Bastille's Feature｜Cheap Slimming Pen for Quick Results? Wait! The Real Cost Is Your Health

Commonly known as "weight‑loss pens" or "slimming pens," prescription injections containing GLP‑1 inhibitors, originally developed to treat type 2 diabetes, have recently become highly sought‑after slimming products. Illegal and counterfeit versions are now rampant across social media, online shopping platforms, messaging groups, and second‑hand trading sites, easily accessible to the public without a doctor’s prescription or any form of medical evaluation.

These products vary widely in price. So‑called "Bangladesh aftermarket" versions sell for HK$300 per vial, while "original Japanese" versions go for over HK$600. In contrast, a doctor‑prescribed injection can cost between HK$2,000 and HK$3,000 per vial. Driven by the price gap, many consumers blindly purchase these cheap alternatives and self‑administer them, unaware of the serious health risks they are inviting.

According to Customs figures, in the first four months of this year alone, authorities uncovered 15 large‑scale smuggling cases involving weight‑loss and beauty injections, with an estimated market value of approximately HK$220 million.

Illegal weight‑loss injections are flooding the market, posing significant health risks. Photo source: Threads image

In an interview with Bastille Post, LegCo member Hon. Nixie Lam and Dr. Charles Ng, a practising physician, both warned that the proliferation of illegal weight‑loss injections poses significant health threats. They urged the government to strengthen inter‑departmental enforcement, enhance public education, and increase the deterrent effect of the law.

Are “Original Japanese Products” Safe?

The current grey‑market weight‑loss pens come from three main sources: “original Japanese products,” “Bangladesh aftermarket versions,” and counterfeit injections manufactured in laboratories in the Chinese Mainland. Prices vary considerably. “Bangladesh injections” sell for around HK$300, while “Japanese injections” are priced at HK$500–600, making them the most commonly sold options.

Although “Japanese injections” are genuine products, their cross‑border transport bypasses proper cold‑chain procedures. “Bangladesh injections” are produced by aftermarket manufacturers, leading to inconsistent drug quality. As for counterfeit injections from the Chinese Mainland, they were originally intended only for animal clinical trials and have never undergone human safety testing before being smuggled into Hong Kong. Their ingredients are unknown, their efficacy is unstable, and their health risks are significant.

According to the latest Hong Kong Customs figures, from January to April 2026, multiple operations targeting controlled injectables and medicines resulted in the dismantling of 15 large‑scale smuggling cases. Authorities seized over 5 million suspected pharmaceutical products and approximately 150,000 controlled injectables suspected of containing Part 1 poisons, including roughly 130,000 anti‑obesity injections and around 20,000 cosmetic injections, with an estimated market value of approximately HK$220 million.

Customs noted that some weight‑loss injections had been transported without proper cold‑chain storage, potentially posing safety risks. Photo source: FB @ Hong Kong Customs

Illegal Slimming Pens Flood Online Market

Hon. Nixie Lam pointed out that in the past, illegal drugs were mostly traded discreetly through traditional pharmacies. Now, the sales model has shifted online. Advertisements for weight‑loss injections can be found across social media platforms such as Instagram, Facebook, Threads, Telegram, and WhatsApp groups. The sellers attract customers through proxy buying and referrals from friends, even boasting that no doctor's consultation is required and offering fake medical certificates. Some sellers even claim that certain versions do not need cold‑chain transportation.

Hon. Nixie Lam, Photo by Bastille Post

She cited an example: a search on Threads using relevant keywords revealed that an account with only a dozen followers had amassed over a thousand views within a few hours of posting its sales ads, indicating a large and eager consumer base.

Dr. Charles Ng revealed that some sellers use second‑hand platforms to arrange face‑to‑face transactions with buyers at MTR stations, treating the exchange as casually as buying ordinary daily necessities, completely disregarding the prescription‑only status and health risks of the drugs. He added that many beauty salons have become "accomplices," introducing and promoting illegal weight‑loss injections to customers. The so‑called resident doctors in these salons are mostly part‑time, some without any registered medical supervision. Customers receive injections without any medical examination or follow‑up health monitoring, and there is even a possibility that teenagers under 18 are using these products, causing long‑term and irreversible damage to their physical development and endocrine systems.

What Are GLP‑1 Inhibitors?

GLP‑1 inhibitors were originally developed to treat type 2 diabetes and have also been applied to the treatment of obesity in recent years. They work by mimicking the body's natural GLP‑1 hormone to promote insulin secretion, inhibit glucagon release, and slow gastric emptying, thereby prolonging the feeling of fullness, suppressing appetite, reducing calorie intake, and regulating blood sugar levels to aid weight loss.

Medical Assessment & Monitoring: A Must for Injection

Dr. Ng explained from a professional medical perspective that subsequent studies have confirmed GLP‑1 inhibitors can be used for weight loss in obese individuals with a BMI of 30 or higher, or patients with a BMI of 25 or higher and accompanying cardiovascular disease. However, they are not general slimming health products, nor are they "beauty injections" suitable for anyone.

Dr. Charles Ng, Photo by Bastille Post

Under standard medical protocol, patients must undergo blood tests for thyroid, liver, and kidney function before using weight‑loss injections. A doctor assesses the risks based on the individual's medical history and prescribes a personalised dosage. Regular follow‑up appointments are also necessary to monitor changes during treatment. Nevertheless, the current parallel trade completely bypasses all these procedures. Individuals can purchase injections online at will, self‑administer at home, and arbitrarily adjust dosages, with potentially disastrous consequences.

Misuse Can Be Fatal

Dr. Ng listed three major fatal risks:

1. Improper storage and transport – Weight‑loss injections are peptide hormone drugs that must be stored at 2–8°C. Most grey‑market products are carried by individuals or transported across borders in ordinary parcels. Uncontrolled temperatures can cause the drugs to deteriorate and breed bacteria, easily leading to serious infections after injection.

2. Counterfeit products with unknown ingredients – Unscrupulous merchants substitute weight‑loss injections with dehydrating drugs or insulin. Misuse can cause severe hypoglycaemia, dehydration, and even kidney failure.

3. Risk of acute severe illness – Even legitimate drugs can cause acute pancreatitis if used improperly, which can be fatal. He noted that in the past, due to abuse and rampant smuggling of weight‑loss injections, European authorities once ordered a suspension of their use for weight loss for six to twelve months.

Weight‑loss injections sold online are frequently transported in ordinary cooler bags without proper cold‑chain protection, raising doubts about their safety and quality. Photo source: Threads image

Cutting Off Online Sales Chains: Lessons from Singapore

Regarding the effectiveness of current government regulation and enforcement, Hon. Nixie Lam said that enforcement is seriously insufficient. She believes authorities focus too much on traditional pharmacy inspections while neglecting the crackdown on online sources, allowing illegal advertisements on social media platforms to spread unchecked.

She suggested that the government learn from Singapore's approach and cooperate with online platforms to block illegal accounts and related advertisements through technical means, cutting off the online sales chain. She also recommended strengthening controls on cross‑border postal channels to curb the large‑scale smuggling of weight‑loss injections through personal shoppers. On public education, she noted that there is currently no easily understandable warning content designed for the social media platforms commonly used by young people.

Dr. Ng suggested a joint effort by three departments. First, Customs should strengthen its controls to combat smuggling at the source. According to him, Customs recently seized a large number of smuggled weight‑loss injections intended for transshipment to Macau at the border. However, smugglers often conceal the drugs on their bodies or in their luggage, making it difficult for Customs to thoroughly inspect every passenger, inevitably allowing some to slip through.

He believes the Police should work with the Health Bureau and the Department of Health to strengthen enforcement. The law clearly stipulates that such drugs cannot be sold without a doctor's prescription, but to his knowledge, many pharmacies in Tsim Sha Tsui are still illegally selling prescription drugs such as weight‑loss injections and pneumonia medications, and current enforcement efforts remain inadequate.

He also stressed that public education should be strengthened, as citizens often focus only on low prices, completely ignoring the potential health consequences and the risks of using counterfeit drugs. Both of them urged the public not to be tempted by low prices and purchase weight‑loss injections of unknown origin through online resellers or private transactions. Instead, the residents should consult a registered doctor first, undergo a professional evaluation, and follow the doctor's advice for treatment, lest they jeopardise lifelong health in pursuit of rapid weight loss.

Hon. Nixie Lam and Dr. Charles Ng, Photo by Bastille Post

Government Response

Hong Kong Customs

Hong Kong Customs, Photo source: reference image

Customs stated that, based on risk management and intelligence, it has strengthened efforts to intercept controlled goods from entering Hong Kong at various border crossings. It has also conducted strict random checks and inspections on goods and travellers from high‑risk areas to prevent the influx of controlled substances at the source. Customs and the Department of Health have coordinated enforcement efforts, urging the public not to purchase or use prescription drugs through illegal channels. The public is reminded that improper storage during transportation, especially for drugs requiring cold‑chain storage, can adversely affect the safety of these drugs and pose a health risk.

Department of Health

The Department of Health, Photo source: reference image

The Department of Health stated that currently registered injectable drugs in Hong Kong for the treatment of obesity include liraglutide, semaglutide, and tirzepatide, all of which are classified as Part 1 poisons and prescription drugs under the Pharmacy and Poisons Ordinance (Cap. 138). Pharmaceutical products and prescription drugs containing Part 1 poisons can only be sold in registered pharmacies by registered pharmacists according to doctors' prescriptions. Anyone who illegally sells such products, including online, or possesses unregistered pharmaceutical products, Part 1 poisons, or sells without a prescription, commits an offence and, upon conviction, is liable to a maximum fine of HK$100,000 and imprisonment for two years. Anyone who imports or exports pharmaceutical products without the relevant permit commits an offence, with a maximum penalty of HK$500,000 and imprisonment for two years.

The Department of Health stated that in the past 12 months, its Drug Office conducted approximately 1,189 surprise inspections of pharmacies in Hong Kong, handling 41 cases involving the illegal sale or possession of unregistered pharmaceutical products or Part 1 poisons, including drugs commonly known as "weight‑loss injections", with two cases involving online sellers. Among the 41 cases, the highest penalty was two months' imprisonment (suspended for three years) or a fine of HK$87,000. Six other cases involving pharmacies illegally selling prescription drugs were also handled during the same period, with the highest fine reaching HK$87,000.

The Department of Health stated that it will continue to monitor drug sales, including online channels, through surprise inspections, market surveillance, and trial purchases. Illegally selling controlled drugs through any means, including online platforms, instant messaging software, or social media, will be subject to criminal liability.

Lung cancer is one of the most common cancers in Hong Kong and carries the highest mortality rate, not only locally but also globally. Professor Rina Hui, Director of the Centre for Cancer Medicine at the University of Hong Kong (HKU), said that cancer treatment is advancing at an unprecedented pace, with new breakthroughs emerging almost every fortnight. These include antibody-drug conjugates (ADCs) that are often referred to as "smart chemotherapy", T-cell engagers, and bispecific antibodies, which combine two different antibodies.

With such rapid progress, the curriculum at HKU’s Li Ka Shing Faculty of Medicine (HKUMed) needs to keep pace. About a year and a half ago, the faculty launched an eight-month integrated cancer medicine course to equip medical students with the latest clinical cancer technologies.

Professor Rina Hui, Director of the Centre for Cancer Medicine at the University of Hong Kong (HKU), Photo by Bastille Post

Professor Hui told Bastille Post that, in Hong Kong, besides lung cancer, the most common cancers include colorectal, breast, and prostate cancer. But lung cancer remains the biggest challenge, since its mortality rate is higher than the other three combined.

She said that besides smoking, other risk factors for lung cancer include second‑hand smoke, the second largest contributor, as well as family history, air pollution, kitchen fumes, occupational exposure (e.g., asbestos and radon), and prior radiotherapy. Smoking, however, remains by far the leading cause.

EGFR Mutations Common in HK Lung Adenocarcinoma

Professor Hui noted that Hong Kong's smoking rate has dropped to 8.5%, according to the latest figures released by the Health Bureau in April. While smoking‑related cancers like small cell lung cancer and squamous cell carcinoma are declining, lung adenocarcinoma is increasing, with half of patients carrying EGFR mutations. "Knowing the cancer type and genetic status is the first step for effective treatment," she said.

She also emphasised that the earlier one quits smoking, the lower the risk of getting cancer. "Quitting need not be abrupt. Nicotine patches and chewing gum can serve as supportive aids. The essential step is to discard all cigarettes, eliminate temptation, and reframe quitting as a long‑term health investment," she advised.

Professor Hui suggested that lung cancer screening is essential for high‑risk individuals. Photo source: reference image

Lung Cancer Screening: Essential for High‑Risk Individuals

Last year, the government announced plans to commission local universities to conduct AI‑assisted lung cancer screening. Professor Hui said that HKU and CUHK are currently running relevant trials, given their importance.

"High‑risk people, like those aged 50 to 75, heavy smokers (30 pack‑years), and those exposed to second‑hand smoke, should get screened regularly," she said. "Taiwan offers a noteworthy approach, where they screen non‑smokers with a family history of lung cancer."

She acknowledged that free lung cancer screening for every individual in Hong Kong is unlikely to be feasible at this stage, due to the high costs involved. However, screening could be carried out through collaboration between the government and private healthcare providers, targeting high‑risk groups. "As I tell my patients, getting screened is like saving up to pay taxes. You're actually gaining in the long run. Early detection means better outcomes and lower treatment costs."

She said that lung cancer treatment regimens are becoming increasingly advanced. "Patients with genetic alterations can use targeted therapies; those without can benefit from immunotherapy, and survival rates have improved significantly." However, she also pointed out that lung cancer remains the world's "number one cancer killer", underscoring the urgent need for continued related research and clinical trials.

Recognising the rapid evolution of cancer treatment, HKUMed has launched an eight‑month integrated cancer medicine course starting in October 2024. Photo source: reference image

New Course to Train Future Doctors

Recognising the rapid evolution of cancer treatment, HKUMed has launched an eight‑month integrated cancer medicine course starting in October 2024, which is delivered in six cohorts per year, ensuring that future doctors stay abreast of the latest developments. "We bring together surgeons, researchers, public health experts, oncologists (including medical oncologists and radiation oncologists), pathologists, and radiologists to teach medical students the basics of immunotherapy, targeted therapies, smart chemotherapy, and radiation, so that no matter what field they go into, they'll be able to handle cancer patients when they see them," she said.

New Cancer Treatments Bring New Hope

Beyond well‑established immunotherapy, Professor Hui highlighted emerging treatments:

One is called Antibody‑Drug Conjugate (ADC), often referred to as "smart chemotherapy" or "missile‑guided chemotherapy." "The antibody carries the chemotherapy drug, entering cancer cells with precision like a missile. When the linker dissolves, it releases the drug directly into the cancer cells, killing them effectively," she explained.

She noted that ADCs have now been proven to benefit patients with stage IV metastatic cancer. Clinical trials are currently combining these drugs with immunotherapy, and data have already shown effectiveness in early‑stage triple‑negative breast cancer patients.

Another future trend in cancer treatment is bispecific antibodies, which combine two different antibodies with fewer side effects and a synergistic effect. For example, VEGF bispecific antibodies combine the dual mechanisms of immune checkpoint inhibitors and anti‑angiogenic therapy, and have already shown effectiveness in cancers such as lung and breast cancer. Combining two targeted drugs also results in fewer side effects and better treatment outcomes for lung cancer patients.

T‑Cell Engagers: A Breakthrough for Small Cell Lung Cancer

Professor Hui also mentioned a new treatment trend called T-cell engagers. "For example, a therapy targeting DLL3 on the surface of small cell lung cancer cells — on one side, it targets DLL3, and on the other side, it attracts the immune system's T-cells, which act like soldiers attacking the cancer cells together. This type of drug is already on the market and has been shown to improve overall survival in extensive-stage small-cell lung cancer. Clinical trials are currently exploring its use in first-line treatment and for stage III patients," she explained.

However, she pointed out that targeted therapy remains a future priority. Since many cancers occur due to genetic alterations, if the genes driving cancer growth can be identified, targeted medications can be utilized and show improved therapeutic efficacy across various cancers. For example, 60% to 70% of breast cancers are hormone receptor-positive, and of those, 30% to 40% have PIK3CA gene mutations. "The corresponding targeted drugs are currently available in Hong Kong, but they are expensive. There is now a phase III clinical trial in which patients can use this type of medication for free, and may even have access to better new drugs. However, patients need to undergo genetic sequencing to confirm whether they have the corresponding genetic mutation before they can participate in the relevant trial," she said.

According to Professor Hui, since many cancers occur due to genetic alterations, if the genes driving cancer growth can be identified, targeted medications can be utilized and show improved therapeutic efficacy across various cancers. Photo by Bastille Post