Silicon & Silicic Acid: Explained Factually

Silicon is the third most abundant trace element in the human body – and yet almost everyone confuses three terms: silicon, silicic acid and diatomaceous earth (kieselerde). In short: silicon is the chemical element, silicic acid is the only form in which your body can absorb it at all, and diatomaceous earth is a silicon-rich raw material. Once you keep these apart, you suddenly read every silicon label with different eyes. In this guide you get the complete map: mechanism, forms, origin from bamboo and horsetail, bioavailability, food sources and an honest look at what is established.

The key points at a glance

• Silicon is a trace element and a natural building block of connective tissue, skin, hair, nails and bones.
• It only becomes absorbable as orthosilicic acid – the dissolved form of silicic acid.
• A distinction is made between mineral diatomaceous earth and organically bound or stabilised silicon.
• The plant sources for supplements are above all bamboo (very silicon-rich) and horsetail (steeped in tradition).
• Cereals, wholegrain products and silicic-acid-containing mineral water supply silicon quite routinely.

What does silicon do in the body?

Silicon is not a passive mineral stone in metabolism, but a structural element. It is found above all where the body needs firmness and elasticity: in connective tissue, in the skin, in the walls of blood vessels, in cartilage and bone. Its role is discussed in expert circles in interplay with collagen and elastin – those protein fibres that make tissue tear-resistant and at the same time stretchable. The highest silicon contents are measured in precisely these connective-tissue-rich structures, which is why it is often described in nutritional science as a "building-block mineral".

The decisive point: in its pure, elemental form (the grey semi-metal from sand and quartz), silicon is completely useless to the body. It simply cannot absorb it. It only becomes usable as silicic acid – a compound of silicon, oxygen and hydrogen. Dissolved in water, it is present as orthosilicic acid, and only this small, dissolved molecular form passes through the intestinal wall. This explains why, with silicon, the form is almost more important than the pure milligram figure.

An illustrative image: picture collagen and elastin like a fabric of threads and cross-links – silicon is associated in the expert discussion with the "nodes" that link individual fibres into a stable, elastic net. Whether and how strongly an additional intake influences this aspect is the subject of research – what remains fact is that silicon must be present at all for the body to work with it. The age question is also interesting: the silicon content of many tissues changes over the course of life, which makes the element interesting for people who consciously keep an eye on their "structural nutrients".

Silicon, silicic acid, diatomaceous earth – the difference in a table

Memory aid: silicon is the raw material, silicic acid the currency the body pays in. Diatomaceous earth is a possible raw-material source – but its value depends on how much dissolved silicic acid it actually releases.

Why many people reach for silicon

Silicon traditionally appears in the context of "beauty from within" – diatomaceous earth is a classic from grandmother's day, and horsetail tea has been drunk for centuries. Today people use it above all in three situations: when they are interested in skin, hair and nails as an overall picture, when they mainly eat refined rather than wholegrain cereal products (which lowers silicon intake), or as a building block in a conscious "connective-tissue routine" together with nutrients such as zinc and biotin. This describes what people do – it is not a promise of effect.

Forms: mineral vs. organically bound

In supplements you encounter two fundamentally different approaches:

• Mineral diatomaceous earth: finely ground, silicon-rich rock, frequently from fossil diatoms ("diatomite"). Inexpensive, widely available – but its solubility, and thus absorption, varies greatly depending on processing.
• Organically bound or stabilised silicon: for example choline-stabilised orthosilicic acid or plant extracts in which the silicon is present in a more soluble form. Usually more expensive, but designed for good availability.

Because only dissolved silicic acid counts, the form is the real quality issue. How bioavailability works in principle and why the chemical form makes such a difference is explained in our article Bioavailability simply explained.

Origin: bamboo and horsetail

Two plants dominate among silicon-rich supplements:

• Bamboo (bamboo extract): the stalks and shoots of certain bamboo species are among the most silicon-rich raw materials of all – highly concentrated bamboo extracts reach very high silicon contents in a small capsule quantity.
• Horsetail: a plant with a long history of use in folk medicine, traditionally used as a tea and extract, likewise rich in silicic acid.

Both are processed into extracts or powders and are suitable for a vegan diet – one reason why plant-based silicon is so popular.

Silicon in foods

You take in silicon quite naturally through a normal diet. Good everyday sources:

The content varies greatly with soil, variety and processing. Important: refining (white flour instead of wholegrain) removes a large part of the silicon – anyone who eats a lot of refined flour takes in noticeably less. A cereal-rich, wholefood diet is the simplest base source.

In practice: dosage form, dosage & quality

Silicon is available as a capsule, powder or gel. Gels and powders are stirred into water; capsules are neutral in taste and practical for on the go. When buying, it is worth looking at:

• Declared Si content: the pure silicon content per daily serving – not just the amount of extract. "500 mg of bamboo extract" says little if the silicon proportion is missing.
• Form & solubility: references to orthosilicic acid or readily soluble silicon are a good sign.
• Purity: lab-tested, especially for heavy metals such as lead and cadmium – these can occur naturally in mineral raw materials.
• Source: plant-based (bamboo/horsetail) or mineral (diatomaceous earth) – according to preference.

Timing is uncritical with silicon; stick to the recommended intake. Anyone taking other supplements at the same time will find guidance in Combining supplements correctly.

Silicon in interplay: the typical connective-tissue routine

Silicon is rarely considered in isolation. In practice, many people combine it with further nutrients that have authorised functions for skin, hair and nails – and here you may be confident, because these are officially authorised health claims:

• Biotin contributes to the maintenance of normal hair and normal skin.
• Zinc contributes to the maintenance of normal hair, nails and skin.
• Copper contributes to normal skin pigmentation and to normal connective tissue formation.
• Vitamin C contributes to normal collagen formation for the normal function of skin, bones and cartilage.

Silicon itself has (see below) no authorised claim – but it is readily placed as a "structural building block" in precisely this context. Anyone wanting to build a conscious routine therefore often combines silicon with these nutrients. Details on the building blocks can be found in our linked guides further down.

For whom is silicon a topic – and for whom less so?

Silicon is particularly relevant for people who mainly eat refined cereal products (white bread, white-flour pasta) and thereby take in less, as well as for anyone who consciously supplements out of an interest in "beauty from within". Those who, by contrast, eat a lot of wholegrain, oats and millet and drink silicic-acid-containing mineral water already cover silicon solidly through their diet. A food supplement in no case replaces a balanced diet – it can complement it within the recommended intake. With existing kidney conditions or during pregnancy and breastfeeding, the same applies as with all supplements: have it clarified by a doctor beforehand.

Honestly put into context: what is established – and what is not

For silicon and silicic acid, there are currently no authorised health claims (health claims under Reg. 432/2012) in the EU. What is established is: silicon is a component of the body and occurs in connective tissue, skin and bones; it is only absorbable as dissolved silicic acid. Its role in connective-tissue and collagen metabolism is being researched, but is not yet scientifically substantiated with authorised claims. We therefore describe silicon honestly as a building-block mineral and describe its forms, sources and quality – without any promise of effect for skin, hair or nails. This honesty is not a disadvantage: it allows you to assess the label realistically instead of believing advertising promises.

Matching products & further guides

Silicon is frequently mentioned in the context of "beauty from within". You will find matching products in the category Beauty – skin, hair & nails as well as in the Trace elements section; an overall overview of vitamins & minerals is offered by Vitamins | Minerals | Trace elements. Further reading: Skin, hair & nails: biotin, zinc & selenium, Nutrients for the hair, Nutrients for strong fingernails, Nutrients for the connective tissue, Collagen: effects & forms and Lab-tested: what does that mean?

Frequently asked questions (FAQ)

What is the difference between silicon and silicic acid?

Silicon is the chemical element. Silicic acid is the compound of silicon, oxygen and hydrogen in which the body can absorb silicon at all – dissolved as orthosilicic acid. Pure silicon is not usable, silicic acid is. Diatomaceous earth, in turn, is a silicon-rich mineral raw material.

Is bamboo or horsetail the better silicon source?

Both are plant-based and suitable for a vegan diet. Bamboo extract is among the most silicon-rich raw materials and supplies a lot of silicon in a small capsule quantity. Horsetail has a long tradition. More decisive than the plant is the declared pure silicon content and the solubility – that is what you should pay attention to when comparing.

Can I cover silicon through my diet?

Often yes. Oats, barley, wholegrain products, bran, millet, bananas and silicic-acid-containing mineral water are good sources. Anyone who, however, mainly eats white-flour products takes in considerably less, since much silicon is lost during refining. A wholefood, cereal-rich diet is the simplest base.

What should I look for when buying a silicon supplement?

The pure silicon content per daily serving (not just the amount of extract), references to the form and solubility (orthosilicic acid is readily available), the source (plant-based or mineral) and laboratory testing for heavy metals such as lead and cadmium, which can occur in mineral raw materials.