Peptides: What are they and are they safe?

Peptides are the latest health craze, with influencers, biohackers and fitness enthusiasts singing their praises. They’re marketed for everything from glowing skin to fat loss and muscle gain. But when something promises a bit of everything, it’s worth asking: is it too good to be true? Let’s dive into what the research says.

What are peptides?

Peptides are short chains of amino acids, the building blocks that make up proteins. Peptides may sound complex, but at their core, they’re simply messengers in the body. Your body is constantly running processes like repairing tissue, balancing hormones, managing energy, and maintaining skin health. For all of this to happen, your cells need clear instructions. Peptides are short chains of amino acids that send those instructions, telling your body what to do and when to do it.

Your body naturally produces peptides (like insulin), and you also get them from protein-rich foods. Some are also made synthetically and used in medications or skincare.

What are the different types of peptides?

Not all peptides are created equal and this is where things get interesting. Peptides come in many different forms and are used in many different ways such as topical, oral or injected. It depends on the type of peptide, what it’s used for, and its benefits.

In Australia, some peptides are approved for use in medicines, some are approved for skincare, and others are not approved for use due to the lack of long term evidence and safety.  

1. Approved prescription-only peptides

These are types of peptides that have gone through clinical trials and are approved for use by the TGA. 

Examples include:

• Insulin for the management of diabetes
• GLP-1 receptor agonists like Semaglutide (Ozempic, Wegovy) for blood sugar and weight management

These have safety and efficacy data from research and trials that allow them to be prescribed to eligible patients. 

2. Topical cosmetic peptides

Common in skincare products, these peptides are used to support:

• Collagen production
• Skin hydration
• Barrier restoration
• Deliver trace minerals
• Reduce inflammatory molecules

They are generally considered low risk when used topically, as their ability to penetrate through the skin is limited. However, longer term studies are needed to determine their uses in skincare. 

3. Unregulated peptides

This is where most of the social media hype and biohacking comes in. These peptides are unapproved products which have not been included in the Australian register of therapeutic goods (ARTG). That means it is illegal to sell these products in Australia.

These peptides are often advertised online labelled “for research use only” and include names like:

• BPC-157
• TB-500
• CJC-1295

The issue? Most have limited or no high-quality human trials, with evidence largely coming from animal or lab studies. Other concerns, especially with injectable peptides, is that they pose a significant safety risk, including contamination, infection or tissue damage. This means we don't know what the long-term effects of injecting these peptides might be.

What are the uses of peptides?

Peptides play a wide range of roles in the body. For example, insulin is a peptide that helps move sugar out of your bloodstream and into your cells for energy. Other peptides signal your body to produce collagen for skin structure, regulate appetite, influence metabolism, or support recovery after exercise.

What’s key to understand is that peptides don’t do the job themselves. They don’t directly build muscle or repair skin. Instead, they signal your cells to start those processes.

Your body naturally produces peptides every day, and they’re tightly regulated. When peptides are introduced from outside the body, like through treatments or supplements, they’re essentially trying to influence those signals. In some cases this is well-researched and effective, but in others, the effects are less predictable.

In simple terms, peptides are part of your body’s communication system, helping coordinate what happens internally to keep everything running smoothly.

Depending on the type, peptides can have very different roles:

Clinically approved uses

• Blood sugar regulation (insulin, GLP-1s)
• Hormone signalling
• Fertility and reproductive health
• Metabolic conditions

These uses are supported by clinical trials and regulatory approval.

Emerging or marketed uses

• Muscle growth and fat loss
• Injury recovery
• Healthy ageing and longevity
• Skin rejuvenation

While these sound appealing, many of these claims are based on early-stage or non-human research, not strong clinical evidence.

Are peptides safe?

This is where nuance matters because the answer isn’t simply yes or no. The short answer is that some peptides are considered safe. Others are unknown and may carry real risks.

What the research shows

1. Approved peptides are generally safe (when prescribed by a Registered Doctor)

Peptides that have gone through clinical trials have well-characterised safety profiles, including known side effects and dosing guidelines.

2. Topical peptides are lower risk

Used in skincare, they are generally well tolerated with minimal systemic effects. However, with all skin care it is important to patch-test before adding anything new to your routine.

3. Unregulated peptides are the biggest concern 

This is where most safety issues arise.

Key risks include:

• Lack of human safety data
• Unknown long-term effects
• Incorrect dosing
• Contamination or mislabelling

Independent testing has found that some peptide products:

• Contain less active ingredient than stated
• Are contaminated with bacteria or toxins
• Contain entirely different compounds than labelled

4. Regulatory concerns

Health authorities like the TGA have raised concerns about peptide safety, leading to restrictions on certain compounds due to insufficient safety evidence.

5. Real-world risks (unsupervised use)

Medical experts report complications from unregulated peptide use, including:

• Hormonal imbalances
• Immune reactions
• Infection risk from injections
• Potential tissue overgrowth or metabolic disruption

Should you use peptides?

Whether you should use peptides depends on the type and how they’re being used. Some peptides are well-researched and used in medicine, but these should only be taken under the guidance of a qualified healthcare professional, such as a registered doctor, who can assess if they’re appropriate and monitor your response.

Caution is needed with peptides sold online for things like fat loss or anti-ageing, as many aren’t well studied, regulated, or tested for safety and quality. It’s best to avoid buying these off the internet. For topical peptides in skincare, they’re generally low risk, but patch testing first is still recommended to check for any irritation.

The bottom line

Peptides aren’t inherently “good” or “bad”, they’re more like tools.

Some are essential, life-saving medications backed by decades of research. Others are still experimental, under-researched, and in some cases, risky.

The key is knowing the difference and not getting swept up in the hype. If you’re considering peptides, stick to options that are backed by research and guided by a qualified healthcare professional, and approach anything unregulated with caution.

Reviewed by the Healthylife health experts May 2026.