Taula de Continguts
Botox is the colloquial name for botulinum toxin type A, a prescription medicine that temporarily relaxes the muscle it is injected into. At Santé Madrid it is used for six uses in the catalogue: expression lines, baby botox, lip flip, bruxism, hyperhidrosis and gummy smile, always after a medical assessment and only if it is indicated. In this guide we explain how it works, what each use aims for, what the product information and the medical literature say about when the effect starts and how long it lasts, and what its side effects and contraindications are.
Key points
- "Botox" is used as a generic name, but what we are really talking about is botulinum toxin type A, a medicine that should only be given by doctors.
- It works by blocking the signal from the nerve to the muscle; the effect is temporary and the muscle regains its function over time.
- Upper-face expression lines appear in the product information for aesthetic use; lip flip, bruxism and gummy smile rely on medical literature with more limited evidence.
- Severe primary axillary hyperhidrosis appears as an indication in the product information of a botulinum toxin medicine.
- It has side effects and contraindications that are reviewed in the consultation. Results vary from person to person.
What botulinum toxin is and why we call it botox
Botox is the brand name of one of the botulinum toxin type A medicines, but the term has spread so widely that today it is used to refer to any of them. In this guide we use "botox" the way you use it when you search for it, without recommending any brand. All of them are prescription medicines, and the product information documents consulted state that they should only be given by doctors with the appropriate qualifications and experience.
Its mechanism is well described. According to the product information authorised by the AEMPS, the toxin blocks the release of acetylcholine at the nerve endings, which is the signal the nerve sends to the muscle to make it contract. The result is a localised relaxation of the treated muscle. The same document explains that the effect is not permanent: over time, the nerve endings regenerate and reconnect with the muscle, which regains its activity.
A practical detail: the product information documents warn that the units of one product are not interchangeable with those of another (another AEMPS product information document). That is why it makes no sense to compare figures between brands, and in this article we do not talk about doses: the product and the amount are decided by the doctor after assessing your case.
Six uses, one mechanism
All the uses in the catalogue are based on the same thing: relaxing a specific muscle or, in the case of sweat, acting on the nerve endings that stimulate the sweat glands, as described in the corresponding product information. What changes is the area, the aim and the support behind each indication. This table summarises it with the sources we have consulted.
| Use | What it aims for | Support consulted |
|---|---|---|
| Expression lines | Softening the frown lines, crow's feet and forehead | Indication included in the product information for aesthetic use |
| Baby botox | A more subtle approach in the same areas | Same medicine and same precautions; it has its own guide |
| Lip flip | Making the upper lip look slightly more everted | Small studies and reviews; it does not add volume |
| Gummy smile | Showing less gum when smiling | Narrative reviews of the literature |
| Bruxism | Reducing the activity of the masseter | Systematic review of trials and observational studies |
| Hyperhidrosis | Reducing excessive sweating | Axillary indication included in the product information |
When a use is not among the indications of the product information documents consulted, it is approached with more caution: the doctor assesses whether it is indicated, explains what it is based on and what the limitations of the evidence are, and only then is a decision made. So-called baby botox uses the same medicine with a more subtle approach; we have a separate guide on it, and here it is enough to know that it shares its side effects and contraindications with the rest.
Expression lines: what the product information says
Expression lines are the ones that appear when you make facial expressions: the frown lines when you frown, crow's feet when you smile and the horizontal forehead lines when you raise your eyebrows. The product information for aesthetic use includes these three areas as an indication in adults, for the temporary improvement of moderate to severe lines when they have a significant psychological impact on the person.
On timing, it is best to stick to what the sources say. According to one of the documents, the improvement is usually noticed during the first week and the described effect lasts up to 4 months. Another product information document describes an improvement that usually begins in the first few days, with the maximum effect around the first month and a duration of up to 4 months. These are clinical-trial data: in practice, the onset and duration vary depending on each person, the area and the strength of the muscle.
The reasonable aim is to soften the movement, not to erase expression. Wrinkles that are already visible at rest may need other approaches, and that is assessed in the consultation. If you want to see how we approach this treatment, see the expression lines page.
Lip flip and gummy smile: uses around the mouth
Lip flip. This involves slightly relaxing the part of the orbicularis muscle around the upper lip so that the lip looks slightly more everted when you smile. A review published in 2025 describes it as an alternative for people who do not want a filler, with a shorter duration than a lip filler. A small prospective study observed a modest increase in upper lip height with no change in volume, and mild, transient adverse effects. In other words: it does not fill, it changes the position of the lip. The same review warns that, while the effect lasts, it may be harder to pronounce some words, drink through a straw or whistle, something to bear in mind if you sing or speak in public for work. There is more detail on the lip flip page.
Gummy smile. A gummy smile is when more gum than usual shows when you smile. When the cause is excessive activity of the muscles that lift the upper lip, the toxin can relax them so that the lip rises less, according to a narrative review on its use in the oral and maxillofacial area and another 2025 review on gum aesthetics. Not every gummy smile has that origin, which is why a prior assessment is essential.
Bruxism and hyperhidrosis: beyond wrinkles
Bruxism. Clenching or grinding your teeth overloads the masseter muscle. A systematic review of clinical trials concluded that the toxin can reduce the frequency of episodes and pain, although it was based on few studies. A 2025 observational study described changes in bite force and in associated symptoms, and noted that age, sex and muscle activity can influence the response. It does not replace the dentist's assessment or the usual measures, such as a night guard. You can read how we approach it on the bruxism page.
Hyperhidrosis. This is excessive sweating that interferes with daily life. The product information of a botulinum toxin medicine lists as an indication severe, persistent primary axillary hyperhidrosis that does not respond to topical treatment. That document asks for secondary causes, such as hyperthyroidism, to be ruled out first with a medical history and examination. A systematic review of dermatological uses describes a well-established efficacy and safety profile in focal idiopathic hyperhidrosis. There is more information on the hyperhidrosis page.
Side effects and contraindications
According to the product information, adverse reactions usually appear in the days after the injection, are transient and are mostly mild to moderate. Those described include headache, a drooping eyelid or eyebrow, redness, local muscle weakness and, as with any injection, pain, stinging, swelling or bruising at the treated point. In the treatment of axillary hyperhidrosis, the corresponding document also describes sweating in other areas of the body.
Very rarely, effects distant from the injection site have been reported. The product information states that you should seek medical help immediately if you have difficulty swallowing, speaking or breathing.
These points come from the product information and the reviewed literature. That is why, in the consultation, we will ask about your medical conditions, your medication and previous aesthetic treatments.
How we work at Santé Madrid
Our clinic is at C. de Amador de los Ríos, 1, Chamberí, 28010 Madrid, open Monday to Friday from 9:00 to 21:00 and Saturdays from 10:00 to 15:00; it is closed on Sundays. Any botulinum toxin treatment is carried out by the Santé Madrid medical team, after a medical assessment and only if it is indicated.
The first step is to talk about what concerns you. If you would like some initial guidance, the aesthetic consultation with a Beauty Coach is free. The medical consultation costs 50 € and is the moment to review your medical history, your medication and the contraindications, and to explain which use makes sense in your case, what it is based on and what its limitations are. Sometimes the conclusion is that the toxin is not the right option, or that it is worth combining it with another approach from the catalogue, such as hyaluronic acid fillers, which work differently.
If you go ahead, the team will give you specific instructions for afterwards and explain what is to be expected and what is not. Results vary from person to person, and the effect is temporary because of the very way the medicine works.
Frequently asked questions
Are botox and botulinum toxin the same thing?
"Botox" is the colloquial name used for botulinum toxin type A, although Botox is actually a brand name. There are several medicines with this substance and their units are not interchangeable. The doctor decides which one to use after assessing your case.
How long does it take to notice and how long does the effect last?
For expression lines, the product information describes an improvement that is usually noticed in the first few days or during the first week and an effect of up to 4 months. These are clinical-trial data; they may vary in each person, and for other uses the evidence on duration is more limited.
Does the injection hurt?
Like any injection, it can cause pain, stinging or slight discomfort at the treated point, and sometimes swelling or a passing bruise. How it feels varies from person to person. If it worries you, mention it in the medical consultation.
Can I be treated if I am pregnant or breastfeeding?
It is not recommended. The product information does not recommend botulinum toxin during pregnancy or breastfeeding, because there are not enough data on its safety in these situations. If you are trying to get pregnant, mention that in the consultation too.
Does a lip flip add volume to the lip?
No. It slightly relaxes the muscle around the upper lip so that it looks slightly more everted, without adding volume. If what you are looking for is volume, the medical team will assess whether another approach, such as hyaluronic acid, makes more sense.
Does it help with bruxism if I already use a night guard?
It can be considered as a complement after a medical assessment and only if it is indicated. A systematic review described fewer episodes and less pain, although with few studies. It does not replace the dentist's assessment or the night guard.
What happens if I do not like the result?
The effect of botulinum toxin is temporary: over time, the nerve endings regenerate and the muscle regains its activity. If you notice something that worries you, such as a drooping eyelid, contact the clinic so the medical team can assess it.
Botulinum toxin is a medicine with well-studied uses and others with more limited evidence. Understanding how it works, what can be expected from each use and when it is not indicated helps you decide calmly, together with the Santé Madrid medical team and always after an individual assessment.
