repair.

Vitamin C for Wound Healing

Of all effects of vitamin C on skin health, its beneficial effect on wound healing is the most dramatic and reproducible. Vitamin C turnover at wound sites, due to both local inflammation and the demands of increased collagen production, means that supplementation is useful, and both topical application and increased nutrient intake have been shown to be beneficial.  Supplementation with both vitamin C and vitamin E improved the rate of wound healing in children with extensive burns, and plasma vitamin C levels in smokers, abstaining smokers and non-smokers were positively associated with the rate of wound healing.

Inflammation in the skin underlies a number of debilitating conditions such as atopic dermatitis, psoriasis and acne, with symptoms including pain, dryness and itching. Nutrition plays an
integral part in both these aspects and numerous studies have investigated the impact of dietary manipulation for alleviation of acute and chronic pathologies, although firm conclusions as to efficacy remain elusive. Treatments involving supplementation with essential omega-fatty acids, lipid-soluble vitamins E and A are often employed in an attempt to assist the generation of the lipid barriers and to retain moisture in the skin.

Wrap Up

In this complete guide, I found that Vitamin C (ascorbic acid) is an essential part of skin health both as an antioxidant and for collagen synthesis. Vitamin C contributes to photoprotection, decreases photodamage, and wound healing. Oral supplementation with vitamin C can help prevent UV-induced damage by intrinsic and environmental aging, especially in combination with vitamin E. Despite inconsistencies in vitamin C derivatives and whole source, data suggest that L-ascorbic acid is most effective in protecting against damage induced by UV light and also has utility in the treatment of photodamage and/or skin wrinkling. Although vitamin C appears to benefit dry skin and may support wound healing, further research is needed. The greatest synergy of vitamin C supplementation are seen when it is combined with other micronutrients, such as vitamin E.

ANNIES DIY

DIY Serum: 5 minutes to make, 1-2 weeks shelf life.

• 20 ml Amber airtight dropper container
• 2 grams L-Ascorbic Acid powder (NutriBiotic)
• ¼ teaspoon
• Distilled (or deionized) water
  • Metals in your water can speed up how quickly l-ascorbic acid decomposes
• PH strips
• Baking Soda

Without baking soda it’s a bit too acidic and can cause unnecessary irritation.

Bonus – you can use aluminum foil to protect your product from light

IF you have a larger container, see equation below:

Percentage you want / 100 X volume of container = mass of LAA (in grams)

Prep Work: Sanitize bottle. (Don’t need to be too thorough because solution will be at a low pH which microbes have a hard time surviving in)