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Supplements · Detox & Binders
Fulvic Acid: Benefits, Dangers, Dosage, Humic Acid & Shilajit
What fulvic acid is, how it differs from humic acid and shilajit, what the human studies show for allergies, gut bacteria and skin, how to take it as a gentle binder, and the purity and safety issues to know first.
Evidence-based43 sources citedUpdated October 20, 2026
The Dr. Axe Score™
Scientific Evidence
3.4/10
A few small fulvic acid trials, a larger drink trial that stopped early and one humic acid study with no comparison group.
Bioavailability & Absorption
3.6/10
The oral trial had no way to measure fulvic acid in the blood, so absorption was judged by its effect on an allergy skin test.
Clinical Effectiveness
4.6/10
Our judgment: a gentle, long-term binder and gut support in Dr. Axe's approach, with early human signals for the allergy response and gut bacteria.
Safety & Tolerability
5.2/10
Mild, short-lived side effects in trials; deductions for heavy metals in some products, thyroid effects in animals and its tie to a bone disease where it occurs in drinking water.
Why this score?
Why Fulvic Acid scores 4.1 / 10
Longer trials of a metal-tested product would raise it. Weighting: Evidence 30% · Bioavailability & Absorption 25% · Clinical Effectiveness 25% · Safety & Tolerability 20% (3.4×0.30 + 3.6×0.25 + 4.6×0.25 + 5.2×0.20 = 1.02 + 0.90 + 1.15 + 1.04 = 4.11, shown as 4.1). How we score
A transparent, weighted index built for supplements. See how it’s calculated →
Interaction check: Low. No drug interactions have been documented for fulvic acid. Like any binder, it can hold onto a medicine taken at the same time, so take it 2 hours apart from medications, including thyroid medication.7 Interactions are rated separately and don't change the score.
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View the protocol →Fulvic acid at a glance
Fulvic acid is the part of humic substances, the dark organic matter that forms as plants break down in soil, that dissolves in water at any pH, and it's one of the main active fractions of shilajit; I use it as a gentle binder for an ongoing detox, alongside high-dose probiotics.1234
- Allergies: in a placebo-controlled trial of 21 men who each tried both, a week of a lab-made fulvic acid shrank allergy skin-test bumps from 6.63 to 4.97 mm, against 7.03 to 6.73 mm on placebo5
- Gut: in a study of 14 healthy adults with no comparison group, humic acid capsules raised the concentration of gut bacteria in stool about 30% without changing their variety6
- How to take it: dilute liquids in water or juice, start low, and take it 2 hours apart from food, other supplements and medications57
- Before you start: choose a product with a published heavy-metal test, and skip it during pregnancy, while breastfeeding and for children89
Fulvic acid is part of humus, the dark organic matter that forms as plants and microbes break down in soil. It belongs to a family of compounds called humic substances, which give decaying leaves and rich topsoil much of their brown-to-black color.1 In supplements, it comes as liquid drops, capsules and powders, and it's one of the main active fractions of shilajit, the dark mineral resin prized in Ayurvedic medicine.102
I am a huge fan of humic and fulvic acid and ultra-high-dose probiotics. I think those are the best detoxifiers.Dr. Josh Axe, DC, DNM, CNSFrom She GAVE UP Her Medical License After This..., The Dr. Josh Axe Show (2025), at 25:46
The research has tested several different products, mainly a lab-made fulvic acid, humic acids and shilajit, and each study below names the one it used.
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Open the free protocol →Did you know?
About half of the dissolved organic matter in rivers is humic substances, the family fulvic acid belongs to.1
Humic substances hold onto minerals in soil and make them available to plants, one reason they matter so much to soil fertility.111
Shilajit, fulvic acid's best-known natural source, is found in almost 20 regions of the world, mainly the Himalayas.82
What is fulvic acid?
Quick answer
Fulvic acid is one of the three main fractions of humic substances, the organic matter that forms as plant and microbial remains decay in soil, water, peat and brown coal, and it's the fraction that stays dissolved in water at any pH.1 Supplements extract it from peat, lignite or shilajit, or make it in a lab from sugar.111012
Humic substances form through a slow process called humification, as plant lignin, the woody part of plants, breaks down along with sugars, proteins and fats.1 Chemists separate them into three fractions:
- Humic acids: They dissolve in alkaline water and drop out when the water is made strongly acidic.
- Fulvic acids: They stay dissolved even in strongly acidic water.
- Humin: It doesn't dissolve in either one.
The exact makeup of each fraction depends on the soil or deposit it came from, though their average properties are remarkably similar from source to source.1
One form used in research is made in a lab instead, by oxidizing table sugar with only oxygen and water; its developers designed it to avoid the variation and contaminants of materials taken from the ground.12
Fulvic acid vs. humic acid
Fulvic acid and humic acid come from the same decaying plant matter, and many supplements, and shilajit itself, carry both.1110
| Fulvic acid | Humic acid | |
|---|---|---|
In strongly acidic water | Stays dissolved1 | Drops out of the liquid1 |
Molecule size and color | Generally smaller and lighter in color13 | Generally larger and darker13 |
Human studies on this page | A lab-made fulvic acid: a week-long allergy trial by mouth and a 4-week eczema cream trial513 | Humic acid capsules: a 45-day study of gut bacteria6 |
What is fulvic acid good for?
Quick answer
Fulvic acid's best human result is a calmer allergy response: in a placebo-controlled trial of 21 men who each tried both, a week of a lab-made fulvic acid shrank allergy skin-test bumps more than placebo.5 A fulvic acid cream improved eczema ratings in a placebo-controlled trial of 36 people, humic acid capsules raised gut bacteria in 14 healthy adults in a study with no comparison group, and lab research shows humic substances binding heavy metals.1368
Where the research stands
Fulvic acid itself has been tested in a few human trials, most of them of a lab-made form: by mouth for a week in 21 men who each tried both it and a placebo, as a skin cream for 4 weeks in 36 people, and as a daily drink in 332 adults with HIV, each against a placebo.51314 The drink trial stopped early when India changed its rules for supplement trials.14 A smaller placebo-controlled skin trial tested another preparation, oxifulvic acid, in 23 people with allergies, and a study of humic acids followed 14 healthy adults with no comparison group; most of the rest is lab and animal work.156 Although the research so far is minimal, a 2018 review found substantial evidence to keep pursuing fulvic acid for preventing chronic inflammatory diseases, including diabetes.16
| Use | Evidence | What was studied | What the research shows |
|---|---|---|---|
Allergy response | Emerging | Lab-made fulvic acid by mouth; oxifulvic acid cream | Skin-test bumps shrank more than on placebo; the cream calmed skin reactions much as hydrocortisone did515 |
Gut bacteria | Emerging | Humic acid capsules | Gut bacteria concentration up about 30%6 |
Eczema | Emerging | 3.5% lab-made fulvic acid cream | Better overall improvement rating than the same cream without it: 1.77 vs. 2.94 on a 0-6 scale where 0 is clear13 |
Testosterone, muscle and bone | Emerging | Shilajit, rich in fulvic acid | Higher testosterone, faster fracture healing, better strength retention and bone density17181920 |
Heavy metals | Preclinical | Humic substances in shilajit | Bind and help detoxify around 12 heavy metals8 |
Brain | Preclinical | Fulvic acid | Blocked tau protein from clumping21 |
Fulvic acid benefits: what the research shows
Ranked by evidence, fulvic acid's human research points first to a calmer allergy response, then to gut bacteria and skin; its binding of heavy metals and its effects on the brain have been studied in the lab.
1
A calmer allergy response
Emerging evidenceHuman studyPlacebo-controlled trial · 30 men started, 21 finished · each tried bothIn a placebo-controlled trial, 30 men with allergies confirmed by skin-prick testing took 40 mL of a 3.8% lab-made fulvic acid twice a day for 1 week and a placebo for another week, with a week's break in between, so each man tried both. Neither the people nor the researchers knew who got what, and 21 finished. The bump raised by each man's strongest allergen shrank from 6.63 to 4.97 mm after fulvic acid, against 7.03 to 6.73 mm after placebo, and 81% had a smaller bump after fulvic acid, against 62% after placebo.5 In an earlier placebo-controlled trial of 23 people allergic to grass or house dust mites, a 4.5% cream of oxifulvic acid, another fulvic acid preparation, calmed the skin's reaction 15 minutes after an allergen injection, much as a 1% hydrocortisone cream did; each person tried each cream in turn, and neither the people nor the researchers knew which was which.15 For more ways to calm symptoms, see natural allergy relief.
Study takeaway: a week of a lab-made fulvic acid shrank allergy skin-test bumps more than placebo did.
After a week of fulvic acid, allergy skin-test bumps shrank more than on placebo
2
More gut bacteria
Emerging evidenceHuman studyHumic acids · 14 healthy adults · no comparison groupIn a study of 14 healthy adults aged 24 to 64, each person took humic acid capsules, 2,400 mg a day for 10 days and then 1,200 mg a day through day 45, and gave stool samples before and during the course; there was no comparison group. The total concentration of colon bacteria in their stool samples rose 20% by day 10, 30% by day 31 and 32% by day 45, and 24 of 35 major bacterial groups increased, while the variety of bacteria and each person's own bacterial profile stayed the same.6 This study tested humic acids, which come from the same plant matter as fulvic acid. As I've said on my show, humic and fulvic acid help detoxify and nourish your gut microbiome, and they're especially good in a probiotic supplement. Along with zinc and L-glutamine, they're among the top things you can do to heal your gut.22
Study takeaway: in a study with no comparison group, humic acid capsules raised the concentration of gut bacteria about 30% in a month.
Gut bacteria rose about 30% on humic acid capsules
3
Eczema relief on the skin
Emerging evidenceHuman studyPlacebo-controlled trial · 36 people aged 2 and older · skin creamIn a 4-week trial of 36 people aged 2 and older with eczema, one group applied a cream with 3.5% of a lab-made fulvic acid twice a day and the other group the same acidic cream without it; neither the people nor the researchers knew who got what. On a 0-to-6 scale where 0 means completely clear, the researchers' overall rating averaged 1.77 with the fulvic acid cream, close to "marked improvement," against 2.94, about "moderate improvement," with the same cream without it, and in both groups the researchers' redness and severity scores and the patients' own ratings of their eczema improved.13 In lab tests, the same lab-made fulvic acid killed Candida yeast, including yeast growing in protective biofilms, and in rats it helped infected wounds heal.2324
Study takeaway: a 3.5% fulvic acid cream earned better overall ratings in eczema than the same cream without it.
4
A gentle binder for detox
PreclinicalIn vitro (lab)2024 review of shilajit research, including the binding chemistry of its humic substancesHumic substances can grab onto metals, and a 2024 review found that the humic substances in shilajit bind and help detoxify around 12 heavy metals in lab and chemistry research.8 For an ongoing heavy metal detox, which is what I prefer, I use the gentle binders: spirulina and chlorella, apple or citrus pectin, zeolites, and humic and fulvic acid. They're much better for long-term use than activated charcoal, which is fine for a week or two in certain protocols but backs you up and binds to a lot of your nutrients and minerals.3 I support the body's own detox with glutathione alongside the binders.25
Study takeaway: the humic substances in shilajit bind heavy metals in lab and chemistry research.
5
Brain research in the lab
PreclinicalIn vitro (lab)Lab studyIn a lab study, fulvic acid kept tau protein from clumping into fibrils and broke apart fibrils that had already formed; tangles of tau are one of the hallmarks of Alzheimer's disease.21 The same research group has called for clinical trials of shilajit and its fulvic acid for the memory changes that come with aging.2
Study takeaway: fulvic acid kept tau protein from clumping in a lab study.
How does fulvic acid work?
Lab, animal and early human research on humic substances points to three actions: they bind metals, calm an overactive immune response and help the gut bacteria already there grow.826276
1Formed as plants break down
Humic substances form as plant and microbial remains decay in soil, water and peat, and fulvic acid is one of their three main fractions.1
2Binding: it grabs onto metals
In lab and chemistry research, the humic substances in shilajit bind heavy metals.8
3Immune: activated cells calm down
In lab research, humic substances calmed activated human immune cells, and in rats they eased several kinds of allergic and inflammatory reactions, which fits the calmer allergy response seen in people.26275
4Gut: the bacteria already there grow
In a study of 14 healthy adults without a comparison group, gut bacteria rose on humic acid capsules because the groups already living there grew.6
Fulvic acid vs. shilajit
Quick answer
Shilajit is a whole natural resin, and fulvic acid is one of its main active fractions: more than 80% of shilajit's weight is humic substances, along with minerals, amino acids and plant compounds.102 Shilajit's trials test the whole resin, with its fulvic acid, minerals and other compounds together.
Shilajit is a dark, sticky resin found in rocky mountain regions, mainly the Himalayas, and it forms over centuries as microbes slowly break down plant matter.218 It's a rasayana, a rejuvenating tonic, in Ayurvedic medicine, and Persian medicine, which calls it momiai, used it by mouth to help broken bones mend.2818 Shilajit is rich in fulvic acids and trace minerals.29
Shilajit has more placebo-controlled trials than fulvic acid alone, and they point to bone, muscle and collagen:
| What was studied | Who, and the design | Daily amount and length | Result |
|---|---|---|---|
Fracture healing | 160 adults after surgery for a broken shinbone; placebo-controlled | Two 500 mg capsules of momiai for 28 days | Bone joined in 129 days on average, against 153 on placebo, with no difference in side effects18 |
Strength after a hard workout | 63 active young men; placebo-controlled | 250 or 500 mg for 8 weeks | In the stronger half, strength fell 8.9% after a fatiguing leg workout on 500 mg, against 16.0% on placebo19 |
Collagen building | 35 trained young men; placebo-controlled | 500 or 1,000 mg for 8 weeks | A blood marker of new collagen rose from 42.5 to 82.3 ng/mL on 500 mg and from 42.7 to 113.1 ng/mL on 1,000 mg, with no change on placebo30 |
Bone density | 60 postmenopausal women with low bone density; placebo-controlled | 250 or 500 mg for 48 weeks | Bone density fell on placebo and was better preserved on shilajit, more so at the higher amount20 |
Our shilajit guide covers the resin's other uses. Choose purified, metal-tested shilajit; the safety section below explains why.
Fulvic acid benefits for men
Quick answer
The men's-health research is on shilajit, which is rich in fulvic acid: in a 90-day placebo-controlled trial of 96 healthy men aged 45 to 55, 250 mg of purified shilajit twice a day raised total testosterone about 20%, from 4.84 to 5.83 ng/mL, while it fell on placebo.17 Free testosterone and DHEAS also rose more than on placebo in the 75 men who finished.17 A 2024 systematic review of testosterone boosters rated purified shilajit extract possibly effective for men with low testosterone that comes with age.31
In a study of 35 men with low sperm counts and no comparison group, 100 mg of processed shilajit twice a day after meals for 90 days raised total sperm count 61.4% and testosterone 23.5% from their starting levels in the 28 who finished, with liver and kidney tests unchanged.32 The strength and collagen trials in the shilajit section above were also in men.
Shilajit fits a bigger plan for men's hormones, built on food, sleep, strength training and managing stress. For those steps, see how to increase testosterone naturally.
Want help fitting fulvic acid into your routine?
Ask Dr. Axe AI. Answers are grounded in this library, with sources shown.
Fulvic minerals: what's in a fulvic acid supplement?
"Fulvic minerals" is the name on many liquid fulvic acid products, and it describes fulvic acid together with the minerals it carries. Humic substances hold onto minerals, which is part of how they keep soil fertile.11 What ends up in the bottle depends on the source: shilajit is almost 20% calcium, potassium and magnesium by weight, carries chromium, selenium and cobalt too, and varies in makeup from region to region.10
The same grip that holds useful minerals also holds unwanted metals, so a fulvic mineral product is only as clean as its source. The safety section covers the testing to look for.
How to take fulvic acid: forms, dosage and timing
Quick answer
No standard dose has been set for fulvic acid, so follow the label of a product with a published heavy-metal test, dilute liquids in water or juice, and start low.5 Take it first thing in the morning, between meals or at bedtime, 2 hours apart from food, medications and supplements other than probiotics.25733
Here are the forms you'll find, with the amounts used in studies:
| Form | What it is | Amounts in studies |
|---|---|---|
Liquid concentrate | Fulvic acid in water, often sold as fulvic minerals; acidic, so it's diluted | 15 mL a day of a 3.8% solution, diluted, judged safe by the researchers of the week-long oral trial, which tested up to 40 mL twice a day5 |
Capsules or powder | Dried humic and fulvic acids | Humic acids at 2,400 mg a day for 10 days, then 1,200 mg a day6 |
Shilajit extract or resin | Purified shilajit, rich in fulvic acid | |
Skin cream | 3.5% lab-made fulvic acid | Twice a day for 4 weeks13 |
In my protocols, binders go 2 hours away from food, herbs, supplements and medications, because they trap everything indiscriminately, and they call for more water, since they're dehydrating.7
If you're going to take a natural binder, I would do it either right before bed, first thing in the morning, or between meals.Dr. Josh Axe, DC, DNM, CNSFrom Reverse Microplastic Toxicity NATURALLY (Heals Mitochondria, Gut, Brain), The Dr. Josh Axe Show (2026), at 28:25
A few more steps make it easier on your body:
Dilute every dose. Stir liquid drops into a glass of water or juice; in the oral trial, the throat irritation at the highest dose was put down to the liquid's acidity.5
Start low. Begin below the label amount and build up as your digestion allows.
Pair it with probiotics. I like humic and fulvic acid in certain cases mixed with high-dose probiotics, and some probiotic supplements already include humate, so the two can go together.3334
Dangers of fulvic acid: side effects, purity and who should skip it
Quick answer
In studies, fulvic acid's side effects were mild and passed on their own: diarrhea, headache and a sore or burning throat, mostly at the highest dose, which the researchers put down to the liquid's acidity.5 The issues to plan around are product purity, thyroid effects seen in animals and its tie to a bone disease where it occurs in drinking water; skip it during pregnancy, while breastfeeding and for children.
Side effects in studies
In the week-long oral trial, the researchers first gave rising single doses from 5 to 40 mL, then 20 or 40 mL twice a day for 3 days, before the allergy test. Liver, kidney and blood tests and heart tracings stayed in normal ranges, apart from one man whose liver enzymes rose, which the researchers put down to a viral infection, and then returned to normal. Diarrhea, headache and a burning or sore throat came mostly at 40 mL twice a day, were mild and passed, and the researchers put them down to the liquid's acidity.5
In the largest of the fulvic acid trials, 332 adults with HIV in India took a wellness drink made with the lab-made fulvic acid, plus selenium and L-glutamine, or a placebo drink three times a day, and neither the people nor the researchers knew who got which. Liver and kidney function held steady and no serious side effects occurred; 7 people on placebo, but none on the fulvic acid drink, left the trial because their liver enzymes rose. Diarrhea, headache, and nausea and vomiting came up a little more often on the drink, a small difference that could have been chance, and the researchers judged it safe and well tolerated.14
In the humic acid study of 14 adults with no comparison group, 1 developed loose stools and bloating, and in the placebo-controlled eczema trial of 36 people, the fulvic acid cream caused some short-lived burning when it went on.613 In rats, a fulvic and humic acid preparation made from lignite caused no organ damage over 90 days at the highest amount tested, 2,000 mg per kilogram of body weight a day, and both it and the lab-made form were judged not to damage genes in standard lab tests.1112
Purity and heavy metals
Because fulvic acid binds metals, a product can carry the metals of its source. Shilajit can carry around 65 metals, and a few studies found levels above WHO and FDA limits.8 When researchers tested the two most widely sold kinds of shilajit, from India and Pakistan, both carried lead, arsenic and other metals above permissible limits, with mercury in the Indian sample too, and a 2025 analysis found thallium in raw shilajit and in supplements, with some supplements carrying more than the raw resin.2835 Look for:
A published heavy-metal test for lead, arsenic, cadmium and mercury, ideally from an independent lab and matched to the lot number on your bottle8
The source named on the label: peat, lignite, shilajit or lab-made111012
For shilajit, a purified extract with its own metal test, since some supplements tested higher in thallium than raw shilajit35
Clear directions to dilute it in water or juice5
Thyroid
Animal and water studies point to an effect on the thyroid. Rats fed fulvic acid for 26 days made about 4 times as many antibodies to a test protein as rats on a standard diet, a strong immune boost, but they also had higher TSH and a lower ratio of T4 to T3, a mild underactive-thyroid effect; humic acid in drinking water lowered T4 in rats, and in mice it strengthened the effect of a low-iodine diet on the thyroid.3637 Humic substances in drinking water from coal and shale sources have been linked to goiter in some parts of the world.38 Include iodine-rich foods in your diet, and if you have thyroid problems, read the guidance at the end of this section before you start.
Selenium and long-term use
Kashin-Beck disease is a bone-and-joint disease that starts in childhood, found in a long, narrow belt of the world that runs through parts of China.39 Where it was common, drinking water carried high levels of organic matter, mainly fulvic acid, and in lab and animal studies, fulvic acid injured cartilage cells and built up in bone and cartilage, especially when selenium was low; mice raised on fulvic acid and a low-selenium diet for two generations formed bone irregularly and had weaker bones.404142
Researchers list drinking-water fulvic acid as one of four factors tied to the disease, alongside low selenium, low iodine and moldy grain, and no study has shown that any one of them causes it; a 2020 review from China's disease-control agency points mainly to food factors.4339 This research comes from years of drinking water in selenium-poor farming regions. Eat selenium-rich foods if you take fulvic acid long term.
Good to know before you take fulvic acid
Pregnancy and breastfeeding: skip it. Fulvic acid hasn't been studied for safety in pregnancy, and in one case report, a pregnant woman who took mumijo, another name for shilajit, for 6 months developed persistent high blood pressure and low potassium, which her doctors treated with potassium and by stopping the mumijo.9 My parasite protocol also lists binders on its avoid list during pregnancy and breastfeeding.7
Children: skip fulvic acid supplements by mouth, since Kashin-Beck disease, the bone disease tied in part to drinking-water fulvic acid, begins in childhood.3943
Thyroid conditions or thyroid medication: talk with your doctor before you start, because of the thyroid findings above, and keep the 2-hour gap from your medication.3637
Stomach upset: if diarrhea, stomach upset or a burning throat doesn't settle after you dilute it and lower the amount, stop taking it.5
The bottom line
Should you take fulvic acid?
Yes, as a gentle binder from a clean source. Fulvic acid comes from the slow breakdown of plants in the soil, and in your body its strength is binding: I use humic and fulvic acid for an ongoing detox, alongside high-dose probiotics, because they're much better for long-term use than charcoal.34 In people, a week of a lab-made fulvic acid calmed an allergy skin test in a placebo-controlled trial, a fulvic acid cream helped eczema in another placebo-controlled trial, and humic acid capsules raised gut bacteria in a study with no comparison group, and shilajit, rich in fulvic acid, adds placebo-controlled trials for testosterone, strength, collagen and bone. Those are promising first studies.
Choose a metal-tested product, dilute it, start low, and take it first thing in the morning, between meals or at bedtime. Your body was designed to clear what it doesn't need, and a clean, gentle binder taken at the right time supports that work.
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Open the free protocol →Fulvic acid: frequently asked questions
What is fulvic acid good for?
Fulvic acid's clearest human result is a calmer allergy response: in a placebo-controlled trial of 21 men who each tried both, a week of a lab-made fulvic acid shrank allergy skin-test bumps more than placebo.5 In a 4-week placebo-controlled trial of 36 people with eczema, a fulvic acid cream earned better overall ratings, and in 14 healthy adults with no comparison group, humic acid capsules raised gut bacteria about 30%.136
Which foods contain fulvic acid?
USDA's FoodData Central doesn't measure fulvic acid in foods, so there's no reliable list of fulvic acid foods; humic substances, the family it belongs to, occur naturally in soil and surface water, and shilajit is the traditional concentrated source.110 For the microbes that come with soil and fresh produce, see our guide to eating dirt.
Is fulvic acid safe to take every day?
Daily use was well tolerated in the studies so far: in a placebo-controlled trial of 332 adults with HIV, the researchers judged a drink made with a lab-made fulvic acid, taken three times a day, safe and well tolerated, and in 14 healthy adults with no comparison group, humic acid capsules taken every day for 45 days caused loose stools and bloating in 1 person.146 Rats given a fulvic and humic acid preparation every day for 90 days showed no organ damage.11 Choose a product with a published heavy-metal test.
Does fulvic acid cause detox symptoms?
The side effects seen in studies were mild and came mostly at the highest dose: in a trial of 30 men, diarrhea, headache and a sore or burning throat, which the researchers put down to the liquid's acidity.5 Dilute it in water or juice, start low, drink extra water as with any binder, and stop if symptoms don't settle.7
Does fulvic acid remove heavy metals?
It binds them: in lab and chemistry research, the humic substances in shilajit bind and help detoxify around 12 heavy metals, and I use humic and fulvic acid among my gentle binders for an ongoing detox.83 For the full plan, see our heavy metal detox guide.
Is fulvic acid the same as humic acid?
Is fulvic acid the same as shilajit?
What are the benefits of fulvic acid for men?
The men's research is on shilajit, which is rich in fulvic acid: in a 90-day placebo-controlled trial of 96 healthy men aged 45 to 55, purified shilajit raised total and free testosterone more than placebo, and in an 8-week placebo-controlled trial of 63 active young men, 500 mg a day helped the stronger half hold onto strength after a fatiguing workout.1719
How much fulvic acid should I take?
No standard dose has been set: follow the label of a product with a published heavy-metal test, dilute liquids in water or juice, and start low.5 For reference, the researchers of a week-long trial in 30 men judged 15 mL a day of their 3.8% lab-made fulvic acid, diluted, safe, and a study of 14 adults used 1,200 to 2,400 mg of humic acids a day.56
When is the best time to take fulvic acid?
Can I take fulvic acid with probiotics?
Does fulvic acid affect the thyroid?
It may: in rats, fulvic acid raised TSH and caused a mild underactive-thyroid effect, and humic substances in some drinking water have been linked to goiter.3638 If you have a thyroid condition or take thyroid medication, talk with your doctor before you start, and keep it 2 hours from your medication.
Freshness & update log
October 20, 2026 — Rewrote the page in full. The version published August 30, 2024, described two studies and had no reference list. This version reports each human study with its design, size, amount and result and labels lab and animal work as such. It adds the Dr. Axe Score (4.1) with an interaction check (Low), the allergy skin-test trials, the humic acid gut study, the safety results of a 332-person fulvic acid drink trial, the shilajit trials (labeled as shilajit), two charts and a step diagram, how fulvic acid differs from humic acid and shilajit, and Dr. Axe's guidance on gentle binders and their timing. It corrects the eczema comparison (the trial compared the fulvic acid cream with the same cream without it), labels the tau finding as a lab result, and removes the claims that fulvic acid contains probiotics and that an overdose isn't possible. It gathers the safety guidance in one section, covering product purity and heavy metals, thyroid findings in animals, the Kashin-Beck disease research and the side effects seen in studies, and it removes unsourced dosing, mineral counts and the cancer, SIBO, IBD, flu and UTI claims.
August 30, 2024 — Previous version published.
References
- International Humic Substances Society. What are humic substances? IHSS; 2007. Accessed October 16, 2026.
- Carrasco-Gallardo C, Guzmán L, Maccioni RB. Shilajit: a natural phytocomplex with potential procognitive activity. Int J Alzheimers Dis. 2012;2012:674142. doi:10.1155/2012/674142
- Axe J. Cellular Toxicity: The Root Cause of Aging, Inflammation & Chronic Disease. The Dr. Josh Axe Show. 2026 (charcoal for a week or two and the gentler binders for an ongoing detox, at 33:48 to 34:14 in the YouTube upload, video yNwVs_gAjBc).
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