Is It Safe to Take Silica Every Day? Who Should Ask First

Yes, for most healthy adults: the European food safety assessment found "little evidence of adverse effects of orally ingested silicon", the UK expert group identified no vulnerable groups, and the longest trial gave 12 mg of silicon a day for 12 months without related adverse events.^{1, 2, 3} Silicon has no authorised health claim in Great Britain: the register lists 23 silicon wordings, every one Non-authorised, and there is no nutrient reference value, so a supplement is taken as the silicon on its label.⁴ The silica in this article is dietary silicon: the silicon in food, water and supplements, which is swallowed, dissolved and passed out in urine. It is not crystalline silica dust, which causes silicosis when breathed in at work and which the HSE and the food regulators assess separately, and it is not the silica gel in desiccant sachets, which is not poisonous if swallowed but whose packet can choke a small child (call NHS 111, or 999 if someone is choking).^{5, 6, 7} This page sits under the Wellgard silica guide, beside foods high in silica and types of silica explained, within the vitamins and minerals guide.

Is it safe to take silica every day?

The European Food Safety Authority's nutrition panel assessed silicon in 2004: "In humans, apart from occasional reports of renal stones, mainly associated with long-term use of silicate-containing antacids, there is little evidence of adverse effects of orally ingested silicon. The available data are inadequate to derive a tolerable upper intake level." Typical dietary intake is 20 to 50 mg a day, and "These intakes are unlikely to cause adverse effects."¹ The UK Expert Group on Vitamins and Minerals (EVM, 2003) found "no acute or chronic toxicity data" in people, "No vulnerable groups have been identified", and from animal studies set a Safe Upper Level "for daily consumption over a lifetime" of 700 mg of supplemental silicon a day for a 60 kg adult.² The longest trial gave 136 women 3, 6 or 12 mg of silicon a day as choline-stabilised orthosilicic acid for 12 months, with calcium and vitamin D: "There were no ch-OSA related adverse events observed and biochemical safety parameters remained within the normal range."³ The European panel's missing upper level reflects thin data, not proof that every amount is fine; the UK figure is an animal-derived ceiling for supplements, not a target.

What side effects have been reported?

At trial doses, none attributed to silicon: 22 women took 10.5 mg a day as monomethylsilanetriol for four weeks with "no reported adverse effects".^{3, 8} The one documented upset was a strong herbal tea: in a three-arm pilot study of 12 men, a litre a day at about 750 mg of silicon per litre for three days caused diarrhoea in four, while a weaker tea at about 200 mg per litre "was well tolerated".⁹ One dispute is on record: a published letter argued that four weeks in 22 women are "insufficient to conclude that the use of MMST in food or food supplements is safe"; the authors replied.^{8, 10}

Can silica damage your kidneys, or cause kidney stones?

Not at dietary or label doses. The 2004 assessment: "Silica urolithiasis is generally rare and up to mid 1980 was reported only in patients exposed to magnesium trisilicate", an antacid; the one infant case followed formula made up with spring water at 172 mg of silicon per litre, far above UK tap water.¹ Kidney damage in workers who inhale silica "is thought not to occur by exposure to silicon in food".² Healthy kidneys clear silicon quickly (82 to 96 ml a minute in eight volunteers), so "Patients with renal failure generally have a higher concentration of silicon in plasma".^{1, 11} The NHS line for chronic kidney disease applies: "Check with a doctor or pharmacist if you plan to take any over-the-counter medicines such as painkillers or nutritional supplements."¹² Severe pain in the side of the tummy or lower back, or a high temperature, is a kidney-stone question for an urgent GP appointment or NHS 111.¹³

Is silica hard on the liver?

No signal has been recorded: neither risk assessment lists a liver effect in people, serum biochemistry was unchanged after four weeks in 22 women, and safety parameters stayed normal over 12 months in 136 women.^{1, 2, 3, 8}

How much silica a day is too much?

The European panel drew no line; the UK expert group did, from animal data.^{1, 2} The markers: supplements on one European market provided 1 to 75 mg a day, UK supplements ran "up to 500 mg silicon" and the EVM's lifetime level is 700 mg a day of supplemental silicon.^{1, 2} No reference intake exists; the dose is what the label states. Read it in milligrams of silicon, not "silica" or "extract"; if a product also supplies zinc, count the total against the NHS line of 25 mg of zinc from supplements a day (can you take too much zinc).¹⁴

Who should ask a GP or pharmacist first?

• Kidney disease. Covered above: blood silicon runs higher when the kidneys clear less.^{1, 12}
• Pregnancy and breastfeeding. No trial has tested a silicon supplement in either. Labels say ask a GP; the NHS says "If you need higher dose folic acid or other supplements, speak to a GP."¹⁵
• Regular medicines. Neither assessment documents an interaction between silicon and a medicine.^{1, 2} Horsetail is a herb sold as a silicon source; it is a traditional herbal medicine in its own right, with its own cautions, and is not covered here.
• Children. The EVM found "no data on the effects of silicon on children"; follow the label and ask a pharmacist.²

Is the silica in supplements the same as silica dust?

No. The HSE: "Respirable crystalline silica (RCS) is found in stone, rocks, sands and clays. Exposure to RCS over a long period can cause fibrosis (hardening or scarring) of the lung tissue", and "Silica may also be linked to lung cancer."⁵ The NHS: silicosis is "a long-term lung disease caused by inhaling large amounts of crystalline silica dust".¹⁶ The EVM says this process "is considered not to be relevant to oral exposure to silica or silicon".² Dietary silicon is swallowed as dissolved orthosilicic acid and passed out in urine; no organ is recorded as harmed by it at normal intakes.

What if a child swallows a silica gel sachet?

Silica gel is a desiccant, not a supplement. A one-year review of a national poison centre logged 546 silica gel ingestions, 91.4% in children under six; 2.7% had symptoms, "mainly mild self-limited mouth and throat discomfort".⁶ The hazard is choking on the packet. The NHS poisoning advice: "Call 999 or go to A&E if" you "think you, a child, or someone else may have swallowed, touched or breathed in something harmful" or someone is "choking or gasping"; "Call NHS 111 if" you are "not sure"; and "do not try to make someone sick".⁷ Nothing here is a reason to eat it.

Frequently asked questions

What is silicon dioxide doing in my vitamins, and is it safe?

Silicon dioxide (E551) is an anti-caking agent. EFSA re-evaluated it in 2018 ("Silicon dioxide appears to be poorly absorbed"; "E 551 does not raise a concern with respect to genotoxicity") and in 2024 concluded that it "does not raise a safety concern in all population groups at the reported uses and use levels".^{17, 18} Colloidal silica gave 1% of its dose in six-hour urine in three people, so a few milligrams as an excipient is not a silicon supplement.¹⁹

Why does a liquid silica label list a stabiliser or a zinc salt?

Because the law names them. Annex II of the food supplements directive, as it applies in Great Britain on legislation.gov.uk, lists under "B. Minerals" the silicon sources "choline-stabilised orthosilicic acid", "silicon dioxide", "silicic acid" (in the form of gel) and "organic silicon (monomethylsilanetriol)", and sixteen zinc sources, among them "zinc chloride" (read 10 October 2026).²⁰ Orthosilicic acid polymerises in concentrated solution (a saturated solution holds 0.1%), so liquid products carry it stabilised with choline: hence the name.¹ A zinc salt is simply the form the zinc takes; what counts is the elemental zinc on the label, inside the NHS line of 25 mg a day from supplements.¹⁴ Both are permitted sources, not contaminants.

Is silica bad for your skin, and is the silica in deodorant safe?

No trial reports a skin side effect; the one skin trial measured forearm roughness and is described on the silica guide, and the register authorises no skin wording for silicon.⁴ Silica in deodorant is a cosmetic texture ingredient, outside this page.

Can you take silica and collagen together?

No interaction is documented and no trial has tested them together; each is taken at its label dose. Collagen's trial record is on the Wellgard collagen guide.

Sources

1. EFSA NDA Panel. Tolerable upper intake level of silicon, 2004, in Tolerable Upper Intake Levels for Vitamins and Minerals (EFSA, 2006), pp 287-293. efsa.europa.eu.
2. Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals, 2003: silicon, pp 306-311. UK Government Web Archive.
3. Spector TD, et al. Choline-stabilized orthosilicic acid supplementation as an adjunct to calcium/vitamin D3 in osteopenic females. BMC Musculoskeletal Disorders, 2008. PubMed 18547426.
4. Great Britain nutrition and health claims (NHC) register, 19 May 2026. gov.uk.
5. HSE. Silicosis: causes and risk controls. hse.gov.uk.
6. Lavon O, Bentur Y. Silica gel: non-toxic ingestion with epidemiologic and economic implications. Israel Medical Association Journal, 2015. PubMed 26665312.
7. NHS. Poisoning. nhs.uk.
8. Jugdaohsingh R, et al. The silicon supplement 'Monomethylsilanetriol' is safe and increases the body pool of silicon in healthy pre-menopausal women. Nutrition & Metabolism, 2013. PubMed 23622499.
9. Waterstradt A, et al. Silicon resorption from Equisetum arvense tea: a randomized, three-armed pilot study. Planta Medica, 2022. PubMed 34706374.
10. Vanden Berghe DA. There are not enough data to conclude that Monomethylsilanetriol is safe. Nutrition & Metabolism, 2013. PubMed 24499245.
11. Reffitt DM, et al. Silicic acid: its gastrointestinal uptake and urinary excretion in man and effects on aluminium excretion. Journal of Inorganic Biochemistry, 1999. PubMed 10612067.
12. NHS. Chronic kidney disease: living with. nhs.uk.
13. NHS. Kidney stones. nhs.uk.
14. NHS. Vitamins and minerals: others (zinc). nhs.uk.
15. NHS. Pregnancy vitamins and supplements. nhs.uk.
16. NHS. Silicosis. nhs.uk.
17. EFSA ANS Panel. Re-evaluation of silicon dioxide (E 551) as a food additive. EFSA Journal, 2018. PubMed 32625658.
18. EFSA FAF Panel. Re-evaluation of silicon dioxide (E 551) in foods for infants below 16 weeks and follow-up for all population groups. EFSA Journal, 2024. PubMed 39421729.
19. Sripanyakorn S, et al. The comparative absorption of silicon from different foods and food supplements. British Journal of Nutrition, 2009. PubMed 19356271.
20. Directive 2002/46/EC, Annex II (as it applies in Great Britain): vitamin and mineral substances which may be used in the manufacture of food supplements. legislation.gov.uk.

This article is general information, not medical advice.