SINGAPORE - The pursuit of beauty has led to people buying dodgy weight loss and cosmetics online. But not all products are safe, and some can cause serious health problems.

Between Sept 12 and 19 this year, the Health Sciences Authority (HSA) seized more than 39,000 units of illegal health products, including weight loss products, sexual enhancement drugs and cosmetics. The items have an estimated total street value of more than $133,000, and the cost of each unit ranged from $12 to $70.

Operation Pangea, now in its 10th year, is a global operation coordinated by Interpol that aims to detect and disrupt the sale of illegal health products online. The week-long operation targets three main areas: Internet infrastructure, electronic payment system and delivery service.

The number of units seized has been on the rise in recent years. More than 11,000 units were seized in 2015, worth more than $20,000 in total. This rose to more than 25,000 units last year, worth about about $21,000 altogether.

During this year's operation, three sellers who advertised their illegal products online are assisting HSA in investigations.

One of the items seized was a face cream the HSA had already alerted the public to in June. The brand resurfaced again this month with new packaging to fool buyers.

Tati Skincare, an illegal cosmetic product, contains high levels of mercury level and potent prohibited ingredients such as hydroquinone and tretinoin.

The repackaged brand was advertised as a "new and improved Tati Skincare". The HSA said it is getting website administrators to remove these online advertisements.

The illegal sales of lifestyle health products such as weight loss products, cosmetics and contact lenses online has been a recurring problem, the HSA said.

Ninety per cent of the weight loss products that were seized and tested contained a banned substance known as sibutramine. Some contained other potent medicinal ingredients such as diuretics and antihistamines. The adulterated products include DZ Garcinia Herbal Plus, Gorgeousleem Advanced Capsule, Figure-Up Slimming Pill and XXS Advance.

These weight loss products ranged from pills to beverages, and were labelled with claims such as "100 per cent natural", "herbal ingredients" and "quick effect".

Between 2012 and last year, 35 different products marketed for weight loss were tested and found to contain sibutramine. Sibutramine was previously available as a prescription-only weight loss drug but has been withdrawn from Singapore since 2010, due to an increased risk of heart attacks and strokes, as well as other serious adverse effects.

From 2011 to May this year, HSA received five reports of serious adverse reactions associated with the use of sibutramine, including hallucinations, hearing voices, palpitations and breathlessness. None of these five cases resulted in death.

Associate Professor Chan Cheng Leng, Group Director of HSA's Health Products Regulation Group, said: "While HSA continues in its effort to disrupt the online sale of illegal health products, consumers also play an important role in safeguarding their own health by being aware of the risks associated with internet purchase of health products. Be wary of products that claim quick and effective cures as they may be adulterated with potent ingredients, and pose serious danger to consumers."

Aside from its intensified surveillance during Operation Pangea, HSA works regularly with local e-commerce websites and online forums to detect and remove posts that sell illegal health products.

Said the HSA in its statement to the media: "It is illegal to import and sell prescription medicines without a licence. Sellers should be cautious when sourcing for health products to sell and are reminded of their responsibility in ensuring the safety of the products and adherence to local legislations prior to introducing them to the market.

"HSA takes a serious view against those engaged in the sale and supply of illegal health products and will take strong enforcement action against such persons. Anyone who supplies illegal health products is liable to prosecution and if convicted, may be imprisoned for up to three years, and/or fined up to $100,000."

Members of the public who encounter illegal, counterfeit or other suspicious health products are encouraged to contact the Enforcement Branch of HSA at 6866-3485 or hsa_is@hsa.gov.sg.

They can also find out more about illegal health products found in Singapore here: http://www.hsa.gov.sg/pub/IllegalDrug/ProductListing.aspx

HSA advises the public to take these precautions:

- Weight loss drugs that are approved by HSA are available only from a doctor or pharmacist as these are potent medications and should only be taken under medical supervision.

- Exercise caution when buying health products online. There is no knowing who the sellers are, where they obtained the products, how the products were made, and what they contain.

The products could be counterfeits, or adulterated with undeclared potent or banned ingredients which can seriously harm one's health. The health hazards associated with illegal health products are very real and could have serious health consequences. Do not gamble with your health.

- Be wary of health products that promise quick and miraculous results or carry exaggerated claims like "100 per cent safe", "no side effects" or "scientifically proven".

- Products bought online may be cheaper and appear to be of better value. But in reality, the lower price could be due to unsafe or inferior ingredients, poor manufacturing methods and substandard or unhygienic storage conditions.