Silica
A trace mineral for connective tissue, bought mainly for hair, skin and nails.
- Hair, skin and nails
- Joints
- Bone
A plain-English overview, not advice. Written from published reviews and trials and from what people say in public forums.
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On this page
What is silica?
Silica supplements provide silicon, a mineral the body needs only in small amounts and is thought to use in forming connective tissue. It is sold in two quite different ways: as orthosilicic acid, often stabilised with choline to keep it dissolved, or as a plant extract from bamboo or horsetail, both naturally rich in silica. In the UK it is bought mainly for hair, skin and nails, and by some for bone and joints.
Why do people take silica?
Hair, skin and nails
The thinking. Silicon is thought to play a part in forming and holding together the connective tissue that gives skin its firmness and hair and nails their structure, and it is naturally present in hair itself. Silica is sold as a supplement for exactly this reason, usually as orthosilicic acid or a bamboo or horsetail extract, in the hope of firmer skin and stronger, less brittle hair and nails.
What research has found. Two small trials gave women orthosilicic acid or a placebo for several months, one in women with fine hair and one in women with sun-damaged skin. Both found stronger, less breakable hair by the end; the skin trial also found smoother skin texture and, on a self-rated scale, less brittle nails. Research here is still young: a few studies so far, mostly pointing the same way.
Joints
The thinking. Joints depend on cartilage and connective tissue, the same kind of tissue silicon is thought to help the body form and maintain, so researchers have tested whether taking extra silica changes how joints feel. Trials have looked at both wear-and-tear joint pain and at joint inflammation in a long-term joint condition.
What research has found. A 12-week trial in adults with knee osteoarthritis found no clear difference overall, though men taking the supplement reported less stiffness and pain than men on placebo, an effect not seen in women. A separate small trial in adults with rheumatoid arthritis found lower disease-activity scores and inflammatory markers after taking a horsetail preparation, compared with the control group. Studies here point in different directions, so this one is still being worked out; the dose, how long people took it and who took part all seem to matter.
Bone
The thinking. Bone contains collagen as well as mineral, and silicon has been proposed to play a part in how that collagen forms, alongside the roles of calcium and vitamin D. That has led to interest in silica as a possible addition to standard bone nutrients, particularly for people with lower bone density.
What research has found. One year-long trial added orthosilicic acid, at three different doses, to calcium and vitamin D3 in women with lower bone density, comparing it against calcium and vitamin D3 alone. It found more of a marker of new bone formation at the higher doses, without a consistent dose response, while bone density in the lower spine stayed unchanged. Few studies have measured this yet, so there is little to go on either way.
What does silica do in the body?
Silicon is a trace mineral the body needs only in small amounts, and studies describe it as playing a part in forming and maintaining connective tissue: the material that gives structure to skin, cartilage, bone and the outer layers of hair and nails. It occurs naturally in hair itself, and researchers first became interested in it through its apparent role in bone and cartilage formation.
How well a silica supplement is actually absorbed depends heavily on its form. Plain orthosilicic acid, the form silicon takes naturally in water, is unstable once concentrated and tends to clump together, which lowers how much of it the body can take up; supplements often stabilise it with choline to keep it dissolved. Bamboo and horsetail extracts supply silica bound up differently again, in amounts that vary by source rather than by a fixed formula, which is why labels state the amount directly rather than a percentage.
What do people say about taking silica?
These are anecdotes people have shared, not evidence.
What people like
- Two of the four sources read are retailer product-review pages rather than forum chat, which tend to skew positive; the other two are general hair and beauty forum threads.
- Nails growing harder, stronger or less prone to splitting is the change mentioned most often; several people say this surprised them, given how easily their nails used to break or chip before.
- Several people also report thicker or faster-growing hair that breaks less when brushed or washed, and a couple of long-term users, taking it for well over a year, say their hair and nails have stayed stronger the whole time.
- A few people specifically credit it with stopping hair loss, including one who was taking a combined hair and nail vitamin that also contained silica.
- Smoother or improved-looking skin is mentioned sometimes, but far less often than hair or nails.
Common complaints
- Most reviews on the product pages read are positive, but a consistent minority describe no noticeable change at all in their hair, skin or nails, sometimes even after several months or years of daily use.
- One person who switched from a different, more expensive silica product said the good effects they were used to reversed within a month of changing.
- One poster wondered whether it had caused extra hair growth elsewhere for a family member, though could not be sure it was the cause.
- A small number of reviewers said they saw no benefit and would not buy it again.
How people take it
- Most people take it as a daily tablet or capsule, either a plain silica product or one based on horsetail extract.
- It is often taken as part of a combined hair, skin and nails vitamin alongside other ingredients, rather than as a silica product on its own.
- How long people wait before judging it varies widely, from two weeks to eighteen months, though most who noticed a change describe waiting at least a month or two first.
- Bone and joints are mentioned far less often than hair, skin and nails as a reason for taking it, and none of the reviews read described a change noticed in their joints specifically.
Read from these public discussions:
- Anyone experienced any side effects from taking silica? (Mumsnet, 2015)
- What will actually help my hair grow? (Mumsnet, 2021)
- Customer reviews of a vegan silica tablet (A UK high-street retailer's product reviews, 2026)
- Customer reviews of a horsetail-extract silica supplement (An online supplement retailer's product reviews, 2026)
What forms of silica are there?
| Form | What’s different | Per serving, on products we list |
|---|---|---|
| Bamboo extract | A plant extract naturally containing silica; how much varies by source, so only the amount stated on the label counts. | 200 mg |
| Horsetail | The herb Equisetum arvense, a traditional plant source of silica; content varies by preparation. | not in our price tables yet |
| Orthosilicic acid | Silicon dissolved in water as orthosilicic acid, often stabilised with choline since the plain form is unstable in solution. | not in our price tables yet |
What else is worth knowing about silica?
- Trials of orthosilicic acid used small daily amounts: 10 mg of silicon a day in the hair and skin trials, and 3 to 12 mg a day in the bone trial.
- How much silicon reaches the blood depends on its form and strength: absorption studies found more silicon in blood and urine after orthosilicic acid or horsetail tea than after a placebo or low-silicon water, though a stronger tea caused diarrhoea in some who drank it while a weaker version was well tolerated.
- The bone trial reported no supplement-related adverse events, with safety blood tests staying normal throughout the year.
- Every hair, skin, nail and bone trial was carried out in women; the joint trials included men too, and in the osteoarthritis trial it was only the men who showed a clear change.
If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.
The research behind this page (11 studies)
- Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair. (2007, randomised trial)
- Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin. (2005, randomised trial)
- A 12-week randomized, double-blind, placebo-controlled multicenter study of choline-stabilized orthosilicic acid in patients with symptomatic knee osteoarthritis. (2017, randomised trial)
- Horsetail mixture on rheumatoid arthritis and its regulation on TNF-α and IL-10. (2014, randomised trial)
- Choline-stabilized orthosilicic acid supplementation as an adjunct to calcium/vitamin D3 stimulates markers of bone formation in osteopenic females: a randomized, placebo-controlled trial. (2008, randomised trial)
- Application of Bamboo Plants in Nine Aspects. (2020, review)
- Bamboo: a new source of carbohydrate for biorefinery. (2014, review)
- Bamboo-derived adsorbents for environmental remediation: A review of recent progress. (2023, review)
- Host Factors in the Infection Cycle of Bamboo mosaic virus . (2017, review)
- Bamboo-Fiber-Reinforced Thermoset and Thermoplastic Polymer Composites: A Review of Properties, Fabrication, and Potential Applications. (2022, review)
- Green Composites Made of Bamboo Fabric and Poly (Lactic) Acid for Packaging Applications-A Review. (2016, review)
How much does silica cost?
That depends on the form and the pack, so we work out the price of the same dose of every silica product we can find and rank them.