Polypeptide-1 (SH-Polypeptide-1) is a lab-made human peptide used in anti-aging skincare. Learn what it is, how it differs from proteins, and safety basics.
Polypeptide-1, written as SH-Polypeptide-1 on ingredient labels, is a lab-made, human-identical peptide used as a cosmetic ingredient and most often described by suppliers as a recombinant form of insulin-like growth factor 1 (IGF-1). It appears in anti-aging serums and creams marketed to improve the look of firmness and fine lines, not to treat or cure a disease. In the United States, SH-Polypeptide-1 is regulated as a cosmetic ingredient rather than an approved drug.
What Is Polypeptide-1 (SH-Polypeptide-1)?
The "SH" prefix stands for "synthetic human," a naming convention in the International Nomenclature of Cosmetic Ingredients (INCI). It signals that the peptide is manufactured in a lab to match a sequence found in human biology instead of being extracted from plants or animals.
Recombinant peptides are produced by engineered microorganisms or cell cultures that follow a DNA blueprint and assemble the amino acid chain. Suppliers usually sell SH-Polypeptide-1 as a water-soluble powder that formulators dilute into serums at very low concentrations.
The number "1" is simply an index assigned by the INCI naming committee. It does not indicate potency, concentration, or rank against other peptides.
Polypeptide Structure and How It Differs From a Protein
A polypeptide is a chain of amino acids joined by peptide bonds. Its polypeptide structure is usually described in four levels: primary (the sequence), secondary (helices and sheets), tertiary (the 3D shape), and quaternary (multiple chains bound together).
Size is the practical dividing line in any polypeptide vs protein comparison. Chains of roughly 2 to 50 amino acids are called peptides or polypeptides, while longer chains are classified as proteins.
| Feature | Polypeptide | Protein |
|---|---|---|
| Amino acid count | Roughly 2 to 50 | Usually more than 50 |
| Typical molecular weight | Often under about 10 kDa | Often 10 kDa and above |
| Folding | Limited; mostly short helices | Complex 3D folding |
| Common forms | Glutathione, oxytocin, glucagon | Collagen, albumin, hemoglobin |
Molecular size matters in skincare because it helps predict whether a molecule can cross the skin barrier at all. Large, water-soluble peptides penetrate intact skin poorly, which is why many cosmetic peptides are modified with fatty acids to improve absorption.
What SH-Polypeptide-1 Is Marketed to Do
Growth-factor peptides are sold on the idea that they send signals telling skin cells to behave more like younger skin. In laboratory cell cultures, IGF-1 can encourage fibroblast activity and collagen production.
Cell-culture results are not the same as results on human skin. There is no large, independent clinical trial showing that a topical SH-Polypeptide-1 product removes wrinkles or reverses skin aging.
Concentration and delivery also vary widely between products. Two serums can list the same ingredient while delivering very different amounts to the skin, and brands are not required to disclose percentages on the label.
Polypeptide Examples and Related Ingredients
Skincare shelves are crowded with lookalike names, so it helps to compare them side by side. The table below shows how SH-Polypeptide-1 stacks up against other well-known polypeptide examples.
| Ingredient label | INCI category | Commonly described as | Typical cosmetic role |
|---|---|---|---|
| SH-Polypeptide-1 | Recombinant human polypeptide | IGF-1-like growth factor | Firming and anti-aging serums |
| SH-Oligopeptide-1 | Recombinant human oligopeptide | Epidermal growth factor (EGF) | Repair and barrier claims |
| Copper tripeptide-1 | Synthetic tripeptide | GHK-Cu copper peptide | Tone and firmness |
| Palmitoyl tripeptide-1 | Synthetic lipopeptide | Matrikine-type peptide | Fine lines and elasticity |
Outside of cosmetics, additional polypeptide examples include glutathione (three amino acids), oxytocin (nine amino acids), and glucagon (29 amino acids). That range shows how broad the term is, covering both a serum ingredient and a prescription hormone.
Polypeptide Antibiotics and Commercial Manufacturing
Polypeptide antibiotics are a completely different category from cosmetic peptides. This class includes bacitracin, polymyxin B, colistin, and vancomycin, all of which are prescription drugs used under medical supervision.
Several polypeptide antibiotics are poorly absorbed when taken by mouth, and some, such as polymyxin B and colistin, carry kidney-related risks. They should never be used casually or without a prescriber's guidance.
On the supply side, companies such as PolyPeptide manufacture peptides under good manufacturing practice (GMP) conditions for pharmaceutical and cosmetic customers. Reputable suppliers publish a certificate of analysis that lists purity, sequence, and identity for each batch.
Safety, Regulation, and What to Ask a Dermatologist
SH-Polypeptide-1 is not FDA-approved as a drug for any indication in the United States. Cosmetic ingredients cannot legally claim to treat or cure disease, so marketing language around growth-factor peptides stays focused on appearance.
Some dermatologists have raised a theoretical concern that topically applied growth factors could encourage cell division in skin. No published evidence shows that cosmetic use of SH-Polypeptide-1 causes harm, but people with a history of skin cancer may want to be cautious.
Practical steps before adding a peptide serum to your routine:
- Patch test on your inner forearm for 24 to 48 hours before applying it to your face.
- Avoid layering strong acids, retinoids, and growth-factor peptides until you know how your skin responds.
- Check with a healthcare professional first if you are pregnant, breastfeeding, or being treated for a skin condition.
If a product promises prescription-level results, treat that as a red flag rather than a selling point. A dermatologist or pharmacist can tell you whether a specific peptide product fits your skin and your goals.
Frequently Asked Questions
What is SH-Polypeptide-1?
SH-Polypeptide-1 is a bioengineered, human-identical peptide used as a cosmetic ingredient, and it is most often described in supplier literature as a recombinant form of insulin-like growth factor 1 (IGF-1). The "SH" prefix means "synthetic human," indicating the peptide is made in a lab to match a human sequence. It is regulated in the US as a cosmetic ingredient, not as an approved drug.
Is polypeptide-1 the same as IGF-1?
SH-Polypeptide-1 is commonly described as a recombinant human IGF-1-like polypeptide, but it is not the same product as pharmaceutical IGF-1 (mecasermin), which is an FDA-approved prescription drug given by injection for severe growth failure in children. Cosmetic versions are topical and sold without a prescription. The two should not be treated as interchangeable.
Is SH-Polypeptide-1 safe to use on skin?
Topical use is generally well tolerated, and no published evidence links cosmetic SH-Polypeptide-1 to harm. Some dermatologists have raised a theoretical concern about growth factors and cell division, so people with a history of skin cancer may prefer to avoid them. Patch test first, and talk to a healthcare professional if you are pregnant, breastfeeding, or under treatment for a skin condition.
This page provides educational research information and does not replace medical advice, diagnosis, or treatment.