Boron is an ingredient common amongst many of the best-selling testosterone boosters on the market. My review breaks down the science behind this mineral to answer the question of whether it is actually proven to work.
Boron is a trace mineral naturally present in some foods and in the environment as well. It is vitally important for human health and plays a key role in maintaining bone density, hormonal balance, and mental cognition (1).
Plant-based foods like raisins, almonds, hazelnuts, and apricots are rich in boron. My focus in this article, however, is on boron supplementation.
What better way to answer this question than by referring to scientific literature. There are currently only 3 human trials that have observed the influence of boron supplementation on testosterone levels in men. Let's now go through the major findings that each of these studies has observed.
Number of Subjects
8 healthy male volunteers were brought into a lab 3 times over a 1-week period.
On the first day (day 0), blood samples were collected, after which each subject was given breakfast and 10mg of placebo.
On day 1, a similar procedure was performed but, instead of placebo, subjects were given 10mg of boron. Blood samples were collected every 2 hours for the next 6 hours.
For the rest of the experiment, subjects were instructed to consume 10mg of boron everyday with breakfast.
The final blood samples were collected 1-week after supplementation.
When comparing the blood samples of day 0 to the blood samples of day 7, researchers found that the 10mg daily dose of boron was enough to increase subjects' free testosterone levels by an average of 28%. Total testosterone, on the other hand, remained about the same.
This result is significant because only free testosterone can exert its influence on your body. Total testosterone is simply a measure of free testosterone + bound testosterone (the type that is unable to exert its influence). Boron supplementation caused an increase in free T by decreasing estrogen levels by 39%. Less estrogen meant more testosterone being allowed to remain in its free form. For more on this, view my ultimate guide on testosterone measurement.
Healthy men given a 10mg daily dose of boron for 7-days experienced a 28% increase in free T and a 39% decrease in estrogen. However, given that the experiment spanned over only 7-days, we cannot say whether these results carry over into the long-term.
Number of Subjects
19 male weightlifters (aged 20-27) with a minimum of 1-year of weight training experience volunteered for this study. They were instructed to keep up with their self-adminsistered bodybuilding routines, which had them in the gym for 4-days/week during the 7-weeks of the study.
The 19 subjects were randomly assigned to receive a daily dose of either 2.5mg of boron or placebo over the course of the study.
Blood samples were collected on day 1 and day 49 of the experiment.
Subjects in both groups experienced significant increases in serum testosterone levels.
In placebo, total T increased by 20% and free T by 6.9%.
In the supplement group, total T increased by 33% and free T by 15%.
Lifting weights is a surefire way to increase testosterone levels. This increase is further accentuated when accompanied by boron supplementation.
Number of Subjects
Urine samples were collected from 18 healthy subjects on two different occasions at three weekly intervals. Of the 18 subjects, 8 were recruited into a single-blind, cross-over trial.
Each subject acted as his own control and was instructed to consume a daily dose of 10mg of boron for 4-weeks.
Blood samples were collected before and after the 4-week period.
Subjects experienced, on average, an 11.49% increase in total testosterone levels.
10mg of daily boron supplementation for 4-weeks was enough to increase total testosterone levels by 11.49%.
Boron is able to increase testosterone levels by allowing the body to increase absorption of magnesium (1) and vitamin D (2, 3), both of which are critical micronutrients required for optimal testosterone production.
The research is aligned in finding that boron supplementation does indeed have a positive influence on testosterone levels. That being said, more robust research is needed to confirm the true extent of this effect.
Boron increases estrogen levels in post-menopausal women (4). In men, the research regarding boron's influence on estrogen is conflicting.
In trial #1 listed above, 10mg of boron supplementation for a week was able to decrease estrogen levels in otherwise healthy male subjects by 39%. In trial #3, however, researchers found 10mg of boron supplementation for 4-weeks to increase male subjects' estrogen by a whopping 42%.
In men, the research regarding borons impact on estrogen is inconclusive. One study found supplementation to decrease estrogen while the other found it to increase estrogen.
In trial #2, subjects were training for 4-days/week during the 7-week period and, along with T measurements, researchers also tracked the subjects' before/after strength and lean mass. They found that boron supplementation had no impact on these parameters.
Another finding of trial #1 was boron's tremendous ability to reduce inflammatory biomarkers. Interleukin, C-reactive protein, and tumor necrosis factor α are all markers of inflammation. The less of them you have in your body, the better your body is able to recover.
Boron has been shown to provide a wide variety of benefits outside of the sports performance arena as well. The following are some of these benefits:
According to WebMD, boron use is likely safe when consumed under the upper limit of dosage (20mg). Some possible side effects include:
Also, don't supplement with boron if you have any sort of kidney condition.
Boron does not have a recommended daily allowance because this amount has not yet been established. Nonetheless, eating a varied whole-foods diet should provide anywhere from 2.5-3.5mg of boron per 2000 calories of consumption.
When supplementing with boron, the minimum effective dose is 2.5mg.
The tolerable upper intake limit of boron (the maximum dose at which no negative side-effects are expected) us 20mg.
Given that boron is not yet considered an essential mineral, the optimal dose is not yet known. My recommendation is to stick with a daily dose anywhere between 3.5-10mg.
Boron is a mineral that has been shown in multiple human trials to increase testosterone levels in men. That being said, don't consider it to have a drastic impact. Boron's influence is largely tied back to increasing the rate at which your body absorbs magnesium and vitamin D. If you are currently deficient in these micronutrients, then boron's impact will be more drastic than if you're not deficient. Still, provided the host of other benefits associated with boron, maintaining optimal levels of it is important.