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Overview: Para-aminobenzoic acid (PABA) is a natural substance that is found in some foods and can be made by bacteria in the gut. People often take PABA supplements for skin and hair conditions, although its benefits are not well defined. PABA is also available in topical forms and was historically used in sunscreens. Common side effects of PABA supplements include nausea, upset stomach, and loss of appetite. Before using PABA, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is para-aminobenzoic acid (PABA) used for?

Para-aminobenzoic acid (PABA) is commonly used for skin and hair concerns, although its benefits are not well defined. People may use PABA for the following reasons.

PABA also used to be included as an ingredient in many sunscreens to protect against ultraviolet (UV) radiation. However, the FDA has proposed that PABA is not generally recognized as safe and effective (GRASE) for use in sunscreens because of skin reactions (see the Side Effects section for more details). Learn more about GRASE status here.

Note: The FDA has not reviewed PABA for safety and effectiveness. Learn more about dietary supplements here.

How does PABA work (mechanism of action)?

PABA is a natural substance. It is sometimes called vitamin B10 or vitamin Bx, and it is a member of the vitamin B complex. But it is not actually a vitamin. Instead, PABA is a building block of folic acid (a form of vitamin B9). Folic acid is used to make DNA and to help your cells grow and divide.

Certain microbes in the gut can make PABA. It is also available as a supplement that is taken by mouth. However, PABA deficiencies are uncommon. You can get PABA from certain foods, such as animal products, whole grains, mushrooms, spinach, and molasses.

PABA is thought to work by affecting the production of certain proteins in the body. Some research suggests it may help with collagen formation and skin cell growth. For hair pigmentation, PABA is believed to play a role in producing melanin, the substance that gives hair and skin their color. However, the benefits of PABA are not well defined, and more research is needed to understand how it works.

PABA may also affect the immune system and inflammatory processes, which could explain why there is interest in using it in certain skin and connective tissue conditions. However, evidence in humans is limited for most of these uses.

PABA may also be applied to the skin, and it used to be an ingredient in many sunscreens. The FDA has proposed that PABA is no longer a safe ingredient in sunscreens because of the risk of allergic skin reactions and because it can make skin more sensitive to sunlight. It may also increase the risk of becoming allergic to other compounds that are similar to PABA, including sulfa antibiotics, water pills, local anesthetics, and dyes.

How should I store PABA?

You should store PABA according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of PABA?

The most common side effects of PABA are listed below. These side effects may vary depending on the dose or the product you are using. Tell your health care provider if you have any of these side effects that bother you.

  • Rash or skin reactions (see below)
  • Nausea or vomiting
  • Upset stomach 
  • Loss of appetite
  • Diarrhea
  • Dizziness

There may be other side effects of PABA that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of PABA?

While less common, the most serious side effects of PABA are described below, along with what to do if they happen.

Severe Allergic Reactions. PABA may cause allergic reactions, which can be serious. Stop using PABA and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Liver Damage. There may be a risk of liver damage, also called hepatotoxicity, when taking PABA. The risk may be higher if you are taking high doses of PABA. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish (also called jaundice)

Rash or Skin Reactions. Applying PABA to the skin may cause skin reactions, including allergic skin reactions. These reactions can range from mild to severe. Stop using PABA and contact your health care provider right away if you have any of the following symptoms.

  • Skin redness, swelling, or burning
  • Rash, blisters, or bumps
  • Scaly patches or cracking

Sensitivity to Sunlight. Using PABA on the skin may make your skin very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds. This is called photosensitivity. Use a PABA-free sunscreen and wear a hat and clothes that cover your skin if you need to be in the sunlight. Exposure to this kind of light, even for a short time, can cause your skin to be severely sunburned, blistered, or swollen. Tell your health care provider right away if any of these happen.

Warnings & Precautions

Who should not use PABA?

Allergies to Ingredients. People who are allergic to any of the following should not use PABA.

  • Aminobenzoic acid
  • PABA
  • Para-aminobenzoic acid 
  • Vitamin B10
  • Vitamin Bx
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific PABA products they stock.

What should I know about PABA before using it?

PABA is a dietary supplement. It cannot be marketed to treat or cure a disease.

PABA is available in many forms. Common forms include tablets, capsules, and powders. PABA also used to be an ingredient in many sunscreens. Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep PABA out of the reach of children.

Applying PABA to the skin may cause it to stain or discolor clothes or bedding.

The FDA has not tested PABA dietary supplements to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using PABA?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. Also tell them if you have an upcoming surgery. Sharing this information will help your health care provider know if this or other supplements are right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have or have had any of the following.

  • Kidney or liver problems             
  • An autoimmune condition, such as lupus
  • Skin allergies, irritation, or sensitive skin

Other Medicines and Supplements. PABA may interact with other medicines and supplements. Before using PABA, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how PABA could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if PABA passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does PABA interact with foods or drinks?

There are no known interactions between PABA and foods or drinks.

It is unknown if drinking alcohol will affect PABA.

Does PABA interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking an antibiotic, such as sulfamethoxazole/trimethoprim, which is used to treat certain infections. PABA may reduce how well sulfa antibiotics work, because sulfa drugs act by blocking bacteria from using PABA. Do not take PABA supplements while on a sulfa antibiotic, unless your health care provider says it is okay.

The interactions between PABA and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with PABA is incomplete. Always check with your health care provider before taking PABA with any medicines.

Overdose/Missed Dose

What should I do if I accidentally use too much PABA?

If you or someone else has used too much PABA, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

PABA is available in various forms, such as tablets, capsules, and powders. It may also be found in products that are applied to the skin. Read the product label closely, and speak with a health care provider about how to use PABA safely. Do not take double or extra doses, even if you miss a dose.