Table 1.

Summary and risk of bias for aluminum salt studies.

Study and intervention(s)	HH population and design	Risk of bias	Key results/critical appraisal findings
Flanagan et al.19 a 20% topical aluminum chloride hexahydrate (AC) vs. botulinum toxin A (BTX-A) injections	Axillary Single-center, 12-week, randomized, parallel, open-label, study N = 50 (n = 25 AC, n = 25 BTX-A for 4 weeks); cross over at week 4 allowed for AC patients dissatisfied with treatment	Borderline to high	33.3% HDSS response rate (≥2 grade improvement) in AC-treated patients at week 4 vs. 91.7% in BTX-A group; 33.3% of AC-treated patients were “very satisfied” at week 4 vs. 87.5% of patients in BTX-A group Large cross-over (allowed at week 4) from AC to BTX-A therapy (71%) Safety: >50% of subjects treated with AC reported stinging, itching and redness, and >25% reported pain
Flanagan and Glaser18 Aluminum chloride (15% aluminum chloride (AC) in 2% salicylic acid gel base (compared to baseline)	Axillary Prospective, open-label, uncontrolled, single-arm study (N = 30); 12-week duration	High	72% HDSS responders; 75% somewhat or very satisfied with treatment compared to baseline Safety: moderate to severe redness (14.3%) moderate to severe itching (28.6%), absent to mild pain (92.9%) and moderate pain (7.1%); 2 subjects did not complete trial due to moderate-to-severe axillary irritation (redness, itching, burning)
Goh21 Topical aluminum chloride hexahydrate 20% W/W ethanol (AC) applied to one palm No treatment applied to other palm	Palmar Small (N = 12), W/P, single author, assessor-blinded, 6-week study	Unclear	Approximately, two-thirds likely to experience drier palms within 24 h of AC treatment, lasting for 1–2 days Weekly mean skin vapor loss difference averaged 16.4 g water/m2/h over 4 weeks; all patients reported treated palms to be drier than untreated palms the following morning after starting treatment, and that sweating returned within 2 days of stopping treatment Safety: 1 out of 4 experienced a stinging sensation after application; one patient dropped out due to intolerable side effects
Scholes et al.22 20% aluminum chloride applied with a brush for 1 week	Axillary One case series from two dermatology clinics (N = 65)	High	Authors state that 64/65 patients had “excellent control of sweating”; however, statements appear to be authors’ interpretation from comments received from 42 patients from one clinic who completed a questionnaire 12 months after the study had concluded Safety: 29 experienced some irritation (described as “minor” by authors, but 28 subjects reported relief following application of 1% hydrocortisone cream on the morning after treatment)

Abbreviations. AC, Aluminum chloride; AE, Adverse event; BTX-A, Botulinum toxin A; HDSS, Hyperhidrosis Disease Severity Scale; W/P, Within patient.

^aSOE considered for aluminum chloride body of evidence only.