Injectable peptides are the new anti-ageing trend. But what evidence do we have they’re safe for humans?

Injectable peptides are the new anti-ageing trend sweeping the beauty industry.

These compounds are promoted on social media as tools for skin repair, collagen production and “cellular rejuvenation”. They are widely available online from overseas sellers, despite many peptides being unregulated in Australia.

But what’s in them? And are they safe?

Earlier this year, three people in the United States were fined thousands of dollars for their role in providing peptide injections, at an anti-ageing festival in Las Vegas, to two women who later became critically ill. The pharmacy board was unable to determine why they got sick, and what precisely the serums contained.

Our work with colleagues at Steroid QNECT, a hotline where people can seek confidential advice about enhancement drugs, tell us people are already injecting peptides in Australia.

But regulation is not keeping up. And there are still major gaps in the evidence about whether peptides’ anti-ageing claims stack up, and whether they are safe for humans.

What are injectable peptides, and why are they trending?

Peptides are short chains of amino acids – the building blocks of proteins. They act as chemical messengers in the body and play a key role in many processes. These include helping repair skin and calming inflammation.

The body naturally produces peptides. Synthetic peptides are manufactured to mimic or enhance these natural functions.

Certain peptides have clear medical uses. For example, glucagon-like peptide-1 (GLP-1) drugs, such as semaglutide, are approved for diabetes and weight management – sold as Ozempic and Wegovy. This is based on strong clinical trial evidence they are effective.

But a growing number of peptides are being marketed for cosmetic and anti-ageing purposes, without approval from Australia’s therapeutic goods regulator.

Peptides such as GHK-Cu, BPC-157 and TB-500 are sold online with claims they can enhance collagen production, accelerate skin repair, reduce wrinkles, and even reverse aspects of biological ageing.

Are these products legal in Australia?

Currently, regulated injectable peptides fall under prescription-only medicine categories. This means they should only be accessed through a qualified health professional for a legitimate medical indication.

Australian regulators have already issued fines to companies for illegally promoting weight-loss injections directly to consumers.

The Therapeutic Goods Administration (TGA) lists other synthetic peptides not yet approved for human consumption, such as BPC-157, as Schedule 4 poisons.

To get around this, many products circulating online are sold as “research chemicals” labelled “not for human consumption”.

Yet in practice, they are packaged, dosed and marketed in ways that clearly anticipate human use. Online sellers typically require minimal verification of age or identity, and promise rapid shipping and high purity (for example, “99%+ tested”).

This creates a parallel market operating outside clinical oversight and regulatory safeguards. While importing or possessing prescription-only peptides without authority can lead to fines or legal penalties, enforcement is challenging in global, digital markets.

At the same time, injecting appears to be becoming less taboo, particularly in the cosmetic and wellness industry. Most cosmetic injectables (including anti-wrinkle injections and dermal fillers) also involve prescription-only substances. Yet there are many clinics that offer injections with very little oversight from prescribing doctors.

This broader “injectable culture”, with simulataneous increases in steroid use, may be lowering barriers to more experimental practices, including peptide use.

Read more: Thinking of getting botox or filler? These are the laws for cosmetic injectables

What does the evidence actually say?

For many peptides promoted for anti-ageing and skin health, high-quality human evidence remains limited.

Claims peptides such as GHK-Cu, BPC-157 and TB-500 can help regenerate and repair tissue and calm inflammation are based on a handful of laboratory studies – in cells or animals, not humans.

For example, there is some limited evidence GHK-Cu could play a role in collagen production, and wound healing in mice. But these findings have not been confirmed in humans.

Similarly, some research suggests BPC-157 can promote new blood cell growth, reduce inflammation and heal tissue in rats.

But human evidence is extremely limited. Only three small studies have looked at BPC-157 and these were not well designed, and lacked a control group to compare the reported effects (such as improvement in knee pain). No large clinical trials exist. So its safety and effectiveness in humans remain uncertain.

A consistent pattern emerges:

• evidence is mostly limited to animal studies

• human studies, where they exist, are small and short-term

• there are no high-quality trials reflecting real-world use, including combinations, higher doses or long-term administration.

So currently, we don’t have enough quality evidence to support the many anti-ageing claims made for peptides.

And there are risks

First, there is the issue of unknown product quality. Unregulated peptides may be mislabelled, contaminated or incorrectly dosed – a problem already documented in adjacent markets, such as counterfeit steroids.

Second, there are biological risks. Peptides that influence growth, repair or hormonal pathways may also stimulate unintended processes. In theory, this could include promoting the growth of existing tumours or disrupting normal endocrine function. This cancer risk is amplified by the high presence of heavy metals in illicit enhancement drug markets.

Third, injecting carries its own risks — including infections, abscesses and tissue damage, particularly when products are self-administered without sterile technique.

At Steroid QNECT, we are already seeing people seeking advice after using peptides they bought online – often unsure what they have taken, how much, or what to expect.

In some cases, dosing far exceeds anything studied in clinical trials.

What needs to change?

We need clearer, more consistent regulation of peptide supply and marketing. But this is unlikely to be enough on its own, given the global and digital reach of peptide supply chains.

A more effective response would also include clear, accessible public health information on the potential benefits and risks of peptide use.

Importantly, responses need to reflect reality: people are already using these substances.