Vitamin C for anti-aging: magic potion, or waste of money?

Intro

If you’re tuned in to trends in skin health, you’ve probably heard of vitamin C as a topical agent for anti-aging. Vitamin C, also known as ascorbic acid, is a potent anti-oxidant, and is thought to have anti-aging benefits.

As a “cosmeceutical,” ascorbic acid is an easy pitch for industry marketers. In a society that is hyper-focused on eternal youth, most people would pay good money for the mere possibility of reversing skin aging. But just how much of this is based in actual science versus marketing hype from the skincare industry?

What is ascorbic acid?

Ascorbic acid is a powerful antioxidant in human skin, and has multiple active forms. Of these, L-ascorbic acid is the most biologically active and the best studied. Humans are unable to synthesize vitamin C, because we lack a specific enzyme. Therefore, we must take it externally, in the form of fruits/vegetables, supplements, or – the primary focus of this article – as a topical reagent.

Why does your skin need antioxidants?

External factors, like UV exposure and smoking, are known to accelerate the natural aging process of the skin. Oxidative stress, particularly from UV radiation, leads to the production of “free radicals.” Free radicals are highly unstable, or in other words, highly reactive. The production of free-radicals begins a cascade of quick reactions that wreak havoc on otherwise-healthy cell membranes and proteins. On the macroscale, the result is more wrinkles and dark spots, due to decreased collagen production and increased melatonin production.

Antioxidants like ascorbic acid have the power to prevent oxidative stress, because they scavenge free radicals and halt the cascade of havoc-wreaking reactions.

Does vitamin C really work to reverse and prevent aging?

As usual, the answer is… it depends.
Although some clinical trials have already shown that vitamin C works through a variety of mechanisms to halt collagen breakdown, increase collagen production, and decrease melanin production, there are still some practical challenges.

The main challenge with vitamin C is finding a reliable delivery method. Ascorbic acid is a hydrophilic, or “water-loving” molecule. The outermost layer of our skin, known as the stratum corneum, is just the opposite – it’s hydrophobic. Think of oil and vinegar – slipping and sliding over each other, but not mixing: that’s what happens when you apply ascorbic acid to your skin.

Cosmetic chemists can try to mitigate this by coming up with formulations that increase skin permeability. For example, lowering the pH of the formulation converts ascorbic acid from its charged form to its uncharged form, so that it will more readily penetrate the skin barrier. Studies suggest that a good target is an acidic pH of 3.5 or lower, achieved through the addition of other acids to the formulation.

The stability of ascorbic acid is also an issue for formulation chemists. The same properties that make this molecule so desirable as an antioxidant also mean that it readily breaks down and becomes biologically useless. The half-life of ascorbic acid has been approximated to be about 20 days in a water-oil emulsion. That means that it takes only 20 days for half of the active ingredient to degrade.

One potential solution to this is to use stable, hydrophobic precursors of ascorbic acid. Not only are the precursors stable in your medicine cabinet, but because they’re hydrophobic, they can easily penetrate the skin barrier via simple diffusion. Once they’ve penetrated the skin surface, they release ascorbic acid thanks to enzymatic hydrolyzation. Clinical trials testing hydrophobic precursors have mixed results, but are worthy of further exploration.

The take-away

Vitamin C is already well-known for its anti-oxidant properties, and recent research suggests that topical use may help to increase collagen production while inhibiting collagen break-down, as well as inhibit melanin production to decrease hyperpigmentation, particularly from UV-exposure.

It’s easy to get excited about solutions for cosmetic woes like skin wrinkles and hyperpigmentation, especially when the solution is coming from a familiar, trusted chemical like vitamin C. However, remember that research is still in early stages. More clinical trials are needed to confirm the effects of vitamin C, and more tests are needed to develop optimally effective formulas.

Until then, vitamin C is a relatively low-risk high-reward action you can take towards improving skin appearance. Keep in mind that until formulations are optimized, there is a high likelihood you may be applying a degraded product, and/or a product that doesn’t make it past your outermost skin layer. For now, it seems the worst-case scenario is a bit of wasted money, and the best-case scenario is more youthful looking skin.

References

Al-Niaimi, Firas, and Nicole Yi Zhen Chiang. “Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications.” The Journal of clinical and aesthetic dermatology vol. 10,7 (2017): 14-17.

Boo, Yong Chool. “Ascorbic Acid (Vitamin C) as a Cosmeceutical to Increase Dermal Collagen for Skin Antiaging Purposes: Emerging Combination Therapies.” Antioxidants (Basel, Switzerland) vol. 11,9 1663. 26 Aug. 2022, doi:10.3390/antiox11091663

Pullar, Juliet M et al. “The Roles of Vitamin C in Skin Health.” Nutrients vol. 9,8 866. 12 Aug. 2017, doi:10.3390/nu9080866