What Not to Use with Vitamin C or Niacinamide

You're building a smart routine — but are your ingredients playing nice?

Vitamin C and Niacinamide are both amazing for your skin, but when mixed with the wrong products, they can cause irritation or reduce results. In this guide, we'll walk you through what not to pair with each one — and what to use instead.

What Should You Not Mix with Vitamin C?

🛑 Avoid pairing Vitamin C with:

AHAs/BHAs (like glycolic or salicylic acid)

Reason: Too much acidity can irritate and destabilize Vitamin C, reducing its effectiveness and potentially causing redness.

Fix: Use acids at night and Vitamin C in the morning for maximum benefits without irritation.

Retinol

Reason: Both are active, pH-sensitive ingredients that can cause redness and irritation when layered together, especially for sensitive Indian skin.

Fix: Use Vitamin C in the AM for protection, Retinol at night for repair.

Benzoyl Peroxide

Reason: It can oxidize and cancel out Vitamin C's brightening and antioxidant effects.

Fix: Use them in different routines or on alternate days to maintain effectiveness.

✅ Safe to pair with Vitamin C:

Niacinamide (if layered right – see our Layering Guide)
Moisturizers and sunscreen
Hyaluronic acid
Gentle cleansers

What Should You Not Mix with Niacinamide?

Niacinamide is more flexible than most actives, but still, avoid:

Pure Vitamin C (L-Ascorbic Acid) - The Old Myth

Reason: Old studies said it may cancel out or react with niacinamide — but modern research shows it's fine if layered correctly with quality formulations like ROI's.

👉 See our guide: Can You Use Both Together?

Strong Acids at the Same Time

Reason: Low pH acids like AHAs can potentially irritate when mixed directly with niacinamide in the same application.

Fix: Alternate days or use acids at night, niacinamide in the morning.

Overuse with Multiple Exfoliants

Reason: Too many actives = barrier damage. Niacinamide repairs your skin barrier — don't overload it with harsh exfoliants.

Fix: Keep it simple with niacinamide as your main active, especially in India's challenging climate.

✅ Safe to pair with Niacinamide:

Moisturizers and hydrating ingredients
Hyaluronic acid for extra hydration
Vitamin C (if timed right)
Sunscreen for daily protection
Gentle cleansers

How to Safely Build Your Routine

🕐 Keep it simple. Here's a safe daily routine with both ROI serums:

AM: Cleanser → Vitamin C → Moisturizer → SPF

PM: Cleanser → Niacinamide → Moisturizer

Need help starting out? Try our guide: 👉 Can You Use Vitamin C and Niacinamide Every Day?

Why ROI's Formulations Are Different

Our Korean clinical serums are specifically formulated to work well together:

pH-optimized: Both Vitamin C and Niacinamide are formulated at skin-friendly pH levels
Stable formulations: Less likely to react or cause irritation
Gentle yet effective: Perfect for sensitive Indian skin
Tested compatibility: Designed to layer safely when used correctly