Kiehl's 1cc CollaShot Plumping Serum

By Dr. Kelly Killeen, MD FACS · Board-Certified Plastic Surgeon · Published August 2, 2026

I did find that my skin felt and looked more plump and hydrated when I was using it regularly for the last six weeks. It followed through with its claims and I got a nice result from it. Reasonably priced for a peptide serum.

8

out of 10

Brand

Kiehl's

Price

$78 · 1 fl oz (30 mL)

Where to Buy

Sephora

Key Ingredients

Collagen Polypeptides, Vitamin B12, Rhamnose

Pros

+

Skin looked and felt more plump and hydrated after six weeks

+

Absorbs nicely with no pilling, a common peptide serum problem

+

Does not interfere with absorption of other layered products

+

Tested on GLP-1 users, about 22% cheek laxity firming at two weeks

+

Pump dispenses all the product, nothing wasted in the bottle

+

Reasonably priced for a peptide serum at $78

+

Vitamin B12 gives the natural pink color rather than added dye

Cons

Brand new launch, so little independent long-term feedback yet

At $78 it is still an investment, even if fair for the category

A serum, not a substitute for in-office treatments

Bottom of the Jar Review: Kiehl's 1cc CollaShot Plumping Serum

Disclosure: this product was gifted to me by Kiehl's. As always, this is a bottom of the jar review, meaning I used the entire bottle before giving you my honest opinion.

This one is genuinely hot off the press. The Kiehl's 1cc CollaShot Plumping Serum launched about three days ago, but Kiehl's sent it to me about a month and a half ago. So I've been using it for six weeks and finished the bottle just in time to review it at launch.

What Is It?

It's a serum marketed to increase collagen production and plump the skin. Kiehl's has some decent before and afters on their site, which I don't always say.

Price: $78 for 1 fl oz (30 mL).

The Hero Ingredients

The three actives Kiehl's advertises:

  • Collagen peptides (collagen polypeptides), the headline ingredient
  • Vitamin B12
  • Rhamnose, which targets visible signs of collagen loss like wrinkles and loss of firmness

A fun detail I didn't know until I looked into it: the vitamin B12 is what gives the serum its natural pink color. So that pink tint isn't dye, it's the ingredient itself.

The GLP-1 Data Is Genuinely Interesting

Here's the part that caught my attention most. Kiehl's actually tested this product on GLP-1 users. In that testing, GLP-1 users saw roughly 22% firming or tightening of cheek laxity after two weeks of consistent use.

That's a notably specific population to study, and given how many patients are on GLP-1 medications right now and dealing with facial volume and laxity changes, it's a smart thing to have tested. I appreciate a brand that bothers to study the group most likely to need the result.

How It Feels and Wears

The texture and formulation were a genuine strength:

  • A pink, mid-weight serum
  • Absorbs nicely into the skin
  • No pilling, which is my usual complaint with peptide serums
  • No interference with absorption of my other products layered over it

It comes in a nice glass component with a pump. And a small thing that matters enormously in a bottom of the jar review: the pump got all of the product out of the bottle. No prying the top off to scrape the last week of serum out, which I have absolutely done with other products.

Did It Work?

Yes, within reason. I did find that my skin felt and looked more plump and hydrated while I was using it consistently over those six weeks.

I want to be measured here, this is not a filler substitute and it isn't going to replace what an in-office treatment does. But it followed through on its claims, and I got a nice result from it, which is more than I can say for a lot of serums in this category.

The Bottom Line

Rating: 8/10.

  • Plumper, more hydrated-looking skin after six weeks of consistent use
  • Collagen peptides, vitamin B12, and rhamnose, with the B12 giving it that pink color
  • Tested on GLP-1 users, about 22% cheek laxity firming at two weeks, a genuinely relevant population to study
  • Great texture: absorbs well, no pilling, plays nicely with other products
  • The pump empties the bottle, which I always appreciate
  • Reasonably priced for a peptide serum at $78
  • It's brand new, so there isn't much independent long-term feedback out there yet

It followed through on what it promised and I liked it. If you're in the market for a peptide serum, give it a try.

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