Long-term Effects of Repeated Botulinum Toxin Injection in Cosmetic Therapeutics

Area of Science:

• Aesthetics
• Neurology
• Dermatology

Background:

• Botulinum toxin (BT) is widely used for cosmetic and therapeutic purposes with a known short-term effect.
• Conventional understanding suggests BT results last 3-5 months, but emerging evidence indicates longer-lasting changes.
• This review examines the implications of long-term outcomes from repeated BT injections for cosmetic applications.

Purpose of the Study:

• To review and understand the current literature on long-term outcomes after repeated cosmetic botulinum toxin injections.
• To assess the potential for prolonged effects beyond the typical 3-5 month duration.

Main Methods:

• A comprehensive literature review was conducted.
• 22 publications, including 14 clinical trials, were evaluated for study design and results.
• Focus was on studies reporting outcomes beyond 6 months post-injection.

Main Results:

• Few studies measured outcomes beyond 6 months; many had industry funding.
• Studies with extended follow-up revealed persistent changes from BT injections.
• Observed persistent changes lasted up to 4 years in some cases.

Conclusions:

• Current knowledge on long-term cosmetic BT results is limited.
• Insufficient evidence exists on how prolonged effects might change clinical BT use.
• Further studies with extended follow-up are required to assess long-term impacts on appearance and muscle function.