Peptides are short chains of amino acids, the same building blocks that make proteins. Your body makes thousands of them. Some act as hormones or signals. Manufactured peptides are used in skincare, food supplements and medicines, and each use has very different rules and evidence.
How are peptides different from proteins?
Think of amino acids as beads on a string. A short string is a peptide, and a long folded string is a protein. Collagen is a protein, and collagen peptides are that protein broken into short pieces.
Where are peptides used?
The same word appears on very different products, so check which kind you are reading about.
| Use | Example | What it is for |
|---|---|---|
| Skincare | Copper tripeptide-1 | The look of firmer skin |
| Food | Collagen peptides | A protein supplement |
| Medicine | Insulin, semaglutide | Prescribed medical treatment |
| Unapproved | BPC-157, retatrutide | Not approved for sale in NZ |
Do peptides do the same thing in each product?
No. A skincare peptide is chosen for how skin looks. An injected medicine acts on the body. Results from one kind tell you nothing about another, which is why the rules in New Zealand depend on the product and its use.
How can you tell a peptide on a label?
Look for words ending in peptide, such as tripeptide or hexapeptide. Words such as palmitoyl or acetyl mean the peptide has been modified. You can paste any ingredient list into our peptide ingredient checker.
Where should you go next?
For skin, read what peptides do for skin. For a New Zealand overview, read peptides in NZ.
Common questions
What is the difference between a peptide and a protein?
Length and shape. Peptides are short chains of amino acids, while proteins are longer chains folded into complex shapes. There is no perfectly sharp cut-off, but chains under about 50 amino acids are commonly called peptides.
Are peptides steroids?
No. Peptides are chains of amino acids, while steroids are a different type of molecule built around a ring structure. They work differently, and some peptides are still restricted in sport and medicine.
Are peptides safe?
It depends on the product. Cosmetic peptides on skin are generally well tolerated. Medsafe warns that unapproved injectable peptides have not been assessed for quality, safety or efficacy, so ask a doctor before using one.