What Are the Different Types of Peptides and What Do They Do?

From collagen supplements and skincare serums to discussions about muscle recovery, weight management and anti-ageing, peptides seem to be appearing everywhere in the health and wellness world.

But while they're often talked about as though they're one type of ingredient, not all peptides are the same.

Some peptides occur naturally in the foods we eat and the human body. Others are manufactured for use in skincare products or developed as medicines to treat specific health conditions. Then there are experimental peptides, such as BPC-157 and TB-500, which have attracted attention online for their potential benefits despite limited clinical evidence.

So, what exactly are peptides, what are the different types, and do they actually work?

We’ll explore how peptides function, some of the most commonly discussed examples and what current research tells us about their potential uses, benefits and limitations.

What are peptides?

Peptides are short chains of amino acids, the building blocks that make up proteins.

Amino acids are joined together through chemical bonds known as peptide bonds. Depending on how many amino acids are connected and how they're arranged, they can form peptides with different structures and biological functions.

Peptides occur naturally throughout the body and are involved in various processes, including:

• Cell communication: Some peptides act as signalling molecules, helping cells communicate and respond to changes.

• Hormone regulation: Certain peptide hormones help regulate functions such as blood glucose levels, appetite and growth.

• Skin and tissue function: Some peptides participate in processes associated with tissue maintenance and repair.

• Immune responses: Certain peptides contribute to the body's defence mechanisms.

Peptides can also be obtained from food proteins, manufactured synthetically or developed for pharmaceutical use.

What's the difference between peptides and proteins?

Both peptides and proteins are made from amino acids, but they generally differ in size and structural complexity.

Peptides typically contain shorter amino acid chains, whereas proteins tend to be larger molecules that fold into more complex three-dimensional structures.

However, there isn't one universally accepted number of amino acids that separates a peptide from a protein.

The important thing to understand is that a peptide's function depends on its specific structure and amino acid sequence, not simply the fact that it's a peptide.

This is why collagen peptides, cosmetic peptides and prescription peptide medicines can have very different purposes.

What are the different types of peptides?

Peptides can be grouped in several ways, including their biological functions, sources and intended applications.

In health and wellness discussions, they're commonly encountered in five broad categories: nutritional peptides, cosmetic peptides, tissue-repair research peptides, growth hormone-related peptides and therapeutic peptides.

These aren't strict scientific classifications, and some peptides can fit into more than one category.

1. Collagen and nutritional peptides

Collagen peptides are among the most familiar types of peptides found in nutritional supplements.

They're produced by breaking down collagen, a structural protein naturally found in skin, bones, tendons, ligaments and other connective tissues, into smaller fragments through a process called hydrolysis.

Common examples include:

• Bovine collagen peptides: Derived from cattle, commonly from hides or other collagen-rich tissues.

• Marine collagen peptides: Usually derived from fish skin, scales or other marine sources.

• Porcine collagen peptides: Derived from pigs.

• Other food-derived bioactive peptides: Peptide fragments released from proteins such as milk, soy and eggs during digestion or food processing.

Unlike some synthetic peptides, collagen peptide supplements generally contain a mixture of peptide fragments rather than one precisely defined molecule.

What does the research say?

Collagen peptides have been investigated for their potential effects on skin hydration, elasticity and joint health, with some studies reporting promising results.

For example, a 2023 review published in Nutrients examined 26 clinical trials involving 1,721 participants. Researchers found that people taking hydrolysed collagen supplements experienced improvements in skin hydration and elasticity compared with those taking a placebo. 

For joint health, a 2008 study published in Current Medical Research and Opinion investigated collagen supplementation in athletes experiencing activity-related joint pain. After 24 weeks, researchers reported improvements in certain measures of joint discomfort among participants taking collagen compared with those taking a placebo.

However, not all research has reached the same conclusions. A 2025 review published in The American Journal of Medicine examined 23 clinical trials and found that collagen supplements appeared to improve skin hydration, elasticity and wrinkles overall.

Overall, while some findings suggest collagen peptides may offer benefits for skin and joint health, further studies are needed for more of its potential benefits. 

For those looking to incorporate collagen peptides into their daily routine, Chief Nutrition offers a range of collagen powders that provide a convenient way to supplement dietary collagen intake. 

👉 You can explore the Chief Nutrition range at Aussie Pharma Direct.

2. Cosmetic and skincare peptides

Cosmetic peptides are commonly included in skincare formulations such as serums, moisturisers and anti-ageing creams.

They're generally designed to interact with processes associated with skin appearance, although their actual effects depend on the ingredient, concentration, formulation and ability to reach its intended target.

Some commonly discussed examples include:

GHK-Cu (Copper Peptide)

GHK-Cu is a naturally occurring copper-binding peptide that has attracted interest for its potential role in skin maintenance, collagen production and wound repair. It's commonly used in cosmetic skincare products, particularly those marketed for improving the appearance of ageing skin.

Some early studies have reported promising results for GHK-Cu in skincare.

For example, a 2009 scientific review published in the International Journal of Cosmetic Science discussed several clinical studies involving GHK-Cu creams. One study involving 71 women found improvements in skin firmness, appearance and fine lines after 12 weeks. Another study involving 41 women reported improvements in wrinkles and skin density around the eyes.

However, much of this early research was small, and some findings were originally reported in conference abstracts rather than full peer-reviewed publications.

A separate 2006 clinical study investigated GHK-Cu skincare products in patients recovering from laser skin resurfacing. Although participants using GHK-Cu reported greater satisfaction with their skin's appearance, researchers found no significant differences in objectively measured skin redness, wrinkles or overall skin quality compared with the control group.

Meanwhile, a 2018 review published in Cosmetics highlighted laboratory and animal research suggesting that GHK-Cu may influence collagen-related processes and tissue repair.

Overall, while GHK-Cu shows potential as a skincare ingredient, larger, high-quality human studies are still needed to confirm its effectiveness, particularly for wound healing and other medical applications. Research involving topical skincare products also doesn't establish the safety or effectiveness of injectable GHK-Cu.

Matrixyl (Palmitoyl Pentapeptide-4)

Matrixyl is a trade name associated with certain cosmetic peptide ingredients, including palmitoyl pentapeptide-4.

It's commonly used in skincare products designed to reduce the appearance of fine lines and wrinkles. The peptide has been investigated for its potential to influence collagen-related processes and help improve the appearance of ageing skin.

Some clinical studies have reported promising results for Matrixyl in reducing the appearance of wrinkles.

A 2005 study published in the International Journal of Cosmetic Science involved 93 women aged between 35 and 55. Over 12 weeks, participants applied a moisturiser containing palmitoyl pentapeptide to one side of their face and a moisturiser without the peptide to the other. Researchers found that the peptide-containing moisturiser produced greater improvements in fine lines and wrinkles compared with the regular moisturiser.

More recently, a 2023 study published in the Journal of Clinical and Aesthetic Dermatology investigated palmitoyl pentapeptide-4 and another cosmetic peptide in 21 women over eight weeks. Researchers reported improvements in the appearance of crow's feet among some participants, with palmitoyl pentapeptide-4 showing more favourable results than the comparison treatments.

However, both studies had limitations. The 2005 research was conducted by researchers working for a skincare manufacturer, while the 2023 study involved a relatively small number of participants.

Argireline (Acetyl Hexapeptide-8)

Argireline is a synthetic cosmetic peptide commonly used in skincare products marketed to reduce the appearance of fine lines and expression wrinkles, particularly around the eyes and forehead.

It's sometimes described as a topical alternative to wrinkle-relaxing injections such as Botox. However, this comparison can be misleading, as Argireline has not been demonstrated to produce the same effects or level of effectiveness as botulinum toxin injections.

Some early research suggests that Argireline may help improve the appearance of facial wrinkles.

A 2002 study published in the International Journal of Cosmetic Science investigated Argireline's potential effects on wrinkle formation. Researchers reported that a cream containing 10% Argireline reduced wrinkle depth by up to 30% after 30 days of use among female volunteers. Laboratory findings also suggested that the peptide could influence certain processes involved in cellular signalling.

A later 2013 study published in the American Journal of Clinical Dermatology involved 60 participants who applied either an Argireline-containing product or a placebo around their eyes twice daily for four weeks. Researchers found that the Argireline group experienced greater improvements in the appearance and measured roughness of wrinkles compared with the placebo group.

However, both studies had limitations, including relatively short treatment periods. The 2002 study reported the greatest observed reduction in wrinkle depth rather than an average improvement across all participants, while the 2013 study did not compare Argireline directly with botulinum toxin injections.

3. Peptides being studied for tissue repair and recovery

This category includes several experimental peptides that have become popular in online fitness, injury-recovery and longevity discussions.

Two frequently mentioned examples are BPC-157 and TB-500.

BPC-157

BPC-157, short for Body Protection Compound-157, is a synthetic peptide containing 15 amino acids.

It's commonly promoted online for potential benefits involving tendon and ligament recovery, gastrointestinal health, inflammation and tissue repair.

Much of this interest comes from animal studies and other early-stage research investigating its biological effects. However, there is insufficient reliable human clinical evidence to establish BPC-157 as a safe and effective treatment for these conditions.

Important questions also remain about its appropriate dosing, long-term safety and possible adverse effects.

BPC-157 is not a TGA-approved medicine in Australia.

TB-500

TB-500 is a synthetic peptide fragment associated with thymosin beta-4, a naturally occurring protein involved in cellular processes such as cell movement and tissue maintenance.

It's frequently promoted online for injury recovery, wound healing and muscle or tendon repair. However, an important distinction is that TB-500 is not the same molecule as full-length thymosin beta-4.

Research involving thymosin beta-4 cannot automatically be used as evidence that TB-500 produces the same effects.

Although laboratory and animal research has explored related biological mechanisms, there is insufficient reliable human clinical evidence to establish TB-500 as a safe and effective injury-recovery treatment.

TB-500 is not a TGA-approved medicine.

What does the research say?

For both BPC-157 and TB-500, the evidence supporting commonly advertised recovery benefits remains inadequate. Promising results in animals or laboratory experiments don't necessarily translate into safe or effective treatments for humans. Neither should be confused with established medical treatments simply because they're described as peptides.

4. Growth hormone-related peptides

Some synthetic peptides are designed to influence the body's growth hormone signalling pathways.

These compounds are often discussed in relation to muscle growth, body composition, recovery and anti-ageing, although such claims frequently extend beyond the available clinical evidence.

CJC-1295

CJC-1295 is a synthetic analogue of growth hormone-releasing hormone (GHRH), designed to stimulate the release of growth hormone from the pituitary gland.

It's sometimes promoted online for muscle growth, exercise recovery, fat loss and anti-ageing. However, these claims go beyond what clinical research has established.

Early research has shown that CJC-1295 can influence growth hormone levels, although most studies have focused on its hormonal effects rather than its potential health benefits.

For example, a 2006 study published in The Journal of Clinical Endocrinology & Metabolism examined CJC-1295 in healthy adults across two short-term clinical trials. Researchers found that a single injection increased growth hormone levels by approximately 2 to 10 times for at least six days. Levels of insulin-like growth factor-1 (IGF-1), a hormone involved in growth and tissue development, also increased for around 9 to 11 days.

Another 2006 study published in the same journal investigated how CJC-1295 affected the body's natural growth hormone release patterns. Researchers found that growth hormone continued to be released in pulses, even while overall hormone levels were elevated.

Animal research has also explored its potential effects. A 2006 study published in the American Journal of Physiology-Endocrinology and Metabolism found that CJC-1295 helped restore normal growth in mice genetically modified to lack growth hormone-releasing hormone. However, these findings cannot be directly applied to humans.

While these studies demonstrate that CJC-1295 can affect growth hormone signalling, they do not establish that it improves muscle growth, athletic performance, injury recovery or longevity in humans.

The available human studies were also relatively small and short-term, meaning the long-term safety and effectiveness of CJC-1295 remain uncertain. It is not a TGA-approved medicine in Australia.

Ipamorelin

Ipamorelin is a synthetic peptide known as a growth hormone secretagogue, meaning it stimulates the body to release growth hormone.

It acts through the ghrelin receptor, which is involved in regulating growth hormone release and other physiological processes.

Ipamorelin is sometimes promoted online for muscle growth, exercise recovery, fat loss and anti-ageing. However, its effectiveness for these purposes has not been established through reliable human clinical research.

Early research has demonstrated that ipamorelin can stimulate growth hormone release, although evidence supporting its broader health benefits remains limited.

A 1998 study published in the European Journal of Endocrinology investigated ipamorelin's effects in laboratory experiments and animal studies. Researchers found that it stimulated growth hormone release in rats and pigs. Unlike some other growth hormone-releasing peptides, ipamorelin did not significantly increase cortisol levels in the animal experiments, suggesting it may have a more selective effect on growth hormone secretion.

However, these findings came from laboratory and animal research rather than human clinical trials.

A later 2014 study published in the International Journal of Colorectal Disease investigated whether ipamorelin could help patients recover bowel function after abdominal surgery. The study involved 117 patients who received either ipamorelin or a placebo.

Although patients receiving ipamorelin were able to tolerate a solid meal sooner on average, the difference was not statistically significant. Researchers concluded that ipamorelin did not demonstrate a significant improvement over placebo in the study's main measures of effectiveness.

GHRP-2 and GHRP-6

Growth hormone-releasing peptides 2 and 6, commonly known as GHRP-2 and GHRP-6, are synthetic compounds that stimulate growth hormone secretion through related receptor pathways.

They have been investigated for their hormonal effects, but this doesn't establish their safety or effectiveness as general wellness or performance-enhancing products.

5. Hormonal and therapeutic peptides

Not all peptides are experimental. Some peptide-based medicines have been extensively studied and are used in established medical treatments.

Examples include:

Insulin

Insulin is a naturally occurring peptide hormone produced by the pancreas. It helps regulate blood glucose by allowing the body's cells to take up and use glucose.

Insulin medicines are well-established treatments for type 1 diabetes and are also used in certain circumstances for type 2 diabetes and other medical conditions.

Semaglutide

Semaglutide is a peptide-based medicine belonging to a class known as GLP-1 receptor agonists. It mimics the activity of the hormone GLP-1 and influences blood glucose regulation, appetite and gastric emptying.

Semaglutide has been evaluated in extensive human clinical trials and is approved for specific medical indications, depending on the product.

Read related article: What Are GLP-1s & How They Work for Weight Loss

Teriparatide

Teriparatide is a synthetic form of part of the human parathyroid hormone.

It's used as a prescription treatment for certain people with osteoporosis who are at high risk of fractures. Its clinical use is supported by research demonstrating effects on bone formation and fracture risk.

Tirzepatide (Mounjaro)

Tirzepatide is a synthetic peptide-based medicine commonly known by its brand name, Mounjaro.

It belongs to a class of medicines known as dual GIP and GLP-1 receptor agonists. This means it acts on two hormone pathways involved in regulating blood glucose, appetite and digestion. By activating these receptors, tirzepatide helps improve blood glucose regulation and can reduce appetite and food intake.

In Australia, Mounjaro is a TGA-approved prescription medicine for specific medical uses, including type 2 diabetes and chronic weight management in eligible adults.

What does the research says about tirzepatide?

Tirzepatide has been investigated in several large human clinical trials, with research demonstrating benefits for blood glucose management and weight reduction in certain patient populations.

For example, a 2022 study published in The New England Journal of Medicine involved 2,539 adults with obesity or overweight and at least one weight-related complication, excluding diabetes.

Over 72 weeks, researchers found that participants receiving tirzepatide experienced an average weight reduction of approximately 15% to 21%, depending on the treatment group, compared with around 3% in the placebo group.

The study also reported improvements in several measures associated with cardiometabolic health. However, gastrointestinal side effects, including nausea, diarrhoea and vomiting, were common.

Unlike experimental peptides such as BPC-157 and TB-500, tirzepatide has undergone extensive human clinical testing and has established medical uses.

However, this doesn't mean it's suitable for everyone. As a prescription medicine, tirzepatide must be used under appropriate medical supervision, with consideration of its potential side effects, contraindications and individual patient needs.

Which peptides actually work?

One of the biggest misconceptions about peptides is that they all offer similar health benefits. In reality, the evidence supporting different peptides varies considerably.

Some have undergone extensive clinical trials and received regulatory approval for specific medical uses. Others have been studied in small human trials, while some remain largely experimental.

Here's a simplified comparison.

Note: The TGA approval statuses listed above reflect the regulatory information available as at the date of publication. TGA approval applies to specific therapeutic products and their approved uses, rather than to peptides as a general category. Food products and cosmetic skincare products may fall outside TGA regulation, depending on their ingredients, presentation and claims. For the latest approval statuses and regulatory updates, refer to the official TGA website.

It's worth remembering that a peptide being described as experimental doesn't necessarily mean it has been proven ineffective. Rather, it means the available research hasn't adequately demonstrated that it is safe and effective for the purpose being claimed.

Are peptides safe? Understanding the risks

The safety of a peptide depends on what it is, how it's used and whether its risks have been adequately studied.

Peptides naturally present in foods are part of ordinary nutrition, while collagen peptide supplements and cosmetic products have their own ingredient-specific considerations.

Prescription peptide medicines undergo regulatory evaluation for quality, safety and effectiveness for particular medical uses. They can still cause adverse effects and must be used appropriately.

Experimental peptides raise different concerns.

Why unapproved peptide products can be risky

Some peptides promoted online for recovery, performance or anti-ageing have not undergone adequate human clinical testing.

Potential concerns include:

• Unknown long-term effects: Limited human research may leave important safety questions unanswered.

• Product quality and purity: Unapproved products may contain incorrect quantities, contaminants or substances that differ from their labels.

• Injection-related risks: Products intended for injection can introduce risks involving infection, contamination and improper administration.

• Unproven health claims: Marketing claims may rely on laboratory or animal research rather than reliable clinical trials.

• Hormonal or other biological effects: Some peptides can influence important physiological pathways, potentially producing unintended consequences.

Ultimately, the question isn't simply whether peptides work. It's which peptide you're considering, what it's intended to do and whether reliable research supports that particular use.

Understanding these differences can help you make more informed decisions and look beyond the growing hype surrounding peptide products.

Disclaimer: Not all peptide products are approved by the Therapeutic Goods Administration (TGA) in Australia. Approval and regulatory requirements vary depending on the specific peptide, product and intended use. For the latest information on peptide regulations, safety warnings and approved therapeutic products, visit the official TGA website.