Hyperhidrosis Underarms
Excessive sweating under the arms is an overactive nerve signal to the sweat glands, not a matter of hygiene. It is also the best-studied region: the placebo-controlled trials that treatment of every other area relies on come from here. Two procedures are available — with very different strength of evidence, which I lay out openly.
Hyperhidrosis · Underarm region
Hyperhidrosis Underarms
Excessive underarm sweating is not a matter of hygiene — it is an overactive nerve signal to the sweat glands. Botulinum toxin type A interrupts that signal, not the gland itself. Of all body regions, this one is the best studied: the placebo-controlled trials that the treatment of every other area relies on come from here.
A note on terminology: Many patients search for “Botox” — a brand name of one single product that has become a colloquial umbrella term. The active substance is botulinum toxin type A, contained in several licensed medicinal products. All of them are prescription-only and are injected exclusively by the physician after a medical examination. This page uses the substance name throughout — it refers to the same treatment commonly known as a Botox treatment.
A note on terminology
Many patients search for "Botox." That is the trade name of a single product, which has become a colloquial umbrella term. The active ingredient is called botulinum toxin type A and is contained in several approved medicines. On this page I use the active-ingredient name throughout — the treatment referred to is the same.
Practice Dr. Thomas Ackermann · Methodological stance
Diagnosis comes before treatment: secondary causes such as a thyroid condition or a medication effect must be ruled out. And when it comes to choosing a method, I tell you exactly how solid the evidence for each option really is — even when the less well-supported option would be the more expensive one.
— Dr. med. Thomas Ackermann · Board-Certified Anesthesiologist
Comparing the methods
Two approaches — with very different evidence behind them
Two procedures are available for the underarm region. They differ not only in mechanism and process, but above all in how well they are supported by evidence. That distinction belongs at the beginning of the decision, not at the end.
| Method | Mechanism and process | Evidence |
|---|---|---|
| Botulinum toxin type A | Intradermal injections into the marked area; signal transmission to the sweat glands is temporarily interrupted. Numbing cream is usually sufficient. Effect can be assessed after 10 to 14 days | Well supported. Several large placebo-controlled studies with several hundred participants; the British Health Technology Assessment review rates the evidence for the underarm region as moderate quality with a large effect |
| Micro-focused ultrasound | Focused thermal energy reaches the level of the sweat glands without penetrating the skin surface. No needle. The effect builds up over several weeks | Preliminary. Two small randomized sham-controlled studies; in the more informative one, 67% responded versus 0% under sham treatment, but with only twelve treated participants. Eleven people were followed up at twelve months |
What follows from this: botulinum toxin is the path with solid proof of efficacy, and it needs to be repeated. The focused ultrasound approach can last longer and needs no injection — but the evidence base for that is pilot studies with participant numbers in the low tens. Permanent elimination of sweating is not proven for either method, and I do not promise it.
Common reasons for coming in
Does this sound familiar?
"I buy clothes based on whether it shows"
Dark colors, certain fabrics, a jacket even in summer, a spare top in your bag. The review literature on disease burden describes exactly this avoidance behavior as the real limitation — not the amount of sweat, but what you stop doing because of it.
"Antiperspirants aren't enough for me, or I can't tolerate them"
Aluminum chloride is the right first step and is enough for some people. If it isn't tolerated or isn't enough, the next step is not a stronger product from the same class, but a different procedure entirely. That transition is exactly what the guideline's step-wise scheme provides for.
"I was told a device treatment is a permanent solution"
That is the claim I push back on. Device-based procedures on the underarm can last longer than an injection — that is plausible and suggested by small studies. "Permanent" they are not, and anyone marketing them that way is going beyond the available data.
Important to know
So your expectations are realistic
- The effect wears off. It builds up over ten to fourteen days and then gradually fades. In the 52-week study, median duration of effect was 197 and 205 days respectively. Plan for one to two treatments a year — not a one-time fix.
- It won't be dry — it will be normal. The goal is bringing sweating down to a manageable, everyday level, not suppressing it completely. Some sweat production remains, and that is intentional — the underarm has a function.
- More dose does not mean more effect. In a randomized comparison, one underarm was treated with double the dose of the other in the same person. Across two treatment cycles and 96 weeks, both sides were equally effective at every measurement point. That's why the lowest dose that carries the effect is what's targeted here.
- Not all heavy sweating is primary. Night sweats, sudden onset in adulthood, a generalized pattern, weight loss or fever point to a different cause. In that case, the workup comes first, not an injection.
- There are situations where treatment is not given. Pregnancy and breastfeeding, certain neuromuscular conditions, acute inflammation in the treatment area, an unresolved secondary cause. This is clarified at the initial consultation, before any treatment appointment is scheduled.
Which path fits which situation
Matching the method to your priorities
| Your priority | What speaks for it | What you accept in return |
|---|---|---|
| Reliable result, quickly | Botulinum toxin type A: effect assessable within two weeks, efficacy proven in large controlled studies, dose and area individually adjustable | Repeat treatment once or twice a year; several injections per side |
| No needles, longer-lasting | Micro-focused ultrasound: single session, no injection, effect still present at twelve months in small studies | Effect builds up over weeks; evidence comes from pilot studies with participant numbers in the low tens; result is less finely adjustable |
| Start with the simplest option | Aluminum-chloride antiperspirants, applied at night — the first step in the guideline scheme, and enough for many people | Skin irritation in some users; requires consistent use |
Which path fits you follows from severity, prior treatment and your own priorities. This is a medical decision, not a sales decision — which is why the evidence is presented in the table, not buried in fine print.
Why this practice
The choice of method is not a sales decision here.
This practice offers both procedures — and therefore has no reason to promote the one with weaker evidence. If botulinum toxin is the more solidly supported choice, I say so, even when the device-based treatment would be the larger single sale. That is exactly how you can tell whether advice is independent.
The second point is the workup beforehand. This practice runs a general-medicine consultation with its own laboratory diagnostics — thyroid function, inflammation markers, hormone status and a review of your medication are part of the initial consultation and don't need to be outsourced.
And third, the clinical foundation: as a board-certified anesthesiologist with an additional qualification in emergency medicine, I work with this active ingredient every day, and with the situations where things don't go quite as planned. I am a certified member of the German Society for Aesthetic Botulinum Toxin Therapy (DGBT). If the underarm isn't the only affected region, hands and feet are treated here as well — with regional anesthesia in those cases.
How your treatment works
- Initial consultation and workupHistory, course, prior treatments, medication. If there are signs of a secondary cause, lab testing is done before any treatment decision is made.
- Choosing a methodInjection or device-based procedure — with an open account of the evidence for each, the repeat intervals, and the costs. The consent process is documented in writing.
- Marking the areaThe affected field is determined and marked so the injection points are evenly distributed. The amount is based on the area, not a flat scheme.
- The treatmentNumbing cream is applied and takes effect, then several superficial injections per side with a very fine needle. Both underarms in one appointment, usually 20 to 30 minutes. You return to your day right afterward.
- Follow-upA fixed appointment after ten to fourteen days, once the effect is fully developed. This is when we check whether the area was fully covered and adjust if needed.
Frequently asked questions
Frequently asked questions
The next step
Workup first. Then the method.
At the initial consultation we clarify whether this is primary hyperhidrosis — and which procedure fits your situation. Herzogenaurach, twelve minutes by car from Erlangen.
How effective is the treatment on the underarms?
This is the best-documented region. In the foundational placebo-controlled trial with 320 participants, 94% responded at four weeks versus 36% under placebo, and 82% versus 21% at 16 weeks. In the 52-week study, 75% achieved a two-point improvement on the four-level severity scale versus 25% under placebo.
How long does the effect last?
The most solid figure comes from the 52-week study: median duration of effect 197 and 205 days respectively — roughly six to seven months — versus 96 days under placebo. This varies individually; once you've been treated once, you can estimate your own duration fairly well for planning follow-up treatments.
Does the treatment hurt?
Noticeably less than on the palm or sole. Numbing cream is usually sufficient on the underarm; the injections are superficial and use a very fine needle. Most patients describe it as easy to tolerate.
Ultrasound or injection — which is better?
"Better" depends on what matters to you. The injection is considerably better supported by evidence: large placebo-controlled studies versus two small pilot studies with twelve treated participants in the more informative one. The ultrasound approach needs no needle and can last longer. If you want a reliable result, the injection is the safer path; if needles are a dealbreaker for you, the ultrasound approach is a reasonable option — with that caveat.
Does the device-based procedure work permanently?
That isn't proven. In the pilot study, eleven people were followed up at twelve months and still showed an effect. Twelve months in eleven people is not proof of permanence. Wherever you're promised a permanent solution, that claim goes beyond the data.
Does a higher dose give a longer effect?
No. In a randomized study, one underarm was treated with double the dose of the other in the same person, over two cycles and 96 weeks. Both sides were equally effective at every measurement point. More active ingredient means more cost, not more result.
Will I smell different afterward?
Body odor mostly comes from bacterial breakdown of secretions from the apocrine glands. This treatment targets the eccrine glands, but by reducing the moist environment, many patients also report less odor. That is not promised here as a treatment goal.
What should I keep in mind afterward?
Skip sport, sauna and hot baths on the day of treatment, and don't shave the area the same day. Minor bruising or tenderness at the injection sites is possible and resolves on its own. Please mention any blood-thinning medication beforehand.
When is this treatment not the right choice?
With unresolved secondary hyperhidrosis, during pregnancy and breastfeeding, with certain neuromuscular conditions, and with acute skin conditions in the treatment area. Also when the simpler step hasn't been seriously tried yet.
What does the treatment cost?
Medical services are billed per the German fee schedule for physicians (GOÄ) based on the services actually provided, plus the active ingredient used, by amount. What applies in your case is itemized at the initial consultation, before any treatment appointment is scheduled.
Evidence base
What the studies show
- Naumann M, Lowe NJ, 2001. Botulinum toxin type A in treatment of bilateral primary axillary hyperhidrosis: randomised, parallel group, double blind, placebo controlled trial. BMJ 323(7313):596–599. PMID 11557704. 320 randomized participants at 17 centers: 94% response at four weeks versus 36% under placebo, 82% versus 21% at 16 weeks. Adverse events in 11% versus 5%, without a significant difference.
- Lowe NJ et al., 2007. Botulinum toxin type A in the treatment of primary axillary hyperhidrosis: a 52-week multicenter double-blind, randomized, placebo-controlled study. J Am Acad Dermatol 56(4):604–611. PMID 17306417. 322 participants over one year: 75% achieved a two-point improvement on the Hyperhidrosis Disease Severity Scale versus 25% under placebo. Median duration of effect 197 and 205 days respectively versus 96 days under placebo — the source of the duration figure on this page.
- Heckmann M, Plewig G, 2005. Low-dose efficacy of botulinum toxin A for axillary hyperhidrosis: a randomized, side-by-side, open-label study. Arch Dermatol 141(10):1255–1259. PMID 16230563. Within the same person, one underarm was treated with double the dose, over two cycles and 96 weeks. Both doses were equally effective at every measurement point; the authors explicitly recommend the lower dose for cost and safety reasons.
- Wade R et al., 2017. Interventions for hyperhidrosis in secondary care: a systematic review and value-of-information analysis. Health Technol Assess 21(80):1–280. PMID 29271741. Systematic review of 50 studies commissioned by the British health system: for botulinum toxin at the underarm, evidence is of moderate quality with a large effect versus placebo. For energy-based procedures that damage the sweat gland, the evidence is rated low or very low. The basis for the comparison in the table above.
- Nestor MS, Park H, 2014. Safety and Efficacy of Micro-focused Ultrasound Plus Visualization for the Treatment of Axillary Hyperhidrosis. J Clin Aesthet Dermatol 7(4):14–21. PMID 24765226. Two randomized, sham-controlled pilot studies. In the second, at day 60, 67% of treated participants responded versus 0% of sham-treated participants — with twelve treated and eight sham-treated participants. Eleven people were followed up at twelve months. Positive, but preliminary data.
This comparison is deliberately drawn sharply: both procedures are offered at this practice, which is exactly why the difference in evidence strength needs to be visible. The German S1 guideline "Definition and Therapy of Primary Hyperhidrosis" (AWMF registry number 013-059, July 2023 version) applies in addition.
Related content
Further reading
- Hyperhidrosis overviewAll four regions, the step-wise scheme, and what comes before any treatment.
- Ultrasound Against SweatingThe device-based procedure in detail — process, expectations, limits of the evidence.
- Hyperhidrosis HandsWhy regional anesthesia there is not an extra, but a prerequisite.
- Hyperhidrosis FeetAnkle block at the joint and what to keep in mind afterward.
- Anatomy and Treatment LogicThe clinical background: gland types, mechanism of action, dose finding.
- Laboratory DiagnosticsThyroid, inflammation markers, hormone status — the workup before the indication.
Treating Physician
Dr. med. Thomas Ackermann
Board-Certified Anesthesiologist · Medical Director, Harmonie der Ästhetik
The underarm is the region I have to weigh the least: the treatment is well studied, the effect is clear, and patients notice it within two weeks. The only question that really needs time is the one before it — whether this is primary hyperhidrosis.
This page gives a first overview. What a treatment specifically means for you — which method, which dose, what expectation is realistic — belongs in a personal conversation at the practice. Unhurried, based on findings, with time.
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