A calm, medical explanation of what botulinum toxin does, what it can be used for, and where its limits lie.
The complaint
De klacht
You often hear the term "muscle relaxant" or "botox" mentioned, but what it actually does often remains vague. Perhaps you are reading about it because you suffer from excessive sweating, jaw clenching or teeth grinding, or tension headaches, and you wonder whether this could be something for you. This page explains in a neutral way how it works, what it is and is not intended for, and what considerations a doctor makes.
Mogelijke aanpak
Botulinum toxin is a purified protein that temporarily reduces the transmission of signals between nerve and muscle (or between nerve and sweat gland). Through small injections at precisely chosen sites, a muscle relaxes or sweat production decreases. The effect is always temporary and builds up over the first days to about two weeks.
Dr. De Smedt: "Botulinum toxin is a tool for specific, well-understood indications, not a miracle cure. It is the complaint and the examination that determine whether it makes sense, not the other way around."
Botulinum toxin type A is a purified protein that temporarily blocks the transmission of nerve signals to a muscle or gland. In the muscle, this causes targeted, local relaxation. In sweat glands, it inhibits the signals that trigger the gland to produce fluid. Because the body gradually renews the affected nerve endings, the effect wears off on its own. A treatment is therefore never permanent, and that is intentional.
The term "muscle relaxant" is used for different things in everyday language. There are also oral muscle relaxants in tablet form that your GP can prescribe for acute back pain, for example. Those work in a completely different way, throughout the whole body, and belong with a GP or specialist. This page is about the local, injectable variant with botulinum toxin, which works specifically on a particular muscle or area.
In an aesthetic-medical practice, a few medical applications where botulinum toxin plays an evidence-based role are most relevant.
With hyperhidrosis of the armpits, the sweat glands produce far more moisture than is needed for temperature regulation. Small, superficial injections into the skin (intradermal) reduce the stimulation of the sweat glands in that area. The effect lasts on average about 4 to 9 months and varies from person to person. It is a symptomatic approach: the complaint is temporarily relieved, but the underlying predisposition remains.
With bruxism, you strongly tense the chewing muscles, often unconsciously and especially at night. This can lead to jaw pain, headaches, tooth wear, and sometimes a widened, square appearance of the lower jaw due to an overdeveloped chewing muscle. An injection into the chewing muscle (the masseter) reduces the clenching and grinding force, which decreases the tension. The effect usually lasts about 3 to 6 months. Important: this does not replace a dental assessment. Bruxism often has multiple causes, and botulinum toxin is one possible part of a broader approach.
For some forms of tension headache or excessive muscle activity in the face, targeted relaxation of certain muscles can provide relief. Whether this is useful for you depends strongly on the type of complaint and the findings during examination. This requires an individual assessment.
An assessment is recommended when a complaint hinders you daily, when simpler measures do not help enough, or when you are not sure what the cause is. For excessive sweating, for example, that means regular and medical deodorants no longer keep the problem under control. For jaw complaints, it means you suffer from pain, headaches, or tooth damage. A doctor first checks whether botulinum toxin is even the right route, or whether another approach fits better.
A consultation starts with your story: what complaint, how long, what have you already tried, and what medical history is relevant. The doctor examines the affected area and determines whether treatment is useful and safe. Only then is a possible treatment discussed, including what you can realistically expect and what not.
The treatment itself consists of a few precise injections with a thin needle. Depending on the indication, this takes about 15 to 30 minutes. You can usually resume your day immediately afterwards. The result is not immediately visible or noticeable: it builds up over the first days to about two weeks. A follow-up check helps to assess whether the effect is sufficient or needs to be adjusted.
Botulinum toxin is well studied when used correctly, but no medical treatment is without risk. Around the injection site, temporary redness, a small bruise, or mild tenderness can occur. Depending on the area, there is a chance of unwanted, temporary weakening of neighbouring muscles, such as asymmetry or temporarily reduced muscle strength. Headache or flu-like symptoms are rarer. Because the effect is temporary, most side effects also recover on their own, although it is wise to always discuss persistent or unusual complaints with the doctor.
Let's be honest about the limits: botulinum toxin treats symptoms, not causes. With bruxism, it removes the strength of the chewing muscle, but it does not solve the underlying cause, such as stress or a bite problem. With hyperhidrosis, it temporarily reduces sweat production, but the predisposition remains. Repetition is therefore needed to maintain the effect, and that is a conscious decision you make together with the doctor.
There are situations in which botulinum toxin is advised against or postponed. Think of pregnancy and breastfeeding, certain neuromuscular disorders, an active infection or skin problem at the injection site, a known allergy to an ingredient, or the use of certain medication. Also when expectations are not realistic, or when the complaint is better treated with another approach, botulinum toxin is not indicated. The doctor makes this assessment during the consultation based on your situation.
Botulinum toxin is rarely the only option. Depending on the complaint, other measures can be equally suitable or even more appropriate.
Often a combination works best, with botulinum toxin as one part of a broader approach. What is most useful in your case will become clear from the consultation.
Botulinum toxin is a temporary, local treatment that brings a muscle or sweat gland to rest in a more targeted way. For a few well-supported complaints, such as excessive sweating or jaw clenching, it can provide relief. It is symptomatic, not permanent, and not suitable for everyone. A personal assessment determines whether it is a sensible choice for you and whether another route fits better.
Dr. De Smedt explains
Botulinum toxin works by temporarily dampening the signal between nerve and muscle. Normally the nerve releases a substance (acetylcholine) that makes the muscle contract; botulinum toxin locally inhibits that release. As a result, the muscle in that area contracts less forcefully, exactly where it is needed. In sweat glands the same messenger substance plays a role, so the gland temporarily produces less fluid. Because the body gradually repairs the nerve endings, normal function returns on its own after a few months.
Dr. Thierry De Smedtaesthetic physician, Ghent
Wat je mag verwachten
Risico’s en wanneer niet
Frequently asked questions
Every situation is different. During a consultation in Ghent you receive a personal medical assessment and honest advice about what is and is not useful.
