I am not what you would call a skincare minimalist, but I am certainly not a maximalist either. I like to keep my morning and nighttime regimens as consistent as possible, switching out just one product at a time to get a sense of its effect. That being said, I have worked up quite a familiarity with skincare products and a multi-step regimen to rival the greats. Choosing what to try next has a kid-in-a-candy-store like effect on me as I blank-stare at my top shelf with a mix of wonder and overwhelm. 

So, how did I decide to reach for Clinical Skin Polypeptide Firming Serum, $250? It was when double board-certified dermatologist Karan Lal, DO, FAAD announced the serum "can replace two to three products in a regimen."

The serum was designed to target skin laxity that develops as the skin cells' natural production of collagen and elastin slows, and the structural proteins break down, with age, beginning in the early-to-mid twenties. Potent enough to be used as a standalone treatment, it is also gentle enough to be worked into an existing regimen of products. In fact, the line's co-founder and CMA, Ewelina Aiossa calls it their "hero product," noting that it was also designed to prolong the effects of cosmetic treatments.

I am a total ingredient nerd and wanted to learn more about how the formula worked. As New York-based, board-certified dermatologist Joshua Zeichner, MD, puts it, "Peptides are messengers that tell skin cells to perform a specific action. The peptides in the Clinical Skin Polypeptide Firming Serum boost collagen and elastin levels to strengthen the skin's foundation." Specifically, palmitoyl tripeptide-28 and copper peptides stimulate collagen and elastin, Argireline softens fine lines due to overactive muscle use, and Matrixyl peptide helps to maintain skin integrity. Dr. Zeichner points out that peptides make a great option for sensitive skin because they "address sagging skin without irritation." 

The brand's incorporation of four different forms of barrier-supportive ceramides (i.e., Ceramide AP, EOP, NP, and NG AKA Ceramides 2, 3, 6, and 9), reparative cholesterol, and hyaluronic acid make it an even gentler ride for the dermis. "Think of ceramides like the grout that fills in the cracks between skin cells to keep the skin barrier in the best shape possible," he says. They are a great class of active for dry, sensitive, and reactive skin types because they aid the skin barrier in its functions of keeping moisture in while protecting against potentially-irritating environmental aggressors. But to be frank, they are also ideal for dry weather and anyone with anti-aging or prejuvenation on their agenda — they have been a longtime K-Beauty staple ingredient for this exact reason.

At first glance, I was puzzled by the incorporation of vitamin C (in the form of ascorbic acid) along with copper peptides, having learned that the two active ingredients did not mix well together when in the same formula. However, it turns out that my intel was outdated.

Clean cosmetic chemist Krupa Koestline, founder of KKT Consultants, clarified the issue for me. While she acknowledges a very old paper showing an adverse interaction, she states: "It is very much dependent on the formula composition whether there is a potential interaction [between ascorbic acid and copper peptides]." She explains that that initial paper showed that copper peptides increased the oxidation of vitamin C in vitro, but subsequent animal models showed no effect while electrolytes (like salt) reduced their interaction altogether. In other words, this serum is stable for use, and Dr. Zeicher even notes that it can be layered with an additional vitamin C serum in the daytime.

To shop: $250; clinicalskin.com

Dr. Zeichner's point about the serum's sensitive skin-friendliness is definitely true. I have been using the lightweight, non-greasy serum for several weeks now during a time of heightened skin sensitivity with absolutely zero adverse reaction. My complexion's sensitivity stems from a series of treatments with the anti-acne AviClear laser, which targets the skin's oil glands to result in fewer breakouts. My treatment has been successful, it initially resulted in such dryness that I had to discontinue the use of my retinol, opting for my most-nourishing and hydrating ingredients in the meantime. In order to get that boost of anti-aging, elasticity-promoting ingredients, I called upon the peptides in this serum and a non-sensitizing newcomer, Fibroquin, found in the Revela Fibroquin Essence. 

As for the dryness, ceramides — key components of the brand's A.C.E. Complex — are among my go-to's whenever my skin is feeling extra sensitive, dry, and in need of some barrier repair. Part of a sub-group of lipids called sphingolipids, they are known for being pricy but are worth it as dry skin "is almost always because of a loss of ceramides in the skin," according to Aiossa. Along with lipids like cholesterol and the hydrophilic molecule hyaluronic acid, the serum thus helps with added hydration and moisture-retention. 

To bolster and get an additional boost of ceramides, I looked to two luxury skincare products I adore featuring the class of ingredient: my favorite eye cream of all time, Orveda Eye Unveiler 422, $255, and the new Eighth Day Intensive Moisturizer, $290. (For more affordable alternatives, I like the Dr. Jart+ Ceramidin Eye Cream, $40, and Kiehl's Ultra Facial Advanced Repair Barrier Cream, $48.) To seal it all in, I am always a fan of a good nighttime slugging with a green balm like — which essentially means locking all the actives in with an occlusive layer that prevents overnight transepidermal water loss.

The Splurge is our recurring column dedicated to expensive beauty products that are worth it. This week, why we're rebuying Clinical Skin's Polypeptide Firming Serum despite the $250 price tag.