Boron
Also sold as: Boron · Boric acid · Calcium fructoborate · Boron citrate · Boron glycinate
A dietary trace element marketed for hormones, bone health and joint comfort. Human findings depend on baseline nutrition and, for joint trials, the specific calcium fructoborate formulation.
Focus
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Research
- Focus: Small controlled depletion/repletion studies restored attention and psychomotor function after dietary deprivation; enhancement in well-nourished adults is unproved.
REALITY CHECK // The testosterone story rests on an uncontrolled seven-day n=8 study, while two lower-dose controlled studies were null. Bone mineral balance is not proof of fracture prevention, and joint findings for calcium fructoborate cannot be transferred to citrate or glycinate.
Levels: how we grade evidence. Grey = evidence of no benefit; amber = evidence it makes this goal worse.
Ratings are self-reported by a self-selected group of users: how it felt, not proof that it works.
Check your bottle
Compare what your label says with what was used in trials. This is a trial range, not a personal prescription.
Enter the amount from your label to see the result.
How it was studied
01 // STUDIED_DOSE_RANGE
2.5–10 mg elemental in selected trials
Study contexts differed substantially; 10 mg/day is already the dossier EFSA adult total-intake ceiling.
02 // TIMING_&_MATRIX
Check elemental boron
Compound mass and labelled elemental boron are different quantities. No superior citrate/glycinate absorption or mandatory cycling schedule is established.
03 // EVALUATION_WINDOW
Days to seven weeks
Hormone sampling ran six hours to seven days; controlled training studies ran seven weeks. Long-term fracture and muscle outcomes are unproved.
04 // SAFETY_&_QUALITY_GATE
Diet counts toward the ceiling
Kidney clearance, pregnancy and hormone-sensitive conditions matter. Use supplement-grade material and verify elemental content.
UPPER LIMIT // The dossier reports an adult EFSA upper limit of 10 mg elemental boron/day and US IOM upper limit of 20 mg/day, both including food and supplements. Typical dietary intake is about 1–3 mg/day. A 10 mg supplement already reaches the EFSA ceiling before food; no ceiling is a target.
Summary
Boron is not a substitute for testosterone therapy. An uncontrolled study in eight healthy men using 10 mg/day for seven days found hormone changes at a single morning sample; placebo-controlled studies using 2.5 mg/day for seven weeks found no advantage for testosterone, lean mass or strength. Small calcium fructoborate joint trials are promising but short and partly manufacturer-linked.
Mechanism
Boron may alter mineral retention and steroid hormone handling. Calcium/magnesium balance and SHBG-related changes are surrogate observations; proposed effects on vitamin D metabolism largely come from animals and mechanistic hypotheses.
Typical studied dose
Human studies in the dossier used 2.5 mg elemental boron/day for seven weeks in trained men, 3 mg/day during postmenopausal depletion/repletion, and 10 mg/day for seven days in eight men. A dysmenorrhea RCT used 10 mg/day around menstruation. These are research exposures, not a general dosing instruction; calcium fructoborate compound doses are not extracted.
Upper limit
The dossier reports an adult EFSA upper limit of 10 mg elemental boron/day and US IOM upper limit of 20 mg/day, both including food and supplements. Typical dietary intake is about 1–3 mg/day. A 10 mg supplement already reaches the EFSA ceiling before food; no ceiling is a target.
Popular stacks with Boron
Not enough stack data yet. A combination with Boron appears here once 5 people rate the same set.
Forms and label traps
| Form on label | Active content | Studied range / day | Absorption & GI tolerance | Verdict |
|---|---|---|---|---|
| Boric acid (~17.5% elemental boron) Best for: Understanding compound-to-elemental conversion. |
17.5% elemental / active | 2.5–10 mg | The dossier describes high absorption of boric acid/borates, approximately >85–90%; no clinical advantage over other sources is established. Generally tolerated at studied elemental amounts; excess irritates the gut. |
Studied standard [SOURCE // FORM_SPECIFIC] 17.5% is the source-supplied approximate stoichiometric fraction; research range is elemental boron across studies, not proof for every boric acid product. |
| Boron citrate (label-defined elemental content) Best for: Checking the actual labelled elemental amount. |
Unstandardized: active content unknown | no comparable trial range | High absorption described; no demonstrated superiority over boric acid. Generally tolerated; product-specific data are limited. |
Caution [SOURCE // CHECK_LABEL] No universal citrate fraction or form-specific trial range is established. The source example of a 3 mg elemental label does not identify compound mass. |
| Boron glycinate / bororganic glycine Best for: Checking a chelate label without assuming it is more effective. |
Unstandardized: active content unknown | no comparable trial range | A chelate claim does not establish superior human absorption. Generally tolerated; glycine-related reactions are anecdotal. |
Caution [SOURCE // CHECK_LABEL] The source example of 3 mg boron from about 30 mg material is product-specific, not a universal conversion. |
| Calcium fructoborate (CFB) Best for: Comparing the specific formulation used for joint discomfort research. |
Unstandardized: active content unknown | no comparable trial range | The tested entity has its own small clinical trials; this does not prove better elemental boron absorption. Generally tolerated in short trials. |
Caution [SOURCE // CHECK_LABEL] Compound dose and boron fraction are not extracted here. Do not compare its compound milligrams with an elemental-boron trial interval. |
| Sodium borate / borax decahydrate (~11% boron) Best for: Recognizing a technical-product label to avoid ingestion. |
11% elemental / active | no comparable trial range | Boron absorption can be high; technical purity remains a separate hazard. Excess exposure irritates the gut and may be toxic. |
Avoid / not comparable [SOURCE // CHECK_LABEL] Not a recommended daily supplement or a home protocol; no form-specific supplemental trial interval is supplied. |
Common label traps
- TRAP_01 // BORON IS TESTOSTERONE REPLACEMENT
The n=8, seven-day uncontrolled study measured surrogates; controlled 2.5 mg/day trials were null for testosterone, lean mass and strength. - TRAP_02 // BORON MUST BE CYCLED TO PREVENT ESTROGEN EFFECTS
A mandatory cycling schedule, universal deficiency and an increase in clinical benefit are not established. - TRAP_03 // BORON DEPLETES VITAMIN B2
The dossier contains no scientific evidence for this recurring community claim; added riboflavin does not validate it.
Other outcomes studied
Outside the five leaderboard goals. Same evidence levels as above.
- HORMONE SURROGATES Limited · benefit
Eight healthy men received 10 mg/day for seven days without a weekly placebo arm: free testosterone/estradiol shifted in one 08:00 sample and SHBG/inflammatory markers changed after six hours. Placebo-controlled 2.5 mg/day studies over seven weeks found no testosterone, lean-mass or strength advantage; doses were fourfold different.
PMID 21129941 PMID 7889885 PMID 8508192 PMID 3678698 - BONE MINERAL BALANCE Limited · benefit
Postmenopausal depletion/repletion studies using 3 mg/day found less urinary calcium/magnesium loss, particularly with low magnesium/vitamin D status. These small metabolic studies do not establish BMD gains or fracture prevention.
PMID 3678698 PMID 8329361 PMID 32540741 PMID 8292503 - JOINT DISCOMFORT Limited · benefit
Small short-term placebo-controlled calcium fructoborate trials in adults with knee discomfort/OA suggest symptomatic benefit and lower hsCRP/fibrinogen. Manufacturer links and lack of independent replication limit confidence; disease modification and transfer to other boron forms are unproved.
PMID 24940052 PMID 21607703 PMID 19799205 - INFLAMMATORY MARKERS Limited · benefit
Small studies report hsCRP/TNF-alpha or fibrinogen reductions; the stable-angina study combined CFB with resveratrol, preventing attribution to boron alone. Biomarker change is not a clinical outcome.
PMID 21129941 PMID 21607703 PMID 23153742 - DEPLETION-RELATED COGNITION Limited · benefit
Small controlled feeding studies found attention, short-term memory, coordination and EEG deterioration during low-boron intake and restoration with repletion. They do not show enhancement above nutritional sufficiency.
PMID 7889884 PMID 10050926 - PRIMARY DYSMENORRHEA Limited · benefit
One RCT in young Iranian students used 10 mg/day around menstruation and found less pain severity/duration; inclusion in a micronutrient review does not replace independent replication or justify a universal protocol.
PMID 25906949 PMID 32296659 - VITAMIN D METABOLISM Anecdotal · benefit
Evidence is mainly deficient-rat models and a proposed 24-hydroxylase mechanism; a vitamin D observation in the small male study is not a dedicated human RCT.
PMID 1713047 PMID 7889882 PMID 15504575 PMID 21129941 - ECOLOGICAL ARTHRITIS ASSOCIATION Limited · benefit
Geographical associations between low boron intake and arthritis are ecological observations, vulnerable to confounding and reverse causation, not randomized evidence.
PMID 7889887
Reader questions
Can boron replace testosterone treatment?
No. A small uncontrolled hormone signal did not demonstrate clinical improvements; the controlled training studies were null.
Are citrate and glycinate meaningfully different?
Human comparative evidence does not establish an absorption or clinical advantage. Check labelled elemental boron and individual tolerance.
Is a 10 mg supplement below the EFSA limit?
The dossier limit is 10 mg/day from all sources. A 10 mg supplement reaches it before food; individualized review matters, especially with kidney disease.
Stack interactions
- Caution Estrogen therapy, tamoxifen and hormone-sensitive conditions [CAUTION // EVIDENCE_CONTEXT]
Possible overlap with hormone changes is theoretical; the small uncontrolled hormone study is not an interaction trial.
PMID 21129941 - Caution Magnesium, calcium and vitamin D [CAUTION // EVIDENCE_CONTEXT]
Mineral-retention findings were strongest during restricted intake; this is nutritional context, not evidence that boron replaces those nutrients.
PMID 3678698 - Caution Riboflavin / vitamin B2 [CAUTION // EVIDENCE_CONTEXT]
No supported evidence in this dossier shows depletion by boron; a mandatory B2 stack is folklore.
Red flags: interactions and who should avoid it
Interactions
Hormone-modifying treatment, including estrogen therapy or tamoxifen: potential interaction is theoretical and based on weak hormone data. Mineral status may influence observed effects. Boron-induced riboflavin depletion is not supported by the dossier.
Avoid or ask a doctor first if
Pregnancy, breastfeeding and childhood: supplemental safety is insufficiently established. Reduced kidney clearance may allow accumulation. Hormone-sensitive conditions need clinical review. Excess exposure can cause nausea, vomiting, diarrhea, rash and neurological symptoms; reproductive/developmental toxicity signals are mainly animal data. Never ingest technical borax as a supplement.
Sources (PubMed, 19)
- The importance of boron nutrition for brain and psychological function.
PMID 10050926 · 1998 · reviewSmall controlled feeding studies found attention, short-term memory, coordination and EEG deterioration during low-boron intake and restoration with repletion. They do not show enhancement above nutritional sufficiency.
- Up-regulatory impact of boron on vitamin D function -- does it reflect inhibition of 24-hydroxylase?
PMID 15504575 · 2004 · catalogued study; design described in outcome contextEvidence is mainly deficient-rat models and a proposed 24-hydroxylase mechanism; a vitamin D observation in the small male study is not a dedicated human RCT.
- Effect of boron on vitamin D deficient rats.
PMID 1713047 · 1991 · catalogued study; design described in outcome contextEvidence is mainly deficient-rat models and a proposed 24-hydroxylase mechanism; a vitamin D observation in the small male study is not a dedicated human RCT.
- [New potentialities in symptom-modifying therapy of osteoarthrosis].
PMID 19799205 · 2009 · catalogued study; design described in outcome contextSmall short-term placebo-controlled calcium fructoborate trials in adults with knee discomfort/OA suggest symptomatic benefit and lower hsCRP/fibrinogen. Manufacturer links and lack of independent replication limit confidence; disease modification and transfer to other boron forms are unproved.
- Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines.
PMID 21129941 · 2011 · catalogued study; design described in outcome contextEight healthy men received 10 mg/day for seven days without a weekly placebo arm: free testosterone/estradiol shifted in one 08:00 sample and SHBG/inflammatory markers changed after six hours. Placebo-controlled 2.5 mg/day studies over seven weeks found no testosterone, lean-mass or strength advantage; doses were fourfold different.; Small studies report hsCRP/TNF-alpha or fibrinogen reductions; the stable-angina study combined CFB with resveratrol, preventing attribution to boron alone. Biomarker change is not a clinical outcome.; Evidence is mainly deficient-rat models and a proposed 24-hydroxylase mechanism; a vitamin D observation in the small male study is not a dedicated human RCT.
- A double-blind, placebo-controlled pilot study to evaluate the effect of calcium fructoborate on systemic inflammation and dyslipidemia markers for middle-aged people with primary osteoarthritis.
PMID 21607703 · 2011 · randomized controlled trialSmall short-term placebo-controlled calcium fructoborate trials in adults with knee discomfort/OA suggest symptomatic benefit and lower hsCRP/fibrinogen. Manufacturer links and lack of independent replication limit confidence; disease modification and transfer to other boron forms are unproved.; Small studies report hsCRP/TNF-alpha or fibrinogen reductions; the stable-angina study combined CFB with resveratrol, preventing attribution to boron alone. Biomarker change is not a clinical outcome.
- Oral resveratrol and calcium fructoborate supplementation in subjects with stable angina pectoris: effects on lipid profiles, inflammation markers, and quality of life.
PMID 23153742 · 2013 · randomized controlled trialSmall studies report hsCRP/TNF-alpha or fibrinogen reductions; the stable-angina study combined CFB with resveratrol, preventing attribution to boron alone. Biomarker change is not a clinical outcome.
- Short-term efficacy of calcium fructoborate on subjects with knee discomfort: a comparative, double-blind, placebo-controlled clinical study.
PMID 24940052 · 2014 · randomized controlled trialSmall short-term placebo-controlled calcium fructoborate trials in adults with knee discomfort/OA suggest symptomatic benefit and lower hsCRP/fibrinogen. Manufacturer links and lack of independent replication limit confidence; disease modification and transfer to other boron forms are unproved.
- Effects of boron supplementation on the severity and duration of pain in primary dysmenorrhea.
PMID 25906949 · 2015 · randomized controlled trialOne RCT in young Iranian students used 10 mg/day around menstruation and found less pain severity/duration; inclusion in a micronutrient review does not replace independent replication or justify a universal protocol.
- The Effect of Micronutrients on Pain Management of Primary Dysmenorrhea: a Systematic Review and Meta-Analysis.
PMID 32296659 · 2020 · reviewOne RCT in young Iranian students used 10 mg/day around menstruation and found less pain severity/duration; inclusion in a micronutrient review does not replace independent replication or justify a universal protocol.
- Pivotal role of boron supplementation on bone health: A narrative review.
PMID 32540741 · 2020 · reviewPostmenopausal depletion/repletion studies using 3 mg/day found less urinary calcium/magnesium loss, particularly with low magnesium/vitamin D status. These small metabolic studies do not establish BMD gains or fracture prevention.
- Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women.
PMID 3678698 · 1987 · catalogued study; design described in outcome contextEight healthy men received 10 mg/day for seven days without a weekly placebo arm: free testosterone/estradiol shifted in one 08:00 sample and SHBG/inflammatory markers changed after six hours. Placebo-controlled 2.5 mg/day studies over seven weeks found no testosterone, lean-mass or strength advantage; doses were fourfold different.; Postmenopausal depletion/repletion studies using 3 mg/day found less urinary calcium/magnesium loss, particularly with low magnesium/vitamin D status. These small metabolic studies do not establish BMD gains or fracture prevention.
- Effects of dietary boron in rats fed a vitamin D-deficient diet.
PMID 7889882 · 1994 · catalogued study; design described in outcome contextEvidence is mainly deficient-rat models and a proposed 24-hydroxylase mechanism; a vitamin D observation in the small male study is not a dedicated human RCT.
- Dietary boron, brain function, and cognitive performance.
PMID 7889884 · 1994 · randomized controlled trialSmall controlled feeding studies found attention, short-term memory, coordination and EEG deterioration during low-boron intake and restoration with repletion. They do not show enhancement above nutritional sufficiency.
- Plasma boron and the effects of boron supplementation in males.
PMID 7889885 · 1994 · randomized controlled trialEight healthy men received 10 mg/day for seven days without a weekly placebo arm: free testosterone/estradiol shifted in one 08:00 sample and SHBG/inflammatory markers changed after six hours. Placebo-controlled 2.5 mg/day studies over seven weeks found no testosterone, lean-mass or strength advantage; doses were fourfold different.
- Essentiality of boron for healthy bones and joints.
PMID 7889887 · 1994 · randomized controlled trialGeographical associations between low boron intake and arthritis are ecological observations, vulnerable to confounding and reverse causation, not randomized evidence.
- The relationship between boron and magnesium status and bone mineral density in the human: a review.
PMID 8292503 · 1993 · reviewPostmenopausal depletion/repletion studies using 3 mg/day found less urinary calcium/magnesium loss, particularly with low magnesium/vitamin D status. These small metabolic studies do not establish BMD gains or fracture prevention.
- The influence of a low-boron diet and boron supplementation on bone, major mineral and sex steroid metabolism in postmenopausal women.
PMID 8329361 · 1993 · catalogued study; design described in outcome contextPostmenopausal depletion/repletion studies using 3 mg/day found less urinary calcium/magnesium loss, particularly with low magnesium/vitamin D status. These small metabolic studies do not establish BMD gains or fracture prevention.
- The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders.
PMID 8508192 · 1993 · randomized controlled trialEight healthy men received 10 mg/day for seven days without a weekly placebo arm: free testosterone/estradiol shifted in one 08:00 sample and SHBG/inflammatory markers changed after six hours. Placebo-controlled 2.5 mg/day studies over seven weeks found no testosterone, lean-mass or strength advantage; doses were fourfold different.
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