Cosrx The 6 Peptide Skin Booster Serum – Review

I like keeping my skincare routine simple, but sometimes using the same products can feel a little boring. That’s why, even though I stick to a few trusted serums, I enjoy experimenting with toners and essences. For me, skincare is more than just results—it’s also self-care and should feel enjoyable Peptide Skin Booster Serum

After a recent no-buy period (which only turned me into a mini hoarder once it ended), one of the first products I treated myself to was the Cosrx The 6 Peptide Skin Booster Serum.

These days, many popular Korean brands, including Cosrx, have official storefronts on Amazon. At first, I was skeptical, but curiosity won out—and yes, the products are authentic. Plus, the convenience of next-day Prime delivery beats waiting weeks for international shipping.

I’ve now tested this serum for a while, and here are my thoughts.

First Impressions

Cosrx describes this serum as a peptide-powered booster designed to improve multiple skin concerns: pore control, oil balance, firmness, fine lines, texture, tone, and overall soothing. It’s meant to be the first step in your routine to prep and enhance everything that follows.

Ingredients & Formula

As a long-time Cosrx user, I’ve seen the brand evolve, and while it’s not my main skincare brand, I always keep at least one of their products in rotation. This serum caught my attention because I wanted to add more peptides to my routine.

The formula includes six peptides, each targeting a different concern:

• SH-Polypeptide-121 – Collagen boosting & plumping
• Copper Tripeptide-1 – Improves skin texture
• Dipeptide Diaminobutyroyl Benzylamide Diacetate – Controls excess sebum & pore care
• Oligopeptide-68 – Brightening effect
• Palmitoyl Tripeptide-8 – Reduces sensitivity & soothes skin
• Acetyl Hexapeptide-8 – Smooths fine lines & firms

Other notable ingredients:

• Niacinamide – brightening & barrier support
• Adenosine – anti-aging benefits
• Hyaluronic Acid – hydration
• NAG & Amino Acids – additional skin health support

As expected from Cosrx, the formula is fragrance-free and essential-oil free, making it suitable for all skin types.

Packaging, Texture & Consistency

This serum comes in a 150ml clear pump bottle, which makes it versatile:

• Multiple pumps work perfectly if you’re using it like a toner.
• A single pump feels just right when applying it as a serum.

The texture is lightweight and watery with a slight viscosity—making it feel more like a toner-serum hybrid than a traditional serum. It absorbs quickly, leaves no stickiness, and feels refreshing on the skin.

Price & Availability

• Size: 150ml
• Price: Around $25 / £18.90
• Value: Excellent—most peptide serums cost the same for just 30–50ml, so this larger size makes it a great deal.

My Experience

Here’s how I used it in my routine:

• Toner: Tir Tir Milk Skin Toner
• Essence: HaruHaru Wonder Black Rice Probiotic Barrier Essence
• Serum Step: Cosrx The 6 Peptide Skin Booster Serum

One thing to note: when layered directly after my toner and essence, it sometimes foams up slightly, so I wait a minute or two for my skin to dry before applying.

Performance

While I enjoy peptide products, I keep my expectations realistic—my gold standard for anti-aging will always be retinoids. Peptides, in my opinion, mostly function as hydrating and soothing agents, and this serum fits neatly into that category.

That said, I still enjoyed using it. It feels calming, lightweight, and hydrating, making it easy to incorporate without irritation.

Will I repurchase? Probably not right away, since I have many other products to finish. But if I’m ever in need of an affordable peptide serum, this would be on my list.

Final Thoughts

The Cosrx The 6 Peptide Skin Booster Serum is definitely worth trying if you’re looking to explore peptides without breaking the bank. It’s hydrating, gentle, and suitable for most skin types. Unless your skin barrier is severely compromised, it’s unlikely to cause issues.

Overall, it’s a solid addition to a skincare routine—especially if you value affordability and size.