From the Research
The smallest needle size recommended for injection of hyaluronic acid (HA) filler is a 33-gauge needle, as demonstrated by a recent study that showed no alteration in the viscoelastic properties of HA fillers after passage through a 33-gauge needle 1. When administering hyaluronic acid fillers, the needle size selection depends on the viscosity of the specific filler product, the treatment area, and the desired precision.
- Higher viscosity fillers may require larger needles (27-30 gauge) to allow proper flow,
- while lower viscosity products can be administered through smaller needles. Smaller needles generally cause less pain and trauma during injection, potentially reducing bruising and patient discomfort. However, they require more pressure to extrude the filler and may increase the risk of needle blockage. Many practitioners prefer using cannulas (typically 25-27 gauge) instead of needles for certain areas as they can reduce the risk of vascular complications. The choice between needle sizes should be based on the specific filler product being used, the anatomical area being treated, and the injector's experience and preference. A study from 2020 found that injection through small-bore needles can alter the physical properties and rheological equilibrium of soft tissue fillers, suggesting that smaller needles may affect the clinical performance of fillers 2. However, another study from 2022 demonstrated the safe and effective use of a 33-gauge needle for HA filler injection, with no observed side effects except for standard post-treatment bruises and edema 1. In contrast, a study from 2010 described the use of a 31-gauge insulin syringe for filler injections, which may enhance the injection process and produce a more balanced and symmetrical outcome for patients 3. Ultimately, the selection of needle size should prioritize the safety and effectiveness of the procedure, as well as the patient's comfort and satisfaction. The most recent and highest quality study, which is from 2022, supports the use of a 33-gauge needle for HA filler injection 1.