Peptide & Experimental

Torasemide

Loop diuretic (water pill); approved prescription-only medicine, banned in sport at all times as a diuretic · torsemide, torasemide, loop diuretic

9 min read 10 sources, checked November 12, 2026

In the BK-Score: Well supported – human evidence 8 out of 10, safety data 8 out of 10. The data in humans are solid.

Torasemide is a loop diuretic, one of the strongest water pills there is. It is approved for fluid retention and high blood pressure and is one of the standard drugs in heart failure. Because it removes water from the body so quickly, it is also used in bodybuilding before competitions, and that is why it is on the prohibited list in sport.

In short

Torasemide reliably does what it is approved for: it flushes out water. For a long time it was considered the better choice over furosemide, because it is absorbed more evenly as a tablet and an early observational study showed fewer deaths. The large randomized TRANSFORM-HF trial with 2,859 patients did not confirm this: after a hospital stay for heart failure, equal numbers of people died on both drugs. In bodybuilding, the diuretic effect is used to lose water before going on stage. There is no study on this, but dangerous derailments of potassium and fluid balance are documented, and for torasemide a death after use without a prescription.

What torasemide is

Like furosemide, torasemide belongs to the loop diuretics, the strongest water pills. According to the US prescribing information, it is approved for treating fluid retention (edema) in heart failure, kidney or liver disease and for lowering high blood pressure. In Germany, torasemide is prescription-only.

Prescribed by a physician, it relieves the heart and lungs when fluid builds up. In sport, the same effect is used for other reasons: diuretics serve to lose weight quickly, for example for a weight class, and to mask other prohibited substances in urine. That is why they are on the World Anti-Doping Agency’s prohibited list.

How it works

Torasemide acts in the thick ascending limb of the loop of Henle, a section of the kidney tubule. There it inhibits a transporter that reclaims sodium, potassium and chloride from the urine. As a result, the body excretes more salt and water. This site of action has also been confirmed in humans in clinical pharmacology studies.

As a tablet, about 80 percent of torasemide is absorbed, and this varies little between people. The effect begins within an hour and lasts about 6 to 8 hours. It is broken down mainly in the liver. Along with water, potassium, sodium, magnesium and calcium are also lost, and that is precisely where the risk lies.

Molecular target

Inhibitor Solute carrier family 12 member 1 Gene SLC12A1 · UniProt Q13621

Data: ChEMBL, UniProt · assigned automatically, as of November 12, 2026. A known target does not mean an effect in humans is established.

What is well supported

Diuretic effect. In a meta-analysis of 10 randomized trials, torasemide and furosemide each clearly reduced weight through water loss, with no difference between the two.
Equivalent to furosemide in heart failure. In TRANSFORM-HF with 2,859 patients, 26.1 percent died on torasemide and 26.2 percent on furosemide.
Approved uses. Edema in heart failure, kidney and liver disease, and high blood pressure, with well-described absorption and duration of action.
The risks are known too. Dehydration, kidney damage, mineral losses and hearing disorders are listed in the prescribing information, not in assumptions.

What the studies show

Mentz 2023: TRANSFORM-HF

2,859 patients who had been hospitalized for heart failure were randomly assigned to torasemide or furosemide at 60 hospitals in the US; the dose was set by the treating physicians. The trial was open-label, so physicians and patients knew which drug was given. Over a median of 17.4 months, 26.1 percent died on torasemide and 26.2 percent on furosemide (hazard ratio 1.02). Death or hospitalization within 12 months: 47.3 versus 49.3 percent, no significant difference. The results were similar in all prespecified subgroups, including by the pumping function of the heart.

Eid 2026: meta-analysis

10 randomized trials with 4,011 patients with heart failure were analyzed. Between torasemide and furosemide there was no difference in mortality (odds ratio 0.99), in hospitalizations for heart failure (0.96) or in weight loss; both drugs clearly reduced weight.

Cosín 2002: TORIC

In this post-marketing observational study, 1,377 patients with heart failure received torasemide, furosemide or other diuretics for one year, not randomly assigned. On torasemide 2.2 percent died, otherwise 4.5 percent; heart failure improved more often, and abnormally low potassium levels were less common (12.9 versus 17.9 percent). The study was not designed as a mortality study. It was the reason for the hope that TRANSFORM-HF later tested.

Nara 2025: death from misuse

A woman in her early 40s had taken torasemide without a prescription for about six weeks and died. The autopsy showed altered kidneys and tissue findings as in pseudo-Bartter syndrome, kidney damage from persistent potassium deficiency; kidney values were elevated. The forensic pathologists determined the cause of death to be poisoning from prolonged torasemide misuse. According to the authors, it is the first published autopsy case of its kind.

Pfisterer 2020: bodybuilder with potassium deficiency

A 22-year-old bodybuilder had taken a different diuretic, triamterene with hydrochlorothiazide, without a prescription and at the same time drank little. He developed muscle cramps, sensory disturbances, paralysis of all four limbs and was unable to empty his bladder. His potassium was 1.8 mmol/l, and the ECG showed a QT interval of 625 milliseconds, a sign of risk for cardiac arrhythmias. With fluids and potassium given intravenously, he recovered within two days.

Where the data stop

No advantage over furosemide. The signal from TORIC was not confirmed in the randomized trial. TRANSFORM-HF, however, was open-label, not blinded.
No study on sport. Whether dehydration before a competition improves appearance on stage has not been examined for torasemide in any controlled study.
Misuse known only from individual cases. The harms are described in case reports; how often they occur has not been systematically recorded.
The studies concern sick people. All efficacy data come from people with heart failure or fluid retention, not from healthy people who want to lose water. How the mineral losses affect healthy people with training and dieting is shown only by the case reports, for example on potassium.

Status, approval and legal

Torasemide is an approved medicine and prescription-only in Germany (annex 1 of the German Ordinance on Prescription-Only Medicines). In the US it is approved for treating edema in heart failure, kidney and liver disease, and high blood pressure.

In sport, torasemide is listed by name on the WADA Prohibited List 2026 under S5, diuretics and masking agents, and is banned in and out of competition. In Germany it is not listed in the annex of the German Anti-Doping Act; the ban on acquiring and possessing non-small quantities therefore does not apply. Manufacturing, trading, supplying and prescribing for doping in sport are, however, prohibited and punishable. Anyone who, as an elite athlete or with substantial income from sport, uses torasemide without a medical reason to gain an advantage in competition is also committing a criminal offense.

Safety

The US prescribing information lists: dehydration, reduced blood volume and a drop in blood pressure, worsening kidney function up to acute kidney failure, deficiency of potassium, sodium, magnesium and calcium, a shift in acid-base balance, rising blood sugar and rising uric acid, rarely gout, as well as tinnitus and hearing loss, usually reversible. The most common side effect in studies was increased urination. Without medical monitoring of blood salts, these shifts are often only noticed when the muscles or heart react: in the case reports, it was paralysis and a dangerously altered ECG, in the worst case death.

When prescribed by a physician, blood salts and kidney values are therefore checked regularly. This supervision is missing when torasemide is taken without a prescription.

BK-Score Well supported

Human evidence		8
Mechanism		9
Safety data		8
Hype gap		6
Track record of use		9

Evidence 8, because the diuretic effect is established and the comparison with furosemide has been tested in randomized form: in TRANSFORM-HF in 2,859 patients with no difference in mortality (26.1 versus 26.2 percent, Mentz 2023), supported by a meta-analysis of 10 trials with 4,011 patients (Eid 2026); not higher, because TRANSFORM-HF was open-label and not blinded and there is no study on dehydration in sport. Mechanism 9, because the site of action in the loop of Henle, absorption and metabolism have been measured in humans. Safety 8, because the side effects are known from the prescribing information and large outcome trials; for misuse there are only case reports (Nara 2025, Pfisterer 2020) – a high number means well studied, not harmless. Hype 6, because the hope from the non-randomized TORIC study (Cosín 2002) that torasemide lowers mortality more than furosemide was not confirmed in randomized form, and dehydration before competitions does without any evidence of benefit. Use 9, because torasemide has been prescribed widely for decades for heart failure, edema and high blood pressure. Direction mixed: the diuretic effect is established, an advantage over furosemide is not, and in sport an unproven benefit stands against documented harm. For comparison: statins (10/9/9/7/10), metformin (8/8/9/5/10), liothyronine (4/9/6/3/8) as a medicine misused in sport.

The score rates the state of knowledge, not the substance. A high safety-data value means well studied – not harmless. A high track-record value means used long and widely – that is not proof of efficacy.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)

Frequently asked questions about Torasemide

Is torasemide better than furosemide?

Tested in randomized form: no. In TRANSFORM-HF with 2,859 patients after a hospital stay for heart failure, equal numbers of people died on both drugs, 26.1 versus 26.2 percent. A meta-analysis of 10 trials also found no difference. The advantage seen in the older TORIC study came from a non-randomized comparison.

Why do bodybuilders take water pills?

To lose water, and with it weight, quickly before a competition. In sport, diuretics are also used to mask other prohibited substances in urine. There is no study showing a benefit for appearance on stage.

How dangerous is misuse?

Life-threatening potassium losses with paralysis and ECG changes after diuretic misuse in bodybuilders have been described. For torasemide, a death after weeks of use without a prescription has been examined at autopsy and published. The prescribing information lists dehydration, a drop in blood pressure, kidney failure and hearing disorders.

Is torasemide banned in sport?

Yes. As a diuretic it is on the WADA Prohibited List under S5 and is banned in and out of competition. In Germany, supplying and prescribing it for doping are punishable under the German Anti-Doping Act, and for elite athletes so is using it to gain an advantage in competition.

Is torasemide available without a prescription?

No. Torasemide is prescription-only in Germany; it is listed in annex 1 of the German Ordinance on Prescription-Only Medicines.

Sources

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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-11-12.