There’s nothing boring about boron – why 3mg of boron should be in multivitamins and some could take 6-10mg

 

Contents of a common multivitamin for adults

I wrote this post a while back and, the more I think about it, the more I see boron as a potentially useful autism therapy. It is safe, OTC, very cheap and has several mechanisms that should be beneficial. Notably, it reduces inflammation (CRP can fall as much as 50% in 10 days) and it increases estrogen receptor beta signaling (relevant to the brain and bones); both these factors are very relevant in severe autism. It has no effect on estrogen receptor alpha, so avoids the side effects of phytoestrogens and estradiol. I started taking it myself.

Believe it or not, even with a strange subject like boron, there is an autism angle.

I originally stumbled upon boron while researching bone metabolism. I expected it to be relevant only for bones and joint pain. Instead, I was surprised by the sheer breadth of its biological effects: inflammation, hormones, detoxification, memory, immunity, even cancer risk.

Boron is one of those nutrients that no one thinks about because it has not yet been officially classified as essential for humans. That means:

·         No recommended daily intake

·         Almost no multivitamin includes it

·         Most people are taking in less than 1 mg/day through diet

And yet clinically meaningful benefits only begin at least 3 mg/day.

This is especially relevant to people with restricted diets. Many autistic individuals eat the infamous “beige diet” of pasta, bread, chips/crisps, and nuggets. Telling them that avocados contain boron or that leafy greens contain manganese goes nowhere.

Even Monty, now 22, who eats very well, does not reach 3 mg/day of boron from food. He would need to drink half a bottle of high-boron Pinot Noir a day to get close!  

This post has some of the science at the back as non-essential reading.

If you are male, make sure to read the part about male hormones. It looks like a potentially good way to avoid benign prostate enlargement as you age. Prostate size was reduced by about 35% in those with high boron in their drinking water. Not surprisingly, this potential therapy has not been seriously followed up.

If you are female take a note of the female hormone effects.

 

What Boron Actually Does

From the open-access paper Nothing Boring About Boron just click on it to read the full paper

Boron influences multiple systems simultaneously. Benefits documented at 3+ mg/day include:

1. Bone health

·  Essential for bone growth and mineralization

·  Improves calcium and magnesium use

·  Synergistic with vitamin D and estrogen

2. Collagen health (Joints, bone matrix, intervertebral discs, eyes etc)

Remarkably, studies show that adults with a high boron intake seem protected from getting osteoarthritis in later life. Boron is even therapeutic in people who already have this type of arthritis. 

·   Boron improves collagen cross-linking, making fibres stronger, more elastic, and more resistant to breakdown.

·   Enhances vitamin D and magnesium biochemistry, both required for hydroxylating proline/lysine — the two amino acids that give collagen structural strength.

·   Reduces collagen-degrading enzymes (MMP-2 and MMP-9), protecting connective tissue from inflammatory destruction.

·   Boosts bone collagen quality, improving bone strength independently of calcium intake.

·   Supports joint cartilage and reduces arthritis symptoms, likely via improved collagen structure and reduced inflammation.

·   May slow collagen degeneration in the vitreous, explaining why boron sometimes helps with eye floaters.

3. Hormone regulation

·  Increases free testosterone in men

·  Normalizes estrogen metabolism in women

·  Enhances vitamin D activation

·  Reduces SHBG (sex hormone–binding globulin)

4. Anti-inflammatory effects

·  Reduces CRP, TNF-α, IL-6

·  Lowers oxidative stress

·  Raises glutathione peroxidase, catalase, and SOD

5. Detoxification

·   Reduces toxicity of heavy metals

·    Mitigates pesticide-induced oxidative stress

·    Improves cell membrane stability

6. Brain health

·    Improves electrical activity in the brain

·    Enhances short-term memory

·    Supports NAD⁺ and SAM-e pathways

·    Has neuroprotective properties

7. Anti-cancer activity

·     Signals against prostate, breast, lung cancer

·     Reduces tumor growth in models

·     Enhances chemotherapy efficacy

·     Protects normal tissue from chemo damage

Across dozens of studies these effects do not appear at <3 mg/day.

Safety is extremely high, with an upper limit of 20 mg/day for adults.

Boron and Autism — Small Study, Big Signal

A 2024 study examined boron in a rat autism model induced by propionic acid (PPA). 

Effects of Boron on Learning and Behavioral Disorders in Rat Autism Model Induced by Intracerebroventricular Propionic Acid

This model replicates:

·   neuroinflammation

·   microglial activation

·   elevated cytokines

·   reduced Purkinje cells

·   learning/social behaviour deficits

·   increased BDNF (a maladaptive elevation)

What 4 mg/kg boron (boric acid) did:

• improved learning and social interaction
• significantly lowered TNF-α, IL-6, IL-1β
• reduced microglial & astrocyte activation
• restored Purkinje cell numbers
• normalised BDNF
• provided broad neuroprotection

This lines up with boron’s known biology:

• anti-inflammatory
• antioxidant
• mitochondrial support
• hormone modulation
• detoxification
• microglial regulation

This does not mean boron is a cure for autism, but it clearly has biological relevance.

Given the low cost, excellent safety, and widespread deficiency, 3+ mg/day makes sense for most people, especially those with restrictive diets or systemic inflammation.

Boron and Hormones — Very Interesting Male vs Female Effects

Boron’s effect on hormones is surprisingly strong and well documented. This is where things get very interesting because the effects differ between men and women.

In Men: Free Testosterone Booster

Studies show that 6 mg/day of boron for 1 week:

• ↑ free testosterone by 25%
• ↓ estradiol by 50%
• ↓ SHBG (sex hormone-binding globulin)
• ↓ inflammatory markers (CRP dropped by 60%)

Why does this matter?

Reduced SHBG means more biologically active testosterone. This is not like taking steroids; it is allowing your existing testosterone to circulate freely.

Results seen:

• increased libido
• improved mood
• better energy
• increased muscle response to training
• reduced inflammation
• possibly lower prostate cancer risk 

There was a Turkish observational study (from the 1990s, often cited in boron research summaries) looking at a village with very high natural boron levels in soil and drinking water.

Men in this village consumed boron intakes around 6–30 mg/day (far above typical Western intake of 1 mg/day).

Compared with men from nearby normal-boron areas, they had:

·         Significantly smaller prostate volumes

·         Lower PSA levels

·         Lower rates of prostate enlargement (BPH)

No increase in adverse effects was detected in these high-boron consumers.

Boron has several effects relevant to prostate size:

·         Lowers inflammation (↓ NF-κB, ↓ cytokines)

·         Improves androgen–estrogen balance

·         Mild increase in free testosterone

·         Mild decrease in estradiol

This combination tends to lead to smaller prostates and lower PSA, especially in older men.

Does This Apply to Supplement Use?

Probably, but not to the same magnitude unless the dosage is comparable.

BORON SUPPLEMENT EFFECTS:

3 mg/day → measurable anti-inflammatory and hormonal effects

6–10 mg/day → stronger hormonal shift

10–12 mg/day → studied in athletes for testosterone effects

Does this explain why boron helps older men?

Yes. Older men typically develop:

·         Low free testosterone

·         Higher estradiol

·         Chronic prostate inflammation

Boron improves those three issues at once.

 

In Women: Estrogen Metabolism & Menopause Support

Boron helps women balance estrogen in a very different way:

·         increases estrogen when estrogen is too low

·         reduces “bad” estrogen metabolites (16α-hydroxyestrone)

·         increases “good” metabolites (2-hydroxyestrone)

·         improves response to vitamin D

·         reduces menstrual pain

·         supports bone density after menopause

In post-menopausal women:

·         urine calcium loss drops dramatically

·         vitamin D activation improves

·         bone turnover markers improve

Women deficient in magnesium or vitamin D benefit especially.

Why the Sex Difference?

Boron seems to act primarily by:

·    lowering SHBG (men see a larger effect), Sex Hormone–Binding Globulin is a protein made in the liver that binds tightly to sex hormones, mainly Testosterone, Dihydrotestosterone (DHT) and Estradiol

·    shifting estrogen metabolites (women see a larger effect)

·    enhancing vitamin D activation (beneficial for all)

·    reducing inflammation (universally helpful)

This dual effect is rare—few minerals have male/female divergence.

Boron-Rich Foods and Typical Intake Levels

Food	Boron (mg per 100 g)	Notes
Avocado	2.1 mg	One of the richest natural sources
Raisins	2.5 mg	Dried fruit is consistently high
Prunes	1.9 mg	Very dense source
Almonds	2.8 mg	Nuts are excellent
Hazelnuts	2.7 mg	Similar to almonds
Peanuts	1.4 mg	Lower but common
Peanut butter	1.9 mg	Higher concentration
Beans (various)	0.5–1.5 mg	Good but variable
Chickpeas	0.7 mg	Decent source
Lentils	0.7 mg	Regular intake helps
Dates	1.1 mg	Very effective
Red wine	0.5–0.7 mg per glass	Grapes are boron-rich
Apples	0.3 mg	Everyday source
Pears	0.4 mg	Another fruit source
Vegetables (general)	0.1–0.6 mg	Depends on soil content

Typical Daily Intake From Diet

·         Developed countries average 0.8–1.4 mg/day

·         Mediterranean diet: 2–3 mg/day

·         Vegan diets: 3–6 mg/day (high fruit/nut consumption)

Nearly all Western omnivorous diets fall below the 3 mg/day threshold associated with documented benefits.

Conlusion

Boron is one of the few nutrients where:

·         the safety is high

·         the benefits are large

·         the deficiency is common

·         the cost is trivial

And because modern diets (and nearly all multivitamins) provide little to none, 3 mg/day is a simple, evidence-based upgrade for anyone—especially those with osteopenia, inflammation, hormonal imbalance, or restrictive diets such as those often seen in autism.

Higher doses like 10mg would seem appropriate for specific groups that are likely to benefit from the effects described in this post.

How much boron did they give the rats with autism?

One thing you very quickly learn when reading animal studies is that the dose used in rats is almost always huge. The same is true in the recent study looking at boron in a propionic-acid model of autism. On paper, the researchers used “2 mg/kg and 4 mg/kg of boric acid.” That sounds modest, rats are small.

In toxicology, a rat “mg/kg” is not the same as a human “mg/kg.” Rats have a much faster metabolism, and their surface-area-to-body-weight ratio is different. If you dose a human the same way you dose a rat, you will rapidly enter “please call poison control” territory.

To make sense of rodent studies, you have to convert the dose using the FDA’s body-surface-area formula. When you do that, the “4 mg/kg” rat dose becomes roughly the human equivalent of:

45 mg/day of boric acid

which equals 7–8 mg of elemental boron, a dose that’s above normal diet but within the range of commercially available supplements.

But, that is a conservative conversion. There are other conversion models that give an equivalent human dose much higher, in the 35-80 mg/day range.

In reality, nobody knows the human dose that would give the same benefits as found in the rat study. Those rats with autism were essentially on very high pharmacological boron, not the gentle nutritional 3 mg/day found in health-food circles.

No wonder the effects were dramatic:

·         inflammation markers (IL-6, IL-1β, TNF-α) crashed

·         microglia and astrocytes calmed down

·         Purkinje cell loss reversed

·         learning and social behaviours improved

All good news — just not at “one avocado per day” boron levels.This is the same situation as resveratrol, curcumin, sulforaphane, luteolin, quercetin, and a dozen other compounds: the rodent study shows us mechanism and potential, but not a directly usable human dose. Still, what is remarkable is that even at low human doses (3–10 mg/day), boron does show measurable changes in humans: reduced inflammation, altered SHBG, higher free testosterone, better vitamin D handling, and nicer bone and joint metabolism.

So the take-home message is that the autism rat study used a boron dose equivalent to well above what humans safely take as a supplement — but it confirms that boron is a potent anti-inflammatory and neuroprotective micronutrient, and that even low doses may be biologically meaningful.

Perfectly reasonable to include boron in a multivitamin. It would save people a lot of bother.

Not reasonable to copy rat dosing, unless you happen to be a rat!