Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
Semaglutide has become one of the most talked-about tools in the weight management space, with Ozempic® being the well-known brand originally prescribed in Australia for type 2 diabetes. While often used off-label for weight loss, Ozempic is a highly regulated, Therapeutic Goods Administration (TGA)-approved medication. In contrast, compounded semaglutide emerged as a ‘customised’ alternative, often marketed during supply shortages as a cheaper or more flexible option. On paper, they may share the same active ingredient, but the biological and legal reality is far more complex than the social media ads suggest.
On a chemical level, compounded semaglutide is often marketed as containing the same active GLP-1 peptide found in Ozempic®. However, since the October 2024 TGA ban on replica compounding, these products have moved into a legal grey area in Australia. While a compounding pharmacy might mix a bespoke formulation for a patient with a rare, documented allergy to a preservative, they are no longer permitted to mass-produce ‘off-brand’ versions of semaglutide.
Unlike the brand-name pen, compounded versions often lack the stabilisers that protect the delicate peptide from breaking down. This means that by the time it reaches your door, the potency may have dropped, making your results unpredictable. Furthermore, many compounded versions have been found to use ‘salt’ forms (like semaglutide sodium) which the TGA warns have never been found safe or effective for human weight loss.
Ozempic® is a TGA-approved medication that uses a standardised, pharmaceutical-grade version of semaglutide. It works by mimicking your body’s natural GLP-1 hormone to regulate appetite and slow gastric emptying, helping you feel fuller for longer. Because it is delivered in a precision-engineered, prefilled pen, you are guaranteed the exact dose every single week, something a hand-mixed vial simply cannot match.
With Australian supply chains now fully stabilised, the need for ‘stop-gap’ compounded versions has largely disappeared. Sticking to a registered medication means your journey is backed by extensive clinical trials and a well-documented safety profile, giving you the peace of mind that what you are putting into your body is both legal and effective.
While compounded semaglutide and Ozempic® might share a name on a prescription pad, they are worlds apart when it comes to the safety checks that protect your biology. In Australia, the TGA maintains strict boundaries between registered medicines and unapproved compounded ones.
Here are the critical differences you need to understand before making a choice for your health:
Ozempic has undergone years of international clinical trials to meet the TGA’s rigorous standards for safety and efficacy. Compounded semaglutide, however, is an ‘unapproved’ product. As mentioned, as of October 2024, the TGA officially banned the compounding of GLP-1 replicas because they hadn't been evaluated for quality. In 2026, choosing a compounded version means stepping outside the safety net that the Australian government has built for you.
Ozempic is manufactured by Novo Nordisk in high-tech, sterile facilities where every single drop is identical. Compounding happens in a pharmacy setting. While pharmacists are highly trained, they lack the industrial-level quality controls of a global pharmaceutical lab. This can lead to variations in potency, meaning one batch might be stronger or weaker than the last, which can make your weight loss results (and side effects) unpredictable.
Ozempic uses the base form of semaglutide, which is the only version proven safe for human injection. Many compounded versions have been found to use ‘salt’ forms (like semaglutide sodium), which are often intended for research, not for your body. The TGA and FDA have both warned that these salts have never been found safe or effective for weight loss.
Ozempic comes in a pre-filled, ‘idiot-proof’ pen designed to deliver a precise dose every time. Compounded versions often come in a glass vial that requires you to draw up the medication yourself using a syringe. This significantly increases the risk of dosing errors and contamination, which can lead to severe nausea or site infections.
Compounded semaglutide often comes with a lower price tag because it bypasses the massive costs of clinical trials, patent licensing, and the industrial-scale quality control that brand-name manufacturers must follow. While the upfront saving is tempting, research consistently shows this comes with significant safety trade-offs.
A 2025 analysis of adverse event reports found that compounded GLP-1 medications were linked to significantly higher rates of serious side effects, including severe nausea, diarrhoea, and gallbladder inflammation, compared to TGA-approved products. Because these versions are hand-mixed, they also carry a much higher risk of dosing errors. In short, while the ‘off-brand version may seem cheaper at the pharmacy counter, the hidden risk of a hospital visit or an ineffective batch makes the TGA-approved Ozempic® the only reliable choice for your long-term health.
Following the 1 October 2024 TGA ban, it is now illegal for pharmacists to mass-produce replicas of Ozempic®. Today, compounding is reserved only for the rarest of clinical exceptions, such as:
Documented Allergies: When a patient is medically proven to be allergic to a specific non-active ingredient (like a preservative) found in the brand-name pens.
Specific Clinical Needs: When a specialist determines that a patient requires a unique concentration that is not commercially available.
Individualised Care: A pharmacist can only prepare the medication for one specific person after receiving a valid prescription, not in bulk ‘batches’ in anticipation of orders.
With the global Ozempic shortage now officially resolved as of late 2025, there is no longer a medical or legal reason to take the risk with unapproved compounded versions. Ozempic remains the gold standard for several key reasons:
TGA-Approved Safety: Every pen is manufactured in a sterile, industrial facility and tested for exact potency.
Predictable Results: Because the dosing is precise, you and your doctor can accurately track your progress without worrying about batch-to-batch variation.
User-Friendly Delivery: The pre-filled pen is designed to reduce the risk of infection and dosing mistakes that come with self-drawing medication from a vial.
Legal Compliance: Using a registered medication ensures you are following the latest Australian health regulations and protecting your own medical liability.
In the world of medical weight management, the distinction between registered and unapproved medications is a critical one for your long-term health. Ozempic® is a TGA-approved, pharmaceutical-grade medication that has undergone rigorous clinical trials to ensure every dose is sterile, potent, and safe. In contrast, compounded semaglutide products are unapproved therapeutic goods that have not been evaluated for quality or efficacy. This is the primary reason for the 2024 regulations: to protect your biology from the risks associated with untested and unregulated chemical variations.
Now that supply chains in Australia are stable, the safest path forward is to prioritise the gold standard of registered treatment. Choosing a TGA-approved medication ensures you are backed by precise industrial standards,predictable dosing, and a well-documented safety profile. By working with your healthcare team to access regulated options, you are moving away from the uncertainties of unapproved mixtures and toward a version of weight management that is safe, legal, and built for your long-term wellbeing.
Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.