Retinol and vitamin C are two of the most powerful ingredients for your skin. Both are known to fight wrinkles, build collagen and fade dark spots and pigmentation.
But fitting them into your skincare routine can be tricky. Should you layer one on top of the other, or will that inactivate them? Which one goes on first? And what about mixing them together?
In this tutorial, you will learn:
- Why you need to consider pH and solubility
- What happens when you mix retinol and vitamin C together
- The right way to use retinol and vitamin C in your skincare routine
- The best retinol and vitamin C products to try
Retinol vs Vitamin C pH
If you're thinking about using retinol and vitamin C at the same time, the first thing you need to check is their pH levels.
All skincare products that are water-based (aqueous) have been formulated to work at a certain pH.
- Retinol typically has a pH between 5.0 and 6.0, as research has shown that's where it operates best. The same goes for retinaldehyde and retinyl esters.
- L-ascorbic acid, the active form of vitamin C, needs to be at pH 3.5 or lower in order to effectively penetrate your skin (as this study proves).
However, there's another category of vitamin C out there—vitamin C derivatives. These are less potent than L-ascorbic acid, but more stable, with varying pH levels.
- Neutral vitamin C derivatives include ascorbyl glucoside, ascorbyl tetraisopalmitate, magnesium ascorbyl phosphate and sodium ascorbyl phosphate, which are all in the 6.0 to 7.0 pH range.
- Acidic vitamin C derivatives are ascorbyl methasilanol pectinate (pH 3.5), ethyl ascorbic acid (pH 4.0 to 5.5) and glyceryl ascorbate (pH 3.0 to 5.0). So these are not quite as acidic as L-ascorbic acid.
Skincare products that don't contain water (anhydrous solutions) don't have a pH.
Retinol vs Vitamin C Solubility
The next thing to think about is whether the ingredients are oil-soluble or water-soluble.
- Retinol is oil-soluble, so it will only dissolve in oil (although it can be encapsulated within a water-based solution).
- L-ascorbic acid is water-soluble, so it will only dissolve in water.
- Vitamin C derivatives are usually water-soluble. The exceptions are ascorbyl tetraisopalmitate (which is soluble in oil) and ethyl ascorbic acid (which is both water-soluble and oil-soluble).
What Happens When You Mix Retinol with Vitamin C
Now that you're familiar with the differences between retinol and vitamin C, let's consider what happens when you use them at the same time or mix them together:
Their pH levels will change: Remember that retinol and L-ascorbic acid have a big gap in pH. So using them together will lower the retinol's pH and raise the vitamin C's pH. We know this can make retinol less active and inhibits vitamin C’s ability to get into the skin. Essentially, they will both become less effective! However, this isn't a concern with the neutral vitamin C derivatives.
They may not dissolve or penetrate: Oil and water don't mix. So if you're adding a water-soluble vitamin C into an oil-based retinol, it will not dissolve. That means it won't penetrate your skin, and you won't get any of the vitamin C's benefits. Another thing to keep in mind is that oils can create a barrier on the skin that blocks the absorption of water-based products.
The Right Way to Apply Retinol and Vitamin C
Fortunately, there IS a way to incorporate both vitamin C and retinol in your skincare routine. You've got four options:
Vitamin C in the Morning, Retinol at Night
Your easiest course of action is to separate vitamin C and retinol from each other and apply them at different times of day. This ensures that each ingredient can work at its correct pH.
Products to try:
- SkinCeuticals C E Ferulic, Drunk Elephant C-Firma Day Serum and Paula's Choice C15 Super Booster all have a 15 percent concentration of L-ascorbic acid.
- Timeless 20% C + E + Ferulic Acid Serum contains the highest concentration of L-ascorbic acid, at 20 percent.
- Drunk Elephant A-Passioni, Lixirskin Night Switch Retinol 1%, Dermalogica Overnight Retinol Repair 1% and The Ordinary Retinol 1% in Squalane are retinol treatments with a high one percent concentration.
Vitamin C and Retinol on Alternate Nights
Most dermatologists believe that retinol should always be applied at night, away from UV light. But did you know you can apply vitamin C at night, too? This study found that DNA damage continues for hours after exposure to UV light, and suggests it could be prevented with a nightly antioxidant, like vitamin C.
By using retinol and vitamin C on alternate nights, you'll get the benefits of both, without having to worry about interactions.
Products to try:
- True Botanicals Vitamin C Booster, The Ordinary 100% L-Ascorbic Acid Powder, Good Molecules Vitamin C Booster Powder and Philosophy Turbo Booster C Powder are all L-ascorbic acid powders that you can mix with water or hydrating serums.
- Arcona Advanced "A" Serum and Avène TriAcneal Night Smoothing Lotion are retinaldehyde treatments (so they're similar to retinol, but possibly even more effective).
Wait 30 Minutes in Between Vitamin C and Retinol
If you must use retinol and L-ascorbic acid at the same time, separate them by 30 minutes. Apply your vitamin C first, since it has the lower pH of the two. Then, wait half an hour before you apply your retinol. Incorporating the waiting period allows your skin's pH to return to normal, so each ingredient can work at its intended pH.
This is also applicable to the vitamin C derivatives ascorbyl methasilanol pectinate, ethyl ascorbic acid and glyceryl ascorbate, since they are usually acidic.
Products to try:
- Dr. Dennis Gross Clinical Grade IPL Dark Spot Correcting Serum features 10 percent L-ascorbic acid.
- Dermadoctor Kakadu C 20% Vitamin C Serum with Ferulic Acid & Vitamin E is an ethyl ascorbic acid serum.
- Dermalogica BioLumin-C Serum contains ascorbyl methasilanol pectinate.
- A313 Vitamin A Pommade and Shani Darden Retinol Reform are surprisingly strong, even though they're made with retinyl esters such as retinyl propionate.
Vitamin C Derivative and Retinol Together
If you don't have time to wait 30 minutes, your bet bet is a vitamin C derivative. Be sure to choose one with a neutral pH, such as ascorbyl glucoside, ascorbyl tetraisopalmitate, magnesium ascorbyl phosphate or sodium ascorbyl phosphate.
Since these forms of vitamin C are close in pH to retinol, it doesn't really matter which one you apply first. Go with whichever one has the lighter texture (keeping in mind that thin, watery products should be applied before thicker emulsions). As soon as the first one absorbs, you can apply the second ingredient and skip the waiting period altogether.
But what if your vitamin C is anhydrous (water-free)? Anhydrous vitamin C solutions typically include oils, silicones or oily solvents, so retinol probably won't be able to penetrate well through them. In this case, I'd apply the retinol first. You can also use them at different times of day or on alternating nights.
Products to try:
- Mad Hippie Vitamin C Serum, Omorovicza Daily Vitamin C Serum, Derma E Vitamin C Concentrated Serum and Skin Design London C Antioxidant Glow all contain sodium ascorbyl phosphate, which is good for brightening, fading pigmentation and even treating acne.
- Skin Inc Supplement Bar Vitamin C Serum, Youth To The People Superfood Firm and Brighten Serum and Glossier Super Glow have magnesium ascorbyl phosphate, which brightens, fades dark spots and boosts collagen production.
- Tatcha Violet-C Brightening Serum, Joanna Vargas Rescue Serum and Sunday Riley C.E.O. 15% Vitamin C Brightening Serum feature ascorbyl tetraisopalmitate (tetrahexadecyl ascorbate), which treats dull skin and pigmentation while it builds collagen.
- The Ordinary Ascorbyl Glucoside Solution 12% is made with ascorbyl glucoside, which is best for boosting radiance and evening out skin tone.
- The Ordinary Ethylated Ascorbic Acid 15% Solution, Hylamide C25 Stabilized Vitamin C Booster and NIOD Ethylated L-Ascorbic Acid 30% Network are all vitamin C derivatives in water-free solutions.
I hope this helps you make the most out of retinol and vitamin C in your skincare routine!
Does your skincare routine include retinol and vitamin C?
How do you prefer to use them?