Which acid is present in human urine?

As humans, we are not always proud of what our bodies produce. But there’s one thing we can all agree on: urine. It’s a subject that often goes uncelebrated, but it’s time to shine the spotlight on this golden liquid and answer the question: which acid is present in human urine?

Urine 101

Before diving into acids, let’s do a quick rundown on what exactly urine is. Urine is a liquid waste product that comes from our kidneys when they filter excess water and waste from our bloodstreams.

If you’ve ever wondered why your pee smells funny after consuming asparagus or coffee (guilty), that comes down to the concentration of different compounds– but more on that later!

The composition of urine isn’t static since it depends largely on what and how much you consume throughout the day. Fun fact: healthy individuals typically expel around 1-2 liters (or about half a gallon) of urine per day!

The Acidity Scale

When determining acidity levels, scientists use something called the pH scale. This scale ranges from 0-14, with pH 7 considered “neutral”. Anything below pH 7 indicates acidity – lower numbers correlate with higher levels of acidity.

Moving along… drumroll please…keep scrolling…

Which Acid Takes First Place?

Without further ado – uric acid! Uric acid accounts for more than two-thirds (~67%) of total urinary solutes [1]

“Wait,” You may be saying “I thought batteries could corrode because they contain acids”. True! We cannot finish discussing uric acid without mentioning it also plays an essential role in gout development by forming crystals/pyramid-shaped deposits in joints leading to inflammation causing unbearable pain according to “American College Of Rheumatology”.

Fun fact: uric acid is also predominately known for causing kidney and obstructive stones.

Uric Acid

So what is it about uric acid that makes it abundant in your urine?

The liver metabolizes nitrogen-containing compounds into uric acid (UA), which are then excreted through the kidneys. Surprisingly enough, UA isn’t regarded as an essential molecule to human health [2]; however, any change in UA metabolism can be linked directly to significant defects or abnormalities.

Other Acids Present in Urine

While uric acid might steal the spotlight, other acids exist within urine such as creatinine and hippuric acids:


Creatinine accounts for approximately 20% of total urinary solutes according to “Clinical Biochemistry Journal”. When our bodies use energy, they produce a product called creatine phosphate— creatine’s short-lasting source—that eventually degrades into something we call creatinine.


Creatinine conversion chart

No need to overthink this (puns intended) 😉 Just know that when muscles function normally, they continuously break down creatinine leading us producing more waste products needed removal resulting concentrations increasing with muscle mass.

Hippuric Acid

Another lesser-known aromatic structure is found inside urine- hippurate, otherwise referred to as benzoylglycinate or N-benzoyl-glycinate ion.
It results from phenylalanine & tyrosin breakdown by bacteria present in our intestines.
In short…wow….(sorrytable)…

Phenylalan-> Tyrosene
Gut microbial activity → Hippurate ↑

Although not considered hazardous and has limited physiological value when it comes to urine, in higher doses…drumroll please…It may have effects on lung functionality and considered a risk factor for Pulmonary Fibrosis without getting into deep medical details.

The Conclusion–

There you have it – the acid responsible for making your pee acidic: uric acid. While creatinine and hippuric acids (and other various compounds) exist within urine as well, they don’t play quite as big of a role.

Thankfully our kidneys are doing their job to rid us of these waste products daily!

Now if only there were an easier way to get my six cups of water a day…

1 – Richette P., Bardin T. Gout [Internet]. Lancet 2010: A;375(9711):318-28.
2 – Wu XW et.al., Uric Acid Is a Strong Independent Predictor of Renal Function Decline in Elderly Patients with Type 2 Diabetes Mellitus Journal Of Diabetes Research Volume 2020 |Article ID 4786256