Matcha is a finely ground powder made from specially cultivated green tea leaves, and its vibrant color has made it a popular beverage. Unlike traditional steeped tea, consuming matcha means ingesting the entire leaf, which concentrates its natural compounds. Many people who enjoy matcha notice a peculiar change afterward: their urine may appear a startling shade of greenish-yellow. This observation, while sometimes alarming, is a common and temporary effect. It results from the high concentration of natural pigments that the body processes and eliminates.
The Direct Answer: Why Matcha Causes Color Changes
Matcha’s intense color is directly responsible for the change in urine hue due to the tea’s high levels of chlorophyll. The leaves used for matcha are shade-grown before harvest, a process that significantly boosts their chlorophyll content, producing the powder’s characteristic deep green color. Chlorophyll is a pigment the human body cannot fully metabolize, meaning much of it passes through the digestive tract relatively unchanged. As the kidneys process and eliminate this pigment, it imparts a noticeable greenish tint to the urine.
This green tinge is often amplified by riboflavin (Vitamin B2), which is abundant in matcha and other green teas. Riboflavin is a water-soluble vitamin, and the body only absorbs what it immediately needs for metabolic processes. Any excess riboflavin is efficiently filtered out by the kidneys and excreted in the urine. Riboflavin has a naturally bright, fluorescent yellow color that, when mixed with the excreted chlorophyll, creates a distinct greenish-yellow shade.
Understanding Normal Urine Pigmentation
The typical straw-yellow color of urine is derived from a compound called urobilin. Urobilin is a natural byproduct of the body’s process of breaking down old red blood cells and is the substance that gives urine its standard appearance. This pigment is formed when bilirubin, a yellow substance resulting from hemoglobin breakdown, is processed by gut bacteria and then excreted. The concentration of urobilin in the urine is what determines the final shade of yellow.
A person’s hydration level is the primary factor affecting the intensity of this color on a daily basis. When someone drinks plenty of water, the urobilin is highly diluted, resulting in pale, almost clear urine. Conversely, low fluid intake concentrates the urine, leading to a much darker amber or deep yellow hue. The color change after consuming matcha is an instance of an external pigment temporarily overriding this usual urobilin-based coloration.
When Green Urine Signals a Medical Concern
While matcha is a benign cause of altered urine color, green urine that is not linked to diet can sometimes indicate a different underlying issue. Certain medications are well-known to cause green or blue-green urine as a temporary side effect, including some anti-inflammatories, specific antidepressants, and the anesthetic propofol. These drugs contain chemical compounds or dyes that are excreted through the renal system, much like the pigments in food.
In rare cases, green urine can signal a bacterial infection, most notably those caused by Pseudomonas aeruginosa. This bacterium produces pigments called pyocyanin and pyoverdin, which create a blue-green color in the urine. If the green coloration is persistent, unexplained by diet or medication, and accompanied by other symptoms like pain or unusual odor, it may warrant a consultation with a healthcare provider. This distinction is important.