Peptides are short chains of amino acids, the building blocks of proteins. Above roughly 50 amino acids, it is usually called a protein. Your body makes thousands of peptides itself, such as insulin and oxytocin, and you come across them in food, cosmetics and medicines.
Peptides in one sentence
Peptides are short chains of amino acids, the building blocks of proteins. If the chains are long (roughly more than 50 amino acids), we usually call it a protein. If they are short, it is called a peptide.
Where do you come across peptides?
Your body makes thousands of peptides itself. Insulin, which regulates your blood sugar, is a peptide. So is glucagon, insulin's counterpart. The same goes for oxytocin, the hormone that plays a role in childbirth and bonding.
Peptides are also found in food and personal care:
- Nutrition: collagen peptides and whey protein hydrolysate are proteins that have already been cut into smaller pieces.
- Cosmetics: creams and serums often contain peptides such as copper peptides or signal peptides.
- Medicines: from insulin to modern weight-loss drugs, many new medicines are peptides.
Why are you hearing so much about them now?
On social media, the talk is mainly about experimental peptides sold as miracle cures for muscle building, recovery or weight loss. The Dutch Health and Youth Care Inspectorate (IGJ) specifically warns against buying and using these yourself online (Kassa, Feb. 2026).
In short
Peptides are very ordinary: your body is full of them and you eat them every day. Whether a specific peptide product is safe and legal depends on what it is and how it is sold. You can read more about this in our blog on peptides and Dutch law.
Frequently asked questions
Is insulin a peptide?
Yes. Insulin is a peptide hormone that your body makes itself to regulate your blood sugar.
What is the difference between a peptide and a protein?
Mainly the length. Up to roughly 50 amino acids it is called a peptide; longer chains are usually called a protein.
