Is Black Tea A Diuretic? You Should Be Aware Of This!

Almost all of us have experienced puffy eyes and a swollen face after a good night’s sleep, isn’t it? This is a completely harmless effect that occurs due to the overnight build-up of fluid in our body. It can take few hours to get rid of this puffiness and start the day completely. Many of us would like to speed up this process and make ourselves more presentable in the morning. Black tea can be one of your best choices in achieving this. Also, black tea helps to get rid of the excessive amount of fluid from our body by a process called diuresis. 

Black tea acts as a diuretic through caffeine. Apart from its various health-related benefits, caffeine in the black tea helps to eliminate excess water from our body through diuresis. The diuretic effect of black tea is beneficial in everyday life and some common disease conditions. 

What is a diuretic?

A diuretic is a substance that increases the amount of salt and water eliminated from our bodies. As we all know, the kidney is the main organ in our body that does this function.

The kidney filters blood and produces urine which contains mostly excessive water. Diuretics act on the kidney to increase the production of urine. Different diuretics act via different mechanisms to bring out this same function.

Generally, they help the kidneys to get rid of the extra amount of fluid in our bodies. This fluid build-up is technically known as water retention.

Diuretics are mainly used as medications (commonly called water pills) for certain medical conditions where there is an excessive build-up of fluids in the body. These conditions include high blood pressure, heart failure, liver disease, kidney disease, brain injuries, and many more [1]Arumugham VB, Shahin MH. Therapeutic Uses Of Diuretic Agents. [Updated 2021 Mar 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan

What are the types of diuretics?

Diuretics can be mainly classified as synthetic and natural. Apart from artificial medications, plenty of natural substances can help remove excess water from our bodies. Following is a list of such substances traditionally used as diuretics in many parts of the world [2]Sameer Hedaoo, Advantages of natural diuretics over synthetic diuretics as a part of treatment, february 2019world journal of pharmacy and pharmaceutical sciences 8(3):310-327 DOI:10.20959/wjpps20193-13240.

Surprisingly, black tea occupies a significant place in the list;

  1. Black tea 
  2. Coriander 
  3. Fennel 
  4. Dandelion 
  5. Radish 
  6. Melon 
  7. Horse gram, etc. 

These naturally occurring diuretics are known to be used by many traditional medicinal enthusiasts to relieve symptoms of water retention. Similarly, we can incorporate this effect daily to get rid of excessive water from our bodies.

Is black tea considered a diuretic?

Whether black tea is a diuretic and, if so, how it acts that way are two questions that were looming in my mind for a long time as a traditional black tea lover. Fortunately, researchers have conducted various scientific studies to identify and evaluate this. 

A group of researchers has conducted a study to assess Sri Lankan hot black tea brew’s potential in acting as a diuretic [3]Ratnasooriya  WD,  Fernando  T,  Ranatunga  R.  Diuretic activity of  Sri  Lankan black tea  (Camellia sinensis  L.)  in rats. Phcog  Res.  2009;1:4-10.. This is a widely consumed black tea variety in the world.

In this study, different doses of black tea infusions were provided to a group of rats, and their urine output was measured. To compare, another group of rats has been provided with frusemide, which is a well-known potential water pill.

This study has shown that brewed black tea infusion has a mild to moderate (even if not as potent as frusemide) diuretic effect. Depending on the dose of the black tea infusion, the diuretic effect has changed. The higher the concentration of black tea taken, the higher the production of urine.


Also, this effect was seen within two hours of consumption of black tea and lasted for around three hours. This research has also found that decaffeinated black tea didn’t have a diuretic effect. This gives us a clue to the main component in black tea responsible for this function; caffeine

A review regarding the diuretic action of caffeine has found that ingestion of large doses of caffeine (around 250mg – 300mg, which is equal to 5 – 8 cups of tea) results in a stimulation of urine output [4]Maughan RJ, Watson P, Cordery PA, Walsh NP, Oliver SJ, Dolci A, Rodriguez-Sanchez N, Galloway SD. A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index. Am J Clin Nutr 2016;103(3): 717–23..

However, it also shows that this effect is more in individuals who haven’t consumed caffeine for a few days or weeks. Regular consumers of caffeine show much less effective compared to the former group. This is due to the effect called tolerance that has been developed during regular consumption.

The black tea you consume, the higher the concentration needed to get its diuretic effect. So if you are someone who cannot live without your two or three cups of black tea every day, you might need a robust cup of tea to achieve the diuretic effect. 

The action of caffeine in diuresis 

According to scientific evidence, caffeine in black tea acts in several pretty amazing ways to bring out its diuretic function [5] Sharangi, A. (2009). Medicinal and therapeutic potentialities of tea (Camellia sinensis L.). Food Res. Int. 42:529–535..

The kidney is the principal organ where the production of urine occurs. It is among the first few organs which have the highest blood supplies in the body. This is a marvelous mechanism of nature to facilitate the excretion of unwanted substances such as urea, uric acid, various salts, and excess water from the blood.

Caffeine is known to increase this blood flow even more, hence producing more urine. It also acts inside the kidney is a complex mechanism to facilitate more and more urine production. Also, it acts on the bladder to signal the need to urinate. 

How can the diuretic effect of black tea be useful?

Most of us are naturally addicted to the early morning tea that gives us a good start for the day. Starting from the exceptional aroma until the incomparable feeling of refreshment, we are slaves to our morning tea.


The good news is, the effects of a cup of black tea don’t end with its feeling of refreshment or its well-known antioxidant properties. It helps us fight the puffy appearance after a pretty long sleep. This is as mentioned above via its diuretic properties.

Diuretics, may it be natural or synthetic, helps us excrete the extra fluids from our body. Even though naturally occurring diuretics are used in various traditional medical practices, it’s not researched or experimented enough to be incorporated into the pharmaceutical industry.

This might have reasonable explanations. However, naturally occurring substances will surely outperform synthetic diuretics because they tend to have fewer side effects. 

Currently, the world mainly consists of an ageing population. Most adults are diagnose with various long-term disease conditions which require the use of diuretic medications. Either a close relative of us, or we already suffering from such a condition, including high blood pressure, heart failure, cirrhosis, liver disease, and kidney disease.

Habitual drinking of black tea can be a beneficial addition to their lifestyles. This has many reasons. Patients with above mentioned chronic diseases tend to form blood clots in their blood vessels.

This leads to fatal outcomes due to the blockage of blood vessels from these clots.

Black tea is a known antioxidant that prevents the formation of such clots and protects us from the main killers of the modern world; heart attacks and strokes.

In addition to that, the diuretic properties of black tea can help get rid of the excessive fluids in their bodies.  

These individuals often require a multitude of medications to control their disease conditions. In most cases, their medications interact with each other and bring out harmful effects. Adding a natural diuretic to their life can reduce the need for a synthetic diuretic.

This can help overcome harmful chemical interactions of their drugs to some extent. However, changes in medications and doses should always be done under the supervision of a doctor. 

Can the diuretic effect of black tea be harmful?

The diuretic effect of black tea can be a blessing in conditions with water retention, and it has a completely harmless effect in normal individuals. Unfortunately, there are situations where you don’t need excessive urine production, and it could even be harmful. 

One is obviously when you are going to sleep. Instead of a good night’s sleep, none of us would opt for waking up in the middle of the night two or three times to empty the bladder.

This is enhanced because diuretic medications are also avoided as much as possible during the night. So a cup of tea just before bed is not the best idea unless you want to stay awake. 


There are certain medical conditions where excessive diuresis should avoid. Some of those are dehydration, conditions with urinary retention, and an overactive bladder. It’s worthwhile knowing these conditions because, at one point, we or someone we know may come across such a situation.

Let’s untwist one by one.

  • Dehydration

Dehydration, as we all know, is the excessive loss of body water. This loss of water occurs at a rate in which we can’t replace [6]Thomas DR, Cote TR, LawhorneL, etal.; Dehydration Council. Understanding clinical dehydration and its treatment. J Am MedDir Assoc 2008;9:292–301.

Hot weather conditions, diarrheal diseases, excess vomiting (particularly in pregnancy), elderly individuals, and hospitalized patients who have undergone major surgeries or trauma are the groups who are most likely to be dehydrated.

This is because they have already lost a lot of water from their bodies or cannot replace the lost amount. So it’s not a good idea to provide excessive amounts of caffeine (such as 5 – 8 cups of black tea) to these individuals.

However, for normal pregnant and breastfeeding mothers, moderate consumption of black tea is ideal for hydrating because the unwanted diuretic effect occurs mainly with high caffeine consumption [7] Maughan RJ,  Griffin J:  Caffeine ingestion and fluid balance: a review.  J Hum Nutr Diet  2003,  16:411–420.

  • Overactive bladder

Overactive bladder is a condition where there is an increased need to pass urine compared to a normal individual. These patients find it difficult to hold the urine.

Interestingly, excessive caffeine consumption also considers a behavior that can cause or contribute to the symptoms of an overactive bladder [8]Ouslander JG (2004) Management of overactive bladder. N Engl J Med 350:786799.. This occurs due to problems at the brain level, spinal cord level, or problems at the bladder and other organs of the urinary tract.

However, the outcome is an excessive passage of urine, leading to an uncomfortable lifestyle for the affected individual. So to prevent further damage, caffeinated beverages such as black tea are best avoided in patients with overactive bladder.

  • Urinary retention

Urinary retention is the inability of our urinary system to pass urine [9]Verhamme KM, Sturkenboom MC, Stricker BH, Bosch R: Drug-induced urinary retention: Incidence, management and prevention. Drug Saf 31: 373–388, 2008. This condition can also have a lot of causes.

Some of them include various drugs (antidepressants, antipsychotics, opioids such as morphine, pain killers such as diclofenac sodium and ibuprofen, etc.), major surgeries [10]Tammela  T,  Kontturi  M,  Lukkarinen  O. Postoperative urinary retention.  I.  Incidence and predisposing factors.  Scand J Urol Nephrol  1986; 20:197-201., and most commonly, prostate enlargement of the adult males [11]Billet  M,  Windsor  TA.  Urinary  Retention.  Emerg  Med  Clin  N  Am. 2019;37(4):649-60..

All these causes make it hard for the individual to pass urine. The collection of urine in the bladder results in severe pain and discomfort. Caffeinated beverages such as black tea, by contributing to excess urine production, can worsen the situation in these patients. So they are advised to avoid such drinks.


Black tea is a proven diuretic when consumed in a high concentration. Its diuretic properties can be effectively utilized in normal individuals and in serious major organ failure conditions where there is fluid retention. We should be careful because, in conditions where diuresis is harmful such as dehydration, black tea consumption should be limited or avoided. 


Is decaf black tea a diuretic?

Decaf black tea does not consider a diuretic because it lacks caffeine. Practically, decaffeinated black tea contains trace amounts of caffeine. However, that concentration isn’t enough to cause a diuretic effect. Yet, the water content in a cup of decaf black tea can give rise to a mild diuresis.

Is unsweetened black tea a diuretic?

Yes, unsweetened black tea is a naturally occurring diuretic. Unsweetened black tea is not different from a sweetened cup of black tea when it comes to its diuretic effect. This is because the main component responsible for the diuretic effect in tea is caffeine. 

Unsweetened black tea is especially beneficial in anyone interested in maintaining pretty decent blood sugar levels. Especially those with diabetes. However, the diuretic effect you get from an unsweetened cup versus a sweetened one is essentially the same. 

Is earl grey black tea a diuretic?

Earl Grey tea is black tea with the addition of oil of bergamot. It acts as a diuretic because it contains a considerable amount of caffeine. In addition to its unique aroma and flavor, earl grey black tea provides the diuretic benefit to the user in relieving the effects of water retention. 

Is black tea a natural diuretic?

Black tea is one of the most effective natural diuretics. Derived from the plant Camellia sinesis, it produces its diuretic effect via the natural stimulant; caffeine. The diuretic effect of black tea can aid in controlling the symptoms of water retention such as early morning facial puffiness.