What Are Peptides?

Peptides are short chains of amino acids — the same building blocks that make up proteins. While proteins typically contain 50 or more amino acids, peptides are smaller, usually between 2 and 50 amino acids in length. This smaller size gives peptides unique properties: they can act as signalling molecules, telling your body’s cells to perform specific functions.

Your body naturally produces thousands of peptides. Insulin, for example, is a peptide hormone that regulates blood sugar. Oxytocin is a peptide involved in social bonding. The peptides used in peptide therapy are either synthetic versions of naturally occurring peptides or novel sequences designed to interact with specific biological pathways.

How Do Peptides Work?

Peptides work by binding to receptors on cell surfaces, triggering specific biological responses. Think of them as chemical messengers — each peptide carries instructions for a particular cellular function. Different peptides target different systems:

Growth hormone peptides signal the pituitary gland to release growth hormone
Recovery peptides may promote tissue repair pathways and reduce inflammation
Cognitive peptides may influence neurotransmitter systems and brain-derived growth factors
Metabolic peptides may affect energy metabolism and insulin sensitivity

Types of Peptides

Recovery and Healing

Peptides like BPC-157 and TB-500 are researched for their potential roles in tissue repair, wound healing, and reducing inflammation. These are among the most commonly discussed peptides in the recovery space.

Growth Hormone Secretagogues

CJC-1295 and Ipamorelin are peptides that stimulate the body’s natural growth hormone production. They are often used together (the “CJC/Ipa stack”) and are popular in anti-aging and body composition protocols.

Cognitive Enhancement

Semax and Selank are peptides developed in Russia and studied for their potential effects on cognition, focus, and anxiety. Both have been approved for clinical use in Russia, though they are not approved in the US, UK, or Australia.

Metabolic Health

AOD-9604 and MOTS-c are peptides researched for their potential roles in fat metabolism, insulin sensitivity, and metabolic regulation.

Immune Support

Thymosin Alpha-1 and KPV are peptides studied for their immunomodulatory properties. Thymosin Alpha-1 is notably approved for clinical use in over 35 countries.

Anti-Aging

GHK-Cu, Epitalon, and SS-31 are peptides researched for their potential roles in skin health, telomere support, and mitochondrial function.

How Is Peptide Therapy Administered?

Most peptides are administered through one of these routes:

Subcutaneous injection — the most common method, using small insulin syringes just under the skin
Nasal spray — used for certain peptides like Semax and Selank
Oral — some peptides like BPC-157 are stable enough for oral administration
Topical — GHK-Cu is commonly used in creams and serums

Learn more in our guides: How to Reconstitute Peptides and How to Inject Peptides.

Are Peptides Safe?

The safety profile varies significantly by peptide. Some key points:

Most peptides studied in clinical settings have shown favourable safety profiles in the short term
Long-term safety data is limited for many peptides, as most research has been in animal models
Quality and purity of the peptide source is critical — only use peptides from reputable sources with third-party testing
Medical supervision is strongly recommended

How to Get Started

If you are considering peptide therapy:

Find a qualified provider — look for a physician or clinic experienced in peptide therapy. Browse our Provider Directory
Get baseline blood work — a responsible provider will order labs before starting any protocol
Understand the regulatory landscape — check what’s legal in your jurisdiction using our Regulatory Tracker
Start with research — explore our Peptide Database to learn about individual peptides

Peptide Database — browse all peptide profiles
Are Peptides Legal? — regulatory guide by jurisdiction
Peptides vs Steroids — key differences explained
Find a Peptide Doctor — what to look for
Dosage Calculator — calculate peptide doses