Peptides Are the Buzziest Skincare Ingredient on the Block—But Which One Is Right for You?
Here's the full breakdown from dermatologists and cosmetic chemists.
It feels a little ironic: peptides—short chains of amino acids —have existed in my body my entire life. Yet I've spent more time thinking, talking, and writing about them in the past six months than ever before. I'm hardly alone. According to Google Trends, searches for "peptides" have climbed 80 percent, while searches for "what is a peptide" are up 70 percent.
The fascination makes sense. In a matter of months, topical peptides have gone from cosmetic chemistry insider speak to skincare's most talked-about ingredient. YSE Beauty launched its Dewy Peptide Serum in March. Dr. Barbara Sturm followed in April. CosRx released one in May, and Remedy announced its own this week. They're suddenly everywhere—but ask what peptides actually do, and the answer is surprisingly murky.
That's because "peptides" isn't a single ingredient in the way hyaluronic acid or niacinamide are. It's an entire category of molecules, each with a different job. Some help support collagen production, others improve hydration or strengthen the skin barrier, while certain peptide blends are marketed for their wrinkle-smoothing, Botox-in-a-bottle effects. The benefits depend entirely on which peptides you're using.
In other words, not all peptides are created equal. Knowing the difference can help you choose the right formula—or decide whether stacking your peptide serums makes sense for your routine. To sift through the science, I spoke with cosmetic chemists to break down what peptides are, how they work, and which ones are actually worth paying attention to.
What Are Peptides?
The short answer: “Peptides are short chains of amino acids, the same building blocks your skin already uses to make collagen and elastin,” explains Susie Wang, chemist and founder of 100% Pure. The long answer: Peptides are pretty nuanced and serve as an umbrella term for many different molecules with a range of skincare benefits. “Some are for firming, some are for brightening, and some are for antimicrobial or anti-inflammatory benefits,” explains cosmetic chemist Ginger King.
Regardless of the intended benefit, peptides function like messengers. When applied topically, they sink into your skin and bind to their respective receptors, signaling your skin to amp up cell turnover, plumping, or glow.
The key differentiating factor between peptides and other anti-aging actives like retinol, alpha-hydroxy acids, or beta-hydroxy acids is that peptides are much gentler and more well-tolerated overall. “They don’t exfoliate or force turnover, but support the skin’s own machinery,” explains Wang. “They’re one of the few high-performance actives you can hand to sensitive skin without hesitation.”
Where Do Peptides Come From?
Because peptides are naturally occurring in your body, most cosmetic peptides are engineered in a lab to be biomimetic, which means they mimic those that already exist in your physiology. This way, once you apply your skincare product, your skin cells will respond immediately—knowing exactly which receptors to target. It’s a work-smarter-not-harder mentality. That said, some brands also prioritize sourcing their peptides from natural sources. They can be derived from everything from plants to quinoa.
Are Topical Peptides Different Than Injectable Peptides?
Despite having the same name, topical and injectable peptides are very different both in their delivery and safety. “Topical peptides act like messengers by triggering cells to produce more collagen and elastin, or soothe and calm and repair the skin’s barrier. Injectable peptides, on the other hand, bypass the skin and go directly into your bloodstream, which can affect the metabolism of the entire body—not just the skin,” says cosmetic chemist Ron Robinson. There’s an obvious trade-off. Injectables have a more full-body, faster-acting effect, while topicals are limited to your skin and take time to work.
Peptides are one of the few high-performance actives you can hand to sensitive skin without hesitation.
Susie Wang, cosmetic chemist
As far as safety is concerned? “Topicals are safe for daily use and integrate into a routine without downtime,” says Wang. Injectable peptides, on the other hand, are a bit of the Wild Wild West. “They have a higher risk from a safety perspective and are unregulated,” says Robinson. While a physician can prescribe certain injectable formulas, there is little FDA regulation, and improper use can lead to serious side effects.
Take, for example, CHK-cu, which is used for skin repair, wound healing, and collagen and hair follicle support. Used topically, it’s generally well tolerated, with the worst side effects limited to some redness or irritation. However, the injectable form of the peptide is much more unwieldy. It’s understudied and not FDA-approved. In fact, until April 23, 2026, CHK-cu, along with six other peptides, was on the FDA’s no-compound list due to insufficient research and safety data. (Note: Its ability to be compounded is being reevaluated at an FDA panel held on July 23-24.)
What Are the Different Types of Peptides in Skincare?
Peptides are a category, not an ingredient. Think of it similarly to the antioxidant family, which encompasses vitamin C, vitamin E, niacinamide, ferulic acid, and so on and so forth. “Not all peptides are equal, and the type dictates the benefit,” says Wang. “So when someone asks 'should I use a peptide serum,' the real question is which peptide, for what goal?”
While there are dozens of peptides, they can be grouped into four families.
Signal Peptides
Chances are, at least one of your skincare products contains a signal peptide. The short of the long: they tell the skin to produce more collagen and elastin. “They’re your firming and smoothing workhorses,” says Wang. Matrixyl, otherwise called palmitoyl pentapeptide, is one of the most studied ingredients on the market. Acetyl Tetrapeptide-2, Decapeptide-4, Tripeptide-1, and Hexapeptide-3 are also popular. “It’s a workhorse for an anti-aging routine and well-tolerated across skin types,” says Wang.
Carrier Peptides
Ever heard of copper peptides? It’s the most popular in the carrier peptide family and probably the one your dermatologist loves the most. Its goal: “These deliver trace minerals that support wound healing and collagen synthesis,” says Wang, making it ideal for those with a compromised skin barrier, mature skin, or those dealing with post-procedure skin. If you’re scanning a label, it’ll often be depicted as Copper Tripeptide-1 or GHK-Cu, says Robinson.
Enzyme-Inhibiting Peptides
If you’re trying to minimize the look of crow’s feet or eleven lines between the brows, then you should probably keep your eyes peeled for enzyme-inhibiting peptides like oligopeptides and soy-derived peptides, as well as decarboxy carnosine HCl. “They slow the breakdown of collagen you already have, so you keep more of your natural firmness,” says Wang. More often than not, you’ll find these in a formula along with a neurotransmitter-inhibiting peptide.
Neurotransmitter-Inhibiting Peptides
While you can’t actually bottle Botox, this peptide family, which includes ingredients like argireline, pentapeptide-3, and acetyl hexapeptide-8 (arguably the most popular), comes pretty damn close to recreating the effects of a line-smoothing neuromodulator. “They temporarily soften the muscle contractions that create expression lines, easing forehead and crow’s feet creasing,” says Wang.
Should I Use Multiple Peptide Serums?
In the injectable space, peptide stacks—meaning the combination of various different peptides used in a given week—is pretty popular. Topicals function a bit differently, though. “When it comes to formulation, specificity, product stability, and product irritation, there’s a lot to take into consideration,” says King. “Peptides are in general expensive, and you can only take so much into the skin without leading to a stability issue or potential irritation. There can be too much of a good thing.”
Consider using one or two peptide serums in your routine (one in the morning and one at night), and see how your skin reacts. In general, keeping your routine more streamlined and less complicated will yield the best results, and not stress out your skin barrier. Remember—more peptides does not always equal better skin. Instead, target your routine to the skincare concerns you want to address the most.
Why Trust Marie Claire
For more than 30 years, Marie Claire has been an internationally recognized destination for news, fashion and beauty trends, investigative packages, and more. When it comes to the products Marie Claire recommends, we take your faith in us seriously. Every product that we feature comes personally recommended by a Marie Claire writer or editor, or by an expert we’ve spoken to firsthand.
Meet the Experts
Ginger King is a cosmetic chemist, beauty industry expert, keynote speaker, and business coach with 30+ years developing iconic beauty products.
Ron Robinson (born 1965) is an American cosmetic chemist and researcher who is the founder of the skincare brand BeautyStat and the formulator of the teen skincare label Yes Day
When Susie Wang was a freshman at UC Berkeley, she saved up a week’s worth of lunch money to purchase an expensive Vitamin C Serum from a famous department store brand. Soon after opening the bottle, Susie noticed the once white serum had turned a tarnished brown, which meant the Vitamin C had oxidized.
During oxidation, the potency of the vitamin is diminished, converting to skin damaging free radicals – the complete opposite of what one would expect from their skincare. Susie then started purchasing other Vitamin C serums and found that all of them had the same issue. Susie committed herself to solving this problem, and quickly figured out a way to stabilize vitamins in order to prevent oxidation. In between her classes, she filed patents for this invention.
As soon as these patents were submitted, Susie received a flood of job offers from several of the largest cosmetic companies in the world. She put school on hiatus and began working on product development, formulations, innovation, and technology for three prestigious cosmetic companies.
