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Boron is a trace mineral found mostly in fruit, nuts, beans and drinks such as coffee, and most people get a little from food every day. Researchers think it may play a part in bone health, calcium and magnesium handling and steroid hormones, but the NIH Office of Dietary Supplements (ODS) notes that no clear biological function has been identified, so boron is not classed as an essential nutrient. The human studies behind popular boron benefits, including the testosterone claims, are small and short. There is an official upper limit for adults, and borax, the cleaning powder some social media videos suggest drinking, is a poison, not a supplement. Here is what the research shows.
Peptide Labs sells a supplement that lists boron among its ingredients, but this article does not recommend it. It is general information, not medical advice.
Key Takeaways
- Boron is a trace mineral in fruit, nuts, beans, coffee and milk; it has no RDA and no Daily Value.
- Possible roles in bone, mineral and hormone metabolism come mainly from small or animal studies.
- Human hormone studies on boron are tiny and short, and none show a meaningful health outcome.
- The NIH lists an upper limit of 20 milligrams a day for adults; children's limits are lower.
- Borax and boric acid are household chemicals. Swallowing them can cause poisoning; call Poison Help.
What is boron?
Boron is an element plants need to build cell walls, grow and set seed. In food it appears as borates and as sugar-borate compounds such as calcium fructoborate. Your gut absorbs most of the boron you eat, roughly 85% to 90%, and turns most of it into boric acid, which you then clear mainly through urine. Blood levels change little even when intake rises sharply, which suggests the body regulates it, although the ODS says the mechanism has not been identified. Doctors do not routinely test boron status.
Because the Food and Nutrition Board found too little evidence to set a Recommended Dietary Allowance or Adequate Intake, boron has no Daily Value. You will see the elemental boron amount on a Supplement Facts label, but no percentage beside it.
Where boron comes from in food
Plant foods carry the most. The ODS lists prune juice, avocado, raisins, peaches, grape juice, apples, pears and peanuts among the richest sources. In the US the biggest contributors are coffee, milk, apples, beans and potatoes, simply because people eat and drink so much of them. Median intake from food is about 0.9 to 1.4 milligrams a day for adults, and vegetarians tend to get more. Soil matters too: boron washes out of soil in rainy regions, so crops from drier areas can contain more.
Boron benefits: what the research shows
| Area | What was studied | What it means |
|---|---|---|
| Hormones | 12 postmenopausal women on a low-boron diet (1987); 8 healthy men for one week (2011) | Blood hormone changes only; tiny, short studies |
| Joint comfort | A few trials of 20 to 60 people, some lasting two weeks, mostly with calcium fructoborate | ODS says more controlled trials are needed |
| Bone | Animal studies; one 10-month trial in 28 young women | No direct effect on bone density seen |
| Brain function | Older studies of low-boron diets | Limited data; deficiency is not well defined |
Boron and hormones
Most interest in boron supplements comes from hormone claims. In a 1987 USDA study, 12 postmenopausal women lived in a research unit on a low-boron diet for 119 days before boron was added. Adding it reduced the calcium and magnesium they lost in urine and raised blood estradiol and testosterone. In a 2011 Iranian study, eight healthy men took boron daily for a week, and their average free testosterone rose while estradiol fell. There was no separate placebo group, and the study measured blood levels, not strength, energy or any health outcome. Neither study shows that a boron supplement does anything noticeable for people eating a normal diet.
Bones and joints
Animal studies suggest boron affects bone growth, but human data are thin. In a 10-month trial of 28 young women, boron shifted some blood mineral levels without directly changing bone mineral density, and an observational study of 134 Korean women found no link between boron intake and bone density. A handful of small trials in people with joint pain, several using calcium fructoborate for only two weeks, reported less discomfort or lower inflammation markers. One was neither blinded nor placebo controlled. The ODS calls the results promising but says confirmation from larger controlled trials is needed.
Boron often appears next to magnesium and calcium in bone formulas. Magnesium has much stronger evidence behind it as a nutrient; our magnesium timing guide explains how its forms and timing compare, and our zinc guide for another mineral where more is not better.
Boron side effects and the upper limit
There are no reports of harm from boron in ordinary food or water. The concern is concentrated boron. The Food and Nutrition Board set Tolerable Upper Intake Levels based on reproductive and developmental effects in animal studies. These are reference limits, not targets:
| Age | Upper limit per day (food and supplements) |
|---|---|
| Infants | None set; food, breast milk and formula only |
| 1 to 3 years | 3 milligrams |
| 4 to 8 years | 6 milligrams |
| 9 to 13 years | 11 milligrams |
| 14 to 18 years, including pregnancy | 17 milligrams |
| 19 and older, including pregnancy | 20 milligrams |
The ODS says boron is not known to have clinically relevant interactions with medications. Still, because the human research on supplements is so limited, people who are pregnant, breastfeeding, have kidney disease (the kidneys clear boron) or have a hormone-sensitive condition should ask a clinician before taking a boron supplement. Keep supplements away from children, who have much lower limits.
Why drinking borax is dangerous
In 2023, videos on TikTok and other platforms claimed that a pinch of borax in water could ease inflammation and joint pain. Poison centers pushed back quickly. A toxicologist at the National Capital Poison Center told NBC News that nothing supports using borax in humans for inflammation, and an epidemiologist at the Florida Poison Information Center said deaths linked to borax, while rare, have occurred. The confusion comes from the word boron: borax is sodium borate, a laundry booster and cleaning powder, not a dietary supplement.
- Short-term poisoning: the National Capital Poison Center says swallowing significant amounts of boric acid can cause nausea, vomiting, abdominal pain and diarrhea, and in severe cases kidney damage and seizures. MedlinePlus lists blue-green vomit, diarrhea and a bright red skin rash as hallmark signs.
- Repeated exposure: the poison center warns that long-term exposure to boric acid may harm the testes, the hormone system and a developing fetus. MedlinePlus notes that people repeatedly given boric acid on wounds in the past became ill, and some died.
- Skin soaks are not safe either: household products are not made for use on the body, and boric acid poisoning can cause skin to peel.
If someone has swallowed borax or boric acid, call Poison Help at 1-800-222-1222 right away, or 911 for seizures, collapse or trouble breathing. Do not wait for symptoms.
Boron supplement labels: what to check
Boron supplements come in many forms, including boron glycinate, boron citrate, sodium tetraborate and calcium fructoborate. The ODS notes there are no data comparing how well these forms are absorbed. A few practical checks:
- The label lists elemental boron, so you can add it to what you already get from food and other products.
- Look for boron hidden in multi-ingredient formulas. Triquetra Health GLP-Activate, for example, lists boron glycinate alongside berberine, green tea extract, Ceylon cinnamon and curcumin. The name references GLP-1, but it is a dietary supplement, not a GLP-1 medication, and its label advises asking a healthcare professional first if you are pregnant, nursing, take medication or have a medical condition.
- A testing seal confirms a label matches the contents, not that the product works; our guide to third-party tested supplements explains what each seal covers.
Boron is often marketed next to flavonoid supplements; our sibling guide to quercetin covers what that compound’s research shows.
Frequently Asked Questions
What are the main boron benefits?
Boron may play roles in bone, mineral and hormone metabolism, but human evidence is limited to small, short studies. The NIH does not class it as an essential nutrient.
Does boron raise testosterone?
One study of eight men found higher free testosterone after a week, and a study of 12 postmenopausal women found hormone changes. Both were tiny and measured blood levels, not health effects.
What are the side effects of boron?
No harm is reported from boron in food. Concentrated boron above the upper limit raised reproductive and developmental concerns in animal studies, and poisoning from borax or boric acid causes vomiting, diarrhea, rash, kidney damage and seizures.
Is it safe to drink borax?
No. Borax is a cleaning product, and poison centers warn against swallowing it. Call Poison Help at 1-800-222-1222 if someone has.
How much boron is too much?
The NIH lists an upper limit of 20 milligrams a day from all sources for adults, with lower limits for children and none set for infants. This is a ceiling, not a target.
Do I need a boron supplement?
There is no RDA, and most people get some boron from fruit, beans, nuts and coffee. Ask a clinician before adding one, especially if you are pregnant or have kidney disease.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Vitamin D3 K2: Why They Are Paired, What Studies Show and Who Should Be Careful, Zinc Supplement Guide: Benefits, Side Effects and Immune Facts, Best Time to Take Magnesium: Morning or Night and Medicine Timing.