Types of aesthetic injectables, explained in plain language

What are the main types of aesthetic injectables?

Aesthetic injectables fall into five main types: hyaluronic acid (HA) fillers, skin boosters, collagen biostimulators, wrinkle-relaxing injections and fat-dissolving injections. They are not interchangeable. Each works on a different layer or process, so the right type depends on whether your concern is lost volume, tired-looking skin, a gradual loss of firmness, expression lines or a small pocket of fat.

• HA fillers add volume and shape in a chosen spot, such as the cheeks, chin or lips.
• Skin boosters spread fine amounts of HA, polynucleotides (PN) or PDLLA through the skin to improve hydration and skin quality, without changing shape.
• Collagen biostimulators such as PLLA and PCL prompt your own collagen to build gradually over weeks to months.
• Wrinkle-relaxing injections use a prescription neuromodulator to soften lines caused by muscle movement.
• Fat-dissolving injections break down small pockets of fat. SkinRev does not offer them.

In Singapore these are medical treatments. At SkinRev Lab every injectable is performed by Dr Sin Yong after a consultation and is priced at consultation; the full list is on the medical treatments page. The sections below explain each type in plain language, compare them in one table, and set out what is common, what is rare and what to do if something does not feel right.

Hyaluronic acid fillers: volume, shape and support

HA fillers are gels of cross-linked hyaluronic acid, a water-holding sugar found naturally in skin, injected to restore volume, define contours or support an area that has hollowed. Firmer gels are generally used for structure, such as the cheeks and chin, and softer gels for the lips and finer areas. The body breaks HA down gradually, at a rate that varies by product and area; firmer, deeper gels tend to persist longer than soft gels in mobile areas such as the lips.

At SkinRev Lab, Dr Sin Yong performs dermal fillers for the cheeks, chin, nose, temples, forehead and under the eyes, and lip filler after a face-to-face assessment. Expect mild swelling, tenderness or bruising for a few days, varying by area. Lip swelling usually peaks over the first one to two days and settles within about a week, and under-eye filler can take a week or so to settle because the skin there is thin.

One practical advantage of HA is that it can be dissolved with an enzyme (hyaluronidase) if a result needs correcting or a complication occurs. A 2022 review found reactions to the enzyme are rare and mostly manageable, and concluded that the enzyme remains beneficial despite this small risk.

Filler has limits. It is a poor fit for loose, heavy skin and for puffy under-eyes caused by fat bulging forward, and it is a poor tool for chasing every line. Fat transfer is not offered at SkinRev.

Skin boosters, including PN and PDRN: skin quality, not volume

Skin boosters improve hydration, texture and overall skin quality rather than adding volume, by spreading small amounts of product through the skin at many points. The main groups are:

• HA boosters: soft HA that holds water in the dermis, used for dehydration and dullness.
• Polynucleotide (PN) boosters: purified salmon DNA fragments that support repair and skin quality, usually given as three sessions a few weeks apart; see polynucleotide (PN) boosters.
• PDLLA boosters: tiny poly-D,L-lactic acid particles that trigger a gradual collagen response.
• Bio-remodelling HA: a very concentrated, lightly stabilised HA that spreads under the skin from a few points on each side of the face; see bio-remodelling HA injections.

PDRN and PN are both purified salmon DNA fragments that differ mainly in chain length, PDRN being the shorter. Injected boosters are usually PN, while c-PDRN is used in facials and skincare. A 2021 consensus report from Italian aesthetic medicine societies set out techniques, doses and session intervals for PN on the face, neck, décolleté, hands and scalp.

Injectable skin boosters are performed by Dr Sin Yong and priced at consultation; expect small bumps and redness for hours to a day or two, and possible bruising. Without needles, the Rejuran® PDRN Facial (S$288 to S$388) and the Needleless SkinBooster (S$288 per region) are non-medical treatments by Aesthetic Therapists, both priced before GST. Boosters will not lift sagging skin, fill hollows or remove pigmentation, and PN is not advised with a known allergy to its fish-derived ingredients.

Collagen biostimulators: gradual change over weeks to months

Collagen biostimulators are injectables that prompt your own skin to lay down new collagen, so change appears gradually over weeks to months rather than on the day. They suit broader, gradual support across an area rather than sculpting a single point.

• PLLA (poly-L-lactic acid): microparticles mixed with sterile water. The water is absorbed within days and the particles then stimulate collagen; a series is spaced about four weeks apart.
• PCL (polycaprolactone): microspheres in a gel that gives some immediate correction while new collagen forms around them.
• CaHA (calcium hydroxylapatite): another biostimulator type, which SkinRev covers only for comparison and does not offer.

A review of PLLA describes it as working mainly as a biostimulator rather than a traditional filler, restoring volume gradually and predictably, with the final result depending on how much product is used and on the quality of the tissue at the start. Patient selection therefore matters, and a course is commonly two to four sessions spaced several weeks apart.

At SkinRev Lab, Dr Sin Yong offers PLLA collagen biostimulators, priced at consultation. Expect a few days of swelling, tenderness or bruising at injection points, usually settling within a week. Unlike HA filler, the collagen change cannot be dissolved, so the plan is built up gradually, one session at a time.

A related approach, RVR ProLift, places a biodegradable collagen-stimulating product by fine needle along mapped vertical vectors, with no threads and no energy device. It is used for mild to moderate descent of the mid-face, jowls and nasolabial folds, and mild swelling and small needle entry marks are common.

Wrinkle-relaxing injections: softening expression lines

Wrinkle-relaxing injections use a prescription neuromodulator to reduce the pull of the small muscles that crease the skin, so lines caused by movement soften. They do not add volume or change skin quality, so they may be combined with other injectables when both are needed.

• Common areas: frown lines between the brows, forehead lines and crow's feet.
• Onset: softening within days, with the full effect at about two weeks.
• Duration: usually three to four months, after which treatment is repeated to maintain it.
• Downtime: usually minimal, with small bumps for 15 to 30 minutes and occasional pinpoint bruising.
• On the day: avoid rubbing or massaging the area, stay upright for a few hours, and skip saunas and hard workouts.

The same type of medicine is used differently for a wide, square jaw caused by a strong masseter muscle. Jaw slimming injections reduce the bulk of the muscle, with slimming usually showing from two to four weeks. Small bumps or occasional bruising settle within a day or two, and chewing tough food may tire the jaw for a few weeks.

At SkinRev Lab, wrinkle-relaxing injections are performed by Dr Sin Yong after examination and priced at consultation; the specific product is named at your visit. They suit lines that appear when you frown, raise your brows or smile. Lines that stay deep at rest may need filler or skin treatments as well, which Dr Sin Yong will explain at the consultation.

Fat-dissolving injections: not offered at SkinRev

SkinRev does not offer fat-dissolving injections. These are injections into a small pocket of fat, most often under the chin, that break down fat cells for the body to clear. The treated area usually swells, sometimes markedly, for several days, and can stay sore, numb, bruised or firm for days to weeks.

If your concern is a double chin or a small pocket of body fat, SkinRev offers other routes:

• SKINSHAPE®: microwave body contouring with no needles, performed by Aesthetic Therapists, at S$288 per 15 × 15 cm area per session, before GST.
• SKINLIFT® Double Chin: focused ultrasound for the under-chin, about 30 minutes, at S$488 per session, before GST, also performed by Aesthetic Therapists.
• Fat freezing, HIFU, VF Lift and Time Freeze Laser LCLR®: doctor-led options performed by Dr Sin Yong and priced at consultation.

SkinRev also does not offer PRP (platelet-rich plasma) for the face or hair, or fat transfer. For skin quality, injectable skin boosters are the closer alternative to PRP. The comparison of fat-dissolving injections with each of these options is in our guide to fat-dissolving injections.

None of these is a weight-loss treatment. They suit people near a stable weight with a small, pinchable area, and an assessment comes first so that loose skin, which needs tightening rather than fat reduction, is not mistaken for fat.

Types of aesthetic injectables compared

The injectable types differ in what they do, how quickly results show and how much downtime follows. This table compares them and shows which ones SkinRev offers.

Injectable risks: what is common, what is rare, and what to do

Most injectable treatments go smoothly. A review of filler complications noted that dermal filling is one of the most common procedures performed worldwide and that most treatments succeed, while mild and serious complications have both been reported across many filler types.

• Common and short-lived: swelling, tenderness, small bumps at injection points and bruising, usually settling over days; the lips and under-eyes take longer.
• Less common: lumps, an uneven result, or filler that has moved or overfilled an area. These can be assessed and are usually correctable, and Dr Sin Yong maps old filler by ultrasound before dissolving it; see filler correction.
• Rare but urgent: filler entering a blood vessel. Early signs described in the medical literature include skin blanching, a mottled or dusky blue-red colour and slow return of colour after pressing, with blisters following days later. Prompt recognition and treatment matter, and HA can be dissolved with the enzyme.

Any change in vision after filler needs a hospital emergency department or a call to 995 at once. Contact the clinic straight away for skin that turns pale or dusky, increasing pain, spreading discolouration or blistering after an injection; if you cannot reach the clinic, go to a hospital emergency department.

You can lower the risk by telling the doctor about every medicine and supplement you take, including ones you stopped recently, and about allergies, bleeding problems, cold sores and previous injections, as the American Academy of Dermatology advises. At SkinRev, treatment is deferred during pregnancy or breastfeeding, with an active infection, or after recent dental work.

Which injectable suits which concern?

The right injectable depends on what is causing the change you see, which is why Dr Sin Yong assesses the face before suggesting a product. As a rough guide:

• Hollow cheeks, temples or under-eyes, a short chin or thin lips: HA filler, placed for structure or shape.
• Dull, dehydrated or tired-looking skin: skin boosters, injected or needleless.
• A gradual, all-over loss of firmness: collagen biostimulators, built up over a course.
• Frown lines, forehead lines or crow's feet when you move: wrinkle-relaxing injections.
• A wide, square jaw from a strong masseter: jaw slimming injections.
• A double chin or small fat pocket: not fat-dissolving injections at SkinRev, but needleless or doctor-led contouring.
• Sagging jowls or heavy, loose skin: usually lifting rather than injectables, because filler cannot lift a heavy jowl.

At the consultation Dr Sin Yong examines your face, asks about previous treatments and medicines, explains the options with their downtime and risks, and gives the price at consultation. If a non-medical treatment, or no treatment, suits you better, you will be told. To start, WhatsApp SkinRev Lab on +65 8266 9585 with your concern and any injectables you have had before, including the product names and dates if you have them.