From Glastonbury-based Indigo Herbs, a company known for pure, simply made botanical products, this tincture is crafted from the green hulls of the black walnut tree, Juglans nigra, a plant with centuries of use in traditional Western herbalism.

The hulls are extracted by cold percolation into ethanol, a time-honoured method that captures the plant's naturally occurring constituents, including its characteristic tannins. Nothing else is added: just black walnut and alcohol, presented in a 100ml amber glass bottle with a dropper for easy measuring. It is suitable for vegetarians and vegans and produced to GMP standards.

The suggested serving is around 20 drops daily in a little water or juice. It is not intended for continuous long-term use, so follow the label directions, and speak to a qualified herbalist if you are unsure whether it suits you.