Safety of Copolyamide Filler Injection for Breast Augmentation

Shunichi Nomoto, MD; Keiko Hirakawa, PhD; Rei Ogawa, MD, PhD, FACS


Plast Reconstr Surg Glob Open. 2021;9(2):e3296 

In This Article

Abstract and Introduction


Background: Although injections with copolyamide fillers (Aquafilling/Los Deline and Aqualift/Activegel) are currently used widely for breast augmentation, many complications have been reported. A recent position statement by a Korean aesthetic/reconstructive breast surgery society indicated these fillers are the same as polyacrylamide gel (PAAG), which is widely prohibited due to complications. To test this statement, this retrospective cohort study examined the clinical complications after breast augmentation with copolyamide fillers. Nuclear magnetic resonance (NMR) analysis of copolymer and PAAG fillers was also conducted.

Methods: All consecutive patients with concerns about or sequelae from copolyamide fillers who visited our hospital in 2018–2020 were identified. The injected formulation, complications, and intraoperative findings were recorded. Copolyamide fillers were compared with PAAG and 2 PAAG fillers (Amazingel and Aquamid) by NMR.

Results: Of the 29 patients (all women; average age, 42 years), 17 complained of breast deformity. Eight had puncture site infections and mammary gland inflammation. Five exhibited induration (single large/small lumps). In 4 cases, the filler had migrated outside of the breast, including to the back and vulva; these cases had severe symptoms. NMR showed that the copolyamide and PAAG fillers bore all of the characteristic peaks of PAAG.

Conclusions: Our clinical/intraoperative and NMR findings showed, respectively, that copolyamide fillers cause the same complications as PAAG fillers and have the same composition. Thus, the risks of copolyamide fillers for breast augmentation are equivalent to those for PAAG fillers. It is strongly recommended not to use copolyamide fillers until their long-term safety is established.


Aquafilling (Biomedica, spol, s.r.o., Czech Republic) is a hydrophilic gel that is composed of 98% sodium chloride solution (0.9%) and 2% copolyamide. It was developed for facial contouring in the Czech Republic in 2005.[1] Since 2018, the same product has been sold under the name Los Deline (Bio Trh, s.r.o., Czech Republic). Aqualift (National Medical Technologies Center Co., Ltd., Ukraine) is a similar formulation that was first copyrighted in 2013 and then renamed to Activegel in 2015. It is also composed of 98% sodium chloride solution (0.9%) and 2% copolyamide.

Shin et al[2] have reported that Aquafilling/Los Deline injections effectively correct mild unfavorable results after breast augmentation with silicone implants. Single large-volume injections for breast augmentation are now employed all over the world, including Europe, Japan, and Korea.

However, the safety of these products remains controversial because sequelae after these injections have been reported by multiple case reports.[1,3–7] These sequelae include mastalgia, gel migration, inflammation, infection, and nodular lesions[1,3–7] and are believed to be due to the copolyamide. Concern about these products led the President of the Korean Academic Society of Aesthetic and Reconstructive Breast Surgery to state in 2016 that the copolyamide in at least Aquafilling/Los Deline is poly(acrylamide-co-N,N'-methy-lene-bisacrylamide), as indicated by the documents submitted by Biomedica to the Korean Food and Drug Administration.[8] This means that the copolyamide has the same composition as polyacrylamide gel (PAAG) fillers, which have been reported to have serious adverse complications when used for breast augmentation, including localized lumps, deformities, infections, gel migration, and loss of the ability to breastfeed. As a result, the President expressed significant concerns about the safety of Aquafilling/Los Deline and opposed its use for breast augmentation until it has been shown to be safe over the long term.[8]

Despite this position statement, the similarities and differences between the copolyamide fillers (ie, Aquafilling/Los Deline and Aqualift/Activegel) and PAAG fillers in terms of complications have never been formally examined. At Nippon Medical School in Tokyo, Japan, we have an outpatient clinic that specializes in sequelae after cosmetic surgery. As a result, we have extensive therapeutic experience with the aftereffects of PAAG fillers, including Aquamid (Contura International A/S, Denmark) and Amazingel (NanFeng Medical Science and Technology Development Co., Ltd., Shijiazhuang, People's Republic of China).[9] In this article, we report the commonalities and differences between conventional PAAG fillers and the copolyamide fillers by retrospectively analyzing the findings of all patients who presented with sequelae from copolyamide filler breast augmentation over a 27-month period in 2018–2020. We also determined the composition of all filler products by nuclear magnetic resonance (NMR) analysis.