+28% free T
Free testosterone rose in one week
Free testosterone, pg/mL
8 healthy men took 10mg a day, twice our 5mg, with no control group.
View study →Boron
testosterone
Abstract
Boron is a trace mineral that influences steroid hormone levels, yet most people get very little of it from food. Early research suggests it may increase free testosterone while reducing estradiol — though the evidence base is still small and more studies are needed to confirm these effects at typical supplement doses.
We include boron as boron citrate, a chelated form designed for absorption. It works through a mechanism distinct from the herbal ingredients in our formula, giving the testosterone-support stack another angle that doesn't overlap with ashwagandha, tongkat ali, or fenugreek.
5mg
Per Serving
5 featured studies13 published studies
Emerging Evidence
Evidence Rating
This ingredient is part of RBRN Vitality
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Boron Benefits — What Studies Found
Some nutrients take months to move the needle. Boron may support free testosterone levels faster than you’d expect.
−39% estradiol
Estradiol fell in the same week
Estradiol, pg/mL
The same 8 men. An earlier 4-week study by the same group found estradiol rose, so this result is not settled.
View study →Why a 5mg dose of Boron
Typical supplemental doses of boron range from 3-10mg. We chose 5mg as a reasonable dose given the available research.
- Within the Research Range 5mg falls in the 3-10mg range used in clinical studies on steroid hormone metabolism.
- Boron Citrate Form A well-absorbed chelated form that delivers consistent elemental boron per serving.
- Distinct Mechanism May affect free testosterone and estradiol through pathways different from the herbal ingredients in the formula.
- Moderate Given Limited Data The key testosterone study used 10mg/day; we chose 5mg given that long-term data at higher amounts is limited.
The study showing rapid testosterone increase used 10mg/day. We chose a somewhat lower dose given the limited long-term safety data, while still providing a meaningful amount.
Clinical Dose Range
5mg · RBRN Vitality
0mg
15mg
3–10mg studied
Clinical studies use 3–10mg daily. Our 5mg dose provides meaningful support without approaching the tolerable upper limit.
BoronHormone Metabolism Regulator
A trace mineral that may shift the testosterone-to-estrogen ratio faster than you'd expect. Small evidence base, promising mechanism, distinct pathway.
01
Free Testosterone Increase in One Week
Naghii MR, et al. (2011). Journal of Trace Elements in Medicine and Biology.
Source
Free Testosterone Increase in One Week
Naghii MR, et al. (2011). Journal of Trace Elements in Medicine and Biology. Source
+28%Free Testosterone
-39%Estradiol
2.2xFree T : Estradiol Ratio
In a small single-arm study of 8 healthy men (placebo baseline on day 0 measured against day 7, no control group), one week of boron at 10mg/day significantly increased free testosterone (11.83 to 15.18 pg/ml, p=0.02) and decreased estradiol (42.33 to 25.81 pg/ml, p=0.01). The strongest results were the hormone ratios: free testosterone to estradiol more than doubled (0.31 to 0.67, p=0.004) and total testosterone to estradiol rose 62% (p=0.009). Inflammatory markers also fell, significantly for TNF-alpha (p=0.05) and by about 45% for hsCRP, though that one did not reach significance (p=0.11). A placebo-controlled trial at 2.5 mg a day for 7 weeks found no effect on testosterone (Green & Ferrando, 1994).
02
Steroid Hormone Effects in Women
Nielsen FH, et al. (1987). FASEB Journal.
Source
Steroid Hormone Effects in Women
Nielsen FH, et al. (1987). FASEB Journal. Source
An early study found that boron supplementation in postmenopausal women on low-boron diets markedly elevated serum concentrations of both 17-beta-estradiol and testosterone. While this was in women, it demonstrates boron’s influence on steroid hormone metabolism.
03
Anti-Inflammatory Effects
Scorei R, et al. (2011). Biological Trace Element Research.
Source
Anti-Inflammatory Effects
Scorei R, et al. (2011). Biological Trace Element Research. Source
A double-blind, placebo-controlled study in osteoarthritis patients found that calcium fructoborate (a form of boron, different from the boron citrate in our formula) reduced CRP by ~60% and fibrinogen by ~14% over 15 days. Inflammation interferes with testosterone production, so anti-inflammatory effects may contribute to hormone benefits. Note: this study used a different boron form at a different dose than our formula.
04
Mineral Metabolism
Nielsen FH, et al. (1987). FASEB Journal.
Source
Mineral Metabolism
Nielsen FH, et al. (1987). FASEB Journal. Source
Research shows boron reduces urinary excretion of calcium and magnesium, potentially supporting bone health and mineral status.
05
Placebo-Controlled Trial in Bodybuilders
Green NR, Ferrando AA. (1994). Environmental Health Perspectives.
Source
Placebo-Controlled Trial in Bodybuilders
Green NR, Ferrando AA. (1994). Environmental Health Perspectives. Source
In the only placebo-controlled trial of boron and testosterone in men, 19 male bodybuilders took 2.5 mg of boron or placebo for 7 weeks while training. Total testosterone, lean mass and strength rose in both groups, and boron at this dosage made no difference to any of them.
Published Research
13 studiesEvery claim we make is grounded in peer-reviewed research. Tap any study to read the abstract.
Year
Title
Journal
Our Assessment: Boron
Emerging Evidence
Evidence Rating
A small but notable study shows free testosterone increase within a week, and anti-inflammatory effects are consistent across research. But results in trained athletes are less clear, and the research base is still small.
What’s Solid
- One study shows rapid free testosterone increase (within one week)
- Anti-inflammatory effects are consistently demonstrated
- Effects on estrogen metabolism are documented
- Mineral metabolism benefits (calcium, magnesium) are observed
What’s Mixed or Uncertain
- Effects in trained athletes may be less pronounced
- Optimal dosing isn’t established
- Mechanism of action isn’t fully understood
- Long-term effects need more research
How Boron Fits the Formula
No ingredient works alone. Boron was chosen because it amplifies — and is amplified by — specific formula partners.
Boron
Fenugreek and Tongkat Ali
All three ingredients have effects on testosterone-to-estrogen balance, but through different mechanisms. Fenugreek and tongkat ali inhibit aromatase. Boron may directly affect estradiol levels and free testosterone through a different pathway. Multiple angles of support.
Zinc
Zinc is essential for testosterone synthesis. Boron may help optimize free testosterone levels and reduce inflammation that interferes with hormone production. Complementary mechanisms.
Ashwagandha
Boron’s anti-inflammatory effects complement ashwagandha’s stress-reducing effects. Both chronic inflammation and chronic stress suppress testosterone production.
Safety and Precautions
Who Should Be Cautious
Boron appears to be generally safe, though human research on long-term adverse effects is limited. There’s no established tolerable upper intake level, and typical supplemental doses range from 3-10mg. Our 5mg dose is within the range used in clinical research and considered reasonable given available safety data.
Note
Those with hormone-sensitive conditions should consult their healthcare provider
Note
Women who are pregnant or nursing (due to limited safety data)
Always consult with a healthcare professional before starting any new dietary supplement, especially if you have an existing medical condition or take prescription medications.
