Drop by drop control is the appeal here. Nature's Greatest Secret supplies its 20ppm colloidal silver in a 100ml amber glass bottle topped with a glass pipette, letting you place small, precise amounts exactly where you want them.

As with the rest of the range, the formula is simply purified water and silver at 20 parts per million, free from preservatives and fragrance. The amber glass protects the solution from light between uses. Apply a few drops to clean, dry skin and allow to dry naturally, as part of a simple daily routine. For external cosmetic use only. Those who prefer a mist can choose the matching 100ml spray version instead; the solution inside is identical.