What it does. An enzyme has to finish collagen before it folds into the strong triple helix in bone, skin, and hair, and that step runs better with dissolved silicon around; block the enzyme and the benefit vanishes 1. Only the dissolved form absorbs well: beer and mineral water deliver it ready to use, the silica locked in plant tissue mostly not 2 3.
The bone signal is real but conditional. Across ~2,800 Framingham adults, the top intake quarter (~40 mg/day) had hip bone density about 10% higher than the bottom, but only in men and women with active oestrogen; off hormones after menopause, it vanished, and a second cohort found the same 4 5. Two double-blind trials at 10 mg/day gave better skin elasticity and hair strength versus placebo 6 7, but both were run by the supplement maker and never replicated. Probably real, definitely modest.
Aim for 25–40 mg a day; your kitchen is the cheapest route.
You can't overdo it: no harmful level was ever found 9.
Nothing happens this week. Silicon is silent: absorbed, used, cleared in urine, nothing felt. The bone-formation marker took a full year to move 10. Over one to two years the skin and hair effects apply: slightly better elasticity, thicker hair, less brittle nails, a holding action rather than a transformation 6 7. Over a decade or two, the bone gap is a small fraction of what decides whether a fall at 75 breaks anything.
Who the bone case fits. Men, and women with active oestrogen. If you're post-menopausal and off hormones, the bone effect is unproven for you, so put the attention on resistance training, protein, and vitamin D instead 5.
Silicon is the smallest lever in its class. Weight-bearing exercise and calcium-plus-vitamin-D move bone more; collagen peptides and retinoids have more direct skin evidence; minoxidil and finasteride beat it for pattern hair loss. Its case is that it stacks underneath these at near-zero cost from food you eat anyway.
The fine print — when to skip it, and what people get wrong
- 1Reffitt DM, Ogston N, Jugdaohsingh R, Cheung HFJ, Evans BAJ, Thompson RPH, Powell JJ, Hampson GN (2003). Orthosilicic acid stimulates collagen type 1 synthesis and osteoblastic differentiation in human osteoblast-like cells in vitro. Bone. link
- 2Sripanyakorn S, Jugdaohsingh R, Elliott H, Walker C, Mehta P, Shoukru S, Thompson RPH, Powell JJ (2004). The silicon content of beer and its bioavailability in healthy volunteers. British Journal of Nutrition. link
- 3Sripanyakorn S, Jugdaohsingh R, Dissayabutr W, Anderson SHC, Thompson RPH, Powell JJ (2009). The comparative absorption of silicon from different foods and food supplements. British Journal of Nutrition. link
- 4Jugdaohsingh R, Tucker KL, Qiao N, Cupples LA, Kiel DP, Powell JJ (2004). Dietary silicon intake is positively associated with bone mineral density in men and premenopausal women of the Framingham Offspring cohort. Journal of Bone and Mineral Research. link
- 5Macdonald HM, Hardcastle AC, Jugdaohsingh R, Fraser WD, Reid DM, Powell JJ (2012). Dietary silicon interacts with oestrogen to influence bone health: evidence from the Aberdeen Prospective Osteoporosis Screening Study. Bone. link
- 6Barel A, Calomme M, Timchenko A, De Paepe K, Demeester N, Rogiers V, Clarys P, Vanden Berghe D (2005). Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin. Archives of Dermatological Research. link
- 7Wickett RR, Kossmann E, Barel A, Demeester N, Clarys P, Vanden Berghe D, Calomme M (2007). Effect of oral intake of choline-stabilized orthosilicic acid on hair tensile strength and morphology in women with fine hair. Archives of Dermatological Research. link
- 8Powell JJ, McNaughton SA, Jugdaohsingh R, Anderson SHC, Dear J, Khot F, Mowatt L, Gleason KL, Sykes M, Thompson RPH, Bolton-Smith C, Hodson MJ (2005). A provisional database for the silicon content of foods in the United Kingdom. British Journal of Nutrition. link
- 9EFSA (2004). Opinion of the Scientific Panel on Dietetic Products, Nutrition and Allergies on a request from the Commission related to the Tolerable Upper Intake Level of Silicon. link
- 10Spector TD, Calomme MR, Anderson SH, Clement G, Bevan L, Demeester N, Swaminathan R, Jugdaohsingh R, Vanden Berghe DA, Powell JJ (2008). 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. BMC Musculoskeletal Disorders. link
- 11Davenward S, Bentham P, Wright J, Crome P, Job D, Polwart A, Exley C (2013). Silicon-rich mineral water as a non-invasive test of the 'aluminum hypothesis' in Alzheimer's disease. Journal of Alzheimer's Disease. link
Dietary Silicon
Food route is free (oats, wholegrain bread, brown rice). ch-OSA supplements run ~$20-30 for a 2-month supply; silicon-rich mineral water adds ~$2-4/L. Trivial at any access tier.
Food route is a routine grain choice with no behavioural change beyond it. Supplement route is one capsule/day. Mineral-water route is swapping a bottle. All sit in the 'know-it-exists, swap one default' tier.
Two double-blind RCTs at 10 mg Si/day as ch-OSA over 20 weeks (skin) and 9 months (hair) showed significantly improved skin viscoelasticity and micro-relief, lower hair/nail brittleness scores, and preserved hair tensile strength + cross-sectional area vs placebo (Barel 2005, Wickett 2007). Effect sizes are modest and the trials are sponsor-run / unreplicated; honest tier is 'real but small visible contribution within weeks-to-months.'
Mechanism is collagen-synthesis support via prolyl hydroxylase (Reffitt 2003); the long-term aesthetic case is a slightly better-preserved hip BMD trajectory and slightly better skin/hair collagen integrity over decades. Real but small contribution on the aging-trajectory axis.
Framingham Offspring (Jugdaohsingh 2004) and Aberdeen Osteoporosis Screening (Macdonald 2012) both show hip-BMD differences of ~5-10% across Si-intake quartiles in oestrogen-replete adults; Spector 2008 moved a bone-formation marker (PINP) at 12 months. No fracture data and effect is absent in postmenopausal women without HRT — small additive contribution to mortality risk via skeletal preservation.
Two large cross-sectional cohorts (Framingham, Aberdeen) with consistent BMD associations; one 12-month RCT moved a bone-formation marker but missed BMD primary; two small sponsor-run dermatology RCTs moved visible endpoints. Mechanism is solid in vitro (Reffitt 2003). Not yet replicated independently at the visible endpoints; not classified as essential by EFSA. Sparse and partly contested literature with plausible mechanism.
Si is silently absorbed and silently renally cleared; the felt effects in weeks are minimal even in the dermatology trials, which use objective instruments rather than QoL endpoints.