From the Research
Botox (Botulinum toxin) typically begins to take effect within 24-72 hours after injection, with the onset sometimes noticeable as early as 1-2 days post-treatment, and peaks around 2 weeks after administration, according to the most recent and highest quality study available 1. The onset and peak effect time of Botox can vary depending on several factors, including the treatment area, dose administered, and individual patient factors.
- The delayed onset occurs because Botulinum toxin works by blocking acetylcholine release at the neuromuscular junction, preventing muscle contraction.
- This process requires time as the toxin must be internalized into nerve terminals and cleave proteins involved in neurotransmitter release.
- Patients should be advised to wait the full two weeks before assessing the complete results of their treatment, and to avoid manipulating the treated area, exercising vigorously, or lying down for 4 hours post-injection to prevent diffusion of the toxin to unintended muscles. The effects of Botox are temporary, typically lasting 3-4 months before gradually wearing off as nerve terminals regenerate, as supported by studies such as 1 and 2.
- However, some studies have shown that high-dose Botox treatment can prolong the antihidrotic effect for more than 19 months, with a relapse-free interval of up to 29 months 3.
- It's also important to note that repeated Botox treatments may prolong the duration of effect or potentiate the effect, as suggested by 1. Overall, the most recent and highest quality study available 1 provides the best evidence for the onset and peak effect time of Botox, and should be used to guide clinical practice.