Boron is a trace element that can be taken in the form of Borax as a dietary supplement. Boron promotes bone formation, relieves osteoarthritis and arthritis, and seems to make vitamin D work better. It increases testosterone levels in men and estrogen levels in postmenopausal women. Of course, Boron is also found in food, especially one.

Boron and Borax

Boron is a chemical element (a semimetal) that occurs in nature, for example, in the form of Borax (the salt of Boron). Borax used to be called tincal. Officially, it is called sodium tetraborate decahydrate, disodium tetraborate decahydrate or abbreviated sodium borate. The last term, in particular, is often read (together with Boron) on the corresponding dietary supplements.

Since two boron compounds are also approved as food additives (but only for real caviar), there are E numbers for them:

• Borax has the E number E285
• Boric acid has the E number E284

In this way, caviar can contain high amounts, namely up to 4 g per kilogram of caviar, corresponding to a borax amount of 4 mg per gram and thus an impressive 120 mg per serving of caviar (30 g).

Normally, with the usual diet, you hardly consume more than 1 to 3 mg of Boron per day. However, since very few people will eat real caviar daily, there is rarely a risk of chronic overdose.

Borax as a home remedy

Borax is an old home remedy. It is highly soluble in water and once had many applications. For example, it has been used against ants (mixed with sugar and dissolved in water) or rust (mixed with vinegar or lemon juice).

In the past, Borax was used as a detergent or softener. In a publication from 1876, it is explained that refined Borax provides a “wash of the most excellent whiteness”. A handful of the powder was added to about 40 litres of hot water, which meant that only half the amount of soap was needed. Borax was also used for washing hair and brushing teeth. And because the powder made water soften so nicely, it was put in the kettle where the tea water boiled.

Borax in silversmithing

In industry and silversmithing, Borax is used, among other things, as a flux for soldering metals. If you wonder whether working with Borax could be dangerous, i.e. whether it could be absorbed through the skin, for example. Our answer: According to this study (44), the absorption through the skin is negligible, so in conclusion, it is even said that gloves are not necessary when working with 5% boric acid or Borax (each dissolved in water).

The trace element is particularly contained in plant foods.

Boron is an alkaline trace element (i.e. basic) vital for plants. Plants cannot thrive without the element. As a result, the substance is always contained in plant food. The boron content of plant foods is one of the reasons why switching to a plant-based diet has such a good effect on many diseases.

Who does not have to/should not take the trace element

Children and pregnant women should not take Boron as a precaution. Even people with kidney disease or impaired kidney functions could not comprehensively excrete excess minerals and trace elements. In these cases, however, you can eat plenty of plant-based food (including prunes), which automatically supplies you well with the trace element. In general, it is easily absorbed. Excesses are excreted within 3 to 4 days in healthy people, so no storage or accumulation occurs with normal intake.

If you eat plant-based food (e.g. vegan or vegetarian) and already eat prunes daily, you are most likely well supplied with Boron and do not need to take any more. More on this at the bottom of our conclusion.

Tasks in the body

Officially, it is said that Boron is not necessary for human health, so it is not essential. In alternative medicine, however, it is regarded as a micronutrient that performs many extremely important tasks in the human body (1). For example, the substance is important:

• For bone health (bone formation and regeneration)
• For wound healing
• For the formation of sex hormones (it increases testosterone levels in men and estrogen levels in postmenopausal women)
• For the activation of vitamin D
• For the absorption of calcium and magnesium
• Because Boron has anti-inflammatory effects, it can relieve pain in joint discomfort (osteoarthritis and arthritis), but it can also improve brain functions.
• The trace element even has anti-cancer properties.

What fact-checkers and consumer advice centres say

It is often said (e.g. by the consumer centres or the so-called fact checkers) that the corresponding studies with Boron are carried out in vitro (in a test tube) or with animals so that the effects cannot be transferred to humans. The studies were also carried out with very high doses, which could not be used in humans as they would be harmful.

We therefore present below (where available) in particular clinical studies, i.e. with humans and only those with the usual dosages. In reality, it has been shown that the substance is sufficiently effective in perfectly harmless doses of 3 to 10 mg.

For the bones

Boron has long been considered an important trace element for bone health in naturopathy and is therefore used in the treatment of osteoporosis (2). The substance could be one of the decisive reasons prunes are considered THE food for the bones. With 2.7 mg per 100 g, they are among the most boron-rich foods.

In studies from 2016, for example, the daily consumption of prunes prevented the bone loss that often occurs due to radiation therapies. In postmenopausal women, it was also shown in 2011 that the consumption of prunes increased bone density and reduced levels of osteoporosis. 

As early as 1985, a study of postmenopausal women took place, which showed that taking 3 mg of Boron daily for 28 days (as Borax) reduced the excretion of calcium in the urine by 44 percent, which means that the body now has more calcium available for incorporation into the bones (9).

Magnesium is at least as important for bones as calcium. This is because magnesium is a cofactor for certain enzymes of calcium metabolism in the bones. Therefore, 60 percent of our body’s total magnesium is found in the bones. However, magnesium is also involved in the supply of energy for the cell, so sufficient magnesium must be provided, especially in the case of a chronic disease such as osteoporosis.

Boron now reduces (as with calcium) the excretion of magnesium and improves its absorption from the intestine and incorporation into the bones. In addition, the trace element inhibits the breakdown of estrogen, thus increasing estrogen levels in postmenopausal women and can also protect against osteoporosis in this way. This is because estrogen levels, which typically decline during menopause, are an important cause of bone loss. Estrogens stabilize the bone and prevent the decrease in bone density (1) (3).

Of course, vitamin D is also essential for good bone health. Even here, Boron is active and improves the effect of vitamin D. In animals suffering from vitamin D deficiency, supplementation with the trace element stimulates bone growth and even alleviates the dysfunctions associated with vitamin D deficiency (4).

Further animal studies (2008 and 2009) showed that bone healing was significantly inhibited in a deficiency, which was not the case with a good boron supply. This is because the element promotes the activity and proliferation of osteoblasts (bone-forming cells) and activates the mineralization of the bone, as it is involved, among other things, in the regulation of the corresponding genes as well as the hormones important for bone formation (estrogen, testosterone, vitamin D) (5) (6) (7) (11) (12) (14) (15) (16) (17) (18).

As an anti-inflammatory

It has long been known that chronic inflammation is present in almost every health problem. They contribute to the development of the respective disease, promote its progression and prevent healing processes. A well-known measure of inflammatory processes is, for example, the CRP value.

It is associated with an increased risk of breast cancer, arteriosclerosis, type 2 diabetes (insulin resistance), fatty liver, prostate cancer, lung cancer, depression, coronary heart disease, stroke, osteoarthritis, rheumatism and obesity. Anti-inflammation is, therefore, at the heart of almost every therapy.

Boron could be an effective comrade-in-arms here because the element lowers the levels of typical inflammatory markers, such as CRP or TNF-alpha (20) (32) (33). The latter is a pro-inflammatory messenger substance that stimulates the formation of cartilage-degrading enzymes and causes painful inflammation in the joints. Our article on the holistic therapy of osteoarthritis describes further natural ways to reduce the increased inflammatory markers in osteoarthritis.

In a small 2011 study with 8 male volunteers, CRP and TNF-alpha levels were significantly reduced with Boron. After a week of taking 10 mg daily (in the form of Borax, i.e. sodium borate), TNF-alpha levels had dropped by 20 percent, CRP levels by about 50 percent, and IL-6 (interleukin-6, another inflammatory messenger) had also dropped by almost 50 percent (20).

For osteoarthritis and arthritis

Especially in the case of joint complaints such as osteoarthritis or arthritis (rheumatism), anti-inflammation is the be-all and end-all. As early as 2012, an article by Walter Last, biochemist, nutritionist, nature therapist and author, appeared in Nexus magazine on Boron. The headline was “The Borax Conspiracy – The End of Osteoarthritis Cure”. The text explains how well the trace element affects the bones and joints and how the borax ban prevents natural osteoarthritis therapy.

Numerous studies – whether epidemiological studies, case reports or controlled animal and human studies – indicate that Boron could be a safe and effective tool in treating osteoarthritis (34) (35).

In 1990, for example, there was a double-blind clinical study with 20 osteoarthritis patients. 10 received 6 mg of Boron daily (25 mg borax) divided into two daily doses, and 10 received a placebo. After three weeks and after another five weeks, the participants were examined. The symptoms improved in 5 patients from the boron group, and the remaining 5 did not. There was only 1 patient improvement in the placebo group, so a clear difference between the two groups could be observed. There were no side effects (10).

It is also known that osteoarthritis occurs with a frequency of up to 70 percent in areas with a daily intake of trace elements of less than 3 mg. However, where 3 to 10 mg of the element is ingested daily, osteoarthritis is almost non-existent or only with an incidence of no more than 10 percent.

The importance of Boron for bones and joints is also indicated by the fact that the concentration of the element in the bones and synovial fluid is lower in osteoarthritis patients than in people without osteoarthritis (37).

Human studies have also shown that the substance can significantly increase the activity of SOD in red blood cells. SOD stands for superoxide dismutase, an enzyme with antioxidant effects. Especially in the case of joint diseases, large amounts of harmful oxygen radicals are produced in the joint, which drive inflammation and the destruction of the joint. The SOD can neutralize the oxygen radicals and thus inhibit the progression of osteoarthritis and arthritis and improve the corresponding symptoms (38)

For this reason, since the 1980s, there have been indications of the good effect of SOD injections directly into the joint, as can be read in the book Superoxide Dismutase as a Therapeutic Agent – Experiences and Perspectives of Flohé and Wilsmann. A case report was also published in 2011, in which a 64-year-old plastic surgeon who had suffered from progressive finger polyarthritis for several years injected 1.2 mg of SOD into the most severely affected joint for 6 weeks and noticed enormous improvements in his condition. The pain subsided, and mobility also improved significantly.

More estrogen for women, more testosterone for men

When Boron is ingested, the levels of sex hormones increase in both men and women (1) (20). If women (after menopause) who had previously eaten very little in Boron were given the trace element, then their estrogen and testosterone levels increased significantly (after 7 weeks). In some cases, the estrogen level even doubled. Women who already receive estrogens via hormone replacement therapy should, therefore, not take additional boron-containing preparations, as otherwise, the risk of cancer could increase if estrogen levels rise too much.

In a 2010 study, the level of free testosterone in men increased from 11.83 pg/ml to 15.18 pg/ml after only 1 week after supplementation of 6 mg boron daily, so a corresponding dietary supplement is considered particularly interesting for older men, as it is precisely in these men that the levels of free testosterone often drop (28).

At the same time, in this study, men’s estrogen levels fell from 42.33 pg/ml to 25.81 pg/ml. Several inflammation levels also fell, such as IL-6 (by almost half), CRP (by about half) and TNF-alpha (by about 30 percent). This study points out that even if Boron is not an essential substance for humans, it can be used as a helpful bioactive element.

However, since studies have shown no effects on hormone levels, the usual holistic point of view applies: Complaints have different causes for each person. The trace element may improve hormone levels in those whose hormone irregularities were partly caused by a corresponding deficiency. If, on the other hand, other causes predominate, taking the trace element may have no effect.

What in the case of estrogen dominance?

If Boron could increase estrogen levels, the question often arises as to whether the trace element could not be taken in hormone-dependent breast cancer under anti-hormone therapy or in estrogen dominance. In these or similar cases, we recommend taking the substance through the diet, i.e., no additional dietary supplements.

However, it is more likely to be regulated that Boron does not increase estrogen levels excessively, but rather – which is particularly helpful during menopause – prevents it from dropping too quickly. But as I said, to be safe, we would not take the trace element in isolated form in the cases mentioned above, especially since plenty of it can also be absorbed through a plant-based diet.

How Boron helps prevent vitamin D deficiency

Vitamin D is an important vitamin that is ideally formed in the skin with the help of sunlight. Since vitamin D is important for bone health, the immune system, and many other bodily functions, a deficiency should be avoided at all costs.

It is known that vitamin D needs other vital substances to work well, such as magnesium. Apparently, Boron is also one of the helpers of vitamin D. This is because it can raise vitamin D levels and increase the bioavailability and also the half-life of vitamin D, among other things by inhibiting an enzyme that would break down vitamin D. In a clinical study of middle-aged men and women, giving them Borax 3 mg daily for 49 days, they were able to increase vitamin D levels by 39 percent (25).

In another study, people who were vitamin D deficient were given 6 mg of calcium fructoborate, a boron compound naturally found in fruit, daily for 60 days (26). Thanks to taking the supplement, vitamin D levels rose by as much as 20 percent (27).

Ointment for atopic dermatitis and psoriasis

Since 2016, there has been an ointment in the USA with a boron-containing compound that can be used for neurodermatitis and psoriasis. The active ingredient is called crisaborole and inhibits the release of inflammatory messenger substances, leading to skin lesions’ healing. The ointment is considered an alternative (especially in children) to creams containing cortisone, which damages the skin (makes the skin thinner) when used for a long time, and as an alternative to the so-called calcineurin inhibitors (active ingredient tacrolimus), which in turn are associated with a certain risk of lymph node cancer.

In two studies, the prescription ointment was able to heal atopic dermatitis in more than 30 percent of the subjects after 4 weeks of use (twice a day). In 15 percent of the participants, the skin had healed after only 8 days. As a side effect, “only” pain and burning on the skin were reported. In Europe, the ointment (Staquis®) was only approved in 2020 (for adults and children aged 2 years and older with mild to moderate atopic dermatitis if it affects up to 40% of the body surface area).

Foods with Boron

In the following, we list some selected foods and their boron contents as examples, whereby prunes (also called dried plums) top the list. For example, you can make a delicious raw vegetable jam from the plums. Of course, you can eat them out of your hand or soak them overnight and add them to your muesli or fruit salad in the morning. But remember: prunes have a laxative effect due to their high sorbitol content, among other things, and can cause flatulence, so slowly get used to eating prunes or switch to alternatives, such as sultanas!

• Dried plums: 2.7 mg boron per 100g
• Raisins/sultanas: 2.5 mg
• Dates: 0.92 mg
• Almonds: 2.3 mg
• Peanuts: 1.8 mg
• Hazelnuts: 1.6 mg
• Avocados: 1.4 mg
• Apples with skin: 0.27 mg
• Broccoli: 0.18 mg
• White bread: 0.02 mg
• Vittel: 0.04 mg/l

Meat and dairy products contain almost no trace elements. Since the contents in mineral water can fluctuate greatly, it is best to ask the appropriate source/your favorite water for the corresponding values by e-mail or telephone. Some waters can also contain well over 1 mg of Boron per litre so that mineral water could serve as a trace element source.

Is the sale of Borax banned?

If you want to take Boron as a dietary supplement, you will always come across the hint that its sale is prohibited. As a loose powder, Borax may no longer be sold for ingestion. Directive 2008/58/E.C. of 21 August 2008 gave the powder the hazard symbol for toxic and classified it as carcinogenic, mutagenic and reprotoxic substances of categories 1 and 2, respectively.

Therefore, providers declare it with the note “for technical purposes”. Since the powder can easily be overdosed and – especially with inexpensive products – the quality is uncertain, we recommend capsules that contain a maximum of 3 mg of Boron per capsule. So the sale is not prohibited.

Possible side effect

When discussing Boron’s side effects, it is always said that it would hurt reproductive function in particular. However, there are no indications from human studies. Therefore, only animal experiments are used as alleged evidence. In these experiments, however, extremely high doses were used, which a person does not even achieve if he takes a dietary supplement (with 3 to 10 mg of Boron).

For example, in a rat study (which had shown a negative effect on sperm), it was 26 mg of Boron per kilogram of body weight. In another animal study with pregnant rats, 13.3 mg per kilogram of body weight was used, which caused damage to the embryo. Converted to a person weighing 65 kilograms, one would have to consume between 139 and 273 mg of the trace element daily at these dosages (equivalent to 2.15 to 4.2 mg/kg body weight (47) in humans, which corresponds to 46 to 91 times the amount of those doses (3 mg) found in many boron supplements.

However, when looking at the fertility of male employees in borax mining in different countries, no negative effects on the fertility of these men could be seen – and this was where their exposure was 1.8 mg per kilogram of body weight, which would amount to 144 mg of Boron for an 80-kilogram man. This is 48 times the amount of dosage contained in dietary supplements.

Other experts with experience with the corresponding dietary supplements (e.g. Uwe Gröber in the Journal of Orthomolecular Medicine) write: No side effects are known in the dosage range between 3 and 15 mg daily.

How toxic is the trace element?

They say that 1 to 3 g of a boron compound per kilogram of body weight could be fatal. So, if you weigh 60 kilograms, you can poison yourself with just 100 g of Borax. But who consumes such an amount? The usual intake is 3 mg, at most 10 mg. Therefore, one often reads that poisoning can occur through continuous intake. This is because the substance accumulates in the body and is only slowly excreted via the kidneys. Over time, symptoms of poisoning would then occur. How unlikely these are, you can read in the next section.

Possible symptoms of poisoning

Of course, anyone who overdoses on Boron must expect symptoms of poisoning. But the same thing happens when you overdose on other substances. Overdoses are always a problem, no matter what the substance is. That’s why the word is called OVERDOSE. So it’s TOO MUCH. If you want to take the trace element now, then you dose it in the RIGHT dose, i.e. 3 mg in capsule form per day, or you eat differently (plant-based) in the future.

An overdose can cause headaches, diarrhea, fatigue, cramps, skin inflammation, menstrual irregularities, hair loss, circulatory collapse, edema, epilepsy, confusion and much more. For these symptoms to appear, you must consume 2 to 5 g of boric acid or 3 to 6.5 g of Borax daily for months. The amount of Borax is higher since the boron content here is only around 11 percent, while it is around 17 percent in boric acid.

The maximum intake levels

According to ECETOC (European Centre for Ecotoxicology and Toxicology of Chemicals), 19.2 mg of Boron per day is safe for a person weighing 60 kg.

The EFSA (European Food Safety Authority) advises not to exceed a maximum amount (from food supplements and food) of 10 mg (in adults). It specifies the following amounts of Boron as the maximum daily intake for each age group (24):

• 1 to 3 years: 3 mg
• 4 to 6 years: 4 mg
• 7 to 10 years: 5 mg
• 11 to 14 years: 7 mg
• 15 to 17 years: 9 mg
• Adults (including pregnant and breastfeeding women): 10 mg

The WHO takes a more relaxed view. It states that the safe intake for adults is estimated to be 1 to 13 mg daily (21).

In the U.S., the highest safe dose is a maximum of 20 mg (1). Again, these amounts refer to the added amounts from food and dietary supplements. You can see from the figures of most authorities that panicking about an overdose is unnecessary.

Conclusion: Should you take Boron or not?

So what to do now? Should you take Boron or not? First, consider the section above: “Who should not take the trace element”. Apart from that, given all the available data, studies and warnings (against overdoses), the suspicion is that the substance is particularly helpful if you have yet to consume enough of it.

Therefore, if you already eat plant-based, i.e. lots of vegetables, nuts and regularly dried plums daily, you are most likely well supplied with the trace element.

Suppose you eat differently and have chronic complaints. In that case, a change in diet is worthwhile – not only because of the possibly increased boron content but also because of the many other advantages of a plant-based diet (vitamins, minerals, antioxidants, plant substances, bitter substances, fibre, etc.). Our recipies will help you make the transition!

In this case, you could eat more prunes (if you can tolerate them) or test a dietary supplement (3 to 10 mg of Boron per day). You should be able to see an effect within four to six weeks.

However, discontinue the preparation repeatedly to see whether the healing effect of your new diet may make a corresponding dietary supplement redundant in the meantime. Be sure to think about other important measures in treating chronic diseases! Because Boron is certainly not THE panacea!

If you already eat plant-based food and still suffer from a chronic disease for which the substance could prove helpful, you could start a trial with an appropriate dietary supplement (3 mg per day).

But first of all, think about possible other causes of your complaints. Because here, too, a boron deficiency alone will not be the problem.