A peptide is a short chain of amino acids linked together by peptide bonds. Think of them as small proteins — just made of fewer building blocks.
- Peptides typically contain 2 to 50 amino acids.
- Proteins are larger and usually contain 50 or more amino acids.
Each peptide is made according to a specific sequence of amino acids, which determines its function in the body.
🔗 How Are Peptides Formed?
A peptide bond forms when the carboxyl group of one amino acid binds to the amino group of another. This reaction produces a chain — a peptide.
🧠 What Do Peptides Do?
Peptides are essential to life. They act as:
- Hormones (e.g. insulin, growth hormone-releasing hormone [GHRH], TRH)
- Neurotransmitters (e.g. endorphins)
- Signaling molecules (e.g. glucagon, oxytocin)
- Antibiotics (e.g. defensins in the immune system)
- Structural components (in skin, hair, and tissue repair)
Their small size allows them to act quickly, often by binding to specific receptors on cell surfaces and triggering a biological response.
🧪 Examples of Natural Peptides:
| Peptide | Function |
|---|---|
| Insulin | Regulates blood sugar |
| Glucagon | Raises blood sugar |
| Oxytocin | Promotes bonding, childbirth, and milk letdown |
| TRH (Thyrotropin-Releasing Hormone) | Stimulates TSH release from the pituitary |
| GHRH | Stimulates growth hormone release |
| Endorphins | Reduce pain and promote pleasure |
💊 Peptides in Medicine and Supplements
Peptides are used in:
- Diabetes treatment (insulin, GLP-1 analogs)
- Growth hormone stimulation (like sermorelin, a GHRH analog)
- Anti-aging and skin repair (collagen peptides, copper peptides)
- Wound healing and immune support
- Fitness (e.g., BPC-157, TB-500 — though many of these are unregulated or experimental)
🔍 Types of Peptides:
| Type | Description |
|---|---|
| Dipeptide | 2 amino acids linked |
| Tripeptide | 3 amino acids linked |
| Oligopeptide | A few amino acids (typically up to 10–20) |
| Polypeptide | Many amino acids (over 20, but less than 50) |
| Protein | One or more polypeptides folded into a functional structure |
🧠 Summary Table:
| Feature | Peptide |
|---|---|
| Made of | Short chains of amino acids |
| Size | Smaller than proteins |
| Function | Hormones, messengers, growth factors, defense |
| Produced by | Cells, glands, immune system |
| Used in medicine | Hormone therapy, skin care, diabetes, fitness |