If you Google how to use Vitamin C you’ll likely find a mix of opinions. The goal here is to clarify and provide guidelines for you to get the most out of your Vitamin C serum. There’s constant innovation in the beauty industry, so while I would suggest these rules for almost all forms of Vitamin C there are exceptions.
For the sake of this post, the information is specific to L-Ascorbic Acid
Vitamin C is known for two key benefits: it functions as an antioxidant with the ability to protect skin from damaging free radicals ( the bad guys who age our skin, create sun damage, and break down collagen ), and aiding collagen and elastin production to fight wrinkles, ensuring even skin tone and texture.
While working on these culprits of aging it Vitamin C brightens skin tone, fades hyperpigmentation and age spots, and preventing future damage. The majority of Vitamin C formulations are marketed as antioxidant treatments to prevent free radical damage in the skin.
Rewind… how does Vitamin C work?
Antioxidant serums work to prevent oxidative strain caused by pollution and UV radiation we’re exposed to during the day, so they’re ideal for use under a sunscreen.
Think of it like this: you’re at a bar with your girlfriends and off in the corner you see a hot mess having a little too much fun, and the bouncer kicks the hot mess out. Antioxidants and Vitamin C are the bouncers in your skin kicking out free radicals.
Clusters of cells in your skin break down over time and environmental aggressors speed up the process. Instead of having a cluster of 100 healthy cells, 10 become damaged from free radicals and fall off. Your cell cluster continues to regenerate by copying its self, but now it’s damaged so this leads unwanted issues like hyperpigmentation, skin cancer, wrinkles, etc. If you’re using an antioxidant it will bind to the missing parts of the cluster and continue to regenerate as a normal, healthy cell. Which leads us to…
Stability of your Vitamin C serum is key. If it’s not stable it won’t be able to penetrate past the surface of your skin where it matters. I’m not a fan of DIY treatments or copycat budget formulas for this reason. It’s likely not passing through where it needs to to make the biggest impact on your skin.
Not all Vitamin C products are created equal, either. They need to fit within certain guidelines to remain stable, and even then many do not penetrate the stratum corneum. L-Ascorbic Acid needs to be under a pH of 3.5 with ingredients to aid in stability, commonly other antioxidants.
Some hold the belief that because of the instability of Vitamin C there’s no benefit in using one at all because as soon as it’s exposed to air and light they degrade. This couldn’t be further from the truth as stable, pH balanced formulas exist—you just won’t find them in your pantry or on Amazon for $25.
Should I apply Vitamin C morning or night?
Always apply Vitamin C in the morning! L-Ascorbic Acid based treatments are intended for daytime use because of their ability to neutralize free radicals. Using your serum at night isn’t necessary because it creates a reservoir that remains in the skin when used daily.
If your Vitamin C serum is suggested to be used in the evening it may use a form that isn’t stable for daytime. If you’re unsure use this rule: if your serum is advertised as an antioxidant, use it during the day; if it’s promoted as a collagen, anti-aging treatment use it in the evening.
What about skin regenerating at night and creating more collagen?
Vitamin C accumulates in the skin, so there’s no need to apply at night to aid in collagen production. Your skin can still create collagen during the day, it doesn’t stop working when you wake up in the morning. If you’re applying an antioxidant serum in the morning your skin is protected against photodamage caused by free radicals, preventing collagen breakdown. If your concern is collagen production I would suggest using Retinol in the evening instead.
What about using it morning AND night?
Your skin can absorb no more than 20% L-Ascorbic Acid within 24 hours. Unless there’s a small concentration of Vitamin C in your serum there is no reason to apply both AM and PM. If your serum contains more than 10% Vitamin C my concern is the manufacturer wants you to use up the serum quickly so you’ll repurchase sooner, or the formulation may not build up in the skin like it should and needs to be used more often for efficacy. Most quality products would be a waste to use twice a day.
But what about Vitamin C being destroyed by the atmosphere?
A serum stabilized by other antioxidants provides no reason for concern as they protect each other and your skin. L-Ascorbic Acid has shown to protect skin from UV-induced erythema, superficial redness in the skin, when paired with Vitamin E. This proves your serum is working continuously throughout the day without being destroyed.
How often should I use Vitamin C?
Every. Single. Day.
L-Ascorbic Acid optimally accumulates in your skin after 72 hours. In theory, this means you could use your serum every 2-3 days, but for best results, you would want to use it daily for optimum free radical protection. We’re exposed to free radicals every day unless you live in a bubble… but even then, UV rays would get into your bubble. Unless it was a UV-protective bubble….
What should I avoid?
You could use AHA, BHA, and Retinol but you might experience irritation. It’s best to use your Vitamin C in the morning and use your exfoliating treatments and Retinol at night. However, avoid Copper Peptides as their benefits are similar and cancel out the benefits entirely when used with Vitamin C.
How do I layer with other products?
Always cleanse, tone, apply serum, moisturize, and finish with your SPF. If you’re applying another serum in your routine your antioxidant should go first so it can properly protect your skin.