Horsetail, Equisetum arvense, is an ancient plant that has been around since the dinosaurs. It is loaded with silica, aka quartz, aka silicon dioxide, which is a component of bones, skin, hair, and nails.
It can be tinctured, made into tea, capsules, salves, and powders. It has been used in powder form to impart a smooth finish to wood. It has been used to scour tin bakeware, drinking cups, and cooking pots. The young shoots have been cooked and eaten and the roots used in basketry. It is an all-around very useful plant. Be careful though, if you harvest it, as a few varieties are protected in some areas and other varieties are considered an invasive, noxious weed.
I use it in a salve for my cuticles made with slippery elm and sunflower oil. Some people take it internally and externally as a hair strengthener. It can add elasticity to skin.
It is astringent and can be useful as a styptic. It is used as a remedy for osteoporosis in women. It is used in tooth powders as a remineralizer. It is a mild diuretic.
It contains alkaloids, carbohydrates, proteins and amino acids, phytosterols, saponins, sterols, ascorbic acid, silicic acid, phenol, tannin, flavonoids, triterpenoids, and volatile oils.
Pharmacological studies have shown that horsetail possesses antioxidant, anticancer, antimicrobial, smooth muscle relaxant effects of the blood vessels and ileum, anticonvulsant, sedative, anti-anxiety, dermatological, immunological, antinociceptive, anti-inflammatory, antidiabetic, diuretic, inhibition of platelet aggregation, promotion of osteoblastic response, and anti-leishmania.
All of that sounds wonderful! Horsetail for all! We should keep in mind, however, that studies need to be repeated and confirmed. Just because a plant shows beneficial actions in a lab does not mean it will be beneficial to you if you consume the plant or a particular component of that plant. Plants contain hundreds of chemicals working in concert to produce both beneficial and harmful effects. Most studies are conducted on mice, rats, rabbits, and worms. What proves beneficial to them may or may not have the same effect for you and in the case of most herbaceous plants more studies are needed on humans.
Taking too much horsetail over time can result in a thiamin deficiency. Too much of a good thing. One should be careful not to inhale it. Silicosis is a very serious lung disease caused by inhalation of silica. There is no cure. It can be detrimental and even poisonous to horses and other herbaceous barnyard animals.
I sell it in tincture form here.