Hyaluronic acid fillers

Also known as: Juvederm, Restylane, RHA, Belotero, Voluma, HA fillers, dermal fillers

Hyaluronic acid (HA) fillers are gels made from a sugar molecule the skin already contains, cross-linked so it holds its shape after injection. They physically fill folds, restore lost volume in cheeks and lips, and can be dissolved on demand with the enzyme hyaluronidase. The evidence base is deep: more than 20 randomized trials support their use for nasolabial folds alone, and the main midface product held correction for 2 years in its FDA registration trial. Results and complication rates depend heavily on injector skill and product choice.

How it works

Cross-linked HA gel is injected under or into the skin, where it takes up space and binds water, immediately pushing up folds and hollows. Different products vary in firmness and lift: thin soft gels for fine lines and under-eyes, thick cohesive gels for cheeks and jawline. The body slowly breaks the gel down over months to a couple of years, and hyaluronidase can dissolve it within hours if needed.

What the evidence says, claim by claim

These are the results measured in studies, not the results shown in ads. Where the research is weak, the grade says so.

For wrinkles and fine lines

Strong evidence

A 2022 meta-analysis pooled 22 randomized controlled trials with 1,848 subjects on nasolabial fold correction and found consistent improvement in wrinkle severity scores through 52 weeks, with monophasic (smooth cohesive) gels outperforming biphasic (particle-based) gels at most timepoints. Correction of moderate folds typically holds 6 to 12 months. Nasolabial fold treatment is the on-label FDA-approved indication for most HA fillers.

Multiple randomized controlled trials or a meta-analysis support this use. The effect is real and repeatable.

Monophasic and Biphasic Hyaluronic Acid Fillers for Esthetic Correction of Nasolabial Folds: A Meta-Analysis of Randomized Controlled Trials (Aesthetic Plastic Surgery, 2022; meta-analysis)

For volume loss

Strong evidence

In the single-blind randomized controlled registration trial of Juvederm Voluma XC for age-related midface volume loss (235 treated patients), 85.6 percent improved at least 1 point on a validated volume deficit scale at 6 months, and correction was maintained up to 2 years in a subset. Patient-reported outcomes tracked the clinician ratings: 79 percent still rated their cheeks improved at 2 years. Cheek augmentation is an on-label FDA-approved use for several HA products.

Multiple randomized controlled trials or a meta-analysis support this use. The effect is real and repeatable.

Volumizing hyaluronic acid filler for midface volume deficit: 2-year results from a pivotal single-blind randomized controlled study (Dermatologic Surgery, 2013; RCT)
A Multicenter, Single-Blind Randomized, Controlled Study of a Volumizing Hyaluronic Acid Filler for Midface Volume Deficit: Patient-Reported Outcomes at 2 Years (Aesthetic Surgery Journal, 2015; RCT)

For dark circles

Moderate evidence

For under-eye hollows (tear troughs) that cast shadows and read as dark circles, a 2024 meta-analysis of 31 reports covering 2,556 participants found a pooled patient satisfaction rate of 91 percent with HA filler. The catch: most included studies were uncontrolled case series rather than randomized trials, and filler helps shadowing from hollowness, not true pigment. The under-eye is also the least forgiving injection site, with swelling, lumpiness, and a bluish Tyndall effect as known problems. Most tear trough treatment is off-label.

Randomized trials support this use, but they are few, small, or short. The effect is probably real. The size of it is less certain.

The Efficacy and Safety of Hyaluronic Acid Injection in Tear Trough Deformity: A Systematic Review and Meta-analysis (Aesthetic Plastic Surgery, 2024; meta-analysis)

Risks and what can go wrong

Common effects are bruising, swelling, and tenderness for a few days, plus occasional lumps or asymmetry. Delayed nodules and inflammatory reactions can appear weeks to months later. The rare but serious risk is vascular occlusion: filler injected into or compressing an artery can cause skin necrosis or, in the worst case around the nose and glabella, blindness. This risk is directly tied to injector anatomy knowledge, so practitioner choice matters more here than with almost any other cosmetic treatment. A key safety advantage of HA over other fillers is reversibility with hyaluronidase. Avoid with active skin infection at the site and during pregnancy (unstudied rather than known harmful).

The practical details

Typical US pricing is 600 to 1,000 dollars per syringe, and many treatments use 1 to 3 syringes. Nasolabial fold and lip results generally last 6 to 12 months; firmer cheek products can last 18 to 24 months. Touch-ups commonly happen at 9 to 18 month intervals. Many Juvederm and Restylane products are FDA approved for nasolabial folds, cheeks, lips, chin, or jawline depending on the specific product; under-eye use is off-label for most products.