Ibuprofen

Limits on what this shows

• Key negative/null findings: No ibuprofen-specific human study measuring intestinal mitochondrial function, ATP levels, or a validated in-vivo mitochondrial-burden biomarker was located; all ibuprofen-specific data identified is in vitro, in isolated rat liver mitochondria rather than intestinal tissue.
• At-risk subgroups: Not established from human data; the in vitro literature does not identify a dose, duration, or patient subgroup at differential risk.

Regulatory status

Not addressed anywhere in the FDA label; the label's mechanism language for GI injury names prostaglandin inhibition only (see dl.pk above), not mitochondrial effects.

Population evidence

Browne et al. 1999 (PMID 10075090): in vitro rat liver mitochondria exposed to ibuprofen, flurbiprofen, and ketorolac; R-ibuprofen inhibited beta-oxidation stereoselectively, and all three drugs moderately reduced mitochondrial respiration, at concentrations the authors describe as potentially achievable in the gastrointestinal tract. Bjarnason et al. 2018 (PMID 29221664), a broad review of NSAID GI-damage mechanisms, states that NSAIDs as a class "uncouple mitochondrial oxidative phosphorylation, which initiates biochemical changes that impair function of the gastrointestinal barrier," without naming ibuprofen individually (Tier C for this specific statement). Sigthorsson et al. 1998 (PMID 9712237) directly visualized this phenomenon by electron microscopy in rat enterocytes for indomethacin, a different NSAID (excluded cohort for ibuprofen), showing in vitro uncoupling of oxidative phosphorylation at low concentrations alongside enterocyte ultrastructural change.

Mechanism

Named: direct inhibition of mitochondrial fatty-acid beta-oxidation and reduced oxidative phosphorylation efficiency, proposed (for the NSAID class generally) as a COX-independent contributor to enterocyte injury alongside the labeled prostaglandin-mediated mechanism. This is a genuinely separate mechanism from ibuprofen's therapeutic COX-1/COX-2 inhibition and is not filed as a restatement of it.

Counter-evidence held on record

All ibuprofen-specific evidence is in vitro and in hepatic, not intestinal, mitochondria; extrapolation to a clinically meaningful intestinal mitochondrial burden in humans is Tier B mechanistic plausibility only. The class-level review (Bjarnason 2018) supports the general phenomenon but does not stratify by individual NSAID. This is laboratory evidence of a direct mitochondrial effect, not a demonstrated clinical burden in people taking ibuprofen, and must never be presented as an established human finding or paired with a supplement recommendation of any kind.

Limits on what this shows

• Key negative/null findings: None identified; no ibuprofen-specific study reporting a null redox result in gastric tissue was located, though the search was constrained by this session's access limits (see Sources) and a fuller literature check could not be completed.
• At-risk subgroups: Not established; both identified sources are animal gastric-lesion models, not stratified human data.

Regulatory status

Not addressed in the FDA label.

Population evidence

Jimenez et al. 2004 (PMID 15621707), "Role of L-arginine in ibuprofen-induced oxidative stress and neutrophil infiltration in gastric mucosa," Free Radical Research: an ibuprofen-specific rat study; title and journal indexing confirmed via PubMed search-listing, but the full abstract text could not be independently re-verified this session (see Sources). Balasubramanian et al. 2004 (PMID 15632983), "Taurine prevents Ibuprofen-induced gastric mucosal lesions and influences endogenous antioxidant status of stomach in rats," ScientificWorldJournal: similarly confirmed by title/indexing only, full abstract not independently re-verified this session.

Mechanism

Proposed by the cited titles: ibuprofen-induced gastric mucosal injury is accompanied by oxidative stress and neutrophil infiltration, and by a measurable change in endogenous antioxidant status. This is a redox-marker-level claim, not a restatement of the mitochondrial-function data in the entry above, and is graded on its own evidentiary basis per protocol.

Counter-evidence held on record

Both sources are animal, gastric-mucosal-lesion models specifically, and this session could not independently re-verify their full abstract text (see access note in Sources); the finding is reported here at the confidence level the confirmed title, journal, and indexing support, and no stronger claim is made. This is local gastric-mucosal redox evidence in rats accompanying drug-induced lesions, not evidence of a systemic oxidative stress burden in people taking ibuprofen, and must never be presented as a reason to add an antioxidant supplement.

Limits on what this shows

• Key negative/null findings: Gkiouras et al. 2025 (PMID 40728676), a systematic review and meta-analysis spanning 89,522 participants across randomized and observational studies, found that "low-dose and short-term ibuprofen administration may not be associated with UGIB compared to paracetamol or other non-selective NSAIDs," while still showing increased risk relative to non-users and to celecoxib. Older direct blood-loss studies in healthy volunteers (Porro et al. 1977, PMID 330286; Guentert et al. 1992, PMID 1304448) documented measurable but variable fecal blood loss at study doses without reporting anemia as an outcome over their (shorter, 2-week-scale) durations.
• At-risk subgroups: Age 60 or older, prior ulcer or GI bleed, concurrent aspirin/anticoagulant/corticosteroid use, 3+ alcoholic drinks daily (per OTC label warning), and — most centrally — sustained/high-dose use for chronic arthritis rather than occasional use.

Regulatory status

FDA label: NSAID-class upper GI ulcer/bleed/perforation incidence "approximately 1% of patients treated for 3 to 6 months, and...2 to 4%...one year" (not iron-specific, but the exposure driving the downstream effect). OTC Drug Facts monograph caps self-directed use at 1200 mg/day and warns to stop after 10 days for pain.

Population evidence

PRECISION trial GI substudy (Yeomans et al. 2018, PMID 29667211): 24,081 osteoarthritis/RA patients randomized to celecoxib 100-200 mg BID, ibuprofen 600-800 mg TID, or naproxen 375-500 mg BID, all with esomeprazole co-therapy; iron-deficiency anemia hazard ratio celecoxib-vs-ibuprofen 0.43 (95% CI 0.27-0.68, p=0.0003), and clinically significant GI event incidence 0.74% (ibuprofen) vs 0.34% (celecoxib). Bowen et al. 2005 (PMID 16271337): 31 healthy subjects given ibuprofen 800 mg three times daily for 4 weeks showed mean chromium-51-labeled fecal blood loss of 2.55 mL/day (SD ±3.2) versus a 0.36 mL/day baseline, with occasional single-day spikes to 66-73 mL in a minority of subjects. Bhala et al. 2013, Coxib and traditional NSAID Trialists' Collaboration (PMID 23726390): individual-participant-data meta-analysis of 280 placebo-controlled NSAID trials (124,513 participants) found an ibuprofen relative risk of 3.97 (95% CI 2.22-7.10, p<0.0001) for upper GI complications, with the authors' own interpretation flagging that this elevated estimate likely reflects "high-dose...possibly ibuprofen" regimens. Castellsague et al. 2012, SOS project (PMID 23137151): observational meta-analysis found ibuprofen among the lower-risk individual NSAIDs overall (RR 1.84, 95% CI 1.54-2.20) but confirmed a class-wide dose-response gradient, with high daily NSAID doses carrying 2-3 times the risk of low daily doses.

Mechanism

Named: nonselective COX-1 inhibition reduces protective gastric/duodenal mucosal prostaglandins, producing mucosal injury and chronic (sometimes intermittently brisk) occult blood loss. Iron deficiency here is a downstream consequence of sustained blood loss — not a direct effect on iron absorption, transport, or metabolism.

Counter-evidence held on record

Gkiouras 2025's null finding at low dose/short-term use (above) is the central bound on this claim. Separately, osteoarthritis and rheumatoid arthritis populations carry an elevated baseline prevalence of anemia of chronic disease independent of which NSAID, if any, they take (Wilson et al. 2004, PMID 15050886; Abdel-Noor et al. 2019, PMID 31333004) — confounding by indication is presumed and any iron-status difference observed in this population should be read as relative to the comparator drug studied, not as an absolute ibuprofen-vs-no-treatment effect. This is a downstream consequence of chronic gastrointestinal blood loss, not a direct nutrient-absorption or metabolic effect of ibuprofen, and it must never be filed as though the GI bleeding or ulceration itself were the nutrient finding. It has not been established for occasional or short-course OTC use. The consumer-facing wording should specify "with regular, higher-dose, long-term use (e.g., arthritis treatment)," not a bare "ibuprofen depletes iron."

Limits on what this shows

• Key negative/null findings: Same as the existing entry: Gkiouras 2025's null finding for low-dose/short-term ibuprofen and upper GI bleeding bounds the size of the only pathway that connects ibuprofen to iron status at all.
• At-risk subgroups: Same as the existing entry above; no additional subgroup identified for a non-bleeding iron pathway.

Regulatory status

Unchanged from the existing entry above; no additional label language bearing on iron absorption, transport, or storage was located.

Population evidence

No new ibuprofen-specific study of iron absorption, hepcidin, transferrin saturation, or a non-bleeding iron-status pathway was located in this pass. All ibuprofen-specific iron evidence identified continues to run through fecal blood loss and clinically significant GI events (PRECISION/Yeomans 2018, Bowen 2005, Bhala 2013, Castellsague 2012), already cited and graded above.

Mechanism

Absent, for any route other than the blood-loss route already named above. Ibuprofen is not described anywhere in the label or literature reviewed as a direct iron chelator, an inhibitor of intestinal iron transporters (DMT1, ferroportin), or a modifier of hepcidin synthesis.

Counter-evidence held on record

None beyond what is already on record in the existing entry. No study was found showing ibuprofen affects iron status independent of gastrointestinal blood loss, in either direction. This entry must never be read as a second, independent iron finding stacked on top of the existing one. There is one iron mechanism for ibuprofen, gastrointestinal blood loss with sustained higher-dose use, and it is scored once, in the orange entry above. See the Overlap map below.

Limits on what this shows

• Key negative/null findings: Not applicable; there is no positive claim to null, only an absence of any drug-affects-nutrient study.
• At-risk subgroups: Cannot be assessed; no evidence base exists.

Regulatory status

Not addressed anywhere in the ibuprofen FDA label.

Population evidence

None located for ibuprofen at any tier. Searches for ibuprofen/NSAID and copper status returned only wrong-direction or wrong-drug results: Lopez-Anaya et al. 1994 (PMID 7514021) and Konstantinova et al. 1994 (PMID 8061949, PMID 7958724) study how pre-existing copper deficiency changes aspirin's or indomethacin's pharmacokinetics and antioxidant enzyme activity in rats, the nutrient affecting the drug, not the drug affecting the nutrient, and neither names ibuprofen.

Mechanism

Absent. Ibuprofen has no described chelating, ceruloplasmin-modulating, or copper-transporter-interacting activity in the pharmacokinetic or pharmacology literature reviewed.

Counter-evidence held on record

The wrong-direction and wrong-drug studies above were the only copper-related results this search returned; they are recorded to show the search was performed, not as support for any ibuprofen-copper claim. An evidence gap is not evidence of safety. This must never be reworded as "ibuprofen does not affect copper" or converted into a yellow or white entry; it is printed exactly as a gap, per protocol.

Limits on what this shows

• Key negative/null findings: This is a single cross-sectional study; no ibuprofen-specific longitudinal or interventional microbiome study, and no study reporting clinical dysbiosis outcomes (e.g., diarrhea, secondary infection) tied to the reported compositional differences, was located.
• At-risk subgroups: Not established from this single cohort; the study population was general adult self-reported medication users, not stratified by dose or duration.

Regulatory status

Not addressed in the FDA label; the label's GI warnings concern mucosal injury and bleeding, not microbiome composition.

Population evidence

Rogers & Aronoff 2016 (PMID 26482265): cross-sectional study of 155 adults with drug use ascertained over the prior 30 days and stool specimens analyzed for bacterial composition; logistic regression with AUC analysis found medication type had a greater influence on gut microbiome composition than medication count, and specifically distinguished ibuprofen users (enrichment of Acidaminococcaceae, Enterobacteriaceae, similar to celecoxib users) from naproxen users and non-users (higher Propionibacteriaceae, Pseudomonadaceae, Puniceicoccaceae, Rikenellaceae in ibuprofen users).

Mechanism

Not fully characterized by the source itself, which states the composition-level relationship between NSAIDs and the gut microbiome "has not been fully characterized." Plausible contributing routes include COX-independent mucosal barrier effects and altered luminal pH/bile handling from mucosal injury, distinct from the frank blood-loss mechanism graded under Iron.

Counter-evidence held on record

Confounding by indication and by diet/comorbidity is presumed and not excluded in this cross-sectional design; the study measured drug use in the 30 days before a single stool sample and cannot establish that ibuprofen use, rather than the condition prompting its use or unmeasured dietary factors, caused the compositional difference. This is bounded to a single-timepoint, self-reported-exposure, observational design, which is why it is graded orange rather than red. A compositional difference in stool bacterial families is not the same as a proven harmful dysbiosis, a nutrient deficiency, or a clinical outcome, and must not be presented as such. This is distinct from, and must never be merged with, the gastrointestinal bleeding/ulceration mechanism already graded under Iron.

Limits on what this shows

• Key negative/null findings: None identified; equally, no study was found either confirming or excluding a measurable drop in cellular ATP levels in any human or animal tissue exposed to ibuprofen.
• At-risk subgroups: Not established; no human data exists to stratify.

Regulatory status

Not addressed in the FDA label.

Population evidence

Browne et al. 1999 (PMID 10075090), the same source cited under Mitochondrial Burden: ibuprofen, flurbiprofen, and ketorolac "moderately reduced" mitochondrial respiration in isolated rat liver mitochondria, at concentrations judged achievable in the gastrointestinal tract. No dedicated ATP-quantification study (e.g., luminescent ATP assay, 31P-MRS energy-charge measurement) for ibuprofen in any tissue was located in this session's search.

Mechanism

Named, and identical to the mechanism named under Mitochondrial Burden: inhibition of mitochondrial oxidative phosphorylation, the process that synthesizes ATP, at gastrointestinal-tract-relevant concentrations. No additional or distinct mechanism specific to ATP output (as opposed to mitochondrial structure/function generally) was identified.

Counter-evidence held on record

This entry rests on the same single in vitro source as Mitochondrial Burden above; no second, independent line of evidence exists for ATP production specifically. See the Overlap map below, which documents this explicitly to prevent the two entries from being read as two independent findings. This is a reduced-respiration finding in isolated rat liver mitochondria, not a measured drop in ATP in any human tissue, and must never be presented as established evidence of "low energy" from ibuprofen use or paired with any supplement or dosing suggestion.

Limits on what this shows

• Key negative/null findings: Not applicable; no positive claim exists to null in this specific, non-anemia sense.
• At-risk subgroups: Cannot be assessed; no distinct evidence base exists. Anyone with ibuprofen-associated iron-deficiency anemia (see Iron above) already has a defined, differently-named risk pathway for reduced oxygen-carrying capacity; that risk is not duplicated here.

Regulatory status

Not addressed anywhere in the FDA label beyond the GI-bleeding and renal-perfusion language already cited under Iron and the renal-retention entry.

Population evidence

None located for ibuprofen specifically measuring tissue oxygenation, VO2, muscle oxygen extraction, or hypoxic markers independent of the anemia pathway. Searches returned only unrelated results (ibuprofen used as a drug-delivery conjugate in materials-science studies, and studies of ischemia/reperfusion or nitric-oxide physiology that did not test ibuprofen itself).

Mechanism

Absent, for any route distinct from the iron-deficiency-anemia pathway already graded orange above. No description was found of ibuprofen directly impairing hemoglobin function, mitochondrial oxygen utilization efficiency, or tissue oxygen extraction.

Counter-evidence held on record

None beyond the absence of results itself; see the Overlap map below for how this entry relates to the existing Iron entry. This gap must never be filled by restating the existing anemia finding under a new label, and must never be read as reassurance that ibuprofen has no effect on oxygen delivery; it is simply where the distinct evidence would go if it existed.