What Not to Mix With Copper Peptides

Here’s the scoop. Keep copper peptides away from vitamin C, retinoids, exfoliating acids, and benzoyl peroxide. Niacinamide, hyaluronic acid, and other peptides are fine in the same routine.

Want it all sorted for you? The Routine Builder puts these rules into a morning and night plan for the products you own.

Quick answer

Product	Use with copper peptides?	Safe default
Vitamin C (L-ascorbic acid)	Keep apart	Vitamin C in the morning, copper peptides at night
Vitamin C derivatives	Keep apart to be safe	Same as vitamin C
Retinol or retinal	Advice differs	Different nights
Prescription retinoid	Ask your doctor	Keep your prescription schedule. Ask your doctor before adding copper peptides
AHA or BHA	Keep apart	Different nights or times of day
Benzoyl peroxide	Keep apart	Different times of day
Niacinamide	Yes	Same routine is fine
Hyaluronic acid	Yes	Same routine is fine
Other peptides	Yes	Same routine is fine

Vitamin C

Short version: use vitamin C in the morning and copper peptides at night. Pure vitamin C (L-ascorbic acid) is very acidic. The Ordinary, which makes a popular copper peptide serum, advises keeping the two in separate routines. In lab tests, copper ions speed up the breakdown of vitamin C. We found no study that tested these two together on skin, so think of this as a cautious default.

Vitamin C derivatives

Advice on vitamin C derivatives is pretty limited. The Ordinary says not to use its ethylated vitamin C with copper peptides. We found no study on other derivatives. Keeping them apart is the safer default.

So treat them like regular vitamin C. Morning for the vitamin C, night for the copper peptides.

Retinol and retinal

Use retinol and copper peptides on different nights. Both can make skin more sensitive, and The Ordinary recommends alternating them. Some experts also say a low pH can make copper peptides less stable. Plenty of people use copper peptides in the morning and retinol at night instead. Advice on this differs, and we found no study that tested these two together on skin.

Prescription retinoids

Ask your doctor before adding copper peptides if you use a prescription retinoid like tretinoin. Keep your prescription schedule as your doctor directed.

Advice on combining them differs. Some brands, like Evenskyn, suggest using copper peptides in the morning. Others, like The Ordinary, suggest using them on different days.

The Routine Builder leaves copper peptides out of your plan when you use a prescription retinoid. It never changes when or how often you use a prescription.

Vitamin C and retinoids

Use vitamin C in the morning and your retinoid at night. The American Academy of Dermatology recommends vitamin C in the morning before sunscreen and a retinoid before bed. A 2024 clinical review agrees. GoodRx gives the same advice. The Ordinary is more cautious and suggests not combining them. If your skin gets irritated, use them on different days and talk to a dermatologist.

AHA and BHA

Use exfoliating acids and copper peptides at different times of day, or on different days. That goes for AHAs like glycolic acid and BHAs like salicylic acid. These acids have a low pH, and The Ordinary says a low pH can raise the risk of peptides breaking down. We found no study that tested these together on skin.

Benzoyl peroxide

Use benzoyl peroxide and copper peptides at different times of day. FDA rules require benzoyl peroxide labels to warn that it can irritate skin, with redness, burning, itching, or peeling. Keeping your other products at a separate time is the cautious way to go. We found no study or official brand guidance on using these two together.

Benzoyl peroxide is an acne treatment, so follow the product’s directions or your doctor’s advice. The Routine Builder never changes when you use it. It puts copper peptides at the other time of day.

Niacinamide

Good news here! No conflict is known, so you can use niacinamide and copper peptides in the same routine. Niacinamide is not on The Ordinary’s list of products to avoid with its copper peptide serum. Copper peptides are not on the avoid list for its niacinamide serum either.

Hyaluronic acid

Easy one. Hyaluronic acid and copper peptides can go in the same routine. The Ordinary’s copper peptide serum already has hyaluronic acid in it.

Other peptides

Same deal for other peptides like Matrixyl and Argireline. They can go in the same routine as copper peptides, and The Ordinary’s copper peptide serum already contains them.