Key points
- Hyaluronic acid fillers are generally regarded as a safe and effective treatment, and most adverse reactions were temporary and mild to moderate [1].
- Each product has different physical and chemical properties, so they are used for different purposes, such as fine lines, midface volume, and the area around the mouth and the lips [2].
- Serious adverse reactions are rare but can last for months, and in some areas, such as the temples, risks such as blocked blood vessels, skin necrosis (death of skin tissue), and blindness have been reported [1, 3].
- Hyaluronic acid fillers can be broken down with hyaluronidase, but limits have been pointed out in the enzyme's role when vision has been lost because of a filler embolism (filler blocking a blood vessel) [4].
What is hyaluronic acid filler treatment?
Hyaluronic acid filler treatment involves injecting a gel-like material into wrinkles or hollow areas to restore volume. Hyaluronic acid is found throughout the body and is broken down naturally within it, and it is described as having a limited likelihood of triggering an immune response [4]. A literature review of treatments around the eyes summarized that fillers can be an alternative to some types of surgery, with the advantages that results are visible right away and recovery time is short [4].
Methods used to fill wrinkles or soft tissue defects have included the patient's own dermis (the deeper layer of skin), the patient's own fat, donor dermis, synthetic implants, and fillers [6]. Tissue-engineering approaches, in which living cells are added to the filler, have also been developed and have been used clinically in some cases [6].
Types of products and their uses
Each hyaluronic acid filler product has different physical and chemical properties, and the recommended uses differ accordingly [2]. A 2014 literature review described separate products for correcting fine lines, for restoring lost volume in the midface, and for lines around the mouth and lip enhancement [2].
A 2015 systematic review of a 20 mg/ml volumizing filler used for age-related volume loss in the midface analyzed 13 papers, of which 10 were clinical trials and 3 were expert opinions and survey studies [5]. This product consistently showed good results for age-related volume loss, cosmetic improvement, and HIV-related facial fat loss (lipoatrophy) [5]. However, the researchers added that longer follow-up and studies of areas other than the midface are needed [5].
- For correcting fine lines
- For restoring midface volume
- For lines around the mouth and lip enhancement
Injection methods and tools
Fillers are injected with a needle or with a thin, blunt-tipped tube (microcannula), and the use of cannulas is described as an evolving technique [2]. In high-risk areas such as the temples, a method has been reported in which the filler is injected while ultrasound shows the cannula and the filler going in in real time [3]. The researchers who described this method targeted the space between layers of connective tissue (the interfascial space) as the injection layer [3].
Which tool and which layer to choose depends on the anatomy of the area and the change you want. In a 2024 systematic review as well, the occurrence of adverse reactions differed depending on the filler product and the injection technique [1].
Common reactions and rare serious complications
A 2024 systematic review analyzed 48 studies with a high level of evidence, consisting of randomized controlled trials [1]. Most adverse reactions were brief reactions at the injection site that settled on their own, and they generally improved within a few weeks without treatment [1]. When symptoms lasted longer, they were treated with topical steroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and hyaluronidase [1].
Serious adverse reactions such as severe swelling or angioedema (deep swelling under the skin) were rare, but they lasted for months and required active treatment [1]. Around the eyes, filler can move to other areas or remain much longer than expected, and delayed inflammatory reactions can occur because of contamination or immune stimulation [4]. Mild vascular occlusion (blockage of a blood vessel) is not uncommon, and blindness caused by filler is considered rare [4].
For filler in the temples, risks that have been reported include irregular contours, vascular occlusion, skin necrosis, hair loss, blindness, stroke, and non-thrombotic pulmonary embolism (blockage of blood vessels in the lungs not caused by a blood clot) [3]. Even if these are rare, the consequences can be serious, so it is important to receive a thorough explanation before treatment.
The role and limits of the dissolving enzyme
Hyaluronic acid fillers can be broken down with an enzyme called hyaluronidase, and for some complications, injecting it in time can be effective [4]. However, recent research has shown that this enzyme does not pass well through artery walls or the sheath surrounding the optic nerve, which has raised questions about the role of injecting the enzyme behind the eyeball when vision has been lost because of a filler embolism [4]. The fact that filler can be dissolved does not mean that every complication can be reversed.
Factors that affect results and what to check during your consultation
A literature review of fillers around the eyes considered good results to depend on careful selection of the patient, the product, and the technique [4]. A 2024 systematic review also concluded that thorough explanation and consent, patient education, and specialized training for practitioners are important for safe results [1].
How long filler lasts and how the results feel vary from person to person. It is a good idea to plan your treatment together with a specialist after an examination of your facial structure and the change you want.
- The type of product to be used and the injection areas
- Whether a needle or a cannula will be used
- Your history of previous filler treatments and any filler that may remain
- What will be done if a vascular complication is suspected
- Symptoms that require you to contact the clinic right away after treatment
Frequently asked questions
- Are hyaluronic acid fillers relatively safe?
- A 2024 systematic review concluded that hyaluronic acid fillers are generally safe and effective, and that most adverse reactions are temporary and mild to moderate [1]. However, serious adverse reactions occur in rare cases and may require months of treatment [1]. A low risk is not the same as no risk.
- How long does filler last?
- How long it lasts depends on the product, the injection area, and your individual condition, and the sources reviewed for this article do not give a typical duration in numbers. There are also reports that around the eyes, filler can remain much longer than its expected lifespan [4].
- Can it be dissolved if I don't like the result?
- Hyaluronic acid fillers can be broken down with hyaluronidase, which can be effective in treating some complications [4]. This enzyme has also been used to treat long-lasting adverse reactions [1]. Whether and when to use the enzyme should be decided with a specialist.
References
- Kyriazidis I, Spyropoulou GA, Zambacos G, et al. Adverse Events Associated with Hyaluronic Acid Filler Injection for Non-surgical Facial Aesthetics: A Systematic Review of High Level of Evidence Studies. Aesthetic Plast Surg. 2024.PubMed 37563436DOI
- Palm MD. Filler frontier: what's new and heading West to the US market. Semin Cutan Med Surg. 2014.PubMed 25830247DOI
- Desyatnikova S. Ultrasound-Guided Temple Filler Injection. Facial Plast Surg Aesthet Med. 2022.PubMed 36351192DOI
- Murthy R, Roos JCP, Goldberg RA. Periocular hyaluronic acid fillers: applications, implications, complications. Curr Opin Ophthalmol. 2019.PubMed 31261189DOI
- Ho D, Jagdeo J. Voluma: A Systematic Review of Clinical Experience. J Drugs Dermatol. 2015.PubMed 26355610
- Rhee SM, You HJ, Han SK. Injectable tissue-engineered soft tissue for tissue augmentation. J Korean Med Sci. 2014.PubMed 25473206DOI
This article is an English translation of general health information that DOY JUN Plastic Surgery compiled in Korean from the summaries (abstracts) of papers in international academic journals. Treatment methods and results vary depending on each person's condition, so please consult a specialist for an accurate diagnosis and treatment plan.