Aluminium hydroxide

What it is

Aluminium hydroxide is an inorganic aluminium salt used as a medicine in two quite different ways. Swallowed as a gel or suspension it reacts with stomach acid, which is the basis of its use as an antacid; a US Drug Facts label states a 5 mL teaspoonful contains aluminum hydroxide 320 mg. It also binds phosphate in the gut, which is why it has long been given to people with advanced kidney disease to lower blood phosphate. Unlike magnesium and calcium salts it is constipating rather than laxative, which the label itself states.

What the research says

As an antacid, aluminium-containing products raise oesophageal pH more than placebo in people with heartburn, and in a 565-patient randomised placebo-controlled trial an antacid relieved a higher median proportion of a patient's heartburn episodes than placebo. As a phosphate binder it does lower phosphate, but the comparisons are weaker than they look: an open-label crossover trial in 30 patients detected no significant difference against sevelamer, which is a null rather than a demonstration of equal effect, and that trial's own authors concluded in favour of sevelamer; a separate randomised trial in 53 haemodialysis patients found aluminium hydroxide tended to be the most effective binder tested and recorded no hypercalcaemic episodes in its arm. No trial has tested whether it changes survival. The problem is the aluminium itself. Aluminium accumulation in people with kidney failure caused osteomalacia, anaemia and dialysis encephalopathy, and a case of osteomalacia with stress fractures is documented in a man with normal kidneys who took aluminium hydroxide antacid long-term. Whether oral aluminium binders still cause toxicity now that dialysis water is purified is genuinely disputed, and the claim that aluminium causes Alzheimer's disease is not supported by the meta-analysed human data.

Evidence grade: Disputed.

How it works

Drug class: Inorganic aluminium salt; antacid and intestinal phosphate binder

In the stomach aluminium hydroxide neutralises acid. In a single-blind crossover trial in people with heartburn an aluminium/magnesium hydroxide antacid raised oesophageal pH above placebo and was the only antacid tested to raise gastric pH above placebo, acting for about 82 minutes in the oesophagus and 26 minutes in the stomach - and those authors describe the gastric effect as minimal, placing the drug's action mainly in the lower oesophagus. Further down the gut it binds dietary phosphate so less is absorbed, which is why it lowers blood phosphate in kidney failure. It also slows the bowel, and its label warns users they may become constipated. (Source 1)

What it is used for

• Aluminium-containing antacids raise oesophageal pH against placebo, and a 565-patient randomised, double-blind, placebo-controlled trial found an antacid relieved a higher median proportion of a patient's heartburn episodes than placebo (62% against 41%). The effect is short-lived, the trials used combination products or an unspecified antacid rather than aluminium hydroxide alone, and the pH trial - a single-blind crossover trial whose abstract does not state whether treatment order was randomised - has authors who call its gastric effect minimal and place the action in the oesophagus. Evidence: limited. (Source 1)
• In an open-label randomised crossover trial of 30 peritoneal dialysis patients, no significant difference was detected between aluminium hydroxide and sevelamer in lowering serum phosphate - a null in a small trial, not a demonstration of equal effect, and that trial's own authors concluded in favour of sevelamer. In a separate randomised trial in 53 haemodialysis patients, aluminium hydroxide tended to be the most effective binder and no patient in its arm had a hypercalcaemic episode, while both calcium arms did. No trial has tested whether aluminium hydroxide changes survival, and the network meta-analysis of binders does not list aluminium among its eligible agents. Use is now restricted because of aluminium toxicity. Evidence: limited. (Source 2)

Interactions

• Ciprofloxacin (and fluoroquinolone antibiotics generally) (pharmacokinetic study): Taken together, aluminium hydroxide binds the antibiotic in the gut so that only a small fraction is absorbed, which could make the antibiotic fail. (Source 3)
• Levothyroxine (case reports): In a single reported case, an aluminium hydroxide antacid pushed a stable thyroid patient's thyrotropin up, and it returned to normal shortly after the antacid was stopped. The authors put it no higher than that the antacid "may interfere" with thyroxine bioavailability. Limit: One uncontrolled case report, with no rechallenge and no figures of any kind - the abstract gives no thyrotropin values, no antacid dose and no time course beyond "shortly after cessation". (Source 4)
• Riociguat (pharmacokinetic study): An aluminium/magnesium hydroxide antacid cut riociguat absorption by about a third and its peak blood level by over half in HEALTHY MALE volunteers, not in patients, because the drug needs stomach acid to dissolve. The study's authors drew a practical instruction from this: antacids should not be taken within an hour of riociguat, while no dose adjustment is needed for a proton pump inhibitor. Limit: Two open-label crossover studies of 12 healthy males each, single doses. Not tested in people being treated for pulmonary hypertension. The one-hour interval is the study authors' own instruction, quoted from the same abstract, not advice from us. (Source 5)
• Tebipenem pivoxil hydrobromide (an oral antibiotic) (pharmacokinetic study): An aluminium hydroxide/magnesium hydroxide/simethicone suspension lowered the antibiotic's peak blood level by about a fifth and total exposure by about 11%; the omeprazole arm in the same study lowered the peak by about two fifths. Limit: The quote now begins at "Following co-administration" so the reader can see which figure belongs to which arm: 22% is the antacid and 43% the omeprazole. One bound in it is misprinted by the journal itself as "83,2", with a comma where a decimal point belongs; it should read 83.2, and the same misprint appears in both the PubMed record and the publisher's own abstract. Twenty healthy adults, single doses. (Source 6)
• Calcium salts used as phosphate binders (clinical trial): In the haemodialysis trial, people on calcium acetate or calcium carbonate still needed aluminium hydroxide added to control phosphate, so the two are often used together rather than as alternatives, and the calcium arms carried hypercalcaemia that the aluminium arm did not. (Source 7)
• Prescription medicines generally, through the rise in stomach pH (label): Under its Warnings the label states that antacids may interact with prescription drugs and tells anyone taking one to ask a doctor or pharmacist first. (Source 8)
• Alcohol (label): UNTESTED, not tested and found safe. We found no study of an aluminium hydroxide and alcohol interaction in this search. The label's interaction warning is general and says nothing about alcohol either way. Limit: A gap in the literature, not a negative result. Nobody has run the study. (Source 8)

Stopping it

• In the documented antacid-induced osteomalacia case, stopping the aluminium hydroxide was the treatment: bone pain fell, stress fractures healed and bone mineral content rose after withdrawal plus calcium and phosphorus. (Source 9)
• In the single reported levothyroxine case the raised thyrotropin returned to normal shortly after the aluminium hydroxide antacid was stopped. That is what one uncontrolled case showed; it is not a demonstration that the interaction is reversible as a general property, and the authors themselves put it only as the antacid "may interfere" with thyroxine bioavailability. (Source 4)
• For the antacid use the label sets a short course and a stopping rule: it directs users not to use the maximum dosage for more than 2 weeks, and to stop and ask a doctor if symptoms last longer than that. We found no deprescribing or taper trial for aluminium hydroxide in either of its uses. (Source 8)

What goes wrong

A man with normal parathyroid function who took aluminium hydroxide antacid long-term developed osteomalacia with osteitis fibrosa, bone pain and multiple stress fractures, which improved after the antacid was withdrawn. (Source 9)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: A 53-year-old man with long-term aluminium hydroxide antacid ingestion.
• How long: Bone pain and stress fractures over a two-year period.
• Result: Transiliac bone biopsy showed osteomalacia with osteitis fibrosa; after antacid withdrawal plus calcium and phosphorus, bone pain decreased, stress fractures healed and axial bone mineral content increased on computed tomography.
• Funding: Research Support, U.S. Gov't, P.H.S. per the record.

A 53-year-old man with a history of long-term aluminum hydroxide antacid ingestion reported diffuse bone pain and multiple stress fractures over a two-year period.

The authors of a 39-patient desferrioxamine study state as background that aluminium toxicity was frequent in the 1980s among dialysis patients taking aluminium-containing phosphate binders, when the dialysis water could also be contaminated with aluminium. (Source 10)

• Blood level study, Low certainty.
• Size: Background framing in a single-centre study of 39 haemodialysis patients.
• Who: Haemodialysis patients taking aluminium-containing phosphate binders. The source is NOT a review: it is a single-centre prospective study of 39 haemodialysis patients given standardised low-dose desferrioxamine tests at the Royal London and St Bartholomew's.
• How long: The 1980s.
• Result: No rates given in this passage; the authors state toxicity was frequent in that era and exposure came from both the binder and the dialysate water.
• Funding: Research Support, Non-U.S. Gov't per the record. The paper's own Competing interests section discloses: "The Renal Unit at Barts and The London NHS Trust have received research grants from Genzyme Corporation. SLF has received lecture fees and travel bursaries to attend conferences from Genzyme Corporation." Genzyme markets sevelamer, the binder this paper's findings favour over aluminium hydroxide.

Limit of this finding: Two things to know about this source. It is not a narrative review, as this entry previously recorded: it is a 39-patient single-centre desferrioxamine study, and the sentence quoted here is its background framing, not a finding it tested. And it carries a conflict of interest that matters for how it is used: Genzyme Corporation, which funded the unit and paid the senior author lecture fees, markets sevelamer - the comparator binder that aluminium hydroxide is weighed against on this page.

Aluminium (Al) toxicity was frequent in the 1980s in patients ingesting Al containing phosphate binders (Alucaps) whilst having HD using water potentially contaminated with Al.

A narrative review of aluminium toxicity lists respiratory, cardiovascular, gastrointestinal, inflammatory, haematologic, hepato-renal, neurodegenerative, reproductive and developmental pathologies, plus genotoxicity and endocrine and pancreatic effects, as associated with aluminium accumulation, without quantifying any risk from medicinal aluminium. (Source 11)

• Expert review, not systematic, Very low certainty.
• Size: Not stated; no systematic search method reported.
• Who: General and occupationally exposed populations.
• How long: Not applicable.
• Result: No effect sizes are given; the review describes mechanisms including oxidative stress, immune dysregulation, genotoxicity, protein misfolding and apoptosis.
• Funding: not stated.

Limit of this finding: This entry previously listed "bone" among the pathologies. The review's abstract does not list bone or skeletal disease, so we have removed it. Aluminium-related bone disease is real and is reported elsewhere on this page from its own sources - the osteomalacia case report and the dialysis literature - but it is not in this review's abstract, and we could not reach the article body to check whether the review covers it: Europe PMC returns HTTP 500 for the full text of PMC12662758 and the publisher blocks the PMC XML. The review also gives no doses and no risk estimates at all.

The Al toxicity is associated with a wide range of pathologies such as respiratory diseases, cardiovascular complications, gastrointestinal disorders, inflammation, hematologic, hepato-renal and neurodegenerative diseases and reproductive and developmental disorders, genotoxicity as well as endocrine and pancreatic necrosis.

A separate meta-analysis of occupational aluminium exposure found worse measured cognitive performance in exposed workers across several domains. (Source 12)

• Meta-analysis, Low certainty.
• Size: 18 studies, 87 effect sizes across seven cognitive functions.
• Who: Workers occupationally exposed to aluminium, compared with unexposed controls.
• How long: Literature searched to June 2023.
• Result: Significantly worse performance in processing speed, working memory, attention and reaction time after excluding outliers; blood plasma aluminium predicted lower cognitive performance. These are cross-sectional occupational comparisons, not a test of medicinal aluminium and not evidence of cause.
• Funding: not stated.

Limit of this finding: These are cross-sectional comparisons of cognitive test scores in workers with occupational aluminium exposure, not studies of people taking an aluminium antacid, and not studies of dementia incidence. An association of this kind cannot show that aluminium caused the lower scores. The reviewers also note that blood plasma aluminium was the only biomarker that significantly predicted performance, so their other biomarkers did not.

We found significant worse performances in workers occupationally exposed to aluminum regarding processing speed, working memory, attention, and reaction time after exclusion of outliers.

An aluminium hydroxide antacid cut the absorption of ciprofloxacin to roughly a seventh of the amount absorbed without it. (Source 3)

• Randomized trial, Low certainty.
• Size: 12 healthy volunteers.
• Who: Healthy volunteers in a three-way randomised crossover design given ciprofloxacin 750 mg.
• How long: Single doses.
• Result: Relative bioavailability about 15% of control with aluminium hydroxide and about 60% with calcium carbonate; urinary recovery with aluminium hydroxide was about a quarter of that in the calcium carbonate group.
• Funding: Research Support, Non-U.S. Gov't per the record.

When Cipro was given with aluminum hydroxide, the relative bioavailability was approximately 15%.

What the evidence supports

In a randomised trial in 53 haemodialysis patients, aluminium hydroxide tended to be the most effective phosphate binder and no patient in that arm had a hypercalcaemic episode, while mean serum aluminium did not differ between the arms. (Source 7)

• Randomized trial, Low certainty.
• Size: 53 patients on regular haemodialysis.
• Who: Patients on chronic intermittent haemodialysis, randomised to aluminium hydroxide, calcium acetate or calcium carbonate.
• How long: Doses are reported at 12 months; the abstract never states a planned follow-up period.
• Result: Hypercalcaemic episodes in 18% of the calcium acetate arm and 31% of the calcium carbonate arm (p < 0.005) and none in the aluminium hydroxide arm; both calcium arms needed aluminium hydroxide added (1.29 +/- 0.54 g/day alongside calcium acetate and 0.69 +/- 0.27 g/day alongside calcium carbonate)
• Funding: not stated.

Limit of this finding: One figure in the source does not add up, and we have left it as printed. It reports hypercalcaemia in 18% against 31% at p < 0.005 in a 53-patient trial split three ways, which is roughly 18 patients per arm. A difference that size on 18 patients per arm cannot reach p < 0.005; the figure would only make sense if the denominator were episodes or monthly measurements rather than patients, which the abstract does not say. Do not take the p-value at face value. Separately, the trial's own Conclusions - which this entry does not quote - say that per gram of elemental calcium the two calcium salts are equivalent and that calcium carbonate needs significantly fewer capsules, a more favourable reading of the calcium arms than the Results alone give. And the "12-month" framing is assembled from two parts of the abstract: the design sentence does not state a follow-up period.

None of the aluminum hydroxide-treated patients experienced hypercalcemic episodes. Mean serum concentrations of alkaline phosphatase, intact parathormone, and aluminum did not differ between the groups.

In a single-blind crossover trial in people with heartburn, an antacid containing aluminium and magnesium hydroxide was the only one of the two antacids tested to raise gastric pH above placebo. (Source 1)

• Blood level study, Low certainty.
• Size: 83 subjects.
• Who: Subjects with heartburn after a refluxogenic meal. The source calls itself a single-blind crossover trial and never says it was randomised; NCBI gives it the publication type Journal Article only.
• How long: Single doses, pH followed to 4 h after the meal.
• Result: Only the aluminium/magnesium hydroxide product raised gastric pH versus placebo; duration of action 82 min in the oesophagus and 26 min in the stomach.
• Funding: not stated.

Limit of this finding: The authors themselves call the gastric effect minimal and conclude that the lower oesophagus, not the stomach, is the primary site of antacid activity in relieving heartburn. The 82 minutes of oesophageal action is reported against calcium carbonate's 60 minutes, not against placebo.

In the stomach, only Al(OH)3/Mg(OH)2 increased gastric pH compared with placebo.

What the evidence does not support

In the same trial, aluminium hydroxide produced no significant change in blood lipids, whereas sevelamer lowered total and LDL cholesterol. (Source 2)

• Randomized trial, Low certainty.
• Size: 30 patients on continuous ambulatory peritoneal dialysis.
• Who: Stable adults on continuous ambulatory peritoneal dialysis, in an open-label crossover trial.
• How long: Two 8-week periods.
• Result: Sevelamer lowered total cholesterol by 10.5% +/- 9.4% (p < 0.05) and LDL cholesterol by 20.1% +/- 6.8% (p < 0.001) in phase A; aluminium hydroxide produced no significant change in either phase.
• Funding: not stated.

In both phases of the study, AH administration was not followed by a significant change in serum lipid parameters.

A systematic review and network meta-analysis of phosphate binders did not include aluminium-based binders among its eligible agents, so aluminium hydroxide's effect on death and hospitalisation has never been meta-analysed. (Source 13)

• Systematic review, Moderate certainty.
• Size: 28 studies with 8,335 participants; 25 trials in the quantitative synthesis.
• Who: Patients with chronic kidney disease-mineral and bone disorder.
• How long: Trials of at least 4 weeks' follow-up.
• Result: Eligible comparators were calcium salts, sevelamer hydrochloride, sevelamer carbonate, lanthanum carbonate, sucroferric oxyhydroxide, ferric citrate, a phosphorus-restricted diet, placebo or no treatment. No aluminium salt appears in that list, so the review reports no absolute or relative mortality effect for aluminium hydroxide. This is an inference from the absence of aluminium in the eligibility list, not an explicit exclusion statement.
• Funding: not stated.

Limit of this finding: This is evidence of absence by omission, not a stated exclusion: the review never says it excluded aluminium, the agent simply is not in its eligibility list. The 2025 Cochrane review of phosphate binders, 134 studies and 20,913 adults, likewise reports no aluminium comparisons in its abstract.

Eligible trials enrolled patients with CKD-MBD, randomized them to receive calcium (delivered as calcium acetate, calcium citrate or calcium carbonate), non-calcium-based phosphate binders (NCBPB) (sevelamer hydrochloride, sevelamer carbonate, lanthanum carbonate, sucroferric oxyhydroxide and ferric citrate), phosphorus restricted diet, placebo or no treatment, and reported effects on all-cause mortality, cardiovascular mortality or hospitalization at ≥4 weeks follow-up.

In haemodialysis patients taking aluminium capsules but dialysed only with reverse-osmosis water, no patient reached the serum aluminium level defined as a toxic load, and aluminium levels did not track the total amount swallowed. (Source 14)

• Blood level study, Very low certainty.
• Size: 39 patients, 34 anuric.
• Who: Haemodialysis patients with current or past exposure to aluminium hydroxide capsules, never exposed to contaminated dialysate.
• How long: Mean 3.5 capsules a day over 23.0 months.
• Result: Pre-desferrioxamine aluminium above 1.0 micromol/L in only 2 patients and above 3.0 micromol/L in none; no post-desferrioxamine level above 3.0 micromol/L; and no correlation between serum aluminium and the total amount ingested. The R squared of 0.07 for that correlation is reported in the abstract's Conclusions section, which is held under a separate reference, not in the Results section quoted here.
• Funding: Research Support, Non-U.S. Gov't per the record. The paper's own Competing interests section discloses: "The Renal Unit at Barts and The London NHS Trust have received research grants from Genzyme Corporation. SLF has received lecture fees and travel bursaries to attend conferences from Genzyme Corporation." Genzyme markets sevelamer, the binder this paper's findings favour over aluminium hydroxide.

Limit of this finding: The source gives no p value, no n for the correlation and no confidence interval for the R squared of 0.07 anywhere, so it supports "weak and not statistically significant" and no more than that. Note also the funding disclosure: Genzyme, which markets the comparator binder sevelamer, funded the unit and paid the senior author.

No patients had a post DFO Al levels > 3.0 μmol/L. There were no correlations between the serum Al concentrations (pre-, post- or the incremental rise after DFO administration) and the total amount of Al ingested.

A meta-analysis of case-control studies found no association between occupational aluminium exposure and Alzheimer's disease. (Source 15)

• Meta-analysis, Low certainty.
• Size: 3 retrospective case-control studies, 1,056 participants.
• Who: Workers with occupational aluminium exposure; exposure ascertained through surrogate informants in every included study.
• How long: Searches to March 2015.
• Result: Odds ratio 1.00 (95% CI 0.59 to 1.68); 1.06 (95% CI 0.36 to 3.10) excluding low-quality studies.
• Funding: not stated.

Limit of this finding: Three retrospective case-control studies in which exposure was ascertained through surrogate informants in every included study, and no prospective study existed. Both intervals are correctly centred on their point estimates on the log scale, so the figures are internally consistent. The authors keep their own hedge: in the absence of prospective studies with more precise ascertainment of exposure, a role for aluminium cannot be definitively excluded. And none of this concerns antacid or phosphate-binder users: the exposure studied is occupational.

Occupational aluminum exposure was not associated with AD (odds ratio, 1.00; 95% confidence interval, 0.59 to 1.68)

The authors of that crossover trial concluded in favour of sevelamer rather than aluminium hydroxide, on the grounds of tolerability and the lipid profile. (Source 16)

• Randomized trial, Low certainty.
• Size: 30 stable patients on continuous ambulatory peritoneal dialysis.
• Who: Stable adults on continuous ambulatory peritoneal dialysis; open-label randomised crossover.
• How long: Two 8-week periods separated by 2-week washouts.
• Result: The authors' stated conclusion, not a separate analysis: sevelamer is called a well-tolerated alternative to calcium- or aluminium-containing binders, with an improved lipid profile.
• Funding: not stated.

Sevelamer hydrochloride is a well-tolerated alternative to calcium- or aluminum-containing phosphorus binder in the control of serum phosphorus in CAPD patients. Furthermore, SH improves the lipid profile in these patients.

Where the evidence is mixed

In an open-label randomised crossover trial in 30 peritoneal dialysis patients, no significant difference was detected between aluminium hydroxide and sevelamer hydrochloride in how far they lowered serum phosphate. (Source 2)

• Randomized trial, Low certainty.
• Size: 30 stable patients on continuous ambulatory peritoneal dialysis.
• Who: Stable adults on continuous ambulatory peritoneal dialysis with hyperphosphataemia; the trial was open-label, so nobody was blinded.
• How long: Two 8-week periods separated by 2-week washouts.
• Result: Serum phosphorus fell by 1.18 +/- 0.07 mg/dL with sevelamer and 1.25 +/- 0.15 mg/dL with aluminium hydroxide in phase A (p = NS), and by 1.35 +/- 0.25 mg/dL with aluminium hydroxide against 1.23 +/- 0.80 mg/dL with sevelamer in phase B (p = NS). The source calls these "similar reductions"; it does not report a non-inferiority margin.
• Funding: not stated.

Limit of this finding: A p = NS difference in an open-label crossover trial of 30 patients is not evidence that the two binders lower phosphate by the same amount; the trial was not powered to show equivalence and reports no non-inferiority margin. The paper's own conclusion also points the other way from the use we put it to: its authors conclude that "Sevelamer hydrochloride is a well-tolerated alternative to calcium- or aluminum-containing phosphorus binder" and that sevelamer improves the lipid profile. A reader of the source would not come away with a pro-aluminium impression.

There were similar reductions in serum phosphorus levels over the course of the study with both agents: by 1.18 +/- 0.07 mg/dL (0.38 +/- 0.03 mmol/L) with SH and by 1.25 +/- 0.15 mg/dL (0.40 +/- 0.05 mmol/L) with AH in phase A (p = NS), and by 1.35 +/- 0.25 mg/dL (0.43 +/- 0.08 mmol/L) with AH and by 1.23 +/- 0.80 mg/dL (0.39 +/- 0.25 mmol/L) with SH in phase B (p = NS).

What official bodies say

The product's own US label warns that users may get constipated, which is the opposite of what the magnesium and calcium antacids do. (Source 8)

• Official position, Certainty not rated.
• Size: Not applicable - a labelling position.
• Who: Anyone using the over-the-counter antacid.
• How long: Position dated 16 December 2025 (SPL version 4 published date)
• Result: No rate is given. On this label the constipation warning is a bold run-in phrase, "When using this product", sitting inside the SAME Warnings paragraph as the label's drug-interaction sentence - not under a heading of its own. This SPL has no OTC - WHEN USING section (LOINC 50567-7) and no OTC - STOP USE section (50566-9) at all; its Warnings section (LOINC 34071-1) holds four paragraphs, each opened by a bold run-in phrase.
• Funding: Not applicable.

Limit of this finding: A note on how this label is built, because it is easy to over-read. The constipation warning is not a separate Drug Facts warning category on this product: it is a bold phrase run into the middle of the same paragraph that warns about prescription-drug interactions, checked against the label's own markup by LOINC section code rather than by heading text. So read it as the label warning that constipation may happen, and not as the label giving constipation its own warning box. No frequency is stated.

Antacids may interact with certain prescription drugs. When using this product you may get constipated

Where the research disagrees

Whether oral aluminium hydroxide phosphate binders still cause aluminium toxicity now that dialysis water is purified

• Authors of the desferrioxamine-test study in haemodialysis patients on reverse-osmosis water, Single-centre prospective study of 39 haemodialysis patients given standardised low-dose desferrioxamine tests, with a serum aluminium threshold taken from earlier bone biopsy work; the authors call it a small study. Declared conflict of interest, quoted from the paper's own Competing interests section (recorded under aloh-accumulation-competing-interests): the Renal Unit received research grants from Genzyme Corporation and the senior author received lecture fees and travel bursaries from Genzyme, which markets sevelamer, the comparator binder: Yet no patients undergoing HD with RO treated water had evidence of Al toxicity despite doses equivalent to 3.5 capsules of Alucap for 2 years. (Source 17)
• The same authors describing the historical record, and a 1996 randomised binder trial, Background to a randomised prospective trial of 53 haemodialysis patients; the practice change it describes rests on the 1980s case and biopsy literature rather than on a trial: In order to avoid aluminum toxicity, calcium containing phosphate binders are used increasingly, instead of aluminium hydroxide. (Source 18)

Whether aluminium exposure contributes to Alzheimer's disease and cognitive decline

• Authors of the 2015 meta-analysis of occupational aluminium exposure and Alzheimer disease, Meta-analysis of three retrospective case-control studies, 1,056 participants, all using surrogate informants for exposure; no prospective studies available: The findings of the present meta-analysis do not support a causative role of aluminum in the pathogenesis of AD. (Source 19)
• Authors of the 2024 meta-analysis of aluminium exposure and cognitive performance, Meta-analysis of 18 mostly cross-sectional occupational studies with 87 effect sizes; measures cognitive test performance in exposed workers, not dementia incidence, and cannot establish cause: Our results show decreased performance levels in processing speed, working memory, attention and reaction time in workers occupationally exposed to aluminum compared to controls. (Source 20)

How much

• Reference intake: No dietary reference intake applies: this is a medicine. The amount is set by the Drug Facts directions or, for phosphate binding in kidney disease, by the prescriber. The US label published 16 December 2025 for an aluminum hydroxide oral liquid states a 5 mL teaspoonful contains aluminum hydroxide 320 mg and gives the antacid directions as a position. (Source 8)
• Upper limit: The same US label caps its own antacid use at 12 teaspoonfuls in 24 hours and says the maximum dosage should not be used for more than 2 weeks. This is a labelling position dated 16 December 2025, not a toxicological limit for aluminium. (Source 8)
• Studied: The haemodialysis binder trial used aluminium hydroxide 500 mg tablets, with added doses of 1.29 +/- 0.54 g per day alongside calcium acetate and 0.69 +/- 0.27 g per day alongside calcium carbonate. (Source 7)
• Studied: The aluminium accumulation study recorded a mean dose of 3.5 aluminium hydroxide capsules a day over 23.0 months. (Source 14)
• Studied: The ciprofloxacin interaction study gave three 600-mg aluminum hydroxide tablets 5 minutes before ciprofloxacin 750 mg. (Source 3)

A common belief, and what the research shows

The belief: Aluminium in antacids causes Alzheimer's disease.

What the research shows: The meta-analysed human data do not support that. A meta-analysis of three retrospective case-control studies with 1,056 participants found an odds ratio of 1.00 (95% CI 0.59 to 1.68) for occupational aluminium exposure and Alzheimer disease, and its authors concluded that the findings do not support a causative role of aluminum in the pathogenesis of AD, while adding that without prospective studies a role cannot be definitively excluded. A separate meta-analysis did find worse cognitive test scores in aluminium-exposed workers (18 studies, 87 effect sizes), but those are cross-sectional comparisons of workers breathing aluminium at work, not of antacid users, and an association of that kind cannot show a cause. The aluminium harm that is well documented in medicine is different: bone disease, anaemia and encephalopathy in people with kidney failure, and osteomalacia in a man who took aluminium hydroxide antacid long-term.

Questions and answers

What is it?

Aluminium hydroxide is an inorganic aluminium salt taken as a gel, liquid or chewable tablet. A US Drug Facts label states a 5 mL teaspoonful contains aluminum hydroxide 320 mg and gives its purpose as antacid. The same chemical is also used, outside its over-the-counter labelling, to bind phosphate in people with advanced kidney disease. (Source 8)

What does it do in the body?

In the stomach it neutralises acid. In a single-blind crossover trial in people with heartburn an aluminium/magnesium hydroxide antacid was the only one of the two antacids tested to raise gastric pH above placebo, acting about 26 minutes in the stomach and 82 minutes in the oesophagus - and those authors call the gastric effect minimal, placing the drug's action mainly in the lower oesophagus. Further down the gut it binds dietary phosphate, which is why it lowers blood phosphate in kidney failure. It also slows the bowel and can constipate. (Source 1)

Is it good or bad for you?

It works, and the risk depends on the kidneys and the duration. For phosphate control in dialysis, an open-label crossover trial of 30 patients detected no significant difference between aluminium hydroxide and sevelamer, and a separate randomised trial in 53 haemodialysis patients found no hypercalcaemic episodes in its aluminium arm while both calcium arms had them. Against that, aluminium accumulates when kidneys cannot excrete it, and the authors of a 39-patient desferrioxamine study record that aluminium toxicity was frequent in the 1980s among dialysis patients taking these binders, when the dialysis water could also be contaminated. (Source 10)

How do you get more of it?

The antacid form is bought over the counter and its label sets the amount and the duration; the phosphate-binder use is prescribed and monitored. The label's directions, as a position dated 16 December 2025, are two teaspoonfuls five to six times daily after meals and at bedtime, with a ceiling of 12 teaspoonfuls in 24 hours and no more than two weeks at maximum dosage. None of this is advice for any individual. (Source 8)

If it is harmful, what reduces it?

The documented step is stopping the drug. In dialysis medicine the aluminium load is probed with the chelator desferrioxamine, and the threshold for a toxic load is a post-desferrioxamine serum aluminium above 3.0 micromol/L, a figure the study took from earlier bone biopsy work rather than measuring itself. (Source 21)

Why might someone be low in it or missing it?

Does not apply in the way it would for a nutrient. Aluminium hydroxide is a manufactured medicine, not something the body needs or stores, so there is no deficiency state. The relevant direction of concern is the opposite, accumulation: a 2025 narrative review of aluminium toxicity states that chronic and acute exposure lead to systemic accumulation of aluminium that induces aluminium toxicity, and says it is studying the significance of exposure in high-risk populations without naming them in its abstract. (Source 11)

Which whole foods contain it or feed it?

No whole food contains aluminium hydroxide as a medicine. Aluminium itself reaches people through food, water, air and medical products, which a 2025 narrative review of aluminium toxicity lists as its routes of exposure, but we found no study in this search quantifying dietary aluminium against the medicinal dose. (Source 11)

We searched: Europe PMC searches for aluminium or aluminum hydroxide with antacid, phosphate binder, dialysis, toxicity, osteomalacia and encephalopathy; no human study comparing food sources with the medicine was found.

What happens if you do not have it?

Nothing is lost by not taking it, and the alternatives for each use are real. In a 565-patient placebo-controlled trial of self-treated heartburn the median proportion of a patient's episodes relieved was 41% on placebo against 62% on antacid. For phosphate control in kidney failure, an open-label crossover trial detected no significant difference between sevelamer and aluminium hydroxide, so the job can be done without aluminium. (Source 22)

How can you test for it?

Aluminium load is assessed by a serum aluminium measurement, usually after a desferrioxamine challenge, with the toxic threshold taken from older bone biopsy studies. Its reliability is limited: in the 39-patient study, serum aluminium before and after desferrioxamine bore no relationship to how much aluminium the person had actually swallowed, and the authors call the relationship weak and not statistically significant. Bone biopsy remains the reference standard that the blood threshold was calibrated against. (Source 17)

References

1. American journal of therapeutics. Effects of Aluminum/Magnesium Hydroxide and Calcium Carbonate on Esophageal and Gastric pH in Subjects with Heartburn — abstract, first part of the abstract (design and pH results). 1995. PMID 11854825, DOI 10.1097/00045391-199508000-00006. Read the source
2. Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis. Sevelamer hydrochloride versus aluminum hydroxide: effect on serum phosphorus and lipids in CAPD patients — abstract, Results section. 2006. PMID 16722024, DOI 10.1177/089686080602600308. Read the source
3. Antimicrobial agents and chemotherapy. Effects of aluminum hydroxide and calcium carbonate antacids on the bioavailability of ciprofloxacin — abstract. 1992. PMID 1503446, DOI 10.1128/aac.36.4.830. Read the source
4. Archives of internal medicine. Evidence for interference with the intestinal absorption of levothyroxine sodium by aluminum hydroxide — abstract. 1992. PMID 1728914, DOI 10.1001/archinte.1992.00400130181024. Read the source
5. Pulmonary circulation. Effects of omeprazole and aluminum hydroxide/magnesium hydroxide on riociguat absorption — abstract, complete abstract (the abstract is unstructured and carries no section headings). 2016. PMID 27162626, DOI 10.1086/682228. Read the source
6. Antimicrobial agents and chemotherapy. Effect of an Antacid (Aluminum Hydroxide/Magnesium Hydroxide/Simethicone) or a Proton Pump Inhibitor (Omeprazole) on the Pharmacokinetics of Tebipenem Pivoxil Hydrobromide (TBP-PI-HBr) in Healthy Adult Subjects — abstract, first part of the abstract (design and pharmacokinetic results). 2023. PMID 36943038, DOI 10.1128/aac.01495-22. Read the source
7. Clinical nephrology. Aluminum hydroxide, calcium carbonate and calcium acetate in chronic intermittent hemodialysis patients — abstract, Results section. 1996. PMID 8846523. Read the source
8. DailyMed (US National Library of Medicine), SPL from Rugby Laboratories. Aluminum Hydroxide oral liquid - US OTC Drug Facts label, complete content from "Active ingredient" through "Other information"; each paragraph or list item of the label is on its own line, every line break inside a paragraph is rendered as a single space, and the four bold run-in phrases are left inside the paragraphs they introduce, as the source has them. Dec 16, 2025. Read the source
9. The American journal of medicine. Osteomalacia and osteitis fibrosa in a man ingesting aluminum hydroxide antacid — abstract. 1984. PMID 6328994, DOI 10.1016/0002-9343(84)90871-4. Read the source
10. BMC nephrology. Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels? — abstract, Background section. 2011. PMID 21992770, DOI 10.1186/1471-2369-12-55. Read the source
11. Toxicology research. Aluminum toxicity: a comprehensive narrative review — abstract. 2025. PMID 41321987, DOI 10.1093/toxres/tfaf167. Read the source
12. The Science of the total environment. Aluminum exposure and cognitive performance: A meta-analysis — abstract, Results section. 2024. PMID 37777128, DOI 10.1016/j.scitotenv.2023.167453. Read the source
13. PloS one. Comparative Effectiveness of Phosphate Binders in Patients with Chronic Kidney Disease: A Systematic Review and Network Meta-Analysis — abstract, Methods section. 2016. PMID 27276077, DOI 10.1371/journal.pone.0156891. Read the source
14. BMC nephrology. Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels? — abstract, Results section. 2011. PMID 21992770, DOI 10.1186/1471-2369-12-55. Read the source
15. Journal of occupational and environmental medicine. Occupational Exposure to Aluminum and Alzheimer Disease: A Meta-Analysis — abstract, Results section. 2015. PMID 26247643, DOI 10.1097/jom.0000000000000487. Read the source
16. Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis. Sevelamer hydrochloride versus aluminum hydroxide: effect on serum phosphorus and lipids in CAPD patients — abstract, Conclusion section. 2006. PMID 16722024, DOI 10.1177/089686080602600308. Read the source
17. BMC nephrology. Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels? — abstract, Conclusions section. 2011. PMID 21992770, DOI 10.1186/1471-2369-12-55. Read the source
18. Clinical nephrology. Aluminum hydroxide, calcium carbonate and calcium acetate in chronic intermittent hemodialysis patients — abstract, Background and methods section. 1996. PMID 8846523. Read the source
19. Journal of occupational and environmental medicine. Occupational Exposure to Aluminum and Alzheimer Disease: A Meta-Analysis — abstract, Conclusions section. 2015. PMID 26247643, DOI 10.1097/jom.0000000000000487. Read the source
20. The Science of the total environment. Aluminum exposure and cognitive performance: A meta-analysis — abstract, Conclusion section. 2024. PMID 37777128, DOI 10.1016/j.scitotenv.2023.167453. Read the source
21. BMC nephrology. Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels? — abstract, Methods section. 2011. PMID 21992770, DOI 10.1186/1471-2369-12-55. Read the source
22. American journal of therapeutics. Self-Directed Treatment of Intermittent Heartburn: A Randomized, Multicenter, Double-Blind, Placebo-Controlled Evaluation of Antacid and Low Doses of an H(2)-Receptor Antagonist (Famotidine) — abstract, RESULTS section of the abstract. 1995. PMID 11850668, DOI 10.1097/00045391-199505000-00003. Read the source