References: 4 · Products compared: 3 · Status as of Oct 26, 2026
Jump to: What each label states · Using them together · The bottles · What this is not · Common questions
On this page
What each label states
Copper peptide serums on this site were ranked by disclosure, not by a result. NIOD states 1% GHK-Cu plus 1% GHK. COSRX states 0.5% copper peptide and names it as GHK-Cu. The Ordinary's copper serum puts "copper peptides 1%" in the name and lists GHK-Cu in the formula, without saying how much of that 1% is GHK-Cu. Peach & Lily states 0.2% copper peptide. Those figures, and the October 10, 2026 prices, stay on best copper peptide serums. This page did not reprice them.
The Ordinary's retinol page, opened for this check, says Retinol 0.5% in Squalane is a water-free serum containing 0.5% retinol. The ingredient list starts with squalane, caprylic/capric triglyceride, jojoba seed oil and retinol. The brand says it can improve the appearance of fine lines that can arise from a loss of collagen and elastin, and that squalane is there to help skin withstand the drying effects of retinol. The how-to says a few drops on the face in the evening, no other retinoid products, sun protection during the day, and refrigerate after opening. Patch testing is advised.
Ulta's page for the same serum listed $9.30 for the 1.0 oz size on October 26, 2026. The brand page lists 30 mL. This page does not convert one into the other, and it did not find a price on the brand page itself in the text captured that day. The US Amazon buy box for a single retinol bottle was not confirmed, so that serum has no Amazon button. COSRX The Blue Peptide serum was sold by COSRX on Amazon the same day, at $18.90, and that listing says not to use it with retinoids. Hair is a separate page: copper peptides for hair.
We did not find a published trial that compared these serums with each other, or a 0.5% retinol serum with a GHK-Cu serum. A percentage on a label tells you what the brand says is in the bottle. It does not prove a change in skin.
Skin-trial limits for GHK-Cu, including the small wound studies, are on the GHK-Cu profile and GHK-Cu side effects.
Using them in the same routine
We did not find reliable interaction data in the sources reviewed. That does not mean there are no interactions. The Ordinary's own copper serum page lists retinoids among the things not to combine with that serum. The retinol page repeats the ban on other retinoid products in the same routine. Ulta's how-to for the 0.5% serum also names "Buffet" + Copper Peptides 1% as a product not to use in the same routine.
COSRX's copper serum on the serum guide includes bakuchiol, which that brand markets beside retinol. If a bottle already contains a retinoid-like ingredient, the pairing question starts on that label, not with a second serum.
The bottles on this page
1. The Ordinary Retinol 0.5% in Squalane
0.5% retinol, 30 mL on the brand page
States the retinol percentage and the irritation caution
Brand page: a few drops in the evening, sun protection in the day, refrigerate after opening, do not use with other retinoid products.
- Water-free serum, 0.5% retinol, squalane in the base
- Brand caution: irritation, redness and peeling, especially around the eyes and mouth
- If irritation occurs, the brand says rinse, stop, and consult a physician
- Ulta price is $9.30 for 1.0 oz. The brand page lists 30 mL and did not show a price in the text we captured
$9.30 for 1.0 oz at Ulta, October 26, 2026
No Amazon button. The US buy box was not confirmed as Amazon.com or the brand.
2. The Ordinary copper peptide serum
Multi-Peptide + Copper Peptides 1%
Names 1% copper peptides, and says not to use it with retinoids
The name says 1% copper peptides. The brand does not say how much of that 1% is GHK-Cu. GHK-Cu is in the formula.
- Pairing warning includes retinoids, direct acids and direct vitamin C
- $32 for 30 mL is the October 10, 2026 figure on our serum guide
- NIOD states a cleaner GHK-Cu percentage, 1% GHK-Cu plus 1% GHK, on that same guide
- Not an injectable. Injectable GHK-Cu is not an approved drug
$32 for 30 mL on the serum guide, October 10, 2026
This page did not reprice it on October 26. No Amazon button. The copper listing stays off until the buy box is the brand or Amazon.com.
3. COSRX The Blue Peptide serum
Check Today's Price on AmazonAs an Amazon Associate, Straight Up Peptides earns from qualifying purchases.Copper peptide 0.5% and bakuchiol 0.25%
Amazon buy box sold by COSRX on October 26, 2026
The Amazon listing states copper peptide 0.5% and bakuchiol 0.25%, in 1.69 fl oz. The October 10 brand price on the serum guide was $27 for 50 mL. This page did not convert the sizes.
- Listing says patch test, and do not combine with retinoids
- Sold by COSRX, ships from Amazon, one-time price $18.90
- Cosmetic serum. No hair-growth trial is on this page
$18.90 on Amazon, sold by COSRX, October 26, 2026
Ships from Amazon. The listing says to avoid vitamin C, direct acids, or retinoids in the same routine. It is a face serum, not a hair treatment.
What this comparison is not
It is not a ranking of which serum "wins." The sort above follows what the label states, then the date we last saw a price. It is not a prescription retinoid. Tretinoin and adapalene are different products, and this page did not open their labels. It is not a license to buy an injectable copper peptide. Creams sold as cosmetics and vials sold for research are different records. The cosmetic status, the compounding lists, and the Health Canada recall are on is GHK-Cu FDA approved?.
The Ordinary sells the 0.5% retinol serum as a cosmetic, with appearance wording on the brand page. This page did not find an FDA drug approval for that bottle.
Common questions
Is a copper peptide serum better than retinol?
No published trial in our sources makes that comparison. The serum guide also found no trial of 1% GHK-Cu against 0.2%.
Can I use copper peptides and retinol together?
The Ordinary says not to use its copper serum with retinoids, and not to use the 0.5% retinol serum with other retinoid products. We did not find a controlled study of the combination.
What does 0.5% on the retinol bottle mean?
The brand says the serum contains 0.5% retinol in a water-free squalane base. It also says that strength can irritate skin while tolerance builds.
What does the copper percentage mean?
NIOD states 1% GHK-Cu. The Ordinary's "1%" is copper peptides, and the brand does not break out the GHK-Cu share. Percentages and prices are on the serum guide. COSRX states 0.5% on the Amazon listing above. A hair-search page for the same cosmetics is copper peptides for hair.
Is this retinol serum FDA approved as a drug?
This page did not find a drug approval for The Ordinary Retinol 0.5% in Squalane. The brand sells it as a cosmetic serum. Prescription retinoids were not part of this check.
Is injectable GHK-Cu the same as the serum?
No. The serum is a cosmetic. Injectable GHK-Cu is not FDA approved. The file is is GHK-Cu FDA approved?.
Sources, methodology, and changes
Methodology. On October 26, 2026 we opened The Ordinary's US page for Retinol 0.5% in Squalane and Ulta's listing for the 1.0 oz size. Copper serum percentages and the October 10 prices are carried from our serum guide, which opened the brand pages that day. The same day the Amazon buy box for COSRX The Blue Peptide serum, ASIN B0GWPQ7FS4, was sold by COSRX at $18.90. The Ordinary retinol and copper buy boxes were not confirmed as Amazon.com or the brand, so those two have no button. We did not run a test on skin. No injectable seller is linked.
Primary sources.
- The Ordinary, Retinol 0.5% in Squalane: https://theordinary.com/en-us/retinol-05-in-squalane-serum-100440.html
- Ulta, The Ordinary Retinol 0.5% in Squalane, 1.0 oz, $9.30 on October 26, 2026: https://www.ulta.com/p/retinol-05-in-squalane-intermediate-retinol-serum-pimprod2007127
- The Ordinary, Multi-Peptide + Copper Peptides 1% Serum: https://theordinary.com/en-us/multi-peptide-copper-peptides-1-serum-100625.html
- Straight Up Peptides, best copper peptide serums, status October 10, 2026
- Straight Up Peptides, GHK-Cu profile and is GHK-Cu FDA approved?
Changes. October 26, 2026: first published.
