All about Vitamin C, L-ascorbic acid

Normal skin contains high concentrations of vitamin C just like other body organs. But Vitamin C levels go down significantly in aged or photoaged skin. Now, that’s not necessarily what happens to the other organs but the skin just a point where it can’t keep up with the assault we expose it to.

So what’s going on with aged or photoaged skin at a cellular level besides the loss of that plump, dewy, firm and wrinkle free texture?

A number of things but for the purpose of this video, we will focus on the damage of free radicals and how Vitamin counteracts that through its potent antioxidant characteristics.

What are free radicals and why should we worry about them?

Well, free radicals are reactive oxygen species (ROS) as well as reactive nitrogen species (RNS) that are produced by two ways:

1. As part of normal cell metabolisms. We all know Oxygen is an element so incredibly important in life. When cells use oxygen to generate energy, free radicals are created as a consequence of ATP production by the mitochondria
2. From external sources (pollution, cigarette smoke, radiation, poor nutrition-such as fast and processed food, exposure to excessive UV exposure) Ultraviolet (UV) irradiation is well known to induce photodamage and premature skin aging [1]. Ultraviolet-A (UVA) light is particularly associated with oxidative processes involved in photoaging 

Because electrons like to be in pairs free radicals go around the body trying to couple with other electrons. At low or moderate levels these free radicals actually help with cellular responses and immune functions. But when we have high concentration, they generate oxidative stress which causes damage to cells, proteins and DNA. It’s a downward spiral from that point on because Oxidative stress process plays a major part in the development of chronic and degenerative illness such as cancer, autoimmune disorders, rapid aging, neurodegenerative diseases and you name it.

Our body has several mechanisms to counteract oxidative stress by producing antioxidants, which are either naturally produced in the body, or externally supplied through foods and/or supplements. 

But UV light deplete Vit-C content in the epidermis disproportionally. That means, while the rest of your organs might be in check in Vit-C concentrations, the toll tends to be exponential when it comes to the skin. That’s what I will show you today. 

Along with vitamin E, and β-carotene, Vitamin C is one of the most intensively studied dietary antioxidants for prevention of skin photodamage. So, Yes, absolutely---1000%---eat your veggies and fruits rich in vitamin C but your skin could use some extra treat from well formulated topical Vitamin C too. 

Now Ima share with you what literatures say Vit-C is good for: 

1. It is a Co-factor for promoting collagen synthesis and increases proliferation and migration of dermal fibroblast. What that means in simple words is: Collagen fibers make up approximately~75% of the dermis dry weight and Fibroblasts are-major cell type present in dermis and responsible for production of collagen as well as other extracellular matrix components.So it means Vitamin C helps keep your underlying cushin-dermis supple.  

2. Vit-C is a potent antioxidant. It Scavenges free radicals and helps to get rid of toxic oxidants. Vitamin C is effective as antioxidant when used with Vitamin-E. That’s because Vitamin C regenerates oxidized vitamin E (or it recycles Vit E) (lipid soluble)

3. Vitamin C Inhibits melanogenesis-action of tyrosine. This means: vitamin C can reduce tyrosinase activity and stop formation of melanin before it even begins. Through this Vitamin C helps to reduce hyperpigmentation (you know uneven skintone, age or sunspots). These spots tend to result from the skin over-producing the protective agent melanin in certain areas. Vitamin C can help with that and potentially give your skin a more even complexion. Tyrosinase catalyzes the hydroxylation of tyrosine to dihydroxyphenylalanine (DOPA) and the Oxidation of DOPA to orthoquinone.

4. Vitamin C Plays a role in differentiation of keratinocytes by interacting with cell signaling pathways.

Let me explain this one: The cells that make up the majority of the epidermis are called keratinocytes. Keratinocytes divide and proliferate away from the basal layer (which is the closest to dermis). Their differentiation aka “keratinization” involves production of specialized structural proteins, secretion of lipids and the formation of a cellular envelope of cross-linked proteins. Keratinocytes and their intercellular lipids are important components of the human skin barrier, and vitamin C can promote keratinocyte differentiation. Which is a good thing. For example: ceramide, the most abundant lipid in the skin barrier material is generated at the end of keratinocyte differentiation. So vitamin C plays a role for this kind of chain reactions to take place.

5. The other role of Vitamin C is in Skin aging-the skin has its own endogenous antioxidant defense but UV light deplete VitaminC content in the epidermis and accelerate the photoaging process. Good Vitamin C product can help with that.
6. Last one is it’s use in promoting Wound healing.

But please DON”T ever put fresh lemon on your face thinking that’s affordable vitamin C. This is how it works:

Only Uncharged and lipid-soluble molecules can penetrate the stratum corneum. But vitamin C is a water soluble and charged molecule. Oh and btw ascorbic acid quickly oxidizes when exposed to air adding another challenge. So you can rub all you want but you can’t get that vitamin C down the layers of your skin. Which is where you want it. But what ends up happening is you sensitizing your skin and exposing your skin to the other million things that are in fresh lemon besides vitamin C. You’re wrong if you thought lemon just has water and vitamin C in it. But I don’t want to get into that now. Just don’t put lemon on your face, please! 

The Goal is to find stable derivative of vitamin C that is slow to oxidation and one that can convert to L-Ascorbic acid in-vivo. Inside the skin. So to make the penetration of vitamin C possible, either-PH level has to be lower than 4 and/or the right kind of vitamin C has to be used. But PH level below 4 is way too acidic for the skin. 

Solution: different derivates that you might run into when buying

1. L-ascorbic acid is the cheapest and most popular one you’re likely to see in your product ingredient list. That is why you want to read the back of products because they all are likely to say “contains vitamin C”. But not all Vitamin C serums are created equal
2. L-ascorbic acid is water soluble, very unstable cab can lose effectiveness in the presence of light, air and oxygen. To help it penetrate the stratum conrnium, the PH has to be lowed which means this is more likely to be irritating.
3. Adding phosphate group such as magnesium ascorbyl phosphate or sodium ascorbyl phosphate -which are stable, convert to Ascorbic Acid but slowly and they’re poorly absorbed through skin. If you are looking something mild, go for these derivatives
4. Derivatives containing lipid-soluble moieties Eg: palmitate, ascorbyl palmitate. This is an ester formed from ascorbic acid and palmitic acid creating a fat soluble form.

This is non-irritant and has shown increased uptake in animals, but there’s doubt about its conversion to L-Ascorbic acid effectively. Same here, if you have sensitive skin and want to start easy, buy products that have this derivative.

5. Ethyl ascorbic acid. This one has an ethyl group at the third carbon attached to vitamin C which makes the vitamin C very stable and soluble both in water and oil. It’s conversion to L-ascorbic acid is reported to be superior. If you’re more advanced in your journey and looking for some real stuff, this one is for you.

So there you can see products can say vitamin C but what’s really in them could be very different.

Now: How do you use it?

Vitamin C is an antioxidant that is protective against immediate effects of UV damage and improves the efficacy of sunscreen when layered underneath it. 

Inflammation in the skin The pathology underlying these conditions is complex and involves activation of auto-immune or allergic inflammation with associated generation of cytokines and cellular dysfunction, and consequent breakdown of the skin epidermal lipid barrier

AD patients lack several nutrients, including vitamin A and vitamin C.

Vitamin C can stimulate ceramide production in keratinocytes and improve overall epidermal barrier function 

One observational study1 , which included more than 4,000 women in the United States aged 40–74, suggested that a diet rich in vitamin C and linoleic acid (an omega-6 fatty acid found in nuts, seeds and vegetable oils) is associated with younger-looking skin 

A significant body of scientific research supports the use of cosmeceuticals containing vitamin C. Cutaneous benefits include promoting collagen synthesis, photoprotection from ultraviolet A and B, lightening hyperpigmentation, and improvement of a variety of inflammatory dermatoses.

REFERENCES

Farris, Patricia K. "Topical vitamin C: a useful agent for treating photoaging and other dermatologic conditions." Dermatologic surgery 31 (2005): 814-818.

Pullar, J. M., Carr, A. C., & Vissers, M. (2017). The roles of vitamin C in skin health. Nutrients, 9(8), 866.

Sauermann, Kirsten, et al. "Topically applied vitamin C increases the density of dermal papillae in aged human skin." BMC dermatology 4.1 (2004): 13.