The evidence is weak. Most patients studied reduced excessive sweating, but without control groups, in very small samples, and with relaxation always combined with the biofeedback.
Updated :
What the research shows
Biofeedback
Electrodermal (GSR, skin conductance) and water-vapour-pressure biofeedback — hyperhidrosis (adult)
Ages
Adult (18+)
Techniques
Skin conductance (EDA), Other biofeedback
AAPB2Possibly efficaciousNeuroLogic2Possibly efficacioussame vs AAPB
Level 2 maintained. AAPB reviews no randomised trial: the base is two uncontrolled quasi-experiments and two case studies. Duller & Gentry 1980: visual water-vapour-pressure biofeedback in 14 adults, 30-minute sessions from twice daily (inpatients) to twice weekly (outpatients), with three non-responders withdrawn after 10 sessions — 11 of 14 patients reduced excessive sweating on clinical observation or self-report, assessed 6 weeks after the intervention ended. Singh & Singh 1993: skin-conductance biofeedback-assisted relaxation in 10 men — 6 improved significantly, and clinical improvement was associated with lower skin-conductance levels. Rickles 1978 and Sarti 1998 are single cases; in Rickles the patient's control of sweating in the clinic did not generalise to stressful everyday events, while in Sarti it did and held at 3 and 6 months. Relaxation plausibly accounts for part of the effect in both quasi-experiments. No 2022-2026 publication on biofeedback for hyperhidrosis was found, so nothing in the search window changes the level.
In short
Clinical reading
AAPB Level 2, maintained by NeuroLogic: two uncontrolled quasi-experiments (Duller & Gentry 1980, n = 14; Singh & Singh 1993, n = 10) and two case studies, with no randomised trial. The 2022-2026 window adds nothing new.
Protocols
Palmar skin-conductance or site-specific water-vapour-pressure biofeedback, downtraining of sympathetic activation, combined with progressive or autogenic relaxation and practice between sessions.
Limits
No randomisation, tiny samples, subjective rather than gravimetric outcomes; secondary generalised hyperhidrosis is not distinguished from the primary form; the localised form often begins in childhood or adolescence, yet no paediatric study exists.
Study base
Four studies in total, none controlled. 2022-2026 base: no publication indexed in the archive.
Brendan's perspective
Level 2 maintained, and there is nothing to argue about: four studies, none controlled, no randomised trial, and outcomes that are clinical observation and patient report rather than gravimetric measurement of sweat production. Eleven of fourteen improved in Duller & Gentry 1980, six of ten in Singh & Singh 1993 — improvement is interesting, comparative improvement is evidence. Relaxation was in the package every time, so the share belonging to the feedback is unknown. Level 2 is exactly what “several people got better and nobody compared” is worth. That said, skin conductance remains the cleanest peripheral index of sympathetic arousal, and that is how I use it: to read an arousal profile before choosing an EEG protocol, not to treat sweating. What a client should be told is that primary and secondary forms were never separated in this literature, and that nothing exists in children even though the localised form often starts in adolescence.
