How does BOTOX® work? The short version goes like this, courtesy of the U.S. National Library of Medicine: BOTOX works — that is, produces its intended clinical effects — by either weakening or paralyzing small muscle groups, by blocking certain nerves from firing, or both.
Under normal circumstances, BOTOX works locally, within a comparatively short distance of the injection site. Its effects lessen with distance and time. This means BOTOX often needs to be administered in multiple locations during the course of a single treatment. Because its effects are temporary, BOTOX needs to be readministered at regular intervals when patients wish to continue treatment.
That’s the short version. The longer explanation for how BOTOX works is a bit more complicated. First, some background on this popular medication is in order.
What type of treatment is Botox?
BOTOX is a prescription-only medication made from a neurotoxin produced by Clostridium botulinum bacteria. Commonly known by the generic name “Botox,” it’s a popular medication that’s indicated for a wide range of cosmetic, musculoskeletal, and neurological conditions: migraine, brow and forehead lines, bruxism, and TMJ, among others.
Botox is widely used by trained medical professionals and aestheticians around the world. Millions of doses of the medication have been administered since its initial FDA approval for clinical use in 1989.
Like all medications, Botox has known side effects that can, in rare cases, result in serious complications, but it’s broadly regarded by practitioners and health authorities alike as safe and effective when used as indicated.
Nevertheless, many prospective Botox patients — people for whom the medication would likely have significant benefits — are made uncomfortable by the fact that Botox is derived from a potentially deadly neurotoxin. These would-be patients, and anyone considering Botox treatment in the future, deserve a fuller explanation of how Botox works.
What ingredients and dosing make Botox work?
According to RxList, the active ingredient in Botox is sterile, purified botulinum toxin type A produced via fermentation of Hall strain Clostridium botulinum type A. The toxin is synthesized into a complex that contains several accessory proteins and then suspended in a saline solution containing human albumin (a blood protein).
Botox doses are measured in Units, with one Unit defined as the median intraperitoneal lethal dose in mice — that is, the amount of Botox that kills 50% of subject mice when injected into the abdominal cavity. The maximum recommended dose for adult humans, regardless of indication, is no more than 400 Units in a three-month interval. For children, the maximum recommended dose is no more than the lower of 10 Units per kilogram of body weight or 340 Units in a three-month interval.
Botox vials typically contain 50, 100, or 200 Units of medication. Trained clinicians may dilute Botox in preparation for treatment using only a sterile, preservative-free 0.9% sodium chloride (saline) solution. Vials are single-use only; any unused medication left in a vial must be discarded after treatment. These safety precautions are essential for ensuring that Botox treatments work effectively and produce minimal complications.
How is Botox administered for optimal effectiveness?
Botox treatment is delivered via subcutaneous injection to local treatment sites, typically on the neck, face, and forehead. Its effects generally last between three and twelve months, depending on the condition being treated.
According to a study published by the National Institutes of Health, Botox typically requires at least 24 hours to produce visible effects. In many cases, two to three days may pass before this occurs. The medication generally reaches peak effect within one to two weeks and remains effective for several months thereafter, albeit with lessening potency.
Following treatment, Botox patients are advised to rest for 24 to 48 hours, avoiding exercise, strenuous activity, and facial treatments or massages. This rest period gives the medication time to work through the local treatment area and reduces the risk that it will spread to surrounding muscles.
What are the possible side effects of Botox?
Although Botox is safe and effective for most patients, it does have some well-documented side effects. Most side effects are mild and resolve on their own. More serious side effects are rare.
The most common side effects associated with Botox treatment include headache, flu-like symptoms (including low fever and fatigue), redness or bruising near the injection site (more common when the patient is taking blood thinning medication or consumed alcohol within 24 hours of treatment), and symptoms of eye irritation (such as redness or tearing).
These common side effects tend to be mild and transient. The provider may instruct the patient to take measures to make the side effects less likely, such as sitting up or standing and not touching the treated area for several hours after treatment.
In rare cases, Botox side effects can be cause for concern. These include local reactions such as:
- Ptosis (drooping eyelids)
- Facial weakness or numbness
- Drooping smile, drooling, and other signs of weakness around the mouth
In extremely rare cases, Botox can spread beyond the local injection site and cause systemic side effects. Patients are instructed to seek immediate medical attention if they experience:
- Muscle weakness outside the immediate injection area (for example, arm or leg weakness)
- Vision changes
- Difficulty breathing
- Difficulty speaking or swallowing
- Loss of bladder function
These are not all the possible side effects of Botox. Patients who experience any concerning symptoms in the hours or days following treatment should consult their doctor and seek immediate medical attention.
Does Botox not work for anyone?
Now that we know how Botox works, two final questions are in order: Does Botox not work for anyone? And should anyone avoid Botox treatment altogether?
On the first question, Botox is generally regarded as effective in treating the conditions for which it’s indicated when administered properly and in the correct dosage. However, as noted, Botox’s effectiveness period varies depending on the condition being treated, the dosage, and other factors, so Botox may not work for as long as expected in all cases. That is, another treatment may be needed sooner than expected if the medication wears off prematurely.
Relatedly, Botox is not indicated to treat all musculoskeletal conditions of the face and head. For example, certain types of wrinkles do not respond well to Botox treatment. Medical providers will help their patients determine whether Botox is indicated in their specific situation.
The answer to the second question is more clear cut: Medical professionals do recommend that certain individuals avoid Botox. Specifically, people who are pregnant, may be pregnant, or are planning to become pregnant during the course of proposed treatment should defer Botox treatment. People who are breastfeeding should also avoid Botox.
Botox is not indicated for people with certain neurological conditions, including:
- Multiple sclerosis
- Myasthenia gravis
- Existing ptosis
- Existing weakness in certain other facial muscles
If you have been diagnosed with a neurological condition of any kind, consult your doctor before proceeding with Botox treatment.