With facial fillers, there are many approved brand options, but the 'boob jab', as it has come to be known, is a newer procedure and has been on offer to the public for just a few years.

Macrolane biodegrades in the body over about 12 months, and allows women to increase their breasts by a cup size, on average. If more is injected for a bigger boost, however, problems can start.

Other areas, including calf muscles and men's pectorals, can also be better defined with the injections, the company claims in its brochures. The treatment can also be used to enhance buttocks.

Wilson Ho Wai-sun, a plastic surgeon in Central, says he now performs more 'lunchtime' procedures after a 20-30 per cent fall in hospital-based surgery over the past year, a change he attributes to people tightening their belts amid the recession.

Ho has been performing Macrolane procedures for 14 months, and his partner in the surgery is also now offering it, but he says it should be done only by plastic surgeons.

Of course, like most new enhancement products, fears about its safety abound, but Ho dismisses such concerns.

'It is safe,' he says. 'I've checked through all the background. Basically, the ingredients are the same [as Restylane's], but the molecule is a little bit larger.'

Ho also says the product has been used for more than three years in Japan.

'More than 100,000 Japanese women have had it done,' he says. 'There are studies coming out talking about it in terms of safety and cancer surveillance and complications. I think it's a very good product in terms of body shaping and enhancement. We commonly inject the buttocks either because the woman is very slim or has had a massive weight reduction and she wants a more pronounced buttock.

'Men come too [but] in this part of the world, we have far more breast enhancements. In Europe, it's half and half [breasts and buttocks].'

But another local plastic surgeon, Franklin W.P. Li, is less enthusiastic about Macrolane, saying that although he offers it, he does so cautiously.

'I reserve it for only a small proportion of my patients,' Li says. 'First, [I offer it] to patients with an aversion to minor surgery, and secondly, to patients who don't mind spending a great deal of money for a transient result that lasts around a year.

'Moreover, the manufacturer recommends only 100cc per side for the initial injection, creating a very small increase in the size of the breasts. For augmentation with implants, we use 125cc for a small size increase, 200cc for a medium one and over 300cc for a large increase for Asian patients.'

Li also says that as Macrolane is a new product, its long-term effects are unknown.

'Just the material cost alone - HK$30,000-HK$40,000 - can buy a saline implant augmentation that lasts for many years,' he says. 'These are the points I tell my patients. I leave them to decide on the pros and cons.'

For the Times journalist offered it by Q-Med in March last year in return for writing about it, the results were less than brilliant soon after the initial injections.

Initially, the physical results were as good as she had hoped for. But a sudden loss of volume a few months later, lumpiness and the need for top-ups made the reporter concerned and suspicious. She also noticed that the surgical consent form she had signed - which it seems she had not studied in detail - said: 'The use of Macrolane VRF20 and Macrolane VRF30 for breast enhancement has not been established'.

She talked to some plastic surgeons who said they would never offer it because it might interfere with breast screening and could cause changes in the breast, even benign ones.

But Ho is still a fan, saying its simple application is what makes it appealing.

The breast filler takes about 20-25 minutes, and if a patient is very anxious, Ho says he can give them a heavy sedative (although not a general anaesthetic) to keep them calm throughout the procedure.

'We don't need to make any incisions. All we need is to inject the needle and they can go back to work the same day,' he says.

'If they have had [heavy] sedation, they can't drive on the same day, but after maybe a one- or two-hour break they can go back to work. The wound is very small ... it's a small puncture wound and there is just a waterproof bandage.'

Most women he sees get a 1-to-1.5-cup size increase. Pain afterwards has been likened to that of when a new mother initially begins breast-feeding, but that's gone within one to two days, Ho says.

And he's not worried about side effects. 'I have not had one single complication up to this moment,' he says. 'In Japan, there was a study with 4,000 patients and two had infections. Those were well controlled with intravenous antibiotics.'

Of course, if you have too much Macrolane injected, lumpiness is possible, as the skin is stretched too far too soon.

'If you talk about specific lumps that didn't exist before, the chance of that is about seven in 4,000 - very small. But you don't want to have too much [Macrolane].'

However, if you want to upgrade by three cup sizes, you should do it in three sessions.

'We want natural, gradual change,' Ho says.

It seems plenty of Hong Kong women are keen to try it out, despite the cost and lack of long-term studies. Ho says one or two procedures a month 14 months ago have now increased to up to two a week. 'It's getting more and more busy as there is more awareness,' he says.

The price ranges from HK$450 to HK$500 per cc, and 100cc in each side - breasts or buttocks - is a typical treatment. After the substance has dissipated, you can also have top-ups.

Per Heden, a plastic surgeon cited in a Q-Med report given to reporters, says there is growing demand globally for non-invasive aesthetic treatments.

Heden was enlisted to conduct clinical trials on Macrolane, and says he envisions widespread demand from patients looking to achieve a fuller bust, and also more interest from 'guys who want a manlier chest profile'.

But not everyone is sold on the idea, particularly those who are cautious about making a repeated financial outlay.

'As much as I would like bigger boobs - and I really would - I am cautious about these kind of non-essential procedures, especially when they are so new that the long-term effects are still unknown,' says public relations executive Keiko Uchida.

'Also, taking a quick look on Google, I don't know that it's very cost effective. It seems quite expensive, considering that you have to keep having it re-done.'

Plastic surgeon Francis Ho Wing-yun says he will soon be offering Macrolane, but that there are cons as well as pros.

'It has a definite prospect to become a well-accepted alternative to surgery and for those who can afford it,' says Ho. 'But the negatives are its cost and the fact it needs regular top-up injections and may affect radiological imaging of the breasts.'

But it seems there are still plenty who crave a bigger bust and who are willing to take the plunge.