While “Bo” is widely recognized for its role in aesthetic enhancements, its diverse medical applications are equally noteworthy. Botulinum toxin (BoNT-A) is used to treat a range of conditions such as neurological disorders, chronic migraines, hyperhidrosis, and more.


However, recent trends in its cosmetic use have raised concerns about declining treatment efficacy, potentially linked to immunoresistance.

At the recent DASIL/MERZ ASCEND Council Meeting in Hanoi, the Aesthetic Council for Ethical Use of Neurotoxin Delivery (ASCEND) presented alarming findings: 81% of surveyed consumers reported declining efficacy in botulinum toxin treatments, a significant indicator of immunoresistance.


This figure has risen steadily over the years, up from 79% in 2021 and 69% in 2018. These results were based on surveys of 2,599 patients across eight countries, including Thailand, Singapore, South Korea, and Indonesia.


Consumer behavior and contributing factors


One of the key insights from the surveys is that consumer habits may be exacerbating the issue. Over two-thirds (66%) of respondents admitted to increasing dosages, shortening treatment intervals, or continuing ineffective treatments in response to declining efficacy.


Such practices, combined with frequent clinic visits and high cumulative dosages, are significant contributors to botulinum toxin resistance.

Dr. Siew Tuck Wah, Medical Director at Radium Aesthetics in Singapore, shared cases of patients “clinic-hopping” for more frequent injections, often without addressing the underlying issue. “Some patients suffering from declining efficacy opt for the wrong solutions, which may worsen their condition,” he explained.


Role of toxin purity in mitigating resistance


A major topic at the ASCEND panel was the importance of toxin purity in minimizing the risk of immunogenicity. Dr. Niamh Corduff, FRACS, Plastic Surgeon and Clinical Director of RiverEnd Aesthetics, emphasized, “Patients are often unaware that they can develop immunity to botulinum toxin treatments, leading to reduced clinical effects over time. Using a pure BoNT-A formulation is one of the most effective strategies to prevent this.”


Dr. Je-young Park from South Korea echoed this advice, highlighting the need for minimal dosages and thorough initial consultations. “Educating patients about potential side effects and setting realistic expectations is critical to long-term success,” he said.

Impact of increasing dosages and expanded uses


In the aesthetics industry, botulinum toxin usage has expanded to include facial contouring and body sculpting, particularly in markets like South Korea and Thailand. These practices often result in higher cumulative dosages, increasing the risk of resistance. Dr. Park noted that adherence to the minimum effective dose and the use of pure formulations are essential to mitigate this risk.


Recommendations from the ASCEND Consensus paper


The ASCEND panel introduced a consensus paper, “Real-world Implications of Botulinum Neurotoxin A Immunoresistance for Consumers and Aesthetic Practitioners”, led by Dr. Corduff. Key recommendations include:


• • Promoting pure formulations: Over 90% of surveyed healthcare professionals (HCPs) agreed that regular use of impure toxins increases the risk of developing neutralizing antibodies.
• • Screening and management protocols: The adoption of diagnostic and screening tests to detect declining efficacy and the development of standardized management frameworks.
• • Transparent patient education: Including discussions about immunoresistance during initial consultations and informed consent processes.

Dr. Corduff underscored the importance of prevention, saying, “Starting treatment with a pure formulation or switching to one early can prevent long-term complications. Once resistance develops, recovery can take years – or may be irreversible.”


For patients experiencing declining efficacy, switching to a pure toxin or taking an extended treatment break are potential solutions. In some cases, neutralizing antibodies may take years to resolve, if at all.


A call to action


The ASCEND panel concluded with a unanimous call for the aesthetic industry to prioritize safety and efficacy by adopting expert recommendations and regulatory guidelines.


By raising awareness about the risks of resistance and emphasizing toxin purity, practitioners and patients can work together to ensure effective and sustainable botulinum toxin treatments for both medical and aesthetic purposes.

Rising concerns over botulinum toxin resistance highlighted