What Is Silicon?
Silicon is a trace element found abundantly in the Earth's crust (second most abundant element after oxygen), in the human body, and in many foods and water sources. In biological systems, silicon typically exists as silicic acid or silicate compounds rather than as elemental silicon.
Essentiality status: Silicon's classification as an essential nutrient for humans is somewhat controversial. While it's been demonstrated as essential in chickens and rats, and is clearly present in human tissues (especially connective tissue and bone), major health organizations like the FDA and NIH have not officially designated it as essential for humans. However, many researchers consider it a "conditionally essential" or "beneficial" element, particularly for bone and connective tissue health.
What It's Used For (Functions in the Body)
Based on research in animals and observational studies in humans, silicon appears to play several important roles:
Structural functions:
Bone formation and mineralization - Involved in the early stages of bone calcification and collagen formation
Connective tissue synthesis - Essential component of glycosaminoglycans and collagen in cartilage, tendons, ligaments, and skin
Arterial wall integrity - Present in high concentrations in arterial walls; may maintain elasticity
Hair, skin, and nail health - Concentrated in these tissues; supports structural integrity
Biochemical functions:
Collagen cross-linking - Helps stabilize collagen and elastin structures
Mineral metabolism - May influence calcium, magnesium, and other mineral utilization
Gene expression - May affect expression of genes related to bone formation
Antioxidant properties - May help neutralize aluminum toxicity
Enzyme functions:
May be a cofactor for certain enzymes, though specific roles are still being researched
Benefits of Adequate Intake
Research-supported benefits:
Bone health:
Improved bone mineral density: Studies show correlation between silicon intake and bone density, particularly in younger individuals and premenopausal women
Bone formation support: Animal studies show silicon deficiency impairs bone development
May reduce fracture risk: Framingham Offspring Study found higher dietary silicon associated with higher BMD in men and premenopausal women
Osteoporosis prevention: May help maintain bone strength with aging
Works synergistically with calcium: Appears to enhance calcium utilization in bone
Connective tissue health:
Cartilage formation: Important for joint cartilage synthesis and maintenance
Skin elasticity: May improve skin texture and reduce wrinkles (some evidence from topical and oral use)
Tendon and ligament strength: Supports structural integrity of connective tissues
Wound healing: May accelerate healing through collagen synthesis
Cardiovascular health:
Arterial flexibility: Higher silicon intake associated with reduced arterial stiffness
Atherosclerosis prevention: Some studies suggest protective effects against arterial calcification
Blood pressure: May help maintain healthy blood pressure through arterial effects
Hair and nail health:
Stronger nails: May reduce brittleness
Hair thickness: Some evidence for improved hair diameter and quality
Reduced hair loss: Limited but suggestive evidence
Other potential benefits:
Aluminum detoxification: May help reduce aluminum accumulation in body (particularly brain)
Immune function: Some research suggests immune-supporting effects
Anti-inflammatory properties: May reduce inflammation markers
Cognitive health: Through aluminum binding, may protect against aluminum-related cognitive decline
Potential Negatives/Side Effects
Silicon is generally very safe with minimal toxicity concerns at dietary levels.
At normal dietary intake (25-50 mg/day):
Essentially no side effects reported
Excellent safety profile
Well-tolerated by most people
At higher supplemental doses (up to 500 mg/day):
Generally still well-tolerated
Occasional digestive upset (rare)
Mild diarrhea (uncommon)
No serious adverse effects in studies
Specific concerns:
Crystalline silica (silica dust) - occupational exposure:
Silicosis: Lung disease from inhaling crystalline silica dust (mining, sandblasting, construction)
This is NOT a concern from dietary silicon or supplements
Only from inhaled dust exposure over long periods
Kidney stones (theoretical concern):
Very high doses might theoretically contribute to silicate stones
However, this is rare and not well-documented
Orthosilicic acid form appears less likely to cause kidney stones than some other forms
Drug/condition interactions:
Generally minimal
See section below for specific considerations
Form-specific concerns:
Colloidal silica: Some debate about long-term safety
Sodium metasilicate: More alkaline, may cause irritation
Silicon dioxide (as food additive): Generally recognized as safe (GRAS), but some debate about nanoparticle forms
Recommended Intake/Serving Size
There is NO official RDA (Recommended Dietary Allowance) for silicon because it's not recognized as essential by major health agencies.
Estimated typical dietary intake:
Western diet: 20-50 mg/day (highly variable based on diet)
Vegetarian diet: May be higher (40-60+ mg/day)
Asian diet: Can be higher (30-60+ mg/day)
Ranges widely based on food choices and water source
Suggested adequate intake (from research, not official):
Some researchers suggest 5-40 mg/day may be beneficial
Others propose 10-25 mg/day
Framingham Study suggested >40 mg/day for optimal bone health
No consensus on optimal intake
Supplemental doses typically used:
Choline-stabilized orthosilicic acid (ch-OSA): 5-20 mg silicon per day (most common: 10 mg)
Silicon dioxide/silica: 100-500 mg (much less bioavailable)
Horsetail extract (natural source): 300-900 mg extract (provides variable silicon)
Most studies use 5-10 mg bioavailable silicon daily
No established Upper Tolerable Limit:
Dietary silicon appears safe even at relatively high intakes
Supplemental doses up to 500 mg/day studied without serious adverse effects
However, moderation still advisable
Bioavailability varies by form:
Orthosilicic acid: Most bioavailable (50-80% absorption)
Soluble silicates: Moderately bioavailable (30-50%)
Silicon dioxide/silica: Poorly bioavailable (<10%)
Silicon from foods: Varies (5-50% depending on food matrix)
What to Take With It
Synergistic nutrients for bone and connective tissue:
For bone health:
Calcium: Works together with silicon for bone formation (1,000-1,200 mg/day)
Vitamin D3: Enhances calcium absorption and bone health (2,000-4,000 IU/day)
Vitamin K2 (MK-7): Directs calcium to bones (100-200 mcg/day)
Magnesium: Essential for bone health and works with silicon (300-500 mg/day)
Boron: Supports bone metabolism (3-6 mg/day)
Vitamin C: Essential for collagen synthesis (500-1,000 mg/day)
For connective tissue:
Vitamin C: Critical for collagen production
Copper: Needed for collagen cross-linking (1-2 mg/day)
Zinc: Supports tissue repair (15-30 mg/day)
Manganese: Involved in connective tissue formation (2-5 mg/day)
Collagen peptides: Type I and III collagen supplements
Hyaluronic acid: Supports joint and skin health
For cardiovascular support:
Magnesium: Arterial and vascular health
Vitamin K2: Prevents arterial calcification
Omega-3 fatty acids: Anti-inflammatory for vessels
Coenzyme Q10: Cardiovascular support
For aluminum detoxification (if that's the goal):
Magnesium: Competes with aluminum
Antioxidants: Vitamin C, E, selenium
Adequate water intake: Helps elimination
What NOT to Take With It (or Use Caution)
Silicon has relatively few concerning interactions, but consider:
Minimal interactions reported, but theoretically:
High-dose antacids containing aluminum:
Silicon may bind to aluminum
While this might be beneficial (reducing aluminum absorption), timing may matter
Space apart by 2 hours if concerned
Very high-dose calcium supplements:
Some theoretical concern about mineral competition
Unlikely to be clinically significant
Normal calcium supplementation fine
Diuretics (water pills):
May increase silicon excretion through urine
Probably not clinically significant
But those on chronic diuretics might have lower silicon status
Bisphosphonates (osteoporosis drugs):
No known direct interaction
But take medications as prescribed by doctor
Space apart from supplements generally (2-4 hours)
Kidney stone medications:
If you form silicate stones (rare), discuss with doctor
Most kidney stones are calcium oxalate, not silicate-based
Generally safe with:
Most medications
Other supplements
Foods
Food considerations:
No significant food interactions
Silicon in foods is poorly absorbed but safe
Fiber may slightly reduce absorption but not concerning
Who Should Consider Taking It
Good candidates for silicon supplementation:
Bone health concerns:
Older adults: Particularly those with osteopenia or osteoporosis
Postmenopausal women: Higher risk for bone loss
People with low bone density: Especially if inadequate dietary intake
Those at risk for osteoporosis: Family history, thin build, smoking history
Athletes with stress fractures: Recurrent bone injuries
Connective tissue issues:
People with joint pain or arthritis: May support cartilage health
Those with connective tissue disorders: EDS (Ehlers-Danlos), joint hypermobility
Athletes with tendon/ligament injuries: May support healing
Individuals with chronic tendinitis: Supportive for connective tissue
Skin, hair, nail concerns:
Brittle nails: May improve strength
Thinning hair: Some evidence for improvement
Skin aging concerns: May improve elasticity
Poor wound healing: Collagen synthesis support
Cardiovascular health:
High blood pressure: May support arterial flexibility
Atherosclerosis concerns: Preventive for arterial health
Arterial stiffness: May improve elasticity
Aluminum exposure concerns:
Occupational exposure: Those working with aluminum
Antacid users: Chronic aluminum-containing antacid use
Concerned about aluminum in food/water: Though usually not necessary
Cognitive health: Theoretical benefit through aluminum binding
Dietary factors:
Low dietary silicon intake: Refined grain-based diet, low vegetable intake
Vegan/vegetarian seeking bone support: Though plant-based diets often higher in silicon
Those avoiding whole grains: May have lower intake
Who Should NOT Take It (or Use Caution)
Very few absolute contraindications, but consider:
Kidney disease:
Severe kidney impairment: May not excrete silicon properly
Kidney stones (silicate type): Rare but if history of silicate stones, avoid supplementation
Dialysis patients: Unclear safety; consult nephrologist
Silicon is excreted primarily through kidneys
Other considerations:
Pregnancy and breastfeeding:
Safety not established in pregnancy/lactation
Dietary sources fine
Supplementation should be discussed with healthcare provider
No known concerns but limited data
Children:
No established dosing for children
Dietary sources appropriate
Supplementation generally unnecessary
Should only supplement under medical guidance
Rare considerations:
Silicon sensitivity: Very rare, but if allergic reactions occur
Those on very low-sodium diets: Some silicon supplements contain sodium
People with specific rare genetic disorders affecting mineral metabolism
Generally safe for:
Most healthy adults
Those with most chronic conditions
Elderly populations
People taking most medications
Deficiency Symptoms
Silicon deficiency is not officially recognized in humans because it's not established as essential. However, research in animals and observational studies suggest potential signs of inadequate intake:
From animal studies (chickens, rats):
Bone deformities and poor bone development
Skull abnormalities
Impaired collagen formation
Connective tissue defects
Stunted growth
Poorly formed cartilage
Potential signs in humans (not definitively proven):
Bone and skeletal:
Poor bone formation or density
Increased fracture risk
Osteoporosis or osteopenia
Slower healing of bone fractures
Connective tissue:
Joint pain or instability
Tendon/ligament weakness
Poor cartilage formation
Increased injury susceptibility
Skin, hair, nails:
Brittle nails
Thinning or weakened hair
Poor skin elasticity
Premature skin aging
Slower wound healing
Cardiovascular:
Arterial stiffness
Potential increased atherosclerosis risk
Reduced arterial elasticity
Risk factors for low silicon status:
Diet high in refined grains (low whole grains)
Very low plant food intake
Soft water (low mineral content)
Chronic diuretic use
Kidney disease
Aging (may reduce absorption/retention)
Important note: These symptoms are non-specific and could have many other causes. True silicon deficiency is likely very rare if it occurs at all in humans.
Toxicity Symptoms
Silicon has very low toxicity from dietary and supplement sources.
Dietary silicon toxicity:
Essentially impossible from food and water
Humans can safely consume high amounts through diet
No documented cases of dietary silicon toxicity
Supplemental silicon:
Very safe even at high doses
Studies using up to 500 mg/day found no serious adverse effects
Upper safety limit not well-established because toxicity is so rare
Mild effects at very high doses (uncommon):
Digestive upset
Mild diarrhea
Bloating or gas
These resolve when dosage reduced
Inhalation toxicity (NOT from supplements):
Silicosis: Serious lung disease from inhaling crystalline silica dust
Only occurs from occupational exposure (mining, sandblasting, construction)
Causes lung scarring, breathing difficulties, increased infection risk
This is NOT relevant to dietary silicon or oral supplements
Theoretical concerns at extremely high doses:
Possible kidney stone formation (silicate stones - very rare)
Potential kidney burden if severe kidney disease present
But these are theoretical; actual documented cases are rare
No known symptoms of:
Liver toxicity
Heart toxicity
Neurological toxicity
Blood toxicity
Immune suppression
Bottom line: Silicon is one of the safest minerals/elements to supplement. Toxicity from oral intake is extremely rare to nonexistent.
Timing and Food Considerations
Best time to take:
Anytime is generally fine - timing not critical
Morning with breakfast: Convenient for most people
With meals: May enhance tolerability (though rarely an issue)
Split dosing: If taking higher amounts, can divide throughout day
Consistency: Same time daily helps maintain routine
With food or without:
Can be taken with or without food
With food may be preferable: Slightly better tolerability, though silicon itself rarely causes stomach upset
Absorption: Food doesn't significantly impair absorption of most bioavailable forms
Orthosilicic acid: Well-absorbed regardless of food
Colloidal silica: May be better with food
Specific timing considerations:
With other bone supplements:
Can take together with calcium, vitamin D, magnesium
No need to separate these
May work synergistically
With medications:
Generally safe to take simultaneously
If taking medications that need empty stomach, follow those medication instructions
No known significant drug interactions requiring timing separation
Form-specific considerations:
Choline-stabilized orthosilicic acid (ch-OSA):
Most bioavailable form
Can take anytime with or without food
Usually liquid or capsule
Some products dissolved in water or juice
Horsetail extract:
Natural source of silicon
Take with water
May be better with food
Some recommend avoiding late at night (mild diuretic effect for some)
Silicon dioxide/silica supplements:
Less bioavailable
Take with food
Adequate water intake
Hydration:
Drink adequate water throughout the day
Helps with silicon metabolism and excretion
Generally good for overall health
Food Sources
Silicon is found in many plant-based foods and beverages:
Excellent sources (high silicon content):
Grains and cereals:
Whole grains: Oats, brown rice, barley, wheat bran (10-40 mg per serving)
Beer: One of the richest sources; 4-12 mg per 12 oz (from barley malt)
Bran cereals: High-fiber cereals (5-20 mg per serving)
Whole wheat bread: 3-8 mg per slice
Vegetables:
Green beans: 4-7 mg per cup
Spinach: 3-6 mg per cup cooked
Leafy greens: Variable amounts
Carrots: 1-3 mg per cup
Asparagus: 2-4 mg per cup
Beverages:
Beer (especially unfiltered): Very high (4-12 mg per 12 oz)
Red wine: 2-4 mg per glass
Coffee: 1-2 mg per cup
Tea: 1-2 mg per cup
Mineral water: Varies widely by source (0.5-10 mg per liter)
Good sources (moderate silicon):
Fruits:
Bananas: 4-5 mg per banana
Raisins: 2-4 mg per 1/4 cup
Apples with skin: 1-2 mg per apple
Oranges: 1-2 mg per orange
Grapes: 1-2 mg per cup
Other:
Nuts: Almonds, peanuts (1-3 mg per serving)
Beans and legumes: Variable (2-5 mg per cup)
Root vegetables: Potatoes, beets (2-4 mg per serving)
Low sources:
Refined grains: White bread, white rice (silicon removed in refining)
Most meats: Very low silicon content
Dairy products: Low silicon
Highly processed foods: Generally low
Water content:
Varies dramatically by source: 1-50 mg/L
Hard water: Generally higher silicon
Soft water: Lower silicon
Mineral water: Can be significant source
Tap water: Depends on geological source
Bioavailability from foods:
Green beans: ~40-50% absorbed
Beer: Very bioavailable due to orthosilicic acid form
Whole grains: Lower bioavailability (5-10%) due to fiber and phytates
Bananas: Moderate bioavailability
Forms of Silicon in Supplements
Most bioavailable forms:
1. Choline-stabilized orthosilicic acid (ch-OSA):
Most studied and bioavailable form (50-80% absorption)
Orthosilicic acid stabilized with choline to prevent polymerization
Available as liquid or capsules
Typical dose: 5-20 mg silicon
Best supported by research
Brand names: BioSil, Jarrow ch-OSA
Best choice for supplementation
2. Orthosilicic acid (OSA):
Highly bioavailable but unstable in solution
Must be stabilized (with choline or other compounds)
The form most readily absorbed and utilized
3. Sodium metasilicate:
Moderately bioavailable
More alkaline, may cause minor GI upset
Less commonly used
Less bioavailable forms:
4. Silicon dioxide (silica):
Poorly absorbed (<10%)
Common as food additive (anti-caking agent)
Needs very high doses to provide meaningful silicon
Less recommended for supplementation
Very inexpensive
5. Colloidal silica:
Suspended silica particles
Variable absorption (10-30%)
Some debate about long-term safety
Mixed quality among products
Natural sources:
6. Horsetail (Equisetum arvense) extract:
Plant naturally high in silicon (5-10% silicon content)
Also contains other compounds (flavonoids, antioxidants)
Bioavailability moderate (20-40%)
Typical extract: 300-900 mg providing 15-90 mg silicon
Popular natural choice
Caution: Should be standardized extract; raw horsetail may contain thiaminase
7. Bamboo extract:
Very high silicon content (70%+ silica)
Popular in hair/skin/nail supplements
Bioavailability lower than orthosilicic acid
Often 300-500 mg providing high amounts of silicon dioxide
8. Diatomaceous earth (food-grade):
Not recommended for supplementation
Very poorly absorbed
Better as filtering agent, not supplement
What to look for in supplements:
Form: Choline-stabilized orthosilicic acid preferred
Dosage: 5-10 mg bioavailable silicon is typical effective dose
Purity: Third-party testing (USP, NSF, ConsumerLab)
Brand reputation: Choose established brands
Avoid: Poorly described "silica" without specific form
Additional Important Information
Silicon and Bone Health Research:
Key studies:
Framingham Offspring Study: Found positive correlation between dietary silicon intake and bone mineral density in men and premenopausal women
Silicon intake of >40 mg/day associated with ~10% higher BMD at hip
Effect more pronounced in younger individuals
Clinical trials:
Studies using ch-OSA (10 mg silicon/day) showed improvements in hair and skin in women
Some studies show improved collagen synthesis markers
Bone studies show promise but need more research
Mechanisms:
Early stages of bone calcification
Collagen synthesis and cross-linking
May enhance calcium deposition in bone
Important for bone matrix formation
Silicon and Aluminum:
Competitive relationship:
Silicon and aluminum compete for absorption
Silicon may reduce aluminum absorption from GI tract
Silicon may help eliminate aluminum from tissues
May bind aluminum in brain tissue
Research context:
Aluminum implicated in some neurological conditions
Silicon-rich mineral water (Spritzer) studied for aluminum reduction
One study showed drinking silicon-rich water reduced aluminum levels in Alzheimer's patients
More research needed
Practical application:
Avoid aluminum cookware if concerned
Adequate silicon intake may offer some protection
Not a proven treatment for aluminum toxicity
Silicon and Skin Health:
Topical applications:
Silicon used in many skin care products
May improve skin texture and elasticity
Wound healing applications
Oral supplementation:
Some studies show improved skin elasticity with ch-OSA
Reduced brittleness of hair and nails
Improved appearance of photoaged skin
Typical study dose: 10 mg silicon daily for 20+ weeks
Silicon in Nature:
Environmental abundance:
Second most abundant element in Earth's crust (27%)
Found in sand, quartz, rocks
Present in most soils
Varies in water depending on geology
Plant uptake:
Plants absorb silicon from soil
Protective function in plants (strengthens cell walls)
Why plant foods are primary silicon source
Silicon and Aging:
Changes with age:
Silicon content in tissues (especially arteries) decreases with age
Arterial silicon content can drop 40-60% from young to old age
May contribute to loss of arterial elasticity
Skin silicon also decreases
Implications:
May partially explain age-related bone loss
Arterial stiffness with aging
Skin aging and loss of elasticity
Suggests increased importance of adequate silicon in elderly
Silicon and Cardiovascular Health:
Arterial health:
Concentrated in arterial walls, especially elastin
Associated with arterial flexibility and compliance
Framingham Study: Higher silicon intake associated with reduced arterial stiffness
May help prevent atherosclerosis
Mechanisms:
Maintains arterial wall integrity
Supports elastin and collagen in vessel walls
May reduce calcification
Anti-inflammatory effects in vessels
Silicon Content in Body:
Distribution:
Total body silicon: ~1-2 grams in adult human
Highest concentrations: skin, bone, connective tissue, arteries
Also found in liver, kidney, heart, lungs
Blood levels: 5-20 μg/dL typically
Silicon Metabolism:
Absorption:
Absorbed primarily in small intestine
Soluble forms (orthosilicic acid) best absorbed
Particulate silica poorly absorbed
Absorption rate: 5-80% depending on form
Excretion:
Primarily through kidneys in urine
Rapid excretion (hours to days)
Not significantly stored long-term
Requires regular intake to maintain levels
Factors affecting silicon levels:
Increase silicon status:
Diet high in whole grains, vegetables
Beer consumption (highest source)
Hard mineral water
Adequate kidney function
Decrease silicon status:
Refined grain diet
Low plant food intake
Diuretic use
Kidney impairment
Aging (reduced absorption/retention)
Quality and Testing:
For supplements:
Look for third-party testing (USP, NSF, ConsumerLab)
Verify silicon content on label
Check for form (ch-OSA best)
Reputable manufacturers
For water:
Can test mineral content of water
Silicon content varies widely (1-50 mg/L)
Some mineral waters advertise silicon content
Practical Recommendations:
To increase dietary silicon:
Eat more whole grains (especially oats, brown rice)
Include green beans, leafy vegetables
Drink mineral water high in silicon
Consider moderate beer consumption (if appropriate)
Choose unrefined grains over refined
Eat variety of fruits and vegetables
For supplementation:
Choose ch-OSA form
Start with 5-10 mg silicon daily
Take consistently
Combine with other bone/connective tissue nutrients
Give 3-6 months to assess effects
Realistic Expectations:
What silicon can help with:
Bone density support (with other nutrients)
Connective tissue health
Skin, hair, nail improvement
Arterial health
May reduce aluminum burden
What silicon cannot do:
Cure osteoporosis alone
Replace medical treatment
Reverse severe arthritis
Eliminate all aluminum exposure effects
Work immediately (takes weeks to months)
Cost Considerations:
Supplementation:
Ch-OSA supplements: $15-35 per month
Horsetail extract: $10-20 per month
Less bioavailable forms: $5-15 per month
Dietary sources:
Most silicon-rich foods are inexpensive
Beer (if you drink it) provides silicon
Whole grains economical
Vegetables affordable
Research Gaps:
What we still need to know:
Optimal intake for humans
Whether it's truly essential
Long-term effects of supplementation
Dose-response relationships
Best forms and bioavailability comparisons
Effects in different populations
Interactions with medications
Ongoing research:
Bone health trials
Cardiovascular studies
Aluminum detoxification research
Skin health applications
Optimal dosing studies
Bottom Line
Silicon is a trace element with important structural roles in bone, connective tissue, skin, and arterial walls. While not officially recognized as essential by all authorities, substantial evidence suggests beneficial effects, particularly for bone density, joint health, skin quality, and cardiovascular function.
Key takeaways:
Status: Likely beneficial element; essentiality in humans not definitively proven but strongly suggested
RDA: None established; typical diet provides 20-50 mg/day
Suggested beneficial intake: 10-40+ mg/day from research (not official)
Functions: Bone formation, collagen synthesis, connective tissue structure, arterial integrity
Benefits: Bone density, joint health, skin/hair/nail quality, arterial flexibility, possible aluminum detoxification
Safety: Extremely safe; virtually no toxicity from oral intake
Best supplemental form: Choline-stabilized orthosilicic acid (ch-OSA), 5-10 mg/day
Food sources: Whole grains, green beans, beer, bananas, leafy vegetables, mineral water
Timing: Anytime, with or without food
Deficiency: Not officially recognized but low intake may affect bone and connective tissue
Toxicity: Essentially impossible from diet/supplements; only inhalation concern (occupational)
Who benefits: Those with bone loss, joint issues, aging concerns, low dietary intake
Contraindications: Severe kidney disease, rare silicate kidney stones
Practical approach:
For most people: Get silicon through whole grains, vegetables, and varied diet
For specific concerns (bone loss, joint problems, skin aging): Consider ch-OSA supplementation 5-10 mg/day
Very safe to supplement: One of the safest minerals
Works best with: Calcium, vitamin D, vitamin K2, magnesium for bone; vitamin C for collagen
Give it time: Effects take 3-6 months to become apparent
Silicon represents a promising but under-researched element. While not officially essential, the evidence strongly suggests important roles in human health, particularly for structural tissues. Supplementation is safe and may benefit those with inadequate intake or specific health concerns related to bone, joints, or connective tissue.