Micro-Gauge Needles with LDSI Improve Patient Comfort and Reduce Botulinum Toxin Wastage

According to recent findings from a prospective, randomized, controlled, single-blind study, a 34-gauge needle combined with a low dead space injector (LDSI) was associated with less pain, reduced bruising in select facial regions, and lower product wastage compared with a 30-gauge fixed-needle insulin syringe for upper-face botulinum toxin injections.¹

Study Design and Patient Cohort

The study included 42 healthy adults aged 18 to 65 years who underwent cosmetic botulinum toxin treatment of the upper face at Baskent University Ankara Hospital in Turkey. Each participant's face was divided into symmetric halves, with 1 side treated using a 34-gauge needle connected to an LDSI and the other using a 30-gauge fixed-needle insulin syringe. Patients were blinded to which facial side received each injection system.

The investigators assessed pain in the frontal, glabellar, and periorbital regions using a 0-to-10 visual analog scale (VAS). Bruising was evaluated the day after treatment using a 4-point scale ranging from no bruising to hematoma. Product wastage was determined by weighing the residual solution remaining in the syringe and needle after the entire injectable product had been administered.

Lower Rates of Pain and Posttreatment Ecchymosis

Pain scores were significantly lower with the 34-gauge needle–LDSI system across all 3 treatment areas. Mean VAS scores for the study versus control sides were 3.90 versus 5.66 in the frontal region, 3.30 versus 5.07 in the glabellar region, and 2.00 versus 3.33 in the periorbital region. All differences were statistically significant.

The investigators also found differences in posttreatment ecchymosis. No bruising was observed on the study side in any of the 3 regions. On the control side, grade 1 bruising occurred in 6 patients in the frontal region and 2 patients in the glabellar region. In the periorbital region, 8 patients developed grade 1 bruising and 3 developed grade 2 bruising. Differences between the 2 injection systems were statistically significant in the frontal and periorbital regions but not in the glabellar region.

Minimizing Neurotoxin Wastage

Product retention in the injection system was also substantially lower with the LDSI. In the frontal region, the mean amount of residual product was 0.0189 g with the study system compared with 0.0501 g with the control system. In the glabellar region, residual product averaged 0.0182 g versus 0.0578 g, respectively, while in the periorbital region it averaged 0.0207 g versus 0.0539 g. All differences were statistically significant.

Across the 3 regions, the investigators calculated an average product loss of approximately 0.0192 g with the 34-gauge needle–LDSI system compared with 0.0539 g with the 30-gauge fixed-needle syringe, representing approximately 2.8-fold greater wastage with the standard syringe system. Based on the study's dilution and weight calculations, the residual product corresponded to approximately 0.48 units of botulinum toxin with the LDSI and 1.36 units with the control syringe.

System Design vs. Needle Gauge

The authors emphasized that the findings should not be interpreted as demonstrating an effect of needle gauge alone. Because the study compared 2 complete injection systems, differences in both needle diameter and syringe design may have contributed to the results. In particular, the reduction in product wastage was considered most likely related to the LDSI's low dead space rather than the 34-gauge needle itself.²

MORE ON AESTHETICS

Although the study's split-face design reduced variability between participants, pain assessment remained subjective. The investigators also noted that pain during injectable procedures can be influenced by factors including solution pH, dilution, injection speed, injection depth, and individual patient sensitivity.

“Therefore, evaluating injection systems in a controlled clinical setting is essential to better understand the combined effect of device-related variables on patient experience and treatment efficiency,” the authors said.1

Overall, the findings suggest that a 34-gauge needle combined with an LDSI may offer advantages for upper-face botulinum toxin treatment, including improved patient comfort, less bruising in some areas, and reduced product wastage. The authors called for larger studies and research designs that isolate individual device components to further clarify the effects of needle gauge and injector design.

References

1. Gultekin G, Koycu A, İnan S, Buyuklu AF. Needle and Syringe Preference in Cosmetic Botulinum Toxin Treatment of the Upper Face: A Randomized, Controlled, Single-Blind Study. J Cosmet Dermatol. 25, no. 7 (2026): e71052, doi:10.1111/jocd.71052

2. Golan S, Pena J, Moore J, Tandalam S, Lelli G. The Association between Needle Size and Waste Product and Its Effect on Cost-Effectiveness of Botulinum Toxin Injections?. Facial Plast Surg. 2020;36(4):484-486. doi:10.1055/s-0040-1713793