Apparatus for stimulating hair growth and/or preventing hair loss

A method of treating or preventing a hair-condition of a user comprising: subjecting the user's scalp to at least 200 distinct electrode-scalp contact events during a time-interval of at most one minute and dividable into 5 non overlapping equal-duration sub-intervals covering the time-interval, method performed such that i. for at least a majority of the electrode-scalp contact events, no electrode of the event enters into the dermis; ii. a duration of each electrode contact event is at most 100 milliseconds; and iii. for each electrode contact event, an electrical current flows between the electrode and the scalp so as to deposit electrode-released ions of a first metal or of a second metal on the scalp, thereby forming a respective metal-ion-deposition island on the user's scalp.