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Diuretics are drugs that enhance urine output (diuresis) and are widely used in amateur and professional bodybuilding. Their ability to dry the body / reduce weight in a short time has been appreciated by many bodybuilders and athletes alike. However, some make the mistake of thinking that diuretics are fat burners, when no diuretic comes close to burning subcutaneous or visceral fat.

It is also a common misconception that diuretics are relatively safe. Perhaps in the recommended doses and for the intended purpose. But at the dosages and purposes for which they are used by athletes, diuretics are definitely not safe. Deaths in bodybuilding due to overdose of diuretics in preparation for a competition are far from uncommon.

Therefore, today we want to talk in detail about diuretic drugs: their types, what mechanisms of action they have and side effects. We hope this article serves as a cautionary tale for those athletes who are planning or already taking diuretics for weight loss.

What is Diuretic?

As already mentioned, diuretics are drugs that cause or enhance the excretion of fluid from the body. Used in strength sports, bodybuilding and martial arts, diuretics help to achieve density, muscle relief, reduce body weight, which allows you to compete in a lower weight category, gaining an advantage over rivals.

But originally, diuretics were not developed for this at all. They were synthesized purely for medicinal purposes: they are prescribed for hypertension (high blood pressure), kidney disease and heart failure, among other things. When a person has a high pressure for a long time, the removal of water allows you to effectively, and most importantly, quickly lower it.

Diuretics directly affect fluid and salt balance (electrolyte balance). The use of diuretics without a medical reason is fraught with dehydration, acute potassium deficiency, and even deadly. This, and the ability of certain diuretics to mask the use of real doping, explains why many of them are banned from sports.

Why Do Bodybuilders Use Diuretics?

A typical training cycle for a more or less serious bodybuilder looks like this: he spends several months of the year training to gain muscle mass, then weeks (maybe months – depending on the level and schedule of the athlete) of preparation for the competition begin, which means drying the body. During this period, the diet is significantly tightened and the cardio load increases, plus, diuretics are connected.

Do not be fooled by the appearance of the jocks, who, when they go on stage, radiate strength and health. In fact, flaunting unrealistic pumping, drawing and muscle vascularity during performance, professional athletes are often on the verge of life and death. They pump themselves so much with recreational drugs (from insulin to diuretics) that there are health consequences.

Surely you have at least once come across a video of a bodybuilder fainting on stage or behind the scenes.

Factors of size, proportion and muscle definition are paramount to winning bodybuilding. To get lean muscles before the competition, both excess fat and accumulated water must be removed from under the skin. Diuretics cope with the latter by 10/10. That’s what competitive pitching loves them for.

There is another reason for the popularity of diuretics in sports: the aforementioned ability to mask the use of hormones, peptides, steroids or pharmacy pharma, whose metabolites remain in the urine for a long time. Therefore, in professional circles, diuretics are also called “masking agents”.diuretics for bodybuilding

How Do Diuretics Work?

To understand the mechanism of action of diuretics, it is necessary to look at the anatomy and physiology of the kidney. This is the only way to understand what the health risks of diuretics are associated with.

Among the functions of the kidneys: filtration of harmful or unnecessary substances from the blood and control over the content of minerals (ions thereof) in internal fluids (electrolytes). That is, the kidneys can “throw” excess substances into the urine or, on the contrary, “hold” them in the body in order to avoid deficiency. Let’s clarify about electrolytes: in cells and intercellular space they are in the form of salt solutions, directly participating in biochemical reactions, such as maintaining the acidity level and water balance of tissues.

In particular, nerve impulses are transferred from cell to cell using an ionic mechanism that is provided by electrolytes. And, if you didn’t know, muscle contraction is impossible without a nerve impulse (first there is an impulse, then a contraction occurs).

Mechanism of Action

Most diuretics have a similar effect on the human body: after ingestion or injection, the active ingredient in the drug stimulates the excretion of sodium. Why sodium? Because 1 teaspoon of sodium salt retains up to 2 liters of water. Thus, the less sodium you have in your body, the lower your fluid levels, including the subcutaneous layers. In simple terms, diuretics interfere with the movement of sodium through the filtering elements of the kidneys, ultimately leaving the body with urine.


Deficiency of any one mineral implies a change in the mineral balance, which leads to disruption of vital functions in the human body. For example, with a deficiency of potassium and magnesium, muscle cramps occur. It would seem, what danger are cramps in the limbs? In the limbs – minimal. But our heart is also a muscle.types of diuretics

Types of Diuretics

There are four main groups of diuretics: osmotic, potassium-sparing, thiazide, and loop diuretics. We propose to consider in detail each group in order to understand which drugs are more effective / safer for bodybuilding purposes.

1. Osmotic Diuretics

Osmotic diuretics are designed for injection or infusion use. These are some of the most powerful diuretics in existence: they increase urine output up to 20% of the total sodium filtered by the kidneys; have an extremely indiscriminate mechanism of action, when, in fact, there is no filtration of useful and removal of unnecessary or harmful substances, which is fraught with severe electrolyte imbalance. In case of an overdose, the development of renal failure is likely.

In bodybuilding, for obvious reasons, they are almost never used, and in medicine they are prescribed mainly in severe cases, such as cerebral edema, an attack of glaucoma, prevention of shock kidney.

2. Potassium-Sparing Diuretics

Diuretics are lighter in their mechanism of action and end effects, however, they have a number of disadvantages that limit the use of potassium-sparing drugs for medical, especially sports purposes.

  • First, this type of diuretic reduces the reabsorption of sodium and water through the kidneys, but does not stop excreting them from the body. As the name suggests, the main difference between potassium-sparing diuretics and other types of diuretics is their ability to store potassium.
  • Secondly, with an individual predisposition and in case of an overdose, they can have the opposite effect: potassium accumulates in excess, sodium is retained, the balance of electrolytes is disturbed.
  • Third, taking potassium-containing supplements, even multivitamins, threatens electrolyte imbalance due to potassium surplus and sodium deficiency.
  • Fourth, there have been cases of cardiac arrhythmias, even sudden death, while taking potassium-sparing diuretics.

A clear demonstration of how dangerous a potassium surplus can be is the fact that this mineral is still used for the death penalty: a direct injection of potassium into the heart leads to its arrest and death of a person.

When using potassium-sparing diuretics in bodybuilding, potassium-containing dietary supplements should be avoided. Conventional potassium-rich foods are generally not a threat.

For the sake of fairness, it should be said that the use of other diuretics that do not store, but excrete potassium, provoking a deficiency of the mineral, is also accompanied by health consequences: muscle weakness, overwork, muscle pain and rhabdomyolysis, among others. When using them, on the contrary, you should use potassium-containing supplements, as well as those fortified with magnesium, since it is impossible to restore potassium levels without magnesium. Magnesium is also “washed out” along with urine.

3. Loop Diuretics

Perhaps the most common type of diuretic in bodybuilding. However, the popularity is due not to safety, but to the power of the drugs. Most of the complications following the use of recreational medications for sporting purposes arise precisely from loop diuretics. They got this name because they influence the Gentle loop (kidney area).

Loop diuretics interact directly with the kidneys and, like osmotic drugs, have a highly non-selective mechanism of action. Literally everything that comes to hand, including potassium and calcium, leaves, which is at least fraught with severe electrolyte imbalance.

Note that in traditional medicine, loop diuretics are prescribed for high blood pressure, swelling, blood poisoning (to remove toxins and other foreign compounds).

Side effects of loop diuretics include low blood pressure, increased blood viscosity, dehydration, fainting, seizures, and renal failure. When combined with other additives that remove fluid from the body, they are dangerous even at the lowest recommended doses.

4. Thiazides

Thiazide diuretics are also far from selective. Together with water from the body, they remove potassium and magnesium. The mechanism of action is due to a decrease in the re-absorption of sodium and fluid, simultaneously increasing the volume of urine.

One of the most unpleasant effects of thiazide diuretics is insulin resistance (they affect the sensitivity of cells to insulin), as a result, an increase in blood glucose levels. With natural or artificial tanning, it threatens to receive severe diuretics bodybuilding

Top 3 Diuretics for Bodybuilding

In martial arts, strength sports and bodybuilding, the following active ingredients are in greatest demand:

  • Thiazides: Hydrochlorothiazide;
  • Loop diuretics: Furosemide and Bumetanide;
  • Potassium-sparing diuretics: Spironolactone.

A common practice among athletes is the combined use of diuretics, for example, when a thiazide and a potassium-sparing drug are used together. This method, firstly, allows the use of the minimum recommended doses of diuretics, and secondly, it partially prevents the loss of potassium, which is otherwise inevitable.

1. Furosemide

Furosemide is marketed under the trade name of the same name. Despite its prescription drug supply, it is literally the most popular diuretic among bodybuilders. The demand for it is due to its low price and high efficiency. Certainly not without health risks.

furosemide for bodybuilding

2. Bumetanide

On sale it is represented by the names Bumex and Burinex, and is also produced under the trade name of the same name. It is a next-generation loop diuretic similar to Furosemide. Compared to previous generations, Bumetanide has improved bioavailability: the absorption rate reaches 80% and the drug can be taken with meals.

We add that, despite the novelty, Bumetanide has already appeared in scandals several times. In particular, it turned out that it was used as an active ingredient in the development of the StarCaps fat burner. Obviously, a significant portion of the mass that StarCaps burned was water, not fat.

bumetanide for bodybuilding

3. Spironolactone

Common names: Aldactone and Verospiron. Spironolactone is in demand not only among athletes but also in fitness. This is due to the ability to block androgen receptors, which weakens androgenic activity during an anabolic steroid cycle. Accordingly, the risk of virilization is reduced. This is in addition to the diuretic’s own effects – fluid excretion / weight loss.

spironolactone for bodybuilding

Side Effects of Diuretics

Most of the side effects of diuretics are associated with electrolyte imbalances. Also, men and women taking diuretics often experience stomach upset. And the most common consequence of their use is frequent urination, since this is the main way to remove excess fluid from the human body.

How likely is a fatal result? The risk is low, if you follow common sense: follow the recommendations, exclude contraindications for use. However, even in this case, there is no 100% guarantee of safety. Here are three examples when the use of diuretics by the most experienced athletes under the supervision of specialists still ended in failure.

In 1988, IFBB bodybuilder Albert Beckles, a multiple member of the Arnold Classic and Mr. Olympia, fainted on stage. Fortunately, the doctors managed to revive him. Subsequently, the jock admits that the cause of fainting in convulsions was severe dehydration while taking diuretics.

In 1992, French pro Mohammed Benaziza dies suddenly after winning the Dutch Grand Prix. The official cause of death is heart failure. During the preparation for the performance, the bodybuilder complained to colleagues of constant thirst, nausea and shortness of breath, which is a symptom of an overdose of diuretics, but decided not to go to the doctor.

In 1996, Austrian Andreas Münzer, also an IFBB professional, dies in hospital due to abdominal bleeding, liver and kidney failure. For 19 hours, surgeons fought for his life, but to no avail. It is assumed that the athlete has neglected the recommended dosages of sports pharmacology, including anabolic steroids and diuretics.

In general, several times a year news comes steadily from the competition, how another quality has lost consciousness on stage or behind the scenes, and then he is diagnosed with total dehydration. Usually everything is attributed to stress, but you and I know where the dog is buried.

side effects of diuretics

Most Common Side Effects

  • Dehydration (dehydration);
  • Violation of water and electrolyte balance;
  • Muscle cramps, cramps;
  • Lowered blood pressure;
  • Impaired coordination;
  • Dizziness and fainting;
  • Headaches;
  • General weakness;
  • Visual impairment;
  • Decreased appetite
  • Skin rash, gout;
  • Heartburn, vomiting, diarrhea;
  • Decreased cognitive function;
  • Hypersensitivity to ultraviolet light;
  • Decreased libido or erectile dysfunction;
  • Failure of internal organs;
  • Sudden death.


  • Calcium / potassium and magnesium deficiency;
  • Avitaminosis;
  • Dehydration symptoms;
  • Pancreatitis and gout;
  • Insulin resistance or diabetes;
  • Lupus;
  • Renal failure;
  • Lowered blood pressure;
  • Heart failure;
  • Violation of the menstrual cycle;
  • Third trimester of pregnancy;
  • Childhood or old age;
  • Allergic reactions.

It is important to understand that contraindications for use vary from drug to drug (depending on the active ingredient). However, if you single out general prohibitions, you get a list of more than 10 items.


The benefits of diuretics for weight loss are controversial. It depends on what you mean by losing weight? If it is fat burning, then they are completely useless. If overall weight loss is then, yes, diuretics will be effective. Less water in the body means less mass.

At the same time, even today, dishonest manufacturers continue to position their own diuretics as fat burners. The buyer, who does not understand the issue, is unaware that he is losing weight solely due to the removal of liquid. Or worse, there are companies that add diuretics to dietary supplements as a hidden ingredient. The consequences of taking such drugs can be fatal.

Be on the lookout, and most importantly, remember that no results of training and dieting are worth the lost health!