By Dr Niall Graham

 

Peptides have moved from underground bodybuilding forums into mainstream longevity and performance discussions. Patients are no longer just elite athletes. They are 18- to 80-year-old professionals training hard, recovering slower, wanting to stay metabolically sharp and injury free.

As a GP with an interest in both longevity and sports medicine, my role is not to hype them or dismiss them. It is to explain what they are, what the physiology suggests, what the evidence shows, and where the risks sit.

At their core, peptides are short chains of amino acids that act as signalling molecules.
They tell cells to do something:

• Repair tissue.
• Release growth hormone.
• Modulate inflammation.
• Influence mitochondrial function.
• They are messengers, not magic.

Some are well established in medicine. Many are not.
That distinction matters.

By Dr Matthew Barber

A lot has changed from the traditional model of medicine, where doctors treat disease as it arises. We’re increasingly focused on holistic care and prevention these days — and that is a great thing. But with the advent of the internet, social media, and now AI, there are huge amounts of information (and misinformation) at our fingertips, constantly infiltrating our feeds. We live in a success culture, and it’s increasingly the role of your primary care doctor to give advice on all sorts of new possibilities, risks, and opportunities when it comes to our health.

A very topical example of this is peptides. Give your algorithm even a hint that you might be interested in them and influencers selling these products will start filling your feed very quickly. At the time of writing, there are close to 100 different peptides being sold online, with reported benefits ranging from weight loss and anti-ageing to muscle growth, sleep, tanning, and tissue recovery.

The striking thing is that many of them have very real physiological effects — and therefore very real side effects. Some peptides have become massive success stories for pharmaceutical companies and are turning huge profits. Those weight loss injections you may have heard of — Ozempic, Wegovy, and Mounjaro — are all peptide-based medications. Retatrutide is another peptide currently in phase 3 clinical trials. It looks promising not just for weight loss (via appetite suppression) but also for improving insulin sensitivity and pancreatic function. Phase 3 trials are the final step before potential approval as a prescription medication — yet retatrutide is already seeing use among some gym-goers and bodybuilders.

So how come it’s so easy to get these products online?

Peptides are simply chains of amino acids — the building blocks of proteins in the body. They can be synthesised relatively easily using automated laboratory processes that have existed since the 1980s. In theory, that might suggest that when you buy peptides online, you’re getting what you pay for.

In reality, when these products are analysed, the contents often vary widely. Some contain incorrect dosages, some contain no active ingredient at all, and others have been found to contain heavy metals or unexpectedly high levels of vitamin B6.

So should you take them?

My answer is: probably not. And if you’re considering it, you should discuss it with a doctor who has some knowledge of the topic.

These substances can have meaningful biological effects. The problem is that we don’t truly understand many of them. Most peptides available online are nowhere near the stage of clinical development that retatrutide has reached. The vast majority have no human data at all — not even phase 1 trials, which are designed to establish basic human safety. Some have limited animal studies or laboratory (in vitro) data. Others are based purely on theoretical knowledge of biological pathways that might produce benefits in humans.

That leads to another important theoretical concern: cancer. Many peptides interfere with pathways involved in cell growth and replication — the very processes that, when dysregulated, lead to cancer. It is biologically plausible that altering these systems could increase cancer risk. That said, this concern itself isn’t evidence-based either — because we simply don’t have long-term human data. The absence of evidence cuts both ways.

History gives us reasons to be cautious. There are countless examples of products with genuine biological effects that were once thought beneficial but later proved harmful. Diethylstilbestrol (DES), a synthetic oestrogen, was prescribed to prevent miscarriage. It later turned out to significantly increase the risk of breast and other cancers. Phenacetin (marketed as Bex powders) was widely used for pain relief. It was metabolised to paracetamol and seemed safe for decades before it was linked to kidney failure and bladder cancer.

What about the confident claims online that these peptides are safe and effective?

The problem is that many of these claims are made by influencers who are also selling the products. The best available data for many peptides is limited to animal models at best. That means we simply do not know — in a rigorous, scientific sense — whether they are safe or effective in humans. Some clearly produce effects that people may find desirable, such as SARMs for muscle building or melanotan for tanning. But we are largely relying on anecdote when it comes to short- and long-term safety.

So what’s the take-home message?

Just because something has a real biological effect doesn’t mean it’s safe. And just because something is sold online doesn’t mean it’s regulated, tested, or understood. Many of the peptides being marketed today may eventually become valuable prescription medications. The key difference is that approved drugs go through years of careful testing to determine the correct dose, the true benefits, the side effects, and the long-term risks.

When you buy peptides online, you’re stepping outside that safety system and effectively experimenting on yourself without those safeguards.

If you’re curious about peptides or interested in optimising your health, that curiosity isn’t a bad thing. But it’s worth approaching the topic with caution, healthy scepticism, and guidance from a qualified doctor who can help you separate genuine medical advances from marketing hype.

If you’ve spent any time on queer health Twitter, Grindr chats, or in a sexual health clinic waiting room lately, you’ve probably heard whispers about DoxyPEP. Some people call it revolutionary. Others call it controversial. A few think it’s “antibiotics for vibes.”

So let’s clear things up — calmly, accurately, and with minimal pearl-clutching.

What is DoxyPEP?

DoxyPEP stands for doxycycline post-exposure prophylaxis. In plain English: it means taking a single dose of doxycycline (200 mg) after sex to reduce the risk of some bacterial STIs.

Think of it as a seatbelt, not an airbag. It doesn’t replace condoms, testing, or good communication — but it can reduce risk when there is higher chance of STIs crashing into your day. This is about harm reduction, not slut-shaming.

Which STIs does it help prevent?

The evidence shows that DoxyPEP can reduce the risk of Chlamydia and Syphilis by 80-90%. It can help prevent Gonorrhoea, but this is only about 50% of the time because gonorrhoea already has significant resistance to doxycycline in Australia.

IMPORTANT!
DoxyPEP does not prevent viral infections like HIV, genital herpes, warts or Mpox.

 

Who is DoxyPEP for?

Australian experts suggest DoxyPEP may be considered for:

• Gay, bisexual and other men who have sex with men (GBMSM)
• Trans and gender-diverse people
• People with a recent history of bacterial STIs (particularly Syphilis, but also Chlamydia and Gonorrhoea) – especially if infections keep happening despite regular testing and safer-sex strategies

In other words, it is aimed at people with ongoing, higher STI exposure, not everyone who’s ever had a hookup.

How does it work?

• You take 200 mg of doxycycline – usually as 2 x 100mg capsules
• As soon as possible after sex, ideally within 24 hours but no later than 72 hours
• Never more than once per day

This isn’t a daily antibiotic and it’s not something you take “just in case” forever without review. It should be prescribed and monitored by a clinician who knows sexual health.

Is it safe?

For most people, yes — doxycycline has been used for decades. But it’s not completely side-effect-free.

Common issues include:

• Nausea and/or reflux (take it with food and stay upright!)
• Sun sensitivity (hello, SPF)
• Vaginal or oral thrush in some people (ugh!)
• Increased pressure in the brain if you are taking the acne tablet Roaccutane (yikes )

What about antibiotic resistance?

This is the big concern, and it’s why DoxyPEP is targeted, not universal. Doxycycline will kill other bacteria on your skin, in your airways and in your gut, and we really don’t know how it will affect them in the longer term. For protected sex or fun stuff without penetration, DoxyPEP is probably overkill. For unprotected sex – especially when the risk is higher (e.g. sex on premises venues, sex parties, weekends with more sex partners than usual) then DoxyPEP could be your best friend.

Used in the right situations, the benefits — fewer infections, less transmission, fewer complications — can outweigh the risks. Open slather could cause problems. That’s why you should listen to a healthcare professional, not a Tik Tok influencer.

Is DoxyPEP right for you?

Maybe. Maybe not. That’s a conversation — not a checkbox.

If you:

• Are having condomless sex
• Are getting repeat STIs
• Want another layer of protection without shame or lectures

…then DoxyPEP might be worth discussing.

And if it’s not right for you? Also completely fine. Sexual health is not one-size-fits-all.

The takeaway

DoxyPEP isn’t perfect. But for some people, it’s a genuinely useful tool — one more way to take control of your sexual health while still enjoying your sex life. If you want to talk about DoxyPEP, come see us. No judgement. No scare tactics. Just evidence-based care — and maybe a little sass.

Women’s health and bridging the gender gap

In the last ten years we’ve witnessed a much larger focus on women’s health and the too often overlooked differences women experience compared to men. Medical science has been a big part of this change and is finally beginning to better describe and help us understand how the experience of women differ to men but there’s no question that a wide gender gap still exists. Women continue to carry a disproportionate burden of unmet health needs across pain, menopause, reproductive health, neurodiversity and chronic disease. The story, unfortunately is still often one of dismissal, delay and lost opportunity.

 

Persistent Disparities

For decades women have been told their experience is “just part of being a woman” and had their symptoms framed in a way that normalises suffering as opposed to challenging it. Conditions that we’ve been aware of for many decades like Endometriosis and Polycystic Ovarian Syndrome (PCOS) affect large numbes of cis women but continue to be under-diagnosed and dismissed. The result of all this is two-fold, the individual suffers a significant and persisting health burden and there continues to be a systemic under investment in research, diagnosis and treatment.

Menopause, miscarriage, sexual function and pleasure are often whispered about rather than proactively discussed and this despite these important areas having far reaching consequences. Menopause especially  has clear and measurable impacts on cardiovascular health, bone health, sexual wellbeing and mental health and there is increasing amounts of evidence that clearly shows women’s trajectories diverge markedly from men’s. We now understand that when women suffer from a heart attack the biological pathway leading to that event is entirely different to what is common for men and yet they are treated the same with a “male model” of cardiovascular health.

 

Neurodiversity and missed diagnoses

The disparities, delays and under diagnoses persist with conditions such as Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) which look different in both girls and adult women. The frameworks developed to diagnose these conditions have been largely developed through male presentations  and so women and girls go undiagnosed  and therefore navigate life without intervention or support. The consequences of this include greater mental health burden, missed educational and employment opportunities and a heightened risk of long term morbidity.

 

Signs of progress

There are glimmers of progress. This year Medicare has introduced new rebates for GPs to address and manage the different health experience of women. The menopause health check allows GPs and practice nurse to spend more time with patients to better understand their individual experiences and tailor health care to their individual situation. At the same time guidelines on conditions like Endometriosis are moving away from requiring laparoscopic (key-hole) surgery before treatment can be initiated. These changes in diagnostic guidelines matter because they allow women to access a diagnosis and therefore treatment and relief earlier than ever before.

 

What this means especially for women over the age of 40

If you are a cis women over the age of 40 the next years of your life are likely to be particularly pivotal. The transition into mid life and beyond carries unique health care challenges and now is the time to intervene to best protect your future health. At this juncture your exposure to crucial health risks (heart disease, bone health, pelvic floor strength, sexual function and mental health) accelerates.

The invitation to engage in comprehensive preventative care is often missed especially if your only exposure to the GP is standard consultations with a specific purpose in mind. Many women internalise the message that pain, discomfort, mood changes or sexual decline are “just the way things are” and this leads to a delay in seeking help. They worry they will be told that these changes are “ just a part of ageing”

 

Why your experience matters

Your symptoms and individual experience of health matter and deserve more than casual dismissal. When pain is dismissed, mood changes are attributes to character rather than hormonal imbalances and when neurodivergence is overlooked the cost is not just delayed diagnosis. It is compromised quality of life, loss of productivity, impaired relationships, avoidable illness and even premature death and disability. It is the frustration of living ignored.

 

What you can do and what our practice offers

At Stonewall Medical Centre we are proud to offer bulk billed women’s health checks. Government funding allows us to target these specifically to cis women over the age of 40. These consultations start with the practice nurse who will collect and help us better understand your situation and finish with the doctor who will tailor a plan specific to you. They are designed to:

• Review your health holistically (not just hormones but cardiovascular risk, bone health, pelvic and sexual function, mood and neurodiversity screening)
• Respond to symptoms you may have learnt to normalise (pain, heavy periods, sexual dysfunction, mood swings and brain fog)
• Ensure you are heard, believed and partnered in decisions about your health and not just brushed off with “that’s just part of being a woman”

If you are a woman over the age of 40 now is the time to take action with regards to your health. Book for a women’s health check at the link below.