When Kiehl’s launched 1cc CollaShot Plumping Serum ($55 for 30 mL; $78 for 50 mL) this summer, the brand called it a serum designed for the skin changes that can follow GLP-1 weight loss. Now, there’s real-world data on how the powerful pink formula performs outside the lab.
In a post-campaign survey of NewBeauty BeautyPass members, conducted the first week of October, 998 people who received the serum through Free Gift Friday and used it reported their results. On a five-star scale, they gave it an average of 4.3. Of those testers, 85.4 percent rated it four or five stars, and 62.6 percent said it works better than similar products on the market.
Rapid weight loss, which is common among people taking GLP-1 medications for weight management, can bring visible changes to the face: deflated cheeks, loss of elasticity and thinner-looking skin. Most plumping serums rely on hyaluronic acid to draw water into the skin’s surface. CollaShot takes a different approach.
The formula centers on recombinant collagen polypeptides, which are biosynthetic collagen fragments, delivered in supra-liposomes that Kiehl’s says are engineered to penetrate 10 layers of skin. It also contains rhamnose, which targets visible signs of aging linked to collagen loss, and vitamin B12, a vegan colorant that gives the gel its pink tint. The “1cc” in the name refers to the recommended daily dose: two pumps, twice a day.
“Collagen is the main structural protein in the dermis and plays a critical role in maintaining skin firmness,” says Dr. Jane Yoo, a dermatologist and Kiehl’s brand partner. She notes that the serum “won’t replace injectables, but it helps the skin stay resilient through the changes GLP-1 patients are experiencing.”
Kiehl’s clinical testing included consumers prescribed a GLP-1 for weight management. In that group, cheek sagging improved by 22 percent at eight weeks. Across testers, skin plumpness improved threefold over the same period. In the brand’s consumer study, 94 percent said their skin looked more radiant, 93 percent said it looked plumper and 90 percent said their facial contours looked more defined.
The BeautyPass survey reached a largely new audience: 66 percent of respondents had never heard of the serum before it arrived through Free Gift Friday. Of those who had, social media was the most common source, at 12.2 percent.
Among the 998 respondents:
- 49.8 percent gave it a perfect five stars, the most common rating. Only 2.1 percent rated it one or two stars.
- 62.6 percent said it performs better than similar serums (25.9 percent “much better”). Only 1.2 percent said it was worse.
- 61.3 percent said there was nothing unappealing about it. The most common complaint was price, at 16.2 percent.
- Ease of use (48.5 percent), effectiveness (45.8 percent), Kiehl’s reputation (44.6 percent) and texture (43.4 percent) were the most frequently cited appealing features.
- 70.1 percent said they were likely or very likely to buy it again.
- 67.8 percent rated their likelihood to recommend it an 8 to 10 out of 10. A perfect 10 was the most common score, at 36 percent.
Many testers singled out the texture and the overnight results. “It sinks into my skin instead of sitting on top of it, and it doesn’t interfere with my makeup,” wrote Melissa T., 45–54. “When I use it at night, my skin looks fuller and more hydrated in the morning.”
“I’m a 77-year-old woman with dry skin. CollaShot is an absolute wonder,” wrote Diane B. “It has really made a difference in my skin’s texture and plumpness.”
Cassie H., 35–44, said the “lightweight and bouncy” gel “sinks in quickly without feeling sticky or heavy” and “wears beautifully under my cream makeup without pilling.” Aura R., 45–54, said she owns roughly 100 serums but uses only about five a day, and CollaShot “always makes its way into my top five.”
Skin-care products marketed for GLP-1 users are a growing category. CollaShot stands out because the brand tested it on GLP-1 patients and because it uses biosynthetic collagen with a delivery system meant to reach below the skin’s surface. The survey results suggest its appeal goes beyond that group: the testers quoted here range from their 30s to their 70s, with dry, oily, normal and combination skin, and all of them rated it five stars.
Kiehl’s recommends applying it morning and night and says clinical results were measured over eight to 12 weeks of twice-daily use. The brand positions it as a complement to in-office treatments, not a replacement for them.
Methodology: NewBeauty BeautyPass Free Gift Friday post-campaign survey, fielded October 1, 2026, by SMS to 1,200 members who received the serum. N = 998 members who tried the product.
