A simple guide to peptides, written for Australians

What are peptides, and what are some of the more common ones used for?

This page walks through what a peptide actually is, how peptides work inside the body, and which specific peptides people across Australia are talking about.

So, what are peptides? Which peptides are Australians talking about?

Start here

So what exactly is a peptide?

It is worth starting right at the beginning, because the word "peptide" gets used constantly without much explanation of what it actually means.

In simple terms, a peptide is a short chain of amino acids. Amino acids are the same building blocks that make up proteins, and a peptide bond is simply the link that holds them together. If it helps, you can picture amino acids as beads and a peptide as a short string of those beads joined end to end.

When you join enough of those beads together, chemists eventually stop calling the result a peptide and start calling it a protein instead. There is no single agreed cut-off point, but as a rough guide, anything in the range of roughly two to fifty amino acids is generally still considered a peptide.

Your body is already full of peptides. Insulin, the hormone that helps manage your blood sugar, is itself a peptide hormone.

What has changed in recent years is that scientists, and increasingly everyday health enthusiasts, have become far better at designing synthetic peptides that mimic, adjust, or amplify these natural signals to produce very specific effects. That development is really the whole reason peptides have become such a widely discussed topic.

The mechanism

How do peptides actually work?

Step 01

A peptide enters the system

Whether it is produced naturally by the body or introduced from outside, the peptide begins circulating and looking for its particular target.

Step 02

It binds to a specific receptor

Much like a key finding its lock, the peptide fits one particular receptor on one particular type of cell, rather than acting broadly across the whole body.

Step 03

A targeted response is triggered

That cell or system then carries out a specific action, such as releasing a hormone or beginning a repair process. This targeted message is what gives each peptide its reputation.

The peptides people discuss

Some of the commonly discussed peptides in Australia

The peptides below are grouped into four broad categories. This is by no means an exhaustive list, since new names come up in conversation all the time, but these are among the ones that people are most frequently discussing at the moment. You can select any peptide to expand it and read a little more.

Most of the peptides described below are not approved by the Therapeutic Goods Administration for the uses discussed here. The weight-loss group is a partial exception, and that difference is explained within it. Everything on this page is general education only and should not be read as a recommendation.

Sports Performance & Body Composition

This group is centred largely around growth-hormone signalling, and it tends to appear in conversations about how the body builds muscle, recovers between sessions, and holds on to lean mass.

What it is. CJC-1295 is a synthetic analogue of growth hormone-releasing hormone. Rather than introducing growth hormone directly, it is designed to encourage the pituitary gland to release more of the body's own growth hormone.

Where it commonly comes up

Conversations about supporting lean muscle development alongside training.
Discussions about recovery between heavier training blocks.
It is very often paired with Ipamorelin, which is thought to help produce a smoother, more sustained release pattern.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. Ipamorelin is a growth hormone-releasing peptide that prompts growth hormone release through the ghrelin receptor. It is generally regarded as more selective than older-generation peptides in the same family, which is often taken to mean it has less knock-on effect on hormones such as cortisol.

Where it commonly comes up

It is very frequently stacked with CJC-1295, and the two are often discussed together as a pairing.
Conversations about recovery and sleep quality.
Discussions about gradual changes in body composition over time.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. Tesamorelin is another growth hormone-releasing hormone analogue. It was originally studied within a specific clinical context, and today it tends to be discussed more broadly within performance and body-composition conversations.

Where it commonly comes up

Conversations about visceral fat and overall body composition.
Discussions that sit alongside CJC-1295 and Ipamorelin.
General athletic recovery conversations.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. Thymosin Alpha-1 is a naturally occurring peptide derived from the thymus gland. It is best known for its association with the regulation of the immune system.

Where it commonly comes up

Conversations about immune resilience during periods of heavy training load.
Discussions about general recovery when the body is under training stress.
It also appears within broader wellness conversations beyond sport.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

A note on common combinations

CJC-1295 and Ipamorelin are frequently talked about together as a pair. In some communities, that pairing is extended by adding BPC-157 and TB-500, both of which are covered under Injury Repair below.

CJC-1295 + Ipamorelin + BPC-157 + TB-500

Performance Protocol Quad Recovery Protocol

These names are informal, and the exact terminology varies considerably depending on who you ask. They are community expressions rather than standardised medical terms.

Injury Repair & Rehabilitation

This is among the most widely discussed groups for anyone working their way back from an injury, a surgery, or a demanding period of training.

What it is. BPC-157 is one of the most talked-about peptides in recovery-focused communities. It is a stable, partial sequence derived from a protein found in gastric juice, and although it was originally studied in relation to the protection of the gut lining, it is now discussed far more broadly.

Where it commonly comes up

Conversations about soft-tissue recovery, including tendons, ligaments, and muscle.
Discussions relating to gut health.
A general framing around repair support within online communities.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. TB-500 is a synthetic version of a fragment found naturally in almost every human and animal cell. It is thought to play a part in cell migration and in the structural repair processes that follow tissue damage.

Where it commonly comes up

Conversations about flexibility and mobility.
It is very frequently mentioned in the same breath as BPC-157.
General discussions about recovery timelines.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. GHK-Cu is a naturally occurring copper-binding peptide. It is well known within skincare formulations, and it is also discussed more broadly in relation to tissue health and collagen.

Where it commonly comes up

Conversations about skin health and wound recovery.
Discussions about collagen, which is also why it appears in anti-ageing circles.

This peptide is also covered under Anti-Ageing & Longevity, because it features prominently in both conversations.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

A note on common combinations

The two combinations below come up regularly in recovery-focused conversations. As with all of these terms, the exact naming varies a great deal depending on the source or community, and none of these are standardised medical terms.

BPC-157 + TB-500

Wolverine Stack Repair Protocol

BPC-157 + TB-500 + GHK-Cu

Glow Stack Glowing Protocol

Anti-Ageing & Longevity

This group is less about performing well today and more about cellular health, skin, energy, and metabolic wellbeing over the longer term.

What it is. Melanotan II is a laboratory-made analogue of alpha-melanocyte-stimulating hormone. It was originally studied in relation to pigmentation, and it now also appears within broader skin and longevity conversations.

Where it commonly comes up

Conversations about tanning and pigmentation.
Discussions relating to appetite or libido.
It is frequently raised in safety conversations, as it is commonly associated with a noticeably strong side-effect profile, including nausea and flushing.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. This is the same copper-binding peptide covered under Injury Repair. It earns a place in two categories because it is a fixture of both skin-repair and anti-ageing conversations, largely on account of its association with collagen signalling.

Where it commonly comes up

Conversations about skin elasticity and overall appearance.
A general framing around collagen support.

The fuller description can be found under Injury Repair & Rehabilitation.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. MOTS-c belongs to a newer class known as mitochondrial-derived peptides, meaning it is encoded within mitochondrial DNA rather than within the cell nucleus. It is discussed primarily within metabolic and longevity research circles.

Where it commonly comes up

Conversations about metabolic health.
It is sometimes framed within discussions as an exercise mimetic.
A general framing around cellular energy and longevity.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

What it is. SS-31 is a small peptide designed to target the mitochondria, the energy-producing part of the cell. It is understood to work by stabilising a molecule called cardiolipin within the inner mitochondrial membrane, which is associated in research with reduced oxidative stress and improved energy production. That focus on cellular energy is why it sits within longevity and anti-ageing conversations.

Where it commonly comes up

Conversations about cellular energy and mitochondrial function.
Discussions about oxidative stress and healthy ageing.
Interest in age-related decline in muscle and heart tissue within research settings.

This peptide is not approved by the TGA for this use, and much of what is known comes from research settings. This description is educational only and is not a recommendation.

What it is. Epitalon is a synthetic version of a naturally occurring pineal-gland peptide. Within research discussions it has been linked to circadian rhythm and to telomerase activity, which is why it appears so regularly in longevity conversations. It is sometimes grouped with the other peptides above, and sometimes left out entirely, depending on the discussion.

Where it commonly comes up

Conversations about sleep and circadian rhythm.
Discussions relating to cellular ageing.

This peptide is not approved by the TGA for this use. This description is educational only and is not a recommendation.

Weight Loss

Weight Loss — the GLP-1 group

This is the group behind most of the current weight-management conversation. These are known as GLP-1 medicines, and they work mainly by acting on the appetite and blood-sugar signals that influence how much we eat.

What it is. Semaglutide is a GLP-1 receptor agonist, meaning it mimics a natural hormone involved in appetite and blood-sugar control. In its registered forms it is best known by brand names such as Ozempic and Wegovy, which most commonly come as pre-filled pens or cartridges.

Where it commonly comes up

Conversations about appetite reduction and weight management.
Discussions about blood-sugar control in type 2 diabetes.
General weight-loss conversations, where it is one of the most widely referenced options.

The branded pen and cartridge products (such as Ozempic and Wegovy) are TGA-registered in Australia for particular uses. Compounded semaglutide is a separate thing and is not permitted here. Educational only.

What it is. Tirzepatide acts on two hormone pathways rather than one, targeting both the GIP and GLP-1 receptors. In its registered form it is best known by the brand name Mounjaro, which likewise most commonly comes as a pre-filled pen or cartridge.

Where it commonly comes up

Conversations about appetite reduction and weight management.
Discussions about blood-sugar control in type 2 diabetes.
Comparisons with semaglutide, as the two are frequently discussed side by side.

The branded pen and cartridge product (Mounjaro) is TGA-registered in Australia for particular uses. Compounded tirzepatide is a separate thing and is not permitted here. Educational only.

What it is. Retatrutide is a newer compound that acts on three pathways at once (GLP-1, GIP, and glucagon). It has attracted a great deal of attention because early trials reported the largest average weight loss of the group, but it is still investigational and has not completed the approval process.

Where it commonly comes up

Conversations about the next generation of weight-management compounds.
Discussions comparing it with semaglutide and tirzepatide on trial results.

Unlike semaglutide and tirzepatide, retatrutide is not TGA-approved in Australia, is not on the ARTG, and is not able to be compounded here. It remains investigational. Educational only.

One important distinction for this group

This group is worth separating from the rest of the page for one simple reason. The branded, pre-filled pens and cartridges — products such as Ozempic and Wegovy (semaglutide) and Mounjaro (tirzepatide) — are TGA-registered medicines, approved in Australia for particular uses.

What is different is the compounded or raw versions of these same molecules. Compounded GLP-1 medicines are not permitted in Australia, and retatrutide is not approved here at all. So while the GLP-1 name covers all of them, only the registered branded products sit inside the approved system.

Getting it in

How are peptides actually taken?

One of the most common questions is simply how peptides get into the body in the first place. There are several different formats, and the right one depends on the specific peptide, the goal, and personal preference.

Subcutaneous injection

Injectable

Injected into the layer of fat just beneath the skin. This is the most common format for many peptides, and much of the research is based on it, which is why injectables are often described as the most reliable for absorption.

Dissolvable films

Needle-free

Thin films that dissolve in the mouth, often under the tongue, releasing the peptide as they break down. A needle-free option that many people find far more approachable.

Capsules & tablets

Oral

Taken by mouth like any other capsule or tablet. Convenient and familiar, though many peptides are fragile in the digestive system, so this format suits some compounds much better than others.

Nasal & oral sprays

Needle-free

Delivered as a spray, either into the nose or the mouth. This is another needle-free route that certain peptides are particularly well suited to.

Topical creams

Applied to skin

Applied directly to the skin as a cream. This is common for skin-focused peptides such as GHK-Cu, where the skin itself is the target, and copper-peptide creams are widely available.

And others besides

Format varies

New formats appear as the science develops, and a single peptide can sometimes be available in more than one form. The format is really just the vehicle; the peptide inside is the same idea throughout.

So why choose one format over another?

There is no single best answer. Injectables tend to be the most potent, and much of the research is built around them, which is why they remain the most talked-about route. For other people, though, needles are a genuine barrier, and formats such as films, capsules, sprays, and creams can make the whole idea feel far more approachable. The practical takeaway is that there is generally an option to suit most people and most preferences, and the right choice depends on the specific peptide, the goal, and the individual.

The Australian picture

How are people getting these in Australia?

A fair question that naturally follows is how people are actually obtaining these compounds. In practice there are broadly three routes being used, and only one of them is the correct, legal, and properly supervised way to approach what are, in most cases, Schedule 4 prescription-only medicines.

Not lawful · high risk

Importing and mixing it themselves

Some people import the raw peptide directly from overseas suppliers and prepare or mix it themselves. There is no reliable way to confirm what has actually been supplied, no independent safety testing or profiling, and no sterility testing. It also means handling prescription-only medicines without a prescription, and it introduces a real risk of contamination, incorrect dosing, and infection.

Not the proper channel

Buying through an unverified reseller

Others buy from what looks like an Australian business, but which is in fact a middleman importing the product from overseas and reselling it. These sellers are typically not working with a licensed Australian compounding pharmacy, and not working with doctors following the proper prescribing process. The result is much the same: no genuine prescription pathway, no guaranteed quality or sterility testing, and no clinical oversight.

The proper, legal route

Through a clinic and a licensed pharmacy

A GP or prescribing doctor with experience in peptide therapy, seen in person or via telehealth, reviews your health history and needs and, where appropriate, provides a prescription tailored to you. The compound is then made to order by a licensed Australian pharmacy, as the law requires, rather than being produced in advance. It undergoes the appropriate sterility and quality testing, and is dispatched either to you to self-administer or to your doctor to administer. Importantly, you are properly screened before you start and monitored over time.

One note on the weight-loss group. Because compounded GLP-1 medicines are no longer permitted in Australia, the equivalent legal route for that group is a prescription for a registered branded product, such as Ozempic or Mounjaro, dispensed through a pharmacy rather than compounded.

Whichever peptide is being discussed, the safe and lawful path runs through a qualified doctor and a licensed pharmacy.

Prefer to listen?

Hear it explained in more depth

If you would rather absorb this by watching, the two explainers below cover a great deal of the same ground in more detail. Each one only begins playing once you choose to press play, so nothing will start on its own.

An in-depth overview of what peptides are and how they behave in the body. It is embedded here for educational context and reflects the views of its creator.

Watch on YouTube instead

A second, longer conversation that explores the science, the wider context, and many of the common questions people have. It is included here purely as further educational viewing.

Watch on YouTube instead

Please read this carefully

The important part

This page exists to explain concepts and to describe the conversations happening around peptides. It is not here to guide decisions about your health, so please take the points below seriously.

This entire page is general education and is not medical advice. Nothing here has been written or reviewed by a clinician, and none of it should be treated as a substitute for professional care.

Most of the peptides here are not TGA-approved for the uses described. The main exception is the weight-loss group, where some branded products are registered while compounded versions are not.

Nothing here is an instruction or an endorsement to acquire, use, or combine any peptide. Describing that something is discussed online is not the same as suggesting that you should try it.

Always speak with a qualified, registered doctor before making any decision about your health, particularly before starting, stopping, or combining anything.

Sourcing, quality, legality, and individual circumstances vary enormously. Something being discussed online is not automatically safe, legal, or appropriate for any given person.

If you are outside Australia, please be aware that regulations differ from one country to the next. This page is written with an Australian audience in mind, so always check your own local rules.

This page has been produced independently and has no affiliation with any company, clinic, product, or brand. It does not sell, promote, or link to anything for purchase. It exists purely to make an increasingly common, and increasingly confusing, topic a little easier to understand.