Not All Peptides Are Created Equal

Peptides may be small, but they're a big deal for your skin, offering powerful solutions for everything from wrinkles to dullness. Yet, with an overwhelming number of peptide-based products flooding the market, distinguishing those that deliver results from those that don't can be challenging. After all, not all peptides are created equal, and understanding the nuances of the peptides you use is crucial to unlocking your skin's full potential.

What Are Peptides?

Peptides are small chains of amino acids, and they come in all shapes and sizes, each helping your skin in unique ways. Whether it's boosting collagen, delivering essential minerals, blocking the breakdown of proteins, or inhibiting neurotransmitters responsible for skin concerns, the peptides in your skincare can be as effective as they are versatile.[1]Yet, while a variety of peptides have been used in skin care for decades, some of the most common options, such as copper tripeptides, tetrapeptide PKEK, manganese tripeptide-1, soybean peptides, black rice oligopeptides, and silk fibroin peptides, lack clinical research to back up their efficacy in human skin.[2] So, while they’re trendy, their true power is still being studied.

Red Flags in Skin Care Peptides

Due to their often untested nature, not all peptides live up to the hype. Here are some of the most common red flags to look for in your skin care peptides:

The Unstable Partner: A Peptide That Can't Handle the Pressure

Some peptides just can't handle the heat—literally. They break down when exposed to sunlight, temperature changes, or even just a little too much air. While they may look great in the lab, they often struggle to stay stable once mixed into your skin care products. For instance, natural peptides are usually unstable in water, while larger peptides often have trouble maintaining their structure under stress.[3] But the threats don’t stop there—once applied to the skin, naturally occurring enzymes can further degrade peptides, rendering them ineffective before they can deliver results[4]. One minute, they’re good to go; the next, they’ve lost their power, leaving your skin high and dry.

When choosing a peptide-based skincare product, it’s not just about the ingredient list—it’s about how well the peptides have been formulated, stabilized, and protected to ensure they can deliver the promised benefits to your skin.

The One Who's Not That Into You: Surface-Level Peptides

Have you ever met someone who looks great on paper but never shows up when it counts? That’s what surface-level peptides are like in your skincare routine. These peptides might give you some initial attention, making your skin feel smoother or more moisturized, but fail to dive deeper when creating meaningful, lasting changes—like boosting collagen or repairing cells.

The skin barrier is a sophisticated structure designed to protect you, making it challenging for active ingredients to pass through.[2] To deliver on their potential, peptides must reach the dermis—home to the cells responsible for collagen production, elastin fibers, and cellular repair mechanisms. One of the key factors is size—generally, molecules must be under 500 Daltons (Da) to effectively pass through the skin barrier.[5] However, even if a peptide meets this size requirement, its polarity can limit its ability to cross the stratum corneum. For example, copper peptide (GHK-Cu) is small enough to pass through. Still, its natural polarity at the body’s pH level restricts its permeability, meaning it may not reach the deeper layers where it’s most needed.[6]

Not all peptides are content to sit on the surface and look pretty—some are designed to dive deeper and do the real work. But getting them past the skin barrier isn’t always easy. Thankfully, there are ways to help peptides reach the dermis, where they can stimulate collagen, support skin repair, and deliver lasting results:

• Clever Chemistry for Better Absorption: Peptides composed of 5 amino acids or fewer (pentapeptides) are more likely to penetrate the skin due to their lower molecular weight.[4] How do larger molecules, like the OS-01 peptide with 10 amino acids, penetrate the skin barrier? These peptides can penetrate the skin if they have a favorable polarity—such as the OS-01 peptide— or they can get a molecular makeover, like adding a palmitoyl group, to improve their ability to pass through the lipid-rich skin barrier.[7,8,9]
• Encapsulation: Some skincare brands use liposomes or exosomes to wrap peptides in a lipid-friendly coating, helping them slip past the barrier. The catch? Not all of these delivery systems penetrate deeply enough—many stop at the stratum corneum without reaching the layers that matter.[10,11]
• Power Up with Skincare Tech: If you're serious about getting peptides deeper, consider science-backed skin treatments that give them a boost, like microneedling, chemical peels, or laser and electrical therapies that help push the peptides in your skin care deeper into the skin.[12] As always, consult your skin care professional for appropriate after care products and best practices.

The Narcissist: All Talk, No Action

When it comes to skincare, you deserve more than empty promises. The term 'peptide' might catch your attention, but it refers to a broad category of molecules with different roles. And there’s no guarantee it will be effective or even beneficial to your skin.

You deserve ingredients that work, are backed by science, and are proven to transform your skin. But unfortunately, the beauty industry is full of overhyped peptides that promise the world yet fail to deliver real, lasting change. These peptides sound impressive—they claim to rebuild collagen, erase wrinkles, and restore a youthful glow overnight—yet often fail to deliver on these promises.

• However, a handful of well-researched peptides have proven beneficial. One of the most commonly studied is palmitoyl pentapeptide-3, which has demonstrated the ability to stimulate collagen and fibronectin production in a double-blind, placebo-controlled, split-face, randomized clinical study.[13] Similarly, the OS-01 peptide was also proven to improve skin barrier function and skin texture via a double-blind split-face clinical study, and shown to improve skin health at the cellular level in published research on human skin cells and samples.

How Can You Be Sure That Your Peptides Work?

Not every skincare product containing peptides will deliver the results it promises. To ensure you’re investing in formulations that will benefit your skin, here are some ways to evaluate if your peptides are pulling their weight:

Clinical Validation

A product promising “youthful, bouncy skin overnight” sounds impressive, but is there science to back it up? Scientifically proven peptides are supported by controlled, peer-reviewed clinical studies that rigorously assess their impact on skin elasticity, collagen production, hydration, and overall skin health. However, like peptides, not all studies are created equal. Here is what to look for from a clinical trial:

• Final Product Testing: The best studies test peptides in their actual formulation, like OneSkin’s split-face study on the OS-01 peptide, published in the Journal of Cosmetic Dermatology.[9]
• Human Skin Research: Peer-reviewed studies should test peptides on human skin biopsies or models, not just in cells or animal models, and will ideally be published in a reputable journal like npj Aging.
• Rigorous Study Design: Look for double-blind, controlled, third-party trials to ensure unbiased results. A split-face study is best to reduce confounding variables.
• Transparency & Credibility: Reliable studies reference past research, acknowledge limitations, and provide full data for verification.
• Published in Peer-Reviewed Journals: True scientific validation comes from respected peer-reviewed journals that vet study methods and results.

From cellular-level biomarkers to surface-level signs of aging like wrinkles and sagging skin, you can read the results of OneSkin’s peptide clinical trials hereto learn more about clinical studies.

Stability and Packaging

When looking for a reliable peptide formulation, look for those that have been stability-tested and supported by scientific and clinical evidence. To maintain potency, skin care products containing peptides should be housed in airtight, opaque containers to help preserve the peptide's potency and prevent degradation.[14]

We took this approach to heart. All of OneSkin’s products are designed, packaged, and shipped with the stability of our peptides and active ingredients in mind.

Functional Specificity

A high-quality peptide product will transparently disclose its active peptides and their mechanisms of action. Whether targeting collagen stimulation, skin barrier function, or hydration enhancement, understanding the function of each ingredient allows for informed decision-making.

Advanced Delivery Systems

For peptides to truly transform your skin, they must reach the deeper layers where they can make the greatest impacts. Seek formulations with penetration studies showing penetration through the skin barrier or delivery technologies like encapsulation with data to prove that the delivery method works.[15]

Safety Studies

Unlike pharmaceuticals, which require FDA approval before they can be legally sold, many cosmetic products often reach the market without clearing similar guardrales.[16] Look for brands that conduct thorough dermatological testing and have data to prove their peptides play nice with your skin because the last thing you want is a "bad first date" with your new skincare product!

For example, the OS-01 peptide falls into the class of senotherapeutics—potent molecules that can influence aging cells at the cellular level. We take skin health very seriously, so we rigorously tested the OS-01 peptide to confirm that our proprietary peptide wouldn't cause adverse effects.[15] The published findings show that OS-01:

• Is non-toxic
• Is non-irritating
• Does not promote growth in tested cancer cell lines

This research-backed validation helps you stay confident that your peptides are safe and effective.

Key Takeaways:

• While many peptides appear in skincare products, not all have been scientifically proven to deliver real skin benefits.
• Some peptides sit on the skin’s surface, offering highly limited effects without deep collagen support.
• Be wary of peptides that sound impressive but have no peer-reviewed research to back their claims.
• The best peptides undergo rigorous scientific and clinical testing to verify their efficacy, safety, stability, and delivery mechanisms.

References

1. https://www.mdpi.com/2079-9284/10/4/111
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC7023394/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC10056213/
4. https://www.sciencedirect.com/science/article/pii/S1773224723009395
5. https://pmc.ncbi.nlm.nih.gov/articles/PMC5799189/#
6. https://pdfs.semanticscholar.org/06ab/fcf1e91850c959866054188b9c2185c4608c.pdf
7. https://pmc.ncbi.nlm.nih.gov/articles/PMC4131521/
8. Zonari, A., et al. Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models. npj Aging, 9(1), 1-15. 2023. doi:10.1038/s41514-023-00109-1
9. Zonari A., et al. Double-blind, vehicle-controlled clinical investigation of peptide OS-01 for skin rejuvenation. J Cosmet Dermatol. 2024. doi:10.1111/jocd.16242
10. https://link.springer.com/article/10.1208/s12249-019-1582-x
11. https://www.sciencedirect.com/science/article/abs/pii/S0378517318307749
12. https://pmc.ncbi.nlm.nih.gov/articles/PMC4976400/
13. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-2494.2005.00261.x
14. https://pmc.ncbi.nlm.nih.gov/articles/PMC9699111/
15. Zonari, A. et al. In vitro and in vivo toxicity assessment of the senotherapeutic Peptide 14. Toxicology Reports 9, 1632-1638. 2022. doi:10.1016/j.toxrep.2022.07.018
16. https://www.fda.gov/cosmetics/resources-industry-cosmetics/small-businesses-homemade-cosmetics-fact-sheet