Colloidal Silica Gel

With silica, the label matters more than the ingredient, because the four forms don't share the same evidence. These are the questions our naturopaths ask in store.

A good fit if

• Hair and nails are your reason, and you want the form that was tested
• You know the trials only cover ch-OSA, and you still prefer the plant version
• Capsules are a struggle and a gel or liquid suits you better

Check with us first if

• You take any prescription medicine. We haven't found an interaction study for mineral silica or ch-OSA, so it's worth a chat rather than a list.
• You take a diuretic, or a heart or kidney medicine, and the product is horsetail. Its one trial caused fluid loss broadly similar to a low-dose thiazide diuretic.
• You plan to take it for months. Traditional horsetail use is recorded for two to four weeks, and silicates have been linked to digestive problems over the long term.
• The product is raw, unheated horsetail powder rather than an extract, because it contains an enzyme called thiaminase that heat destroys.
• You're buying it for your bones, where the evidence is weaker than the shelf suggests.

• Choline-stabilised orthosilicic acid (ch-OSA). Best known for: Hair strength and thickness, and how brittle people rated their nails and hair. Absorption: Silicon in urine rose along with the hair changes, which was used as an indirect sign it was absorbed. Typical use: A branded bead or pellet, taken daily for 20 weeks to nine months.
• Mineral and colloidal silica (silicon dioxide, colloidal anhydrous silica, hydrated silica). Best known for: The plain, general-purpose silica behind most gels, liquids and tablets. Absorption: We hold no absorption trial for this form, so we don't claim anything for it. Typical use: The everyday hair, skin and nail product, with no trials of its own.
• Horsetail-derived silica (Equisetum arvense). Best known for: A traditional European herb for fluid balance, not for its silicon. Absorption: None measured; the one trial tracked fluid balance rather than silicon. Typical use: Whole herb, tea or extract, traditionally for two to four weeks and no longer.
• Bamboo silica (Bambusa species). Best known for: Sold as the plant with the highest natural silica content. Absorption: Not found in any source we hold. Typical use: A stem or leaf extract, usually the vegan choice, and not tested in trials.

Reference values. There's no Nutrient Reference Value for silicon in Australia or New Zealand. Silicon isn't one of the nutrients the NHMRC covers, so there's no Recommended Dietary Intake, Adequate Intake or Upper Level. That's a real regulatory fact rather than a gap in research, and it means no one can tell you that you're short of it.

Typical supplemental range. Both ch-OSA trials used 10 mg of silicon a day, one for 20 weeks and the other for nine months. The one horsetail trial used 900 mg a day of dried extract over four days, and traditional European use is 3 to 12 g a day as tea. We haven't found established Australian label doses for mineral and colloidal silica, so read the product you're holding rather than assuming it matches a trial.

Upper level. We haven't found an upper level for silicon in our sources, and no silica ingredient in Australia's permitted ingredients list has a daily dose cap. That doesn't mean it's fine to take more. Silicates have been linked to digestive problems with long-term use, so more and longer isn't the plan.

Worth knowing. Which dose matters depends on which form you've bought, because only one of the four has been tested at a stated dose. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• Horsetail and bamboo, as herbs rather than everyday foods: both concentrate silica out of the soil they grow in, which is why they're used as supplement sources
• Everyday foods: no verified Australian per-serve silicon figures are held, so no numbers are stated here

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• Pregnancy and breastfeeding. There's no safety data for horsetail, and European guidance says its use isn't recommended.
• Children under 12. Horsetail isn't recommended by mouth or on the skin; from 12 up, adult doses apply.
• Serious heart or kidney disease. Don't take horsetail if you've been told to limit your fluids.
• Kidney problems that affect how you handle potassium. Don't take horsetail, because of the risk of high potassium (hyperkalaemia).
• Known sensitivity to horsetail. There are case reports of rash and swelling of the hands or face, and one of cough, breathing difficulty and itching.
• Raw horsetail powder. It contains thiaminase, an enzyme that breaks down thiamine (a B vitamin), which is switched off at 80°C; standard extracts show no measurable activity, and no deficiency has been reported in traditional European use.
• Long-term use. Silicates have been reported to cause digestive problems, especially over the long term.
• How long to take it. Horsetail's documented traditional use is two to four weeks, with medical advice if symptoms last beyond one week.
• Medicine interactions. We hold no interaction study for mineral silica or ch-OSA, so we don't list any interactions.
• Breathing it in. The three mineral silica entries are allowed in Australian listed medicines only for routes other than inhalation.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.