The grey market for weight-loss medication is usually framed as a price question — same medicine, cheaper, fewer hoops. That framing is wrong in a specific way that matters. What HSA has repeatedly found in seized weight-loss products is not underpriced legitimate medicine. It is something else in the packet. This article covers what has actually been found in Singapore, what the law says about supplying it, and why the missing parts of the transaction matter as much as the contents.
Adulterated product: one containing an undeclared substance. Under the Health Products Act it is a distinct and more serious offence than supplying an unregistered product.
What HSA has found
In an alert published on 29 May 2026, HSA named four weight-loss products sold online. Two of them contained sibutramine — described by HSA as "previously a prescription only weight loss medicine used in the treatment of obesity", which "has been disallowed for sale in Singapore since 2010 due to increased risk of heart attacks and strokes". The other two held a laxative, and an anti-inflammatory with a banned laxative (HSA).
HSA has published alerts of this kind over a number of years. In December 2014 it warned about two illegal weight-loss products bought online — one containing sibutramine and other undeclared substances, after which a teenager was hospitalised, and one containing yohimbine, after which a consumer suffered acute kidney failure. In October 2018 it seized 4,520 units of illegal health products during an INTERPOL-coordinated operation, and the items seized included weight-loss products (HSA enforcement announcements).
What those cases have in common is not that every online product is adulterated — they are specific named-product findings. It is that in each case the product was bought online, looked ordinary, and what was actually in it was identified in a laboratory rather than by the buyer.
What "compounded" means, and does not
The word does a lot of work in marketing and very little in law.
In Singapore, every semaglutide and tirzepatide product on HSA's register is a specific registered product with a licence number and a Prescription Only classification (HSA register). Registration means a manufacturer submitted a dossier, and the product's quality, safety and manufacturing were assessed.
A compounded or unregistered version supplied outside that framework has not been through any of that. It may contain the right molecule at the right concentration. It may not. Nobody has checked, and the buyer has no means of checking.
The Health Products Act treats these as distinct offences. Supplying an unregistered health product carries a fine of up to $50,000 or two years' imprisonment. Supplying an adulterated, counterfeit or tampered product carries up to $100,000 or three years (Health Products Act).
The parts of the transaction that go missing
Contents are the risk people think about. Three others matter and get less attention.
Dose. GLP-1 medication is deliberately started low and increased in steps, because gastrointestinal reactions cluster at escalation (prescribing information). A vial of uncertain concentration makes that schedule meaningless. You cannot titrate carefully with a product whose strength you cannot verify.
Storage. These medicines have storage requirements set out in their product information. A package that spent a week in a courier network may look identical to one that was handled correctly.
The assessment. This is the one that gets dismissed as a hoop. It is where a doctor finds out whether you have a history that makes this medicine a poor idea, what else you take, and what to monitor — and where someone knows to contact if something goes wrong. Buying around it does not remove the need for it; it removes the person who would have caught the problem.
Recourse. MOH's 2024 reply states plainly that "HSA does not have extra-territorial powers", and that around 14% of illegal listings on major local platforms in 2023 came from overseas sellers (MOH 2024). If an overseas seller ships you something harmful, there is no practical remedy.
The legal exposure
For sellers, the current penalty is a fine of up to $100,000 and/or up to three years' imprisonment under the Health Products Act (MOH 2024). Enforcement is active: HSA participated in two INTERPOL-led international operations and removed over 7,000 online listings (MOH 2024).
For buyers the position is different from selling, and the one allowance that does exist is narrower than it is usually described.
What personal import does and does not permit
This is the area where reasonable people get confused, because there is a genuine legal allowance and it is narrower than it sounds.
HSA permits bringing in up to three months' supply of your own prescribed medicine without prior approval, provided you have a valid prescription or a letter from your doctor and it is in original labelled packaging (HSA). It does not extend to supplying anyone other than immediate family for whom the medicine was prescribed, and controlled substances need prior approval separately.
Read that carefully and the limit is obvious: the allowance assumes a prescription already exists. Ordering prescription medicine from an overseas site that does not require one is not personal import of your own prescribed medicine. It is buying a prescription-only product without a prescription.
How to tell the difference
The blunt answer is that you often cannot, from the outside, and that is exactly why the registered framework exists. Adulterated products are manufactured to look legitimate — the sibutramine cases were sold on a mainstream platform with ordinary-looking packaging.
What you can check is the route rather than the product: whether a Singapore-registered doctor assessed you before anything was supplied, whether the provider is a licensed healthcare service, and whether there is a named clinician you can contact. HSA's own advice is direct: "Do not buy products from unknown or unverifiable sources, and exercise caution when buying online or from overseas" (HSA 2024).
We set out the specific questions worth asking any provider in how to choose a GLP-1 clinic.
At GetLean, a doctor assesses you before anything is supplied, and we dispense the medication ourselves rather than routing you to a third party.
This article describes the position as verified against primary sources in July 2026. If you have taken a product from an unverified source and feel unwell, seek medical attention and tell the clinician what you took.
A specific gap gets advertised into here. Is there a GLP-1 that is not an injection explains why no oral GLP-1 is a registered weight-management option in Singapore, which is the space anything sold as an oral weight-loss GLP-1 is occupying.
Two molecules drive most of the searching that ends up here. What each is actually registered for in Singapore is set out in the semaglutide injection registrations and the tirzepatide registrations.
Common questions
Is compounded semaglutide legal in Singapore?
Every semaglutide product registered here is a specific registered product classified Prescription Only (HSA register). A compounded or unregistered version supplied outside that framework is not a registered health product, and supplying one carries penalties under the Health Products Act (HPA).
What has HSA actually found in illegal weight-loss products?
In an alert published on 29 May 2026, HSA named four weight-loss products sold online; two of them contained sibutramine, disallowed for sale in Singapore since 2010 because of increased risk of heart attacks and strokes (HSA). Earlier cases involved hospitalisations.
Why is buying from a Telegram seller risky?
You cannot verify contents, concentration or storage, and there is no assessment and no recourse. HSA advises against buying from unknown or unverifiable sources (HSA 2024), and its reach over overseas sellers is limited (MOH 2024).
What happens to the seller if they are caught?
Penalties run to a fine of up to $100,000 and/or up to three years' imprisonment under the Health Products Act (MOH 2024).
Is there any way to tell if a grey-market product is genuine?
Not reliably from the outside — adulterated products are made to look legitimate, and HSA identified the sibutramine cases by laboratory testing. What you can verify is the route: whether a registered doctor assessed you, and whether the provider is a licensed healthcare service.