Hyperhidrosis is more than “sweating a lot". For some people, it’s persistent, localised sweating that happens even when you’re not overheated or exercising, and it can be difficult to control with standard antiperspirants. Because it sits somewhere between a medical issue and a quality-of-life concern, it’s easy to feel unsure about what’s normal, what’s treatable, and which options are actually evidence-based.
Botulinum toxin injections are one of the better-known clinical options for focal hyperhidrosis, especially underarm sweating. They work by blocking nerve signals that trigger sweat glands in the treated area (they do not suppress sweating across the whole body). Effects are temporary, and response, longevity, and practicality vary depending on the area treated and the individual.
In this guide, you’ll learn how the treatment is performed in a typical clinic setting, which areas may be considered, what a realistic timeframe looks like for onset and duration, and how to think about risks, aftercare, and repeat appointments. We’ll also cover where this sits alongside other treatments, and what to ask in a consultation so you can make a calm, informed decision.
What Causes Excessive Sweating?
Sweating is controlled by the sympathetic nervous system, which is responsible for regulating your body's fight-or-flight response. When your sympathetic nervous system senses an imminent threat, it activates sweat glands in order to cool down your body and help you prepare for action. Excessive forehead sweating and facial sweating can be triggered by things like fear or anxiety, but also by exercise and hot temperatures – even if you're not aware of it happening!
Hyperhidrosis is the medical term for excessive underarm sweating and can be classified as primary and secondary. Primary hyperhidrosis can happen for no obvious reason. It normally affects both sides of your body and is more pronounced during the daytime. It usually has an effect on the scalp, face, underarms, palms and feet. Secondary hyperhidrosis occurs as a result of an underlying medical condition, which will require investigation and treatment of the underlying cause first.
How Do Botox Injections Stop Underarm Sweating?
Botox injections work by blocking nerve impulses from triggering sweat glands. As a result of these small injections with a fine needle (which should only be administered by experienced doctors, nurses and other medical injectors), you'll begin to sweat less.
The treatment will only stop sweating in the area it has been injected.
What Does Botox for Excessive Sweating (Hyperhidrosis) Treatment Involve?
A Minor’s starch iodine test may be performed prior to your treatment to determine the potential treatment area. This involves applying iodine to the area you experience excessive sweating allowing it to sweat and once it dries a small amount of starch is placed on the affected area highlighting the affected areas in dark blue colour. Experienced medical professionals who treat hyperhidrosis will inject a small amount of botulinum toxin into each affected area to control sweating.
The entire process takes about 30 minutes per area treated, though you might need more than one session if your sweating is severe or widespread over several body parts such as the forehead, back and feet.
The injected area can be numbed beforehand so you don't feel too much pain, but you may see some redness and swelling in your armpits following injectable treatments.
This will settle after a few hours and you can go back to your normal routine straight away. Results usually take two weeks to take effect and you will not need to apply deodorant when the botulinum toxin starts working.
Botox injections are not a permanent treatment for your excessive sweating problem, but it usually lasts between three to six months. If you sweat excessively, you may need to book follow-up treatment for additional injections during this time period, so be sure you are committed to using Botox to treat underarm sweating before going ahead with treatment.
How Much Does It Cost to Treat Excessive Sweating With Botox?
The price will usually depend on what areas you're having treatment; for example, it's likely to cost more to get a sweaty back treated vs. your underarms due to the surface area needing injections.
For two underarms, botox injections are priced are around £400 on average. This can also be influenced by practitioner experience and the clinic's location – London is generally more expensive than the rest of the UK!
Are There Side Effects to Treating Excessive Sweating?
Possible side effects to Botox injections and other brands of botulinum toxin are rare, but can include:
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Headaches
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Skin irritation
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Pain or bruising at the injection site
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Swelling
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Allergic reaction
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Droopy eyelids (for facial injections)
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Dry eyes or mouth
The most dangerous complications with Botox injections are double vision and difficulty breathing, but these are thankfully extremely rare.
If you experience any side effects or complications around your sweat glands, contact your practitioner immediately.
Who Should You Trust to Perform Your Botox for Excessive Sweating (Hyperhidrosis)?
Botulinum toxin for excessive sweating is offered 'off-label' for all areas apart from under the underarms, which means that there isn't lots of research and testing confirming its effectiveness and safety. You should therefore only see experienced medical professionals who have lots of experience in performing injectable treatments and are familiar with medical conditions associated with excessive sweating.
We highly recommend that you only undergo hyperhidrosis Botox treatment with a medically-qualified professional, who will have undergone training in anatomy and physiology, as well as be accountable to a regulatory body such as the General Medical Council (GMC), Nursing and Midwifery Council (NMC) or General Dental Council (GDC).
They should also be able to advise you of the risks of injectable treatment and be confident in handling complications if they arise.
Check out our handy guide for finding a practitioner you can trust to perform Botox injections.
Book a Consultation Today!
To find out if using Botox injections to treat your excessive sweating, you'll need a detailed consultation with a medical professional. Your nearest accredited and verified Botox clinics are listed below.
As always, if you have any questions you can use our Botox Q&A where you can ask for more advice direct from a trusted, experienced medical practitioner.
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