Silica
Silicon dioxide (silica)
Minerals. Modern nutrition.
Also called Silicon, Silicon dioxide, Orthosilicic acid, Silicic acid
Pinyin: guī
Spanish: Sílice
Horsetail may lower vitamin B1A form of silicon found in plants, water and sand. Silica supplements are sold for hair, skin and bones, but the proof is weak.
Did you know? Horsetail plants are so full of silica that people once used them to scour pots, which is how they got the name scouring rush.
What it may help, and how strong the proof is
- Bones. Silica plays a role in bone formation in animals. Some small human studies of silicon supplements found small bone changes, but good trials are missing.Traditional proof
- Skin. Silica supplements are sold for skin, hair and nails. A few small trials found some improvement in skin texture, but the studies are small and few.Traditional proof
Parts of the body
Traditional use
Horsetail has been used in European folk medicine for bleeding and for kidney and bladder problems. It was also used for scrubbing pots.
How it is classified
How people take it
No RDA or AI has been set for silica or silicon. No upper limit has been set for silica from food. Supplement trials have often used about 10 mg a day of elemental silicon.
Food, capsule and tablet.
Where to get it
Good sources are whole grains such as oats, brown rice and barley, green beans, bananas, leafy greens, root vegetables and strawberries. Beer, which is made with barley, also contains silicon. Pills come as orthosilicic acid, often in liquid form, and as horsetail extract or silica powder.
Be careful
Silica from food is safe. Supplement forms have few reported problems at normal doses, but long-term safety is not well studied. Horsetail can contain thiaminase, an enzyme that breaks down vitamin B1, if it is used heavily over time.
Avoid if: pregnancy (not studied).
Mixing with other things
- Works well together
Horsetail is a plant source of silica, though it has its own cautions.
- Worth knowing
Horsetail may contain thiaminase, which can lower vitamin B1 if used heavily.
The honest take
Silica is common in food and water, and the body uses a little for connective tissue. No deficiency has been proven in people, and trials of silica pills for hair, skin or nails are small. Beauty claims are mostly marketing so far.