Boron Benefits: Vitamin D, Hormones, Dosage and Food Sources

Boron is a trace mineral found in fruits, vegetables, nuts and legumes that helps the body use vitamin D, magnesium, estrogen and testosterone. Most people get about 1 mg a day from food, and a review of the research found boron's benefits at intakes of about 3 mg a day. This guide covers what boron does, what human studies show, food sources, how much to take and the safe upper limit.

It is educational, not medical advice.

Key Takeaways

• A vitamin D and magnesium helper: boron affects how the body uses vitamin D, estrogen and testosterone, and it boosts magnesium absorption.
• Low intake: diets low in boron were linked to lower blood calcium and lower vitamin D (25-hydroxyvitamin D) levels.
• Hormones and inflammation: in healthy men, 10 mg a day for one week raised free testosterone and vitamin D and lowered CRP and TNF-alpha, two inflammation markers.
• Dose: about 3 mg a day matches the research; the adult upper limit is 20 mg a day from all sources.
• Food first: prune juice, avocado, raisins, nuts and beans are among the best sources.

What Is Boron?

Boron is a trace element that occurs naturally in many foods and in supplements, often as boron glycinate, boron citrate or calcium fructoborate. Plant foods contain the most. There is no official daily requirement (RDA) for boron, but there is a Tolerable Upper Intake Level of 20 mg a day for adults (NIH Office of Dietary Supplements).

Boron Benefits: What the Research Shows

Vitamin D, magnesium and bones

A 2015 review describes boron as important for growing and maintaining bone, for the body's use of vitamin D, estrogen and testosterone, and for boosting magnesium absorption (Pizzorno 2015). In human diet studies, low boron intake appeared to reduce plasma calcium and serum 25-hydroxyvitamin D, the vitamin D level your doctor measures (NIH ODS). That is why boron is often grouped with magnesium and zinc as a vitamin D cofactor; see Vitamin D and Magnesium: Can You Take Them Together?

Testosterone, estrogen and inflammation

In eight healthy men, a single 10 mg boron capsule lowered sex hormone binding globulin, CRP and TNF-alpha within six hours. After a week of 10 mg a day, free testosterone rose, estradiol fell, and vitamin D and dihydrotestosterone rose, while all three inflammation markers were lower (Naghii 2011). In women after menopause, low-boron diets may lower estrogen levels (NIH ODS). For more on hormones, see Supplements to Support Testosterone.

In a 7-week placebo-controlled trial in 19 male bodybuilders, 2.5 mg of boron a day raised plasma boron in some participants but did not change testosterone, lean body mass or strength compared with placebo (Green and Ferrando, 1994).

Joint comfort

In one trial of 60 adults with self-reported knee discomfort, 6 mg of boron a day as calcium fructoborate for two weeks significantly reduced knee discomfort (NIH ODS).

Antioxidant and brain effects

The same review summarizes studies in which boron raised antioxidant enzymes such as superoxide dismutase and glutathione peroxidase, and improved the brain's electrical activity, cognitive performance and short-term memory in older adults (Pizzorno 2015).

Food Sources of Boron

Plant foods, especially fruit, tubers and legumes, contain the most boron. In US diets, coffee, milk, apples and beans supply much of it, and median adult intake is about 0.9 to 1.4 mg a day (NIH ODS).

Food	Boron per serving
Prune juice, 1 cup	1.43 mg
Avocado, raw, half cup	1.07 mg
Raisins, 1.5 ounces	0.95 mg
Peach, 1 medium	0.80 mg
Apple, 1 medium	0.66 mg
Peanuts, roasted, 1 ounce	0.48 mg

Serving sizes and amounts from the NIH Office of Dietary Supplements.

How Much Boron to Take

A 2015 review noted that boron's benefits in the studies it covered did not appear at intakes above 3 mg a day, and it supported 3 mg a day for people whose diets are low in fruits and vegetables (Pizzorno 2015). The adult upper limit is 20 mg a day from food and supplements combined, and 17 mg for pregnant or breastfeeding teens aged 14 to 18 (NIH ODS).

For zinc amounts by age and the 40 mg adult upper limit, see how much zinc per day.

Boron Supplement Forms: Glycinate vs Citrate and Others

Boron supplements come in many forms, including sodium borate, sodium tetraborate, boron amino acid chelate, boron aspartate, boron citrate, boron gluconate, boron glycinate, boron picolinate and calcium fructoborate. Common supplements provide 0.15 to 6 mg of elemental boron per serving (NIH ODS).

Boron glycinate and boron citrate are both boron bound to a carrier: glycine, an amino acid, in glycinate, and citric acid in citrate. The body absorbs about 85% to 90% of the boron you swallow, and most of it is turned into boric acid in the gut. No studies have compared how well the different forms are absorbed, so the amount of elemental boron on the label matters more than the form (NIH ODS).

How to Choose a Boron Supplement

• Elemental boron per serving: about 3 mg matches the research.
• Your total: add up boron from every product, including multivitamins and mineral blends, and stay under 20 mg a day.
• Form: glycinate, citrate or another form; choose by dose, price and the rest of the label.
• Labeling: every ingredient listed with its own amount, and third-party tested ingredients.

Boron Side Effects and Safety

At supplement doses, boron is not known to have clinically relevant interactions with medications. Very large accidental exposures to boric acid or borax, far beyond supplement amounts, cause nausea, vomiting, diarrhea and skin flushing (NIH ODS). Stay under 20 mg a day in total, and talk to a clinician first if you have kidney disease, a hormone-sensitive condition, or are pregnant or breastfeeding.

Boron Side Effects: What People Ask

The short answer is reassuring. Boron is part of everyday food: most American adults get about 0.87 to 1.35 mg a day from their diet. The body keeps blood levels fairly steady by clearing extra boron in the urine, and boron is not known to have any clinically relevant interactions with medications (NIH ODS).

• Is 3 mg a day safe? Yes for healthy adults. It is well under the 20 mg adult upper limit, and 3 mg a day is the amount a 2015 review supported for people who eat few fruits and vegetables (Pizzorno 2015).
• Where does the upper limit come from? The 20 mg limit is based on reproductive and developmental effects seen at high intakes in animals (NIH ODS), which is why pregnancy is a time to ask first.
• What does too much look like? The cases described involve very large accidental exposures to boric acid or borax, far beyond any supplement, with nausea, vomiting and diarrhea.
• Who should ask first? Anyone with kidney disease, since the kidneys clear boron, anyone with a hormone-sensitive condition, and anyone pregnant or breastfeeding.

How to take boron comfortably

• Add up every label: boron turns up in multivitamins and mineral blends, so keep the total under 20 mg a day.
• Stay near the studied amount: about 3 mg a day.
• Pair it with the nutrients it works with: vitamin D and magnesium, covered below.

Our Vitamin D Cofactor Capsules are planned with boron 3 mg (as boron glycinate), magnesium 100 mg and zinc 10 mg per 2 capsules. They are coming soon; join the waitlist on the product page, and no payment is taken.

Boron With Vitamin D, K2 and Magnesium

Because boron affects how the body uses vitamin D and magnesium, it is often taken with them. For the full picture, read Vitamin D3 and K2: Benefits, How Much to Take and When, Magnesium Bisglycinate vs Glycinate, our vitamin D3 ingredient page and our zinc bisglycinate ingredient page, since zinc is the third common vitamin D cofactor. Our Vitamin D3 + K2 Drops pair vegan vitamin D3 with vitamin K2 as MK-4 and MK-7, one drop a day.

Coming soon from Synchronicity: our Vitamin D Cofactor Capsules give boron 3 mg with magnesium 100 mg and zinc 10 mg per 2 capsules, made to pair with our Vitamin D3 + K2 Drops. Join the waitlist on the product page to hear when they launch; no payment is taken.

For how magnesium and zinc fit together, with adult amounts and upper limits for both, see magnesium and zinc together.

Boron is one of several vitamin D cofactors; our guide to vitamin D cofactors covers magnesium, vitamin K2 and zinc as well, with upper limits for each. For boron taken with magnesium and zinc, see our guide to magnesium, zinc and boron.

Frequently Asked Questions

What does boron do in the body?

It helps the body use vitamin D, magnesium, estrogen and testosterone, supports bone, and is linked to lower inflammation markers.

What happens if you take boron every day?

In healthy men, 10 mg a day for a week raised free testosterone and vitamin D and lowered inflammation markers. Keep total intake under the 20 mg adult upper limit.

How much boron should I take?

About 3 mg a day matches the research. Most people already get about 1 mg from food.

What are the side effects of boron?

At supplement doses, side effects are not expected. Very large amounts, such as accidental borax or boric acid exposure, cause nausea, vomiting and diarrhea.

What should you not mix with boron?

Boron has no known clinically relevant medication interactions. Count every supplement that contains boron so the total stays under 20 mg a day.

Does boron help vitamin D?

Yes. Low boron intake was linked to lower vitamin D levels, and boron supplementation raised vitamin D in a small study of healthy men.

What foods are high in boron?

Prune juice, avocado, raisins, other fruit, nuts and beans.

Is boron glycinate or boron citrate better?

Neither has been shown to be better. The body absorbs most boron well, and no studies have compared the forms, so compare the elemental boron per serving instead.

What is a boron supplement used for?

People take boron to support how the body uses vitamin D, magnesium and hormones. A research review supported about 3 mg a day for people whose diets are low in fruit and vegetables.

Is boron safe to take every day?

For healthy adults, yes, at amounts like 3 mg a day. Keep the total from all sources under the 20 mg adult upper limit.

Is boron bad for your kidneys?

The kidneys are how the body clears boron, so healthy kidneys handle normal amounts. If you have kidney disease, ask your clinician before taking it.

How much boron do you get from food?

Most American adults get about 0.87 to 1.35 mg a day from their diet, mainly from fruits, vegetables, nuts and legumes.

Sources

• NIH Office of Dietary Supplements. Boron: Health Professional Fact Sheet. Updated June 2022. ods.od.nih.gov
• Pizzorno L. Nothing boring about boron. Integr Med (Encinitas). 2015. PubMed 26770156
• Naghii MR, and others. Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. J Trace Elem Med Biol. 2011. PubMed 21129941
• Green NR, Ferrando AA. Plasma boron and the effects of boron supplementation in males. Environ Health Perspect. 1994;102 Suppl 7:73-7. PubMed 7889885

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.