While used more liberally in the times of World War two and earlier, boron has been remained relatively obscure micronutrient during the Atomic and Information Era. In the European Union, regulatory agencies have not established the recommended daily dosage. Safe tolerated upper intake limit for adults has been calculated as 20 mg/day[1]. Some medical applications (epilepsy) exceeding this limit for more than an order of magnitude have been shown to cause side effects when used chronically (alopecia, dermatitis, anorexia, indigestion). Animal studies have found that such high, nonsafe doses cause testicular atrophy, reduced testosterone level and reduced fertility. However, genotoxicity is not a concern. Acute toxicity can be described as low or very low and genotoxicity is not a concern [1]. The primary reason why boron is not formally recognized as a beneficial micronutrient with a recommended daily dosage is that its precise mechanism of action remains somewhat unclear and the beneficial effect has not been established by large studies (that can usually be afforded by pharmaceutical industry that is more interested in molecules that can be patented).

Boron is a micronutrient – vegetables, fruits and nuts but are good sources while dairy and meat have minimal boron levels. Positive effects of boron have been underappreciated and negative effects overestimates as has been the case with vitamin D not so long time ago. The potential benefits of boron have been discussed in longecity.com and bodybuilding.com forums as well as in scientific papers. An excellent review with a catchy title “Nothing boring about boron” has been published in 2015 [2]. This paper highlights some interesting pieces of information of boron for people aiming at enhancing their biological functioning:

  1. Boron increases wound healing (it is used as an externally applied 3% boric acid solution for this purpose).
  2. Boron strenthens bones at least by several mechanisms: increasing the level of sex hormones, type 1 collagen and bone morphogenetic proteins.
  3. Boron (6 mg for one week) increases free testosterone in men (from 12 pg/mL to 15 pg/mL) and reduces estradiol (from 42 pg/mL to 26 pg/mL). In women, it approximately doubles both testosterone and estrogen. Principally, boron is a testosterone amplifier that counteracts effects of sex hormone binding globulin (SHGB) that keeps testosterone from interacting with testosterone receptors, and it inhibits the decomposition of estradiol by an microsomal enzyme (CYP24A1).
  4. Boron somewhat reduces inflammation biomarkers such as IL-6, TNF-alpha and halves C-reactive protein (that are associated with psychological distress, joint pain and cardiac risk, respectively, for example).
  5. Boron helps to increase vitamin D and magnesium level. Supplementation (6 mg/day) has helped to raise vitamin D level by 20% even in winter when the levels were expected to decline, instead. Some people do not gain benefit from vitamin D supplemetantion because their vitamin D levels do not raise to desired levels with vitamin D supplementation. Boron supplementation has helped vitamin D supplementation to take effect in these people because it inhibits decomposition of vitamin D by microsomal enzymes CYP24A1 and CYP2R1. The increased absorption of magnesium is downstream effect of blocking degradation of estradiol.
  6. Epidemiological evidence, case reports and both animal and human studies have shown that boron is of interest for preventing and treating osteoarthritis. Dietary of boron intake is associated with – drastic is not a word too strong – reduced arthritis rates. Boron (6 mg/day) used in a small medical intervention study reduced symptoms in 50% of subjects while placebo helped only 10%. In another study, boron (8 weeks, 6 mg as boron fructoborate) reduced osteoarthritis pain by 70% and lion’s share of those previously suffering ceased taking analgesic (ibuprofen).
  7. Boron-rich diets (boron is found in vegetables, fruits and nuts) and boron-rich water and soil areas correlate with reduced rates of cancers such as cervical cancer and prostate cancer. In addition, subjects chronically exposed to relatively high levels of boron (boron miners) do not suffer from overt negative effects.
  8. Finally, boron may have have played a role in the origin of life – of the many sugars present in organisms, it seems to selectively stabilise ribose, constituent of RNA. While it cannot be said that boron is necessary for stabilisation of RNA of today’s life, it may have served this function before more elaborate protein-based DNA-stabilization.

IMPORTANT: some data sources discuss doses converted to milligrams of elemental boron while others discuss the doses of parent compounds whose molecular masses are very different from that of boron and each other.

[1] https://www.ncbi.nlm.nih.gov/books/NBK222322/

[2] https://www.ncbi.nlm.nih.gov/pubmed/26770156