Not in the same routine. Layering vitamin C with AHAs (such as glycolic acid) or BHAs (such as salicylic acid) can lower the skin's pH, which may cause irritation, redness and peeling. Use vitamin C in the morning and AHAs or BHAs in the evening.
That is the guidance for the morning person Stem-C Vitamin C Brightening Serum with Ferulic Acid, and it is the simplest way to build a routine around any vitamin C serum.
Why shouldn't vitamin C and acids be layered together?
AHAs and BHAs are exfoliating acids. Vitamin C is an antioxidant. Applied one on top of the other, they can lower the skin's pH, and that is what may lead to irritation, redness and peeling. Splitting them across the day gives each one its own time.
What does a morning and night split look like?
| Morning | Evening | |
|---|---|---|
| Step 1 | Cleanse | Cleanse |
| Step 2 | Vitamin C serum | Your AHA or BHA |
| Step 3 | Mineral SPF 50+ moisturizer | Moisturizer |
The morning side is the three-step routine from morning person: the Antioxidant Plant Protein Face Cleanser, the Stem-C Vitamin C Serum and the Daily Repair Moisturizer with Mineral SPF 50+. The cleanser can be used morning and night.
Does vitamin C need sunscreen on top?
Yes. Vitamin C may increase sun sensitivity, so pair it with a broad-spectrum SPF of at least 30. The morning person Daily Repair Moisturizer has mineral SPF 50+ with 12% non-nano zinc oxide, and it works as your moisturizer, too. Reapply at least every 2 hours.
What kind of vitamin C is in the serum?
The Stem-C serum uses 5% Sodium Ascorbyl Phosphate, described on the product page as the top clinical concentration for this gentler, more stable form of vitamin C. It fades dark spots and uneven tone without the irritation of traditional L-ascorbic acid. For more on the two forms, see Sodium Ascorbyl Phosphate vs L-Ascorbic Acid.
A gentler form of vitamin C does not change the rule. Keep acids for the evening.
What does Ferulic Acid add?
Ferulic Acid reduces the appearance of dark spots, hyperpigmentation and uneven skin tone by inhibiting melanin production. Combined with vitamins C and E, it enhances their effectiveness. Read more in Ferulic Acid for Skin: Benefits, How It Works and How to Use It.
Frequently asked questions
Can I use vitamin C and AHA on alternate days instead?
The guidance above is a morning and evening split. If you want a different schedule, keep the same principle: don't layer them in one routine.
How long should I wait before moisturizer?
Wait until the serum has absorbed. The product page gives 5 to 10 minutes, depending on how fast it absorbs.
Is the serum gentle enough for sensitive skin?
Yes. Witch Hazel and Aloe Vera soothe and protect, which the product page gives as the reason it is gentle enough for sensitive skin. It is also fragrance-free.
How long does a bottle last?
45 to 60 days for the average daily user, about $0.75 to $1.00 a day.
How long until I see results?
Dark spots take 12 to 16 weeks and wrinkles 6 to 12 months. Consistency is key.
