Boron
SupplementThe medical evidence (medical_score 47) is based on very small RCTs and depletion studies without large clinical endpoints [s7, s8]. Community perception (community_score 68) is more positive, as many users subjectively report pronounced effects on testosterone and well-being [c1, c2, c3], which is not sufficiently supported by controlled studies.
Unlock full information
Dosages, side effects, studies and more — free after registration.
Register for freeRating Scales
TL;DR
Boron is a cheap and low-risk trace mineral with its strongest single data point from a pilot study (n=8): 10 mg/day for 7 days significantly raised free testosterone and reduced estradiol by ~39% — but the evidence base is thin. Community sentiment around free testosterone and SHBG reduction is above average, though a meaningful minority reports no effect or side effects like hair loss at higher doses. Notably, the German BfR recommends a maximum of just 0.5 mg/day in supplements — far below the 3–10 mg used in studies. Anyone using boron for hormonal effects should treat the EFSA upper limit of 10 mg/day as an absolute ceiling.
Description
Boron is a trace element that may support bone health, hormonal balance, and cognitive function; evidence is limited but growing [s1, s2].
Boron (chemical symbol B) is a non-metallic trace element found in nature primarily in plant-based foods (nuts, legumes, fruits, vegetables) [s1]. The German Nutrition Society (DGE) and EFSA have not established an official daily reference value, as boron is not yet recognized as an essential trace element for humans [s9, s10]. Nevertheless, depletion-repletion studies and smaller clinical investigations suggest that boron is biologically relevant [s2, s3]. The most important potential areas of application include: bone health (calcium and vitamin D metabolism), hormonal modulation (testosterone, estrogen, SHBG), and cognitive function [s1, s2, s4, s5]. A pilot study in postmenopausal women demonstrated a positive correlation between boron intake and bone mineral density [s6]. Nielsen and Meacham (2011) described several potentially essential functions of boron, including support of bone and joint tissue, modulation of steroid hormones, influence on inflammatory markers (TNF-α, IL-6, IL-1β), and support of wound healing [s2]. Due to the limited data from randomized controlled trials in humans, the overall clinical evidence must be classified as moderate to weak. Most positive findings derive from depletion-repletion experiments, animal studies, or small pilot studies [s1, s2, s3].
Legal Status (DE)
{'bfr_max_nem_mg_day': 0.5, 'bfr_source': 's9 (updated 2021) + s9b (BfR Opinion 006/2024)', 'bfr_warning_de': 'Food supplements containing boron must carry the notice: not suitable for children and adolescents.', 'efsa_ul_mg_day': 10, 'efsa_source': 's10 (EFSA 2004, unchanged as of 2026)', 'note_de': 'There is a substantial discrepancy between the BfR recommendation (0.5 mg/day for food supplements) and the EFSA UL (10 mg/day total). The BfR value is a conservative maximum amount for supplements (not the total UL); it is based on the EFSA UL divided by a safety factor of 2 for residual intake via food supplements. '}
Mechanism of Action
Boron acts predominantly indirectly by influencing the metabolism of other nutrients and hormones. Boron compounds form reversible ester complexes with cis-diol groups of organic molecules (e.g., ribose in RNA, steroids, vitamin D) [s3]. Through this mechanism, boron may inhibit certain enzymes such as steroid hydroxylase, thereby slowing the catabolism of testosterone and other steroid hormones [s1, s2]. In depletion-repletion studies, boron supplementation (3 mg/day) following a 63-day low-boron diet increased serum concentrations of 17β-estradiol and testosterone, improved calcium and magnesium retention, and elevated serum levels of 25-hydroxy-vitamin D3 [s4]. A plausible explanation is that boron reduces renal excretion of calcium and magnesium and influences the enzymatic conversion of 25-OH-D3 to the active form 1,25-(OH)2-D3 [s4, s5]. Regarding inflammation, animal and in vitro studies show that boron inhibits the NF-κB signaling pathway and reduces pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, CRP) [s2, s11]. Clinical data from a human study demonstrated significant reductions in hs-CRP, TNF-α, and IL-6 after 7 days of supplementation with 10 mg/day boron [s7]. In the area of cognitive function, depletion studies suggest that low boron intake is associated with poorer attention, memory performance, and manual dexterity; the precise mechanism remains unclear [s5].
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Hair loss No published case report or clinical safety report on hair loss due to boron supplementation is retrievable in peer-reviewed databases. Community reports only (not clinically verified). | selten | leicht |
| Palpitations No published case report or clinical safety report on palpitations due to boron supplementation found. Community reports only (not clinically verified). | selten | leicht |
Contraindications
Boron can increase estrogen and testosterone levels; theoretical influence on tumor growth in hormone-dependent malignancies is possible [s7, s8].
Reproductive toxicology data from animal studies; supplementation beyond normal dietary intake should be avoided during pregnancy and lactation [s9, s10].
Boron is primarily excreted renally; accumulation may occur in impaired renal function [s9].
Interactions
Synergistic
Boron influences vitamin D metabolism and may promote the conversion of 25-OH-D3 to its active form; combined supplementation potentially synergistic for bone health [s4, s5].
Boron reduces renal magnesium excretion and improves magnesium retention; interaction potentially beneficial for bone and muscle health [s4].
Boron reduces urinary calcium excretion and supports calcium mineralization in bone [s4, s5].
Boron and zinc act synergistically on hormonal balance, particularly in supporting testosterone production. Both trace elements can jointly increase free testosterone and optimize hormonal balance.
The combination of boron, vitamin D3, and vitamin K2 is considered synergistic for bone health. Vitamin K2 directs calcium into bone, while boron improves vitamin D metabolism and increases calcium retention.
Boron and ashwagandha are both used for natural testosterone support. Combined intake may have an additive effect on hormonal balance.
Boron supplementation can increase DHEA levels by up to 56%. Combined intake with exogenous DHEA should be hormonally monitored but may act synergistically.
Boron and fenugreek both support free testosterone availability via complementary pathways. The combination is recommended in the field of natural testosterone optimization.
Caution
Boron can increase estrogen levels; an additive effect on hormonal status is possible with concurrent HRT or oral contraceptives [s7, s8].
Theoretical interaction via anti-inflammatory properties of boron; clinical relevance not established [s9].
Studies
Tier B — Moderate Evidence
Outcome: Bone health (calcium, vitamin D, sex hormone metabolism)
Community Evidence
Top reported benefits
- Increase in free testosterone and reduction of SHBG
- Improved general well-being and energy levels
- Reduced joint pain
- Better bone density/strength (subjective)
Top reported issues
- Hair loss at higher doses (10 mg+)
- Tachycardia / palpitations in some users
- No noticeable effect in a subset of users
- Concern regarding possible estrogen elevation
Some users report rebound effects after discontinuation and uncertainty regarding optimal dosage and duration of use. The community debates controversially whether boron raises or lowers estrogen, pointing to individual differences and an unclear evidence base [c1, c2, c3].
Scientific Sources
- The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders
Ferrando AA, Green NR (1993). International Journal of Sport NutritionBDOI - Boron and arthritis: the results of a double-blind pilot study
Travers RL, Rennie GC, Newnham RE (1990). Journal of Nutritional MedicineCDOI - The Effect of Boron Supplementation on Kidney Stones in Patients With Nephrolithiasis: A Double-Blind Randomized Controlled Trial
Vousoughi G, Soleimanzadeh H, Radkhah N, Asghari Jafarabadi M, Bahri F, Ostadrahimi A, Ebrahimzadeh Attari V (2025). Food Science & NutritionBPMID:40792045DOI - Pivotal role of boron supplementation on bone health: A narrative review
Rondanelli M, Faliva MA, Peroni G, Infantino V, Gasparri C, Iannello G, Perna S, Riva A, Petrangolini G, Tartara A (2020). Journal of Trace Elements in Medicine and BiologyBPMID:32540741 - Boron - Health Professional Fact Sheet
Office of Dietary Supplements, NIH (2023). National Institutes of Health, Office of Dietary SupplementsBLink - Opinion of the Scientific Panel on Dietetic products, nutrition and allergies [NDA] related to the Tolerable Upper Intake Level of Boron (Sodium Borate and Boric Acid)
EFSA NDA Panel (2004). EFSA JournalADOI - Boron-containing compounds on neurons: Actions and potential applications for treating neurodegenerative diseases
Rodríguez-Vera D, et al. (2022). NeurotoxicologyCDOI - Pivotal role of boron supplementation on bone health: A narrative review
Rondanelli M, et al. (2020). Journal of Trace Elements in Medicine and BiologyAPMID:32540741DOI - Growing Evidence for Human Health Benefits of Boron
Nielsen FH, Meacham SL (2011). Integrative Medicine: A Clinician's JournalBDOI - Update on human health effects of boron
Nielsen FH (2014). Journal of Trace Elements in Medicine and BiologyBDOI - Nothing Boring About Boron
Pizzorno L (2015). Integrative Medicine: A Clinician's JournalBPMID:26770156 - Dietary boron, brain function, and cognitive performance
Penland JG (1994). Environmental Health PerspectivesBPMID:7889884 - A pilot study investigating the influence of dietary boron levels on osteoporosis in postmenopausal women
Rababah EM, et al. (2024). Food Science & NutritionBDOI - Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines
Naghii MR, Mofid M, Asgari AR, et al. (2011). Journal of Trace Elements in Medicine and BiologyAPMID:21129941DOI - Plasma boron and the effects of boron supplementation in males
Naghii MR, Samman S (1997). Biological Trace Element ResearchAPMID:7889885 - Proposed maximum levels for the addition of boron to foods including food supplements (BfR Opinion)
Bundesinstitut für Risikobewertung (BfR) (2006). BfRALink - Aktualisierte Höchstmengenvorschläge für Vitamine und Mineralstoffe in Nahrungsergänzungsmitteln und angereicherten Lebensmitteln
BfR (Bundesinstitut für Risikobewertung) (2024). CLink
Community Sources
Storage
Unopened
Store in a dry, cool place, protected from direct sunlight, at room temperature.
Opened
Keep container tightly closed; avoid moisture.
Notes
Boric acid compounds are chemically stable; no special refrigeration requirements.