What Does pH Balance Mean in the Body?

In chemistry, a pH scale is used to measure how acidic or alkaline something is, including the human body. Having a proper pH balance in your body helps your body self-regulate and perform biological functions that keep you alive. Your organ systems and body fluids also maintain their own pH to support critical chemical reactions that support bodily functions, metabolism, and hormonal balance.

If your body's pH is out of whack, your body may struggle to maintain functions and leave you susceptible to illness. Here's how pH balance affects your entire body. 

A urine pH test

Peter Dazeley / Getty Image

How Does pH Work in the Body?

 A pH is measured on a scale from zero to 14. Zero is the most acidic, 7 is neutral, and 14 is the most alkaline (also called basic). But what does pH actually mean? pH stands for "potential hydrogen" and measures the levels and activity levels of a substance's hydrogen ions. More hydrogen ions lead to a lower pH value (or more acidic). Fewer hydrogen ions lead to a higher pH value (or more basic or alkaline).

In the human body, having a proper pH balance is essential because it helps your body function. Stable pH levels help jumpstart biochemical reactions and create the right environment for your organs to do their jobs.

For example, an overall body pH of about 7.4 helps your body oxygenate your blood and deliver oxygen to your tissues. A balanced pH also helps all the proteins in your body stay in their proper configurations. This is important because proteins power your cells, from creating antibodies to protect your body from viruses to signaling your body to coordinate biological processes. Proteins also need a balanced pH to support the structure, function, and regulation of your tissues and organs. 

Your stomach's gastric juices (aka stomach acid) have an acidic pH from 1.5 to 2. This acidic environment helps kill harmful bacteria and other pathogens in your stomach and helps break down food during digestion. Your skin also has an acidic pH between 4 and 5.5, which helps give your skin a protective barrier from the elements and microbes. 

What Is a Normal pH Level? 

In the human body, a healthy pH is between 7.35 and 7.45. On average, the body has a pH of 7.4, which is a slightly basic pH level. Your body needs to be in this normal, slightly basic pH zone to stay in a stable state (aka homeostasis) and function like business as usual. 

If you're in good health, your body regulates your pH without you even knowing it via your pulmonary and renal systems. These systems regulate pH balance when it needs to increase or decrease. For example, your pulmonary system — which includes your airways, lungs, and blood vessels — can lower pH and become more acidic by releasing more carbon dioxide when you exhale. Breathing in oxygen (which is basic) also helps make your body increase pH and become more alkaline. 

Your renal system, including your kidneys and bladder, also helps regulate pH. Your kidneys excrete acid when you pee to help increase pH. And if your body needs to decrease pH, your kidneys can absorb bicarbonate substances (chemicals that are basic). These processes can adjust your pH in a few days. 

What is Vaginal pH? 

The vagina has a moderately acidic pH level between 3.8 and 5. However, this can vary a bit depending on your age, the stage of your menstrual cycle, and menopause. The vagina naturally has a balanced environment of good and bad bacteria, so the vagina needs to have an acidic pH to help prevent bacteria overgrowth that causes vaginal infections

Too high of a vaginal pH can allow harmful bacteria to thrive and increase your risk of infections like: 

  • Bacterial vaginosis (BV): A bacterial-overgrowth infection that can cause unusual white or gray discharge, fishy odors, itching, and painful urination. 
  • Trichomoniasis: A sexually transmitted infection passed via a parasite that can cause green or yellow discharge, pain during sex, burning while peeing, and vaginal soreness.

What Causes an Unbalanced Vaginal pH?

Your vagina will typically self-balance its pH, but some situations can raise or lower the pH level. These include:

  • Menstruation: During your period, blood makes your vagina more alkaline and can raise your vagina's pH. 
  • Menstrual cycle disorders: Hormonal imbalances that cause abnormal menstrual cycles increase the risk of an unbalanced vaginal pH. 
  • Menopause: Postmenopausal people who no longer have a period can have a slightly higher pH.
  • Unprotected sex: Semen can make the vagina more alkaline and increase some people's risk of infection.
  • Antibiotics: Besides killing harmful bacteria, antibiotics can also kill good bacteria needed to keep the vagina acidic. 
  • Douching: Cleaning the inside of the vagina with special cleansers strips the vagina of good bacteria and creates an abnormal pH that puts you at risk of infection.   

If you have an unbalanced vaginal pH, you'll typically experience a less acidic pH that allows bacterial overgrowth. 

Symptoms of an unbalanced vaginal pH are often the same as BV or other vaginal infection symptoms, including:

How to Re-Balance Vaginal pH

If everything is OK in the vagina, you don't need to think about re-balancing your pH. However, see your healthcare provider if you have symptoms of BV or another infection linked to a high vaginal pH. 

Your healthcare provider will likely prescribe you oral or topical antibiotics to treat an infection linked to a pH imbalance. For recurring BV, they may also suggest using boric acid suppositories with your antibiotic treatment. It's also worth noting that while antibiotics can alter vaginal pH in the first place, treating the infection is essential. 

If you're prone to infections like BV, here are some preventative measures: 

  • Using condoms or other barrier methods
  • Avoiding douches, harsh soaps, and scented vaginal and period products
  • Take probiotics when you take antibiotics

pH-related Conditions

When your body's pH becomes too high or low, your lungs and kidneys usually help you re-balance your pH. However, if your body can't properly regulate its pH, you can face health issues related to acidosis and alkalosis. Acidosis means your body has too much acid and a pH less than 7.35. Alkalosis means your body has too much base a pH more than 7.45.  

The main conditions related to an unbalanced pH include: 

  • Metabolic acidosis: Your body produces too much acid, or the kidneys can't remove enough acid. Some subtypes include diabetic, hyperchloremic, and lactic acidosis. Kidney disease, severe dehydration, and aspirin poisoning can cause this condition.
  • Metabolic alkalosis: Your blood has too much bicarbonate, which increases pH. Kidney diseases often cause this condition. 
  • Respiratory acidosis: Too much acidic carbon dioxide stays in the body because you can't remove enough when you breathe. This can be caused by chest injuries or muscle weakness, chronic lung disease, neuromuscular disorders, and overuse of sedatives. 
  • Respiratory alkalosis: Your blood has low carbon dioxide levels and increases pH because you're breathing too rapidly. High altitude, lack of oxygen, liver disease, lung disease, aspirin poisoning, or fever can cause this.  

If you develop one of these pH-related conditions, your body will often try to overcompensate. So if you develop metabolic acidosis, your body may try to eliminate too much carbon dioxide as you breathe and cause respiratory alkalosis.

Do You Need to Worry About Your pH? 

The human body naturally regulates your pH, so you don't need to worry about constantly balancing your pH levels. Your body has all the tools to balance acids and bases — like your kidneys and lungs. These systems balance your pH thanks to everyday biological functions like breathing and peeing. 

That said, certain health conditions can affect the body's ability to regulate pH. However, for the average healthy person, pH isn't something you need to lose sleep about. That also means it's not necessary to purchase products or follow strict diets that promise to balance your pH. However, if you're concerned about your body's pH, speak with your healthcare provider. 

A Quick Review

pH refers to how acidic or basic (also called alkaline) a substance is. pH balance is essential for the human body to help organ systems function and perform necessary tasks like oxygenating the blood and digesting food. The average pH of the body sits around 7.4, which is slightly alkaline, and your body will naturally regulate this stable state. 

Some of your organs and body fluids also maintain a different pH to help them function and avoid infections. For example, the stomach acid and vagina both have acidic pHs to help prevent bacteria overgrowth. Keeping your pH balanced may seem like a complicated feat of chemistry, but you don't need to worry about actively balancing your pH. Your body naturally does the job for you.

Was this page helpful?
11 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Hopkins E, Sanvictores T, Sharma S. Physiology, acid base balance. In: StatPearls. StatPearls Publishing; 2022.

  2. Hamm LL, Nakhoul N, Hering-Smith KS. Acid-base homeostasis. Clin J Am Soc Nephrol. 2015;10(12):2232-2242. doi:10.2215/CJN.07400715

  3. MedlinePlus. What are proteins and what do they do?

  4. Fujimori S. Gastric acid level of humans must decrease in the future. World J Gastroenterol. 2020;26(43):6706-6709. doi:10.3748/wjg.v26.i43.6706

  5. Prakash C, Bhargava P, Tiwari S, Majumdar B, Bhargava RK. Skin surface pH in acne vulgaris: Insights from an observational study and review of the literature. J Clin Aesthet Dermatol. 2017;10(7):33-39.

  6. Lin YP, Chen WC, Cheng CM, Shen CJ. Vaginal pH value for clinical diagnosis and treatment of common vaginitis. Diagnostics (Basel). 2021;11(11):1996. doi:10.3390/diagnostics11111996

  7. UpToDate from Wolters Kluwer. Bacterial vaginosis: Treatment.

  8. Office on Women's Health. Douching

  9. Mei Z, Li D. The role of probiotics in vaginal health. Front Cell Infect Microbiol. 2022;12:963868. doi:10.3389/fcimb.2022.963868

  10. MedlinePlus. Acidosis.

  11. Brinkman JE, Sharma S. Physiology, metabolic alkalosis. In: StatPearls. StatPearls Publishing; 2022.

Related Articles