Mountain Dew is highly acidic, with a pH of about 3.22, well below the neutral mark of 7.0. That puts it roughly 10,000 times more acidic than pure water and significantly below the pH threshold where tooth enamel starts to break down. The acidity comes primarily from citric acid, which gives the drink its tart, citrusy bite.
How Acidic Mountain Dew Actually Is
A large study published in the Journal of the American Dental Association measured the pH of hundreds of beverages available to American consumers. Regular Mountain Dew came in at 3.22, and Diet Mountain Dew was slightly more acidic at 3.18. To put that in context, the pH scale is logarithmic, so each whole number represents a tenfold difference in acidity. Lemon juice sits around 2.0, and black coffee around 5.0. Mountain Dew lands firmly in the “strongly acidic” range for a beverage.
pH measurements can vary depending on the region and batch. A study testing Mountain Dew sold in Pakistan recorded a pH of 3.87, while other researchers have measured it as low as 2.94. The U.S. formulation consistently falls in the low 3s, which is where most of the research focuses.
What Makes Mountain Dew So Acidic
The main acid in Mountain Dew is citric acid. Unlike Coca-Cola and Pepsi, which rely heavily on phosphoric acid, Mountain Dew contains no measurable phosphorus. Citric acid is the same compound found naturally in lemons, limes, and oranges, and it’s what gives the drink its sharp, tangy flavor. PepsiCo’s own product information lists citric acid as a primary ingredient.
Sodium benzoate, a common preservative in soft drinks, also contributes. When dissolved in water, sodium benzoate increases acidity while serving its main role as an antimicrobial agent. It’s not the dominant source of Mountain Dew’s low pH, but it adds to the overall acidic profile. The combination of citric acid and preservatives creates a drink that stays acidic from the first sip to the last.
How It Compares to Other Drinks
Mountain Dew’s pH of 3.22 places it in a similar range to many popular sodas, though comparisons depend on the specific product. Most colas fall between 2.3 and 2.7, making them even more acidic than Mountain Dew. Sprite and similar lemon-lime sodas tend to land around 3.2 to 3.4, right in the same neighborhood. Orange juice, often thought of as a healthy alternative, typically measures between 3.3 and 4.0.
The key takeaway is that nearly all sodas and fruit juices fall well below the critical pH of 4.0. Above 4.2, research shows erosion to tooth enamel is minimal. Below 4.0, the damage becomes increasingly evident. Mountain Dew sits a full point below that safety line.
What This Means for Your Teeth
Tooth enamel is the hardest substance in the human body, but acid dissolves it. Enamel begins to soften and erode when exposed to beverages with a pH below 4.0, and Mountain Dew’s pH of 3.22 clears that threshold easily. The damage isn’t about a single sip. It’s about frequency, duration of contact, and how you drink it.
Swishing soda around in your mouth or holding it before swallowing dramatically increases how much acid touches your teeth. Sipping slowly over an hour is worse than drinking the same amount in a few minutes, because each sip restarts the acid attack on enamel. Once enamel erodes, it doesn’t grow back.
The American Dental Association offers several practical strategies to reduce acid damage from beverages like Mountain Dew:
- Use a straw positioned behind the front teeth, which minimizes how much liquid bathes the enamel.
- Rinse with water after drinking rather than brushing immediately. Brushing acid-softened enamel can actually wear it down faster.
- Chew sugar-free gum afterward to stimulate saliva, which naturally buffers and removes acids from the mouth.
- Drink milk alongside acidic meals or beverages. Milk contributes to remineralization and helps neutralize acids.
- Avoid acidic drinks between meals when saliva flow is lower and your teeth have less natural protection.
Diet Mountain Dew Isn’t Better
Switching to diet doesn’t help with acidity. Diet Mountain Dew measured at a pH of 3.18, slightly more acidic than the regular version. The sugar is removed, which does eliminate one source of tooth decay (the bacteria in your mouth feed on sugar to produce their own acids). But the citric acid remains, and the erosive potential is essentially the same. Your enamel doesn’t care whether the drink has calories.
Beyond Your Teeth
Acidic beverages can also irritate the lining of the esophagus and stomach in people who are already prone to acid reflux or gastritis. If you notice heartburn or a sour taste after drinking Mountain Dew, the citric acid is a likely contributor. The carbonation adds to the effect by increasing pressure in the stomach, which can push acid upward.
For most people with healthy digestive systems, the occasional Mountain Dew won’t cause lasting harm to the stomach or throat. The body is well equipped to handle dietary acids in moderation. The teeth, however, are the vulnerable point, because enamel erosion is cumulative and irreversible. How often you drink it matters more than how much you drink at once.