Many people wonder about the pH of lemon juice, particularly if they have problems with acidity in their gastrointestinal system. While lemon is quite acidic, it behaves in some very interesting ways within the body.
What is the pH of Lemon Juice?
The pH value of lemon juice is 2.0, making this juice extremely acidic. The pH is a number which expresses the acidity or alkalinity of a solution on a scale of 0 to 14. On the pH scale, a pH of 7 is neutral, anything below 7 is considered acidic, while anything above 7 is alkaline. Lemon juice, in its natural state, has a pH which ranges between 2 and 3, which makes it extremely acidic. Hence, lemon juice is acidic, not alkaline, in nature. 
Something with a similar acidity level is vinegar, while apples are slightly less acidic, and sulfuric acid is more acidic. Although this might make most people think that drinking lemon juice will create an acidic setting in your body, there is more to the story than that.
What Are the Acids Present in Lemon Juice?
There are a number of acids present in lemon juice that provide such an acidic characteristic, including citric acid, ascorbic acid, and malic acid.
Lemons have more citric acid by weight than any other citrus fruit – roughly 8% of their dry weight, in fact. This citric acid is not known for having many effects on the body, but it does have protective effects on the fruit itself, helping to prevent browning and maintaining the sharp, citrusy bite in this fruit juice. 
Ascorbic acid is better known by its common name, vitamin C. The juice from a single lemon would provide roughly 30% of your recommended daily intake of that nutrient, which can act as a major boost to your immune system since vitamin C stimulates the production of white blood cells. Ascorbic acid is also an integral part of the creation of bodily tissues and collagen, which is required for all the repair and growth processes in the body. 
Found in the smallest amount of lemon juice, malic acid is not a well-known acid for human health, although research has found it to help people with certain muscle disorders. Patients who are unable to produce malic acid in their body can benefit from lemon juice, which helps to reduce inflammation and pain in their soft muscle tissue. 
Lemon Juice and the pH of Your Body
As mentioned, the low pH of lemon juice leads many to believe that it will have an acidic effect on the body, but that simply isn’t the case. After the body metabolizes lemon juice and its active compounds, the by-products of lemon juice are actually alkaline. Therefore, even though lemon juice is acidic in nature, it has an alkalizing effect on the urine. Hence the quote, ‘Lemons neutralize acidity.’
Lemon juice is known to alkalize urine, not blood. That being said, the body works very hard to maintain an even pH of blood between 7.35 and 7.45, and there is little that lemon juice can do to affect that. While the benefits of lemon juice are not related to its alkalizing effects on urine, consuming it is good for you for other health reasons. Lemon juice is a rich source of nutrients like vitamin C, calcium, potassium, among others, which helps settle stomach disorders, treat fever, and even promote weight loss. 
Note: Consuming too many lemons and raw lemon juice can affect the tooth enamel and may cause tooth decay. This is because of the acidic nature of lemon before it is ingested, and the high amounts of natural sugars present in it.