I use a lot of base layer stuff both for walking , cycling and under my motorcycle leathers . This stuff was a new thing for me and I'm very impressed. Washing the base layers in ordinary detergent was not helping them and this stuff seems to have restored them all considerably. The base layers are now a lot more comfortable , less smelly to start with and ( apparently , at least) appear to resist getting as smelly as they used to. My smelly hellys have never been so civilized ! Good stuff.
Not sure how long a litre will last so it may prove to be quite expensive. Worth it though .