Compared to other nutrients, you don’t hear much about boron. If fact, if you mention it to many people, they mistakenly think that you’re talking about Borax, a type of cleansing agent known by its full name, 20 Mule Team Borax.
Boron is a trace mineral, well-known for being important for the growth of plants, which was discovered in 1923. In more recent years, however, it’s become apparent that boron doesn’t get the respect it deserves. For one thing, it does play an important role in human nutrition by regulating how the body uses other nutrients, including vitamin D, calcium and magnesium. All three are vital for bone health, and boron may be too.
From a bodybuilding perspective, boron briefly rose to prominence in the late 1980s. At that time a study of 12 older women who were given three milligrams a day of boron showed changes in the proportions of other minerals in their blood as well as an increase in the production of steroid hormones, including estrogen and testosterone. The women ate a low-boron diet for 17 weeks before getting the three milligrams of boron for another seven weeks. Within eight days of the start of boron supplementation, the women showed a drop in urinary calcium excretion of 40 percent and a drop in magnesium excretion of 33 percent. Both minerals are vital to bone health, and women who don’t get enough of them are more prone to acquiring the bone-wasting disease osteoporosis, especially if they are also low in estrogen.
In fact, another study of boron involving 15 women showed increased calcium as well as more of the activated, or hormonal, form of vitamin D, which helps to retain calcium in bone. Boron also lowered the secretion of calcitonin, a substance that encourages calcium loss from the body. Other studies suggested that boron works best to boost bone mass when other bone nutrients, such as calcium, vitamin D and magnesium, are low, which is a common occurrence. In essence, boron helps you get more bang for your buck in terms of mineral and vitamin D use in boosting bone mass.
Boron is commonly found in nature in the form of borates. It also shows up in such items as antacids, lipsticks, skin creams and shampoos, as well as estrogen supplements. It occurs naturally in the human body, with a range of three to 20 milligrams. The highest concentrations are in bone, fingernails, toenails and hair.
Boron seems to have an inverse relationship with arthritis, since arthritic bones are relatively deficient in the mineral compared to healthy bones. There is some suggestion that boron may help prevent arthritis, not just because of its effect on other nutrients but also because it exerts antioxidant and anti-inflammatory effects in the body.
In animals a boron deficiency results in impaired growth and abnormal bone development. Having a boron deficiency also makes a vitamin D deficiency even worse, and studies show that many people are low in vitamin D. The good news is that unlike other minerals, which are difficult for the body to absorb, boron is easily absorbed. Humans appear to be able to absorb 100 percent of a dose of boron. Compare that to the 10 percent rate for chromium or the 20 percent rate for calcium and most other minerals. The body excretes boron mainly in the urine but also in feces, bile, sweat and breath.
While it’s possible to get too much boron, that’s an unlikely event, since the body maintains a tight control on boron levels in the blood, and any excess is rapidly excreted through the kidneys. Most people take in about 1.7 to seven milligrams a day, depending how many servings they eat of fruits and vegetables, the primary dietary sources of boron.
Not all fruits are high in boron, however. Foods notably lacking in it include citrus fruits, berries and pineapple. Leafy greens contain the most, especially when grown organically. Boron is also found in drinking water, but that depends on the location, with some areas containing more than others. The daily requirement for boron is thought to be about one to three milligrams, with an upper limit of 20 milligrams a day for adults.
Besides its influence on bone health, boron may also provide cardiovascular benefits. Studies show that taking it leads to lower levels of low-density-lipoprotein cholesterol, the type most associated with cardiovascular disease, as well as triglycerides, or blood fat, in 14 days. A recent study showed that boron supplementation lowered levels of C-reactive protein, a marker of inflammation in the body, by 50 percent, and higher levels of inflammation are the cornerstone of cardiovascular disease. The study also found that boron lowered other inflammatory mediators, including tissue necrosis factor-A and interleukin-6. Both are classified as cytokines and play a large role in instigating out-of-control inflammation in the body as well as cancer.
Indeed, other studies have found that boron inhibits the spread of prostate cancer. When animals are given boron in their drinking water, precancerous changes in the cervixes of females revert to normal. Boron is also associated with a lower incidence of lung cancer in women, and women lacking sufficient boron in their diets may be at a higher risk for it, particularly smokers. Some studies show that vitamin D offers cancer preventive effects, and boron is known to activate and extend the time that vitamin D lasts in the body. Vitamin D, in turn, activates killer T-cells, immune cells that kill nascent tumor cells.
What about boron’s effect on steroid synthesis? In order for steroid hormones, including testosterone, estrogen and vitamin D, to be activated, they must undergo a process called hydroxylation, which involves adding hydroxyl groups to a steroid ring structure. When that happens, the steroid hormones become activated. It turns out that boron encourages the effect in steroid hormones and so increases their activity. That was originally shown in older women in the late-’80s study mentioned above. While the women showed increases in both estrogen and testosterone after taking just three milligrams a day of boron, it was the bump in testosterone that attracted the most attention in bodybuilding circles. Not long after the study was published, a few companies started selling boron supplements, calling them “anabolic.”
One obvious problem was that the study involved older women. There was no evidence that giving boron to young men would also lead to a boost in testosterone. Another potential problem involved the fact that boron appeared to boost both estrogen and testosterone. The estrogen rise would not be considered desirable in young men, although in older women it would help to retain calcium in the body. A follow-up study published in 1993 examined the effects of boron supplements in 19 male bodybuilders, aged 20 to 27 who took 2.5 milligrams a day of a boron supplement for seven weeks.1 The results showed no significant effects on free testosterone, lean mass or strength in any of the men. In another study, this time of 28 women, aged 19 to 24, who were given three milligrams a day of boron for 10 months, no changes in estrogen, testosterone, progesterone or activated vitamin D occurred.2
Even so, more recent studies have found different results. In one study a group of men took a five-milligram boron supplement for eight weeks.3 After four weeks they showed a significant elevation of estrogen, but the levels were still in the normal range for adult men. It sounds bad, but the authors think that the boron actually boosted testosterone, which was converted to estrogen in the body.
That theory appeared to be confirmed by the most recent study of boron supplements in men.4 This time eight subjects took 11.6 milligrams of boron and experienced a significant decrease in sex-hormone-binding globulin, a protein that ties up testosterone in the blood. When testosterone is attached to SHBG, it is inactive. Only the free, or unbound, form of testosterone can interact with androgen cell receptors. Thus, anything that can lower SHBG will boost testosterone. In this study the men showed higher testosterone after ingesting boron but lower estrogen. They also showed higher dihydrotestosterone— DHT—a by-product of testosterone metabolism, as well as cortisol and vitamin D. Thus, based on this study, boron may actually live up to its previous designation as an “anabolic mineral.”
That raises the question of whether bodybuilders should consider supplementing with boron. If you eat at least five servings a day of fruits and vegetables, particularly leafy greens, you don’t need to add a boron supplement. If you avoid those foods, boron would likely be of help to you. It will help you retain other minerals, such as calcium and magnesium, and may also offer favorable effects on vitamin D metabolism. The more deficient you are in those nutrients, the better boron will work. If you opt to supplement with boron, take about three milligrams a day.
Editor’s note: Jerry Brainum has been an exercise and nutrition researcher and journalist for more than 25 years. He’s worked with pro bodybuilders as well as many Olympic and professional athletes. To get his new e-book, Natural Anabolics—Nutrients, Compounds and Supplements That Can Accelerate Muscle Growth Without Drugs, visit www.JerryBrainum.com. IM
1 Ferrando, A, et al. (1993). The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders. Int J Sports Nutr. 3:140-49.
2 Volpe, S.L., et al. (1993). The effect of boron supplementation on bone mineral density and hormonal status in college female athletes. Med Exerc Nutr Health. 2:323-30.
3 Naghii, M.R., et al. (2008). Elevation of biosynthesis of endogenous 17-B estradiol by boron supplementation: one possible role of dietary boron consumption in humans. J Nutr Environ Med. 17:127-35.
4 Naghii, M.,et al. (2011). Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. J Trace Elements Med Biol. 25:54-58.