Do water pills work for a weight cut?

1. The short answer, and the two reasons it is short

Water pills work in the narrow sense that they increase urine output and therefore reduce body mass on a scale. They do not work in the sense the question is usually asking, which is "is this a viable way to make a limit".

The first reason is regulatory and it is absolute. In tested sport, every prescription diuretic is prohibited at all times. Not restricted, not threshold-limited, not in-competition-only. There is no window in the calendar where holding one is permitted, and no amount that is permitted. That fact alone ends the analysis for any athlete competing under a programme that applies the WADA Code or an anti-doping policy modelled on it. Which promotions and federations those are is a question to put to your own commission or federation rather than to a search result — we did not verify a list of them for this article, and it changes.

The second reason is that the method itself appears to cost more than an equivalent loss achieved another way, and this is the part almost nobody writes down. The evidence is old and it is thin — one study, from 1984 — but it is the only controlled comparison of how the water comes off that exists, and its result points one direction.

Caldwell, Ahonen and Nousiainen measured cardiorespiratory variables in 62 non-endurance athletes who reached a mean weight loss of 4.1% of body mass by one of three routes: sauna, diuretic, or exercise. A control group lost an average of 1.2%. At maximal exercise, oxygen consumption, oxygen pulse, blood lactate concentration and workload all decreased in the sauna and diuretic groups relative to the exercise group. The authors' own conclusion was that "not only the quantity of weight loss but also the method itself may limit physical performance." They also recorded that loss achieved over 48 hours was less detrimental than a more rapid 24-hour reduction by sauna or diuretic.

Read that carefully, because it is easy to over-claim. Sixty-two athletes, in 1984, none of them identified as combat athletes, at one deficit. It is not a modern study and it has not been replicated in fighters. But it is the direct answer to "but does it work": at the same number on the scale, the athletes who got there pharmacologically performed worse than the athletes who got there by training. If the point of making weight is to fight afterwards, the route is not a neutral implementation detail.

2. What the Prohibited List actually says, and which edition

The document in force is the WADA Prohibited List 2026, an International Standard under the World Anti-Doping Code. Its cover states that the List shall come into effect on 1 January 2026. The List is revised annually, so any article quoting a class must name its edition — including this one, which should be re-checked against whatever edition is current when you read it.

Section S5 is headed Diuretics and Masking Agents and sits under Prohibited at All Times (In- and Out-of-Competition). The section states that all prohibited substances in this class are Specified Substances, and that "all diuretics and masking agents, including all optical isomers, e.g. d- and l- where relevant, are prohibited." It then gives examples under the phrase "including, but not limited to".

The named diuretics in the 2026 edition are: acetazolamide; amiloride; bumetanide; canrenone; chlortalidone; etacrynic acid; furosemide; indapamide; metolazone; spironolactone; thiazides, e.g. bendroflumethiazide, chlorothiazide and hydrochlorothiazide; torasemide; triamterene; xipamide. The section also lists vaptans (e.g. conivaptan, mozavaptan, tolvaptan), plasma expanders by intravenous administration (albumin, dextran, hydroxyethyl starch, mannitol), desmopressin, and probenecid.

It closes the list with "and other substances with a similar chemical structure or similar biological effect(s)." That clause is the one that matters most for anyone reasoning about herbal products, and it is dealt with in section 9.

The exceptions, stated exactly. The 2026 edition lists as exceptions: drospirenone; pamabrom; and topical ophthalmic administration of carbonic anhydrase inhibitors (e.g. dorzolamide, brinzolamide); local administration of felypressin in dental anaesthesia. These are exceptions — they are not prohibited. A general web search on the 2026 List returns summaries asserting the reverse, that drospirenone and pamabrom are masking agents under S5. That is an inversion of the published text, and it is the single most likely thing for a reader to get wrong from secondary sources.

The note that catches people who were not even trying to cheat. S5 carries a NOTE in the 2026 edition: detection in an athlete's sample, at all times or in-competition as applicable, of any quantity of certain threshold-limited substances — formoterol, salbutamol, cathine, ephedrine, methylephedrine and pseudoephedrine — in conjunction with a diuretic or masking agent (excepting topical ophthalmic carbonic anhydrase inhibitors and dental felypressin) will be considered an Adverse Analytical Finding unless the athlete holds an approved Therapeutic Use Exemption for that substance in addition to the one granted for the diuretic or masking agent.

In plain terms: a diuretic in the sample does not only fail on its own account. It strips the benefit of the threshold on several ordinary asthma and cold-medicine drugs, and surviving that combination requires two TUEs, not one. An inhaler that was fine on Monday is an Adverse Analytical Finding on Tuesday if a diuretic is in the same sample.

One more piece of vocabulary, because it gets misread. USADA states that from June 2021 WADA applied Minimum Reporting Levels to a set of diuretics including acetazolamide, bumetanide, furosemide, hydrochlorothiazide, torasemide and triamterene, and that "for certain sports or in certain circumstances, results below the MRLs will trigger an investigation by the relevant anti-doping authority." An MRL is a reporting floor for the laboratory. It is not a permitted amount, and it is not a margin.

3. Banned twice: as a weight method and as a masking agent

The class is not called "Diuretics" — it is called "Diuretics and Masking Agents", and the second half of that name is why the ban has no seasonal window.

USADA's own explainer puts the mechanism plainly: "Diuretics like acetazolamide increase the rate at which the body gets rid of water (which dilutes the urine) and change how drugs are metabolized." Dilute urine lowers the concentration of everything in it. Altered renal handling changes how fast other compounds clear. Either effect can degrade the detection of a different prohibited substance, which is why the class is prohibited out of competition, where there is no weight limit to make and no performance to enhance.

This has a consequence for an athlete who genuinely only wanted the weight. The rule cannot read your intent, and the analytical finding does not record it. From the laboratory's point of view a furosemide result on a random off-season test and a furosemide result on fight week look the same. The sanctioning process can take circumstances into account afterwards, and does — but only after the violation exists.

The same logic shows up in how therapeutic use is handled. USADA's acetazolamide page states that it does not grant advance TUEs for altitude-sickness prevention, on the reasoning that "athletes can usually avoid these situations through advanced planning and altitude acclimatization"; genuine acute treatment runs through an emergency or retroactive TUE instead. A TUE is a medical process attached to a documented condition, assessed by the anti-doping organisation. It is not a permission slip that can be obtained in advance because a cut is going badly.

USADA also states the health position directly: diuretic-induced dehydration for weight cutting is prohibited in sport, and "it is also a dangerous practice that can lead to sudden drops in blood pressure, overheating, confusion, organ failure, and seizure."

4. What each class does, and where in the kidney

Four drug classes appear under S5 and they fail in different directions. This section is standard clinical pharmacology rather than a fetched finding — treat the mechanism map as background, and treat the named adverse effects as things documented in patients, not as effects measured in weight-cutting athletes.

Loop diuretics — furosemide, bumetanide, torasemide, etacrynic acid — act on the NKCC2 cotransporter in the thick ascending limb of the loop of Henle. They are the most powerful of the four and the characteristic problems are hypokalaemia, hypomagnesaemia, hypochloraemic alkalosis and volume depletion.

Thiazides and thiazide-like agents — hydrochlorothiazide, bendroflumethiazide, chlortalidone, indapamide, metolazone — act on the distal convoluted tubule, the segment that dilutes urine. Their signature emergency is hyponatraemia, disproportionately in the first weeks of exposure, along with hypokalaemia, hypercalcaemia and hyperuricaemia.

Potassium-sparing agents — spironolactone, amiloride, triamterene, canrenone — act at the collecting duct, on the epithelial sodium channel or the mineralocorticoid receptor. Their characteristic failure is the opposite of the others: hyperkalaemia, potassium too high rather than too low. An athlete who has absorbed "diuretics lower your potassium" as a general rule has the wrong model for this class, and the correction matters because the two errors have different consequences.

Carbonic anhydrase inhibitors — acetazolamide — act at the proximal tubule. Diuresis is weak; the characteristic problems are metabolic acidosis and hypokalaemia.

Across the classes, the adverse-effect set worth naming is: hypokalaemia and the arrhythmia risk that follows it; thiazide-induced hyponatraemia; orthostatic hypotension and syncope; pre-renal acute kidney injury from volume depletion; and rhabdomyolysis risk wherever electrolyte depletion, hypovolaemia, heat and hard exertion coincide.

Hold that last combination in mind, because it is not a hypothetical. Electrolyte depletion, hypovolaemia, heat and hard exertion coinciding is a description of fight week.

5. Stacked on a cut: the combination is the hazard, not the pill

The clinical literature on diuretics describes what they do to patients — people who are euvolaemic, at rest, usually on a stable regimen, under a prescriber's follow-up. A fighter taking one in the last 48 hours before a weigh-in is not that person. They are already volume-depleted, usually already heat-stressed, frequently in energy deficit, and about to exert maximally. The drug is being added to a system that has already spent its reserve.

The most directly relevant evidence comes from a 2026 prospective observational study in Translational Sports Medicine, which followed 30 male combat athletes — 15 MMA, 15 Muay Thai — with measurements around 45 days before competition, at the official weigh-in, and on competition day.

Diuretic ingestion was reported by 100% of the MMA athletes and 40% of the Muay Thai athletes. That is self-report, in a 30-athlete cohort, in one country, and it should never be repeated as a global prevalence — but it does mean the MMA group's results are a picture of what happens when diuretics are part of the protocol.

Blood creatinine in the MMA fighters rose about 21% between baseline and the weigh-in (p = 0.001). Mean eGFR fell from a baseline of 97.7 ± 8.9 to 79.1 ± 15.6 mL/min/1.73 m² at the weigh-in. On weigh-in day, proteinuria was present in 73% of the MMA athletes and 100% of the Muay Thai athletes. The authors concluded that the findings suggest kidney damage associated with decreased glomerular filtration due to dehydration.

The honest limitation is that this design cannot isolate the diuretic. These athletes were also using saunas, restricting fluid and restricting food, and the study did not randomise the method. What it establishes is that the renal cost of the whole protocol is measurable at the weigh-in, not theoretical — and that in this cohort, the protocol included diuretics universally in the MMA group.

The single-athlete version of the same trajectory is in the peer-reviewed record. Kasper and colleagues published a case study in 2019 of a male mixed martial artist who lost 9.3% of body mass in the final 24 hours before a weigh-in. Plasma sodium reached 148 mmol/L (hypernatraemia), serum creatinine 177 µmol/L (acute kidney injury), resting metabolic rate fell by 331 kcal, and testosterone dropped below 3 nmol/L. That is n = 1. It is an existence proof of an end state, not a rate, and it is reported at abstract level here rather than from the full text.

For what the passive heat routes do on their own, sauna suits and hot water immersion covers that evidence separately. The point of this section is the stacking, not the ranking.

6. The fatality question, answered precisely

There is no verified count of deaths caused by diuretics in combat sports, and this article will not print one.

That is a real refusal, not a hedge. The rapid-weight-loss literature does document severe outcomes: a 2025 Frontiers in Nutrition paper on a supervised protocol in professional MMA states in its introduction that "recent reports in the media and scientific literature have documented severe health events, including hospitalizations and even athlete fatalities, associated with poorly managed RWL." That sentence gives no tally, and it is about rapid weight loss in general, not about diuretics. Attaching a number to it would be inventing one.

The deaths most readers will have in mind are the three collegiate wrestlers who died in November and December 1997, documented by the CDC in MMWR: one in North Carolina on 6–7 November, one in Wisconsin on 21 November, one in Michigan on 9 December. Causes were recorded as undetermined, hyperthermia (rectal temperature 108 °F at the time of death) and rhabdomyolysis. All three had restricted food and fluid and exercised in vapour-impermeable suits in hot environments. They were the first identified deaths in collegiate wrestling associated with intentional rapid weight loss since national record keeping began in 1982.

CDC's report does name diuretics — among the extreme practices wrestlers use, and again in the revised NCAA guidelines it reproduces, which prohibit laxatives, emetics and diuretics. What the report does not do is record diuretic use by any of the three men, or attribute any of the three deaths to one. What killed them was food and fluid restriction plus vigorous exercise in vapour-impermeable suits in hot environments.

Those two facts — a literature that mentions fatalities without counting them, and three documented deaths in which no diuretic was implicated — get merged constantly into a confident "diuretics have killed X fighters". They are not the same fact and merging them produces a number that no source supports. Named fighter deaths circulated as diuretic deaths are sourced to journalism and promoter statements, and we could not obtain a coroner's report or a commission finding for any of them.

The same 2025 study is worth one more sentence for a different reason. Its athletes described "the mutual avoidance of pharmacological methods, such as diuretics and laxatives" as reflecting a shared concern about their potential health risks. The literature trying to build a less damaging protocol treats diuretics as the thing to design out, not as a tool to optimise.

7. Sanctions actually handed down

Seven athletes across five USADA announcements. Each is published on usada.org with the substance, the sample date and the sanction, and all of them fall in the period when USADA administered the UFC Anti-Doping Policy, which the UFC moved away from after 2023.

Carls John de Tomas (MMA, UFC) — furosemide, in-competition sample taken 8 December 2017 at a UFC Fight Night in Fresno, California. One year, from 29 December 2017; announced 5 February 2018. USADA's announcement also records that the California State Athletic Commission imposed a further one-year suspension and a $2,500 fine. The anti-doping penalty and the commission penalty are separate, and they stack.

Anderson Silva (MMA, UFC) — methyltestosterone metabolites together with hydrochlorothiazide, out-of-competition sample 26 October 2017. One year from 10 November 2017; announced 18 July 2018. The sanction was reduced on a contaminated-product finding traced to a Brazilian compounding pharmacy; it was a second violation, which would otherwise have carried four years.

Junior dos Santos Almeida, Antônio Rogério Nogueira and Marcos Rogério de Lima (MMA, UFC) — hydrochlorothiazide, anastrozole and other substances from compounded supplements. Six months each, ended on resolution of their cases; announced together on 23 April 2018. USADA sourced supplements from two Brazilian compounding pharmacies, in Rio de Janeiro and São Paulo, and its Salt Lake City laboratory confirmed the contamination.

Jennifer Maia (MMA, UFC) — furosemide, hydrochlorothiazide, chlorothiazide and a thiazide metabolite, out-of-competition sample 16 August 2018. Six months on a contaminated-supplement finding, provisional suspension from 31 August 2018; announced 15 January 2019.

Arika Skoog (boxing) — furosemide, out-of-competition samples on 23 May 2022 and 14 July 2022. One year from 15 July 2022, with results disqualified from 23 May 2022 including forfeiture of medals and prizes; announced 26 October 2022.

Three things fall out of reading the five together.

The standard is a year. Every case that came in below it did so on a contaminated-product finding, and a contaminated-product finding requires proving the source — producing the product, having it analysed, establishing the link. Asserting it does nothing.

Out-of-competition testing catches these. Three of the five announcements involve out-of-competition samples. There is no fight-week-only exposure window, because the prohibition has no seasonal boundary.

Skoog's case is the fact pattern that should worry a reader most, because there is no cheating in it. USADA's announcement records that her violation "resulted from her limited use of a family member's prescription furosemide medication to self-treat acute symptoms she experienced due to a temporary medical condition", and that a reduction was appropriate "due to Skoog's reduced degree of fault owing in part to her physical distress at the time she took the prohibited medication and her relative lack of experience". A prescription that was not hers, taken for symptoms that had nothing to do with competition, still cost a year.

We could not obtain a state athletic commission's own minutes or order for any named diuretic case, so no commission-level rule or threshold is stated here. The CSAC detail above is reported because USADA's own announcement records it.

8. Over-the-counter and herbal water pills: the effect size nobody has measured

Ask what a commercial water pill does to body mass and you find nothing. No human trial of a commercial over-the-counter or herbal water pill reporting a body-mass outcome was located for this article. Not a small one, not an old one, not an industry-funded one.

What exists is thinner than athletes expect.

Dandelion (Taraxacum officinale) leaf extract has one human study: Clare, Conroy and Spelman, 2009, in the Journal of Alternative and Complementary Medicine. Seventeen subjects, a single day, a fresh-leaf hydroethanolic extract given three times. The result was a statistically significant increase in urination frequency in the five hours after the first dose, and an increased excretion ratio after the second. There was no placebo group, no blinding and no control arm, and body mass was not an outcome. The authors call it a pilot and ask for further study. Counting trips to the bathroom in 17 people for one day is not evidence that anything comes off the scale by Friday.

Uva ursi has no clinical trials establishing efficacy, safety or toxicity for this use; the support is traditional and anecdotal.

Juniper berry has no direct human clinical evidence for this purpose. The animal work includes a rat study showing diuretic activity at one dose but not at a higher one — a non-monotonic result in rodents, which is not a human finding and cannot be scaled to one.

"Potassium-sparing herbal blends" have no human trial showing mass loss that we could find, so no effect size for them appears here.

Retailer and brand pages for these products routinely say they relieve water retention or support healthy fluid balance. Those are marketing claims made under a structure-and-function regime, not efficacy findings, and they are not evidence of anything.

The specific vendor claim to name and reject is the "lose 5–10 lb of water weight in 24 hours" shape. There is no trial behind it. There is no published n, no journal and no measured outcome — the number is a marketing figure and it is untraceable to any study. So is "clinically proven diuretic blend": a product described that way has a trial, an n and a journal behind it, or the phrase means nothing.

And "detox" and "flush out toxins" are not mechanisms at all. That is a myth with no physiological basis: diuretics alter renal sodium and water handling, which is a different thing from removing a toxin, and no product on this shelf has evidence of removing anything the kidney was not already handling.

9. Contamination: the risk the athlete did not choose

Here is the part that catches people who never intended to take a diuretic at all.

A 2026 systematic review in Frontiers in Sports and Active Living screened 12,031 records across Scopus, Web of Science and SPORTDiscus and included 44 studies. Its finding: approximately 9–15% of supplements tested in those empirical studies were contaminated with prohibited substances and unapproved pharmacological agents. That is the pooled picture across 44 studies, and the published sentence is narrower than it is usually quoted — it describes supplements tested in empirical studies, not products on a shelf. Analysis was by LC-MS in 28 of the studies.

The contaminant classes break down as stimulants (21 studies), anabolic-androgenic steroids (11), beta-2 agonists (6, mostly higenamine), and diuretics and masking agents (6 studies), the last naming hydrochlorothiazide, chlorazanil, bendroflumethiazide, bumetanide, amiloride and acetazolamide.

The most adulterated product categories were sports and performance supplements (14 articles), steroid and hormonal products (11), and weight-loss and fat-burning products (10). That third category is precisely the shelf a water pill sits on.

This is not a theoretical pathway in this sport. It is what produced three of the seven sanctions in section 7: USADA sourced supplements from two Brazilian compounding pharmacies and its Salt Lake City laboratory confirmed contamination with hydrochlorothiazide and anastrozole among other substances.

Two conclusions follow, and the second is the one that gets missed.

First, "herbal means legal" is false on both halves. Herbal diuretics are not exempt from S5's catch-all for substances with a similar biological effect, and herbal weight-loss products are a documented contamination category. Second, no badge fixes this. Third-party certification reduces contamination risk without eliminating it, and no certification can make an S5 substance permitted — a product certified as tested is still a product, not a defence, and a substance on the List is on the List regardless of what the tub says.

10. Caffeine, and the assumption worth correcting

Caffeine is not a water pill, and treating coffee as one is the wrong mental model.

Killer, Blannin and Jeukendrup ran a counterbalanced cross-over trial in 50 male habitual coffee drinkers, published in PLOS ONE in January 2014. Each participant completed two three-day trials with a ten-day washout, one arm on coffee at 4 mg of caffeine per kg of body mass per day — four 200 mL cups of instant coffee, around 308 mg daily — and one on water. Twenty-four-hour urine volume was 2409 ± 660 mL on coffee versus 2428 ± 669 mL on water: no difference. Total body water was unchanged within and between arms, 51.5 ± 1.4 kg versus 51.4 ± 1.3 kg. No differences appeared across the haematological hydration markers either.

The cohort conditions travel with that result: male, habituated coffee drinkers, at a moderate intake, at rest in free living. It does not describe a caffeine-naive athlete, and it does not describe a large acute dose. Work in the other direction — Seal and colleagues in Frontiers in Nutrition, 2017 — found that coffee with high but not low caffeine content augmented fluid and electrolyte excretion at rest, which is the honest framing: habitual intake, no measurable dehydration; large acute dose, some additional excretion.

Neither of those is a weight-cut study. The practical reading is that an athlete who already drinks coffee is not going to shift meaningful mass by drinking more of it, and the thing caffeine actually is relevant to here is contamination — stimulants are the single largest contaminant class in the adulteration literature, appearing in 21 of the 44 studies. For caffeine's own performance evidence in fighters, caffeine for fighters is the article.

11. A worked scenario

This is arithmetic on published figures, framed as a scenario. It is not a plan, and Fighter Cut has no coached roster — nothing here describes an athlete we have observed.

Take a 70 kg athlete two days from a day-before weigh-in, sitting 2.5 kg over the limit. The temptation to reach for a pill is a mass problem: 2.5 kg is 3.6% of body mass, and fluid is the only compartment that can move that fast.

Run the numbers that actually exist. Caldwell's cohort reached a mean 4.1% loss — for this athlete, about 2.9 kg — and the groups that got there by diuretic or sauna had lower maximal oxygen consumption, oxygen pulse, blood lactate and workload than the group that got there through exercise. Those were 62 non-endurance athletes in 1984, not fighters, and the deficit is close to but not identical to this scenario's. It is the only controlled comparison there is, and it says the route matters.

Set the regulatory side beside it. A prescription diuretic here is an anti-doping rule violation whether or not the athlete makes the limit, whether or not they win, and whether or not anyone intended to mask anything. The comparable published outcomes are one year, reduced only where a contaminated product was proven. Weigh 2.5 kg against twelve months of not competing.

Then the part that has no number attached. In the 2026 combat-sports cohort, the athletes arriving at the weigh-in on a protocol that included diuretics showed creatinine about 21% above baseline and mean eGFR down from 97.7 to 79.1 mL/min/1.73 m². This scenario's athlete has no way to know where in that distribution they sit, because nobody is drawing their blood on weigh-in morning.

The arithmetic that actually resolves the scenario is upstream. A 2.5 kg gap at 48 hours is a camp-planning outcome, not a fight-week emergency: it reflects where walking-around weight sat six weeks earlier. That is the tractable version of the problem, and it is the one a weight plan built from today to the weigh-in — the thing Fighter Cut does — can act on, because it shows the gap while there is still time for it to be a nutrition problem rather than a fluid one.

What happens after the scale is a separate question with its own evidence; how to rehydrate after a weigh-in covers it, and hydration testing at weigh-ins covers what a commission can actually detect when it checks.

12. Who this evidence does not cover

Nearly every cohort cited here is adult, male and professional, and several are small.

The 2026 kidney study is 30 male combat athletes. Caldwell is 62 non-endurance athletes in 1984; the abstract does not report their sex composition, and they are not fighters. Killer's coffee trial is 50 habitual male coffee drinkers. Kasper's case report is one male MMA athlete. The Clare dandelion pilot is 17 people with no control arm. The USADA sanctions are individual cases, not a sample of anything.

Women are under-represented across this literature, and the differences that matter are not adjustable with a coefficient. Total body water as a fraction of body mass differs, and cycle phase affects fluid balance and sodium handling. A figure measured in men does not transfer by scaling it.

Adolescents are barely present at all, and they are the population where scholastic wrestling puts the most athletes into weight-cutting situations. The NCAA's 2025-26 Men's Wrestling Weight Management Program packet bans diuretics — "for example, water pills" — during the playing rules competition season, from 1 September to the end of that season, alongside saunas, vapour-impermeable suits, stimulants and over-heated facilities. Note the two conditions that travel with it: it is the men's collegiate wrestling programme only, and the ban as written is scoped to the competition season rather than to the whole year. That is a narrower prohibition than S5, which has no seasonal boundary at all.

Nothing here is an argument that a diuretic prescribed for a medical condition should not be taken. That is a decision for the prescribing clinician, and in tested sport it runs through the TUE process with the athlete's anti-doping organisation. This article is about diuretics used as a weight-cutting method.

What we could not verify

Any count of deaths caused by diuretics in combat sports. The rapid-weight-loss literature documents fatalities without tallying them, and the three 1997 collegiate wrestling deaths documented by CDC had no diuretic implicated in any of the three cases. Named fighter deaths circulated as diuretic deaths trace to journalism and promoter statements; we could not obtain a coroner's report or a commission finding for any of them, so no figure appears above.

Any body-mass outcome for a commercial over-the-counter or herbal water pill. We found no human trial reporting one. The dandelion pilot measured urination frequency in 17 uncontrolled subjects. The "5–10 lb in 24 hours" figure is untraceable to any study and is not printed here as anything but a marketing claim.

The full-text pharmacology for the nephron map in section 4. Three attempts to obtain a review covering all four classes were blocked — one journal returned 403, two sources sat behind a CAPTCHA. The mechanisms and adverse-effect sets given are standard clinical pharmacology, presented as background rather than as a fetched finding, and the potassium-sparing hyperkalaemia point in particular should be confirmed with a clinician rather than acted on from this page.

That pamabrom is the active ingredient in most US over-the-counter water pills. The exemption for pamabrom is verified word for word in the 2026 List. The claim about which products contain it is common labelling knowledge and we found no primary source for it, so section 2 states the exemption and FAQ 11 handles the product question by telling you to read the panel.

Kasper 2019's figures at full text. Those values are taken from the abstract, not from the full paper.

Any state athletic commission's own diuretic rule, threshold or order. We fetched none. The California suspension and fine recorded in section 7 come from USADA's own announcement, not from a CSAC document.

The edition problem, structurally. The Prohibited List is revised annually. Everything in section 2 is the 2026 edition, in force from 1 January 2026, and it must be re-checked against the edition current at the time of reading.

Sources

Sourced to

1. Prohibited List 2026 — World Anti-Doping Agency, International Standard, in effect 1 January 2026, S5 Diuretics and Masking Agents (page 12)
2. Acetazolamide — U.S. Anti-Doping Agency, Spirit of Sport, accessed 2026-09-23
3. Differential effects of sauna-, diuretic-, and exercise-induced hypohydration — Caldwell JE, Ahonen E, Nousiainen U, J Appl Physiol Respir Environ Exerc Physiol 1984;57(4):1018-23, PMID 6501022
4. Acute Kidney Injury Associated With Dehydration Protocol Used by Combat Sports Athletes — Translational Sports Medicine 2026, doi:10.1155/tsm2/2946676, PMID 41635648
5. Case Study: Extreme Weight Making Causes Relative Energy Deficiency, Dehydration, and Acute Kidney Injury in a Male Mixed Martial Arts Athlete — Kasper AM, et al., Int J Sport Nutr Exerc Metab 2019;29(3):331-338, doi:10.1123/ijsnem.2018-0029, PMID 29989458
6. Undeclared prohibited substances and pharmacological adulterants in dietary supplements: prevalence, detection, and risks in sport — Al-Saad N, Aljaal S, Alessa J, Santhosh ME, Front Sports Act Living 2026;8:1740663, 13 March 2026, doi:10.3389/fspor.2026.1740663, PMID 41908212
7. An alternative structured weight management protocol to rapid weight loss in mixed martial arts: a prospective interventional study of pre-competition weight management strategies in professional athletes — Maurício CA, Artioli GG, Gonçalves AF, et al., Front Nutr 2025;12:1581698, 8 October 2025, doi:10.3389/fnut.2025.1581698, PMID 41132567
8. Hyperthermia and Dehydration-Related Deaths Associated with Intentional Rapid Weight Loss in Three Collegiate Wrestlers — North Carolina, Wisconsin, and Michigan, November–December 1997 — Centers for Disease Control and Prevention, MMWR, 1998
9. No Evidence of Dehydration with Moderate Daily Coffee Intake: A Counterbalanced Cross-Over Study in a Free-Living Population — Killer SC, Blannin AK, Jeukendrup AE, PLOS ONE 2014;9(1):e84154, doi:10.1371/journal.pone.0084154, 9 January 2014
10. Coffee with High but Not Low Caffeine Content Augments Fluid and Electrolyte Excretion at Rest — Seal AD, Bardis CN, Gavrieli A, et al., Front Nutr 2017;4:40, 18 August 2017, doi:10.3389/fnut.2017.00040, PMID 28868290
11. The diuretic effect in human subjects of an extract of Taraxacum officinale folium over a single day — Clare BA, Conroy RS, Spelman K, J Altern Complement Med 2009;15(8):929-34, PMID 19678785
12. Uva Ursi — LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, National Institute of Diabetes and Digestive and Kidney Diseases, PMID 32364691
13. Carls John de Tomas Accepts Doping Sanction — U.S. Anti-Doping Agency, 5 February 2018
14. Anderson Silva Accepts Doping Sanction — U.S. Anti-Doping Agency, 18 July 2018
15. Compounding Pharmacies Supply Tainted Supplements Behind Three Positive Tests — U.S. Anti-Doping Agency, 23 April 2018
16. Jennifer Maia Accepts Doping Sanction — U.S. Anti-Doping Agency, 15 January 2019
17. Arika Skoog Accepts Doping Sanction — U.S. Anti-Doping Agency, 26 October 2022
18. International society of sports nutrition position stand: nutrition and weight cut strategies for mixed martial arts and other combat sports — Ricci AA, Evans C, Stull C, et al., J Int Soc Sports Nutr 2025;22(1):2467909, doi:10.1080/15502783.2025.2467909, PMID 40059405
19. 2025-26 NCAA Men's Wrestling Weight Management Program Packet — National Collegiate Athletic Association, 2025-26 edition, accessed 2026-09-23

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