Fat dissolving injections vs fat freezing:
which suits which pocket?

How do fat dissolving injections and fat freezing work?

The target is the same: the adipocyte, the fat cell that stores lipid under the skin. The route to it is different.

The evidence for deoxycholic acid is the pair of placebo-controlled phase 3 trials behind the 2015 US approval and the pooled safety data in the prescribing information; for submental cryolipolysis it is Kilmer and colleagues' 2016 multicentre study. The two have not been compared head to head, so the choice rests on the pocket rather than on a winner.

Which pocket suits injections, and which suits freezing?

Three things decide it: how much fat there is, what shape it makes, and whether the skin over it still recoils.

Pocket size

A medicine is dosed by the number of injection points, so the volume rises and the swelling rises with it as the pocket gets bigger. That favours injections for a small, discrete pad under the chin and counts against them for a heavy submental pad or any body pocket. An applicator treats whatever fold it can hold, so it suits a pocket large enough to be drawn in, which under the chin means enough fat to form a fold and on the body means the flank, lower abdomen, inner thigh or bra-line pocket that the stubborn fat page describes.

Pocket shape

A grid of injections can follow an irregular or asymmetric pad; an applicator treats a fixed footprint, and a very small, flat pocket under the chin can be hard to draw into a cup at all, which is where an injection is the more practical tool.

Skin quality

Neither method does anything for the skin, so both depend on the skin shrinking back over a smaller pocket. Where a pinch of skin is slow to return, or the neck gathers when the head tilts down with little fat to pinch, removing fat by either route can leave the area looking looser. That is a laxity question, and the relevant pages are HIFU for a double chin for focused ultrasound and the VF Lift – Vertical Facelift for radiofrequency on Volnewmer.

“Injections and cooling are two ways to kill the same cell. The question I am answering at the pinch test is not which is better; it is whether the cell is the problem at all.”

Dr Sin YongOn Fat dissolving injections vs fat freezing

What is the downtime pattern after each?

Both produce a reaction, because both rely on the body clearing dead fat cells, but the reaction looks different and is felt differently.

• After deoxycholic acid: swelling is the dominant feature, and the area can look fuller before it looks smaller. Tenderness, warmth, bruising, numbness and a firm feel across the grid are expected. The uncommon but important effects are weakness of the lower lip or an asymmetric smile from injury to the marginal mandibular nerve, difficulty swallowing, and skin injury from an injection placed too superficially. All are reduced by keeping to the approved area, depth and no-go zones.
• After cryolipolysis: the treated fold is red, firm and numb when the applicator comes off, and is massaged to help break up the cooled tissue. Numbness, tenderness, bruising at the applicator edge and a tingling or aching sensation over the following days are expected. The specific uncommon risk is paradoxical adipose hyperplasia, in which the treated area enlarges rather than shrinks some months later; it is discussed before any treatment on the fat freezing page.

In broad terms, injections produce more visible swelling in a small area; cooling produces less visible change but more numbness over a larger area. Neither is described here in days, because the course varies with the volume treated and the individual.

What does neither method do for loose skin?

Nothing. Both act on the fat cell and leave the dermis untouched. This is the point most often lost in advertising for a double chin, because the word covers four different things: submental fat, lax skin, the position of the platysma muscle, and a short chin that makes a modest pad look larger. Fat dissolving injections and fat freezing answer the first. The double chin treatment page separates the four at assessment.

Where the skin leads, the methods on this site that reach the dermis are focused ultrasound, the VF Lift – Vertical Facelift on Volnewmer for the face and neck, and on the body the VF Lift – Vertical Figure Lift, which heats the dermis and the septa under it along vertical vectors and is not a fat treatment. Where fat and skin both need attention on the body, the 4K Body Lift on Secret Duo delivers radiofrequency to compact fat while heating the skin over it, and Onda Pro microwave is absorbed by fat while reaching dermal collagen. A short chin is a projection question for chin enhancement, and a prominent submandibular gland is not fat at all.

Which page covers each, and how is the choice made here?

Each method has its own page: fat dissolving injections explains deoxycholic acid, its approved area and its regulatory status in Singapore; fat freezing explains cryolipolysis and the pinch test. The medicine is defined under deoxycholic acid in the glossary.

Dr Sin Yong, an aesthetic physician on Orchard Road, Singapore, examines the pocket in person before either is named: a pinch test for fat, a tilt test for laxity, a look at chin projection and the gland, and ultrasound mapping to separate fat from filler where earlier filler is involved. Fat freezing, Onda Pro and the 4K Body Lift are the fat-directed options on this site; fat dissolving injections are discussed as a prescription medicine whose availability is confirmed at consultation, not as a default. Larger volumes, and loose skin with separated muscles, are referred to a plastic surgery specialist. Fees are set in writing after assessment, as how fees are quoted explains.