The answer depends entirely on which pH you’re trying to lower, because your body maintains different pH levels in different places, and the strategies for each are completely different. Blood pH sits in a tightly controlled range of 7.35 to 7.45 and almost never needs outside intervention. Urine pH, vaginal pH, and stomach pH, on the other hand, can shift in ways that cause real symptoms, and there are practical steps you can take for each.
Why You Can’t Really Change Blood pH
Your blood pH averages 7.40, and your body defends that number aggressively. A network of chemical buffers, your lungs, and your kidneys work together to keep it within the 7.35 to 7.45 window at all times. The primary system is the bicarbonate buffer: carbon dioxide from your cells dissolves in blood, forms carbonic acid, and splits into bicarbonate and hydrogen ions. Your lungs adjust how fast you breathe out CO2, and your kidneys fine-tune how much bicarbonate they retain or excrete.
If blood pH drifts above 7.45 (a condition called alkalosis), the kidneys respond by reducing bicarbonate reabsorption so more of it leaves through urine, pulling pH back down. This compensation happens automatically. The common causes of alkalosis are prolonged vomiting, overuse of certain diuretics, and excess intake of calcium-containing antacids. These are medical problems that require clinical treatment, not dietary tweaks. No food, drink, or supplement you consume will meaningfully shift your blood pH outside its normal range in a healthy body.
Lowering Urine pH Through Diet
Urine pH is a different story. Unlike blood, urine pH swings considerably based on what you eat, typically ranging from about 4.5 to 8.0. Some people need lower (more acidic) urine to reduce the risk of certain kidney stones, particularly calcium phosphate and struvite stones, which form more easily in alkaline urine.
Researchers use a measurement called the Potential Renal Acid Load (PRAL) to estimate how much a food will acidify or alkalinize urine. Foods with a positive PRAL score push urine toward acidity. The formula weighs protein and phosphorus (which generate acid) against potassium, calcium, and magnesium (which generate base). In practical terms, foods that lower urine pH include:
- High-protein foods: meat, poultry, fish, and eggs are the strongest urinary acidifiers because protein metabolism produces sulfuric acid as a byproduct
- Grains and bread: wheat, rice, oats, and corn have moderately positive PRAL scores
- Cheese: high in both protein and phosphorus, making it one of the more acid-forming dairy products
Foods that raise urine pH (make it more alkaline) are fruits and vegetables, especially potatoes, bananas, and spinach, because of their high potassium and magnesium content. If your goal is lower urine pH, shifting toward more protein and grains while moderating your fruit and vegetable intake will move the needle. In one large study of older adults, 71% already had acid-forming diets (PRAL above zero), with average scores around 15.7 mEq per day. Most Western diets are already on the acidic side because of high protein and grain consumption.
Cranberry juice is a popular home strategy. It does lower urine pH modestly, though the effect varies from person to person. Vitamin C (ascorbic acid) supplements can also acidify urine, but high doses carry their own risks, including increasing oxalate levels, which can promote a different type of kidney stone.
Restoring Vaginal pH
A healthy vaginal pH in reproductive-age women sits between 3.5 and 4.5, which is quite acidic. This acidity is maintained by beneficial Lactobacillus bacteria that produce lactic acid as they metabolize glycogen. When these bacteria are disrupted by antibiotics, douching, semen exposure, or hormonal changes, pH rises and conditions like bacterial vaginosis (BV) can develop. Symptoms include unusual discharge, fishy odor, and irritation.
Lactic acid is the key molecule. Women with a Lactobacillus-dominated vaginal environment maintain lactic acid concentrations around 0.8 to 1% and a pH between 3.45 and 4.12. Beyond just lowering pH, lactic acid has been shown to directly inactivate BV-associated bacteria and even pathogens like chlamydia and gonorrhea through mechanisms that go beyond acidity alone. The protonated form of lactic acid, which predominates at pH below about 3.9, appears to be the active agent.
Practical approaches to lowering vaginal pH include:
- Lactic acid gels or suppositories: available over the counter, these directly introduce acid into the vaginal environment and can help restore a favorable pH
- Boric acid suppositories: commonly used as a second-line option for recurrent BV or yeast infections, these lower pH and create conditions that favor Lactobacillus regrowth
- Probiotics: oral or vaginal formulations containing Lactobacillus crispatus or Lactobacillus rhamnosus aim to repopulate the beneficial bacteria that produce lactic acid naturally
Avoiding douching is one of the simplest protective steps. Douching strips away the Lactobacillus colonies that maintain acidity and is consistently linked to higher rates of BV and other infections.
Increasing Stomach Acidity
Stomach pH normally drops as low as 1.5 to 3.5 during a meal, which is intensely acidic. Some people, particularly older adults and those on long-term acid-suppressing medications, produce less stomach acid than needed for proper digestion. This condition, called hypochlorhydria, can cause bloating, belching, a feeling of fullness after small meals, and poor absorption of nutrients like iron, calcium, and vitamin B12.
Betaine hydrochloride (betaine HCl) is the most widely used supplement for this purpose. The standard approach used by integrative medicine practitioners involves starting with one capsule of 350 to 750 mg taken with a protein-containing meal. If you feel no warmth, tingling, or discomfort, you increase to two capsules at the next meal. You continue adding one capsule every two days, up to a maximum of about 3,000 mg per meal, until you notice any burning, tingling, heartburn, or general discomfort. That signals you’ve exceeded your need, and you drop back by one capsule. If discomfort occurs at the very first dose, it suggests low stomach acid isn’t your issue.
This protocol is widely used in clinical practice with positive anecdotal results, though it hasn’t been tested in rigorous controlled trials. Capsules that combine betaine HCl with pepsin (a digestive enzyme) are commonly recommended and may offer additional benefit for protein digestion. If you experience burning at any point, dissolving a teaspoon of baking soda in water neutralizes the acid quickly.
What “Acidic Body” Claims Get Wrong
A significant portion of the content online about “lowering your pH” or “making your body more acidic” stems from the alkaline diet movement, which claims that modern diets make the body too alkaline or too acidic and that correcting this prevents disease. The core claim misunderstands how the body works. Diet absolutely changes urine pH, and it can modestly influence saliva pH. But blood pH, the measurement that actually reflects your systemic acid-base status, stays locked between 7.35 and 7.45 regardless of what you eat. Your buffer systems, lungs, and kidneys ensure this.
When blood pH does fall outside that range, it’s a medical emergency, not a dietary inconvenience. Acidosis (pH below 7.35) can result from uncontrolled diabetes, kidney failure, severe dehydration, or poisoning. Alkalosis (pH above 7.45) can stem from persistent vomiting, certain medications, or hormonal disorders. Neither condition responds to food choices alone, and both require professional evaluation. If you’re experiencing symptoms that made you search for ways to change your pH, identifying which body system is actually involved is the first step toward a solution that works.