Aluminum Chloride for Sweaty Feet: 12.5% vs. 30% in a Small Trial

If a foot antiperspirant has not helped, bring the bottle to a pharmacist before buying a stronger one. The evidence below compares two concentrations, then checks the application details that can affect skin tolerance.

What the six-week comparison found

A randomized half-side trial published in 2012 included 20 volunteers with excessive sole sweating, or plantar hyperhidrosis. It compared antiperspirants containing 12.5% and 30% aluminum chloride hexahydrate for six weeks.¹

Researchers used a clinical sweating scale, an iodine-starch test, a standardized sniff test, questionnaires and skin-surface pH. Both concentrations reduced rated sweating and the sweating area; the sniff test also improved. Tolerability assessments did not differ, and the authors favored 12.5% for outpatient treatment.¹

We verified the original publisher’s abstract and the PubMed record. Full methods and numerical results were not accessible, so we cannot provide a percentage reduction, response rate or reproducible application schedule.¹

The trial supports possible benefit at the lower concentration. Twenty people followed for six weeks cannot establish an ideal strength or long-term safety. Improvement with both products does not prove equal effectiveness for everyone.¹

Why guidance still discusses higher concentrations

The International Hyperhidrosis Society² lists topical aluminum chloride among first-line treatments for plantar hyperhidrosis, and says higher concentrations, up to 30%, may be needed. That is treatment guidance for clinicians, rather than a finding that 30% works better for every foot.²

Its practical advice emphasizes sweat-free skin before application, overnight use followed by washing off, and waiting until the product has dried completely before putting on socks. Moisture can increase irritation. The Society says a two-week trial with adherence is usually sufficient to assess whether a topical antiperspirant helps an individual.²

Bring your product and current routine to a pharmacist or clinician before deciding it failed. Ask which concentration, amount, frequency and review date apply to you. Record applications alongside dampness and any stinging, so a review can distinguish poor effect from poor tolerance.

One foot-product label has its own schedule

As a UK example, Anhydrol Forte’s current patient leaflet identifies 20% w/v aluminum chloride hexahydrate for armpits, hands or feet. It says to apply to completely dry skin at bedtime, allow it to dry and wash it off in the morning.³

Its initial schedule is two nights of use followed by two nights without use, with subsequent frequency adjusted to requirements and side effects. That differs from a nightly start described in some general guidance. Use the instructions for your actual product and have a pharmacist reconcile any conflicting advice.³

The leaflet prohibits application to broken or irritated skin, warns that excessive use can cause irritation and redness, and says to stop and tell a doctor or pharmacist if side effects become serious. The solution is highly flammable and can damage fabrics and surfaces.³

This example is a label check, not a brand recommendation or a schedule for a different bottle. Products and availability vary by country.

If the skin cannot tolerate it, discuss another option

The American Academy of Dermatology⁴ advises telling your dermatologist about irritation. Adjustments may include longer intervals, a different formulation or ensuring very dry skin. Its treatment page also describes iontophoresis for hands and feet, using an electrical current through tap water. That requires a treatment plan and instruction in use.⁴

The NHS⁵ advises assessment when excessive sweating interferes with daily activities, self-care is not helping, it occurs at night, or you are taking medicine for another condition. A change in treatment may depend on why the sweating happens.⁵

Odor needs its own check. The NHS⁶ lists sweat and bacteria, as well as fungal infections such as athlete’s foot, among causes of smelly feet. It advises letting shoes dry before wearing them again and seeking care if odor persists despite self-care or affects daily life. A better sniff-test result is not proof that an antiperspirant treats a fungal infection.⁶

Our aluminum chloride irritation guide covers the reaction and product-label questions in more detail. Chapter 7, “Sole Searching,” in Arms Up includes logging shoes, hours worn, socks, wetness, smell and visible skin changes before reviewing a foot-care plan.