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Other Names:

4-Aminobenzoic Acid, ABA, Acide 4-aminobenzoïque, Acide Aminobenzoïque, Acide p-aminobenzoïque, Acide Para-Amino-Benzoïque, Acide Paraaminobenzoïque, Acide Para-Aminobenzoïque, Acido Para Aminobenzoico, Aminobenzoic Acid, Aminobenzoate Potassium...
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Para-aminobenzoic acid (PABA) is a chemical found in the folic acid vitamin and also in several foods including grains, eggs, milk, and meat.

PABA is taken by mouth for skin conditions including vitiligo, pemphigus, dermatomyositis, morphea, lymphoblastoma cutis, Peyronie’s disease, and scleroderma. PABA is also used to treat infertility in women, arthritis, “tired blood” (anemia), rheumatic fever, constipation, systemic lupus erythematosus (SLE), and headaches. It is also used to darken gray hair, prevent hair loss, make skin look younger, and prevent sunburn.

PABA is best known as a sunscreen that is applied to the skin (used topically).

PABA doesn’t seem to be taken by mouth as often as it used to be, possibly because some people question its safety and effectiveness.

How does it work?

PABA is used as a sunscreen because it can block ultraviolet (UV) radiation to the skin.

PARA-AMINOBENZOIC ACID (PABA) Uses & Effectiveness What is this?

Effective for:

  • Use as a sunscreen, when applied directly to the skin. PABA is approved by the U.S. Food and Drug Administration (FDA) for use as a sunscreen. PABA seems to be effective during sweating, but not when skin is submerged in water - during swimming, for example.

Possibly Ineffective for:

  • Treating a condition that causes hardening or thickening of the skin (scleroderma). Although PABA is FDA-approved for scleroderma, there is only limited evidence that it is effective. Some research studies suggest it might help for some symptoms of scleroderma, but the most convincing evidence shows that it does not help.

Insufficient Evidence for:

  • Various skin conditions such as dermatomyositis, vitiligo, pemphigus, morphea, Peyronie’s disease. PABA is FDA-approved for use in these skin conditions, but there is only limited evidence that it is effective. Although PABA is sometimes used to treat vitiligo, it has also been reported to cause vitiligo.
  • Infertility in women.
  • Arthritis.
  • “Tired blood” (anemia).
  • Constipation.
  • Headaches.
  • Preventing hair loss.
  • Darkening gray hair.
  • Other conditions.
More evidence is needed to rate the effectiveness of PABA for these uses.


PABA is safe for most people when applied directly to the skin. There haven’t been any reports of significant harm, although there have been reports that PABA increases the likelihood of sunburn in some people, even though it usually works as a sun block.

When taken by mouth, PABA seems safe if taken correctly. PABA can cause skin irritation and might also stain clothing with a yellow color. Nausea, vomiting, upset stomach, diarrhea, and loss of appetite might sometimes occur. Taking more than 12 grams per day can cause serious side effects such as liver, kidney, and blood problems.

Special Precautions & Warnings:

Children: When applied directly to the skin, PABA appears safe for children. Although PABA might be safe for children to take by mouth, serious side effects can occur. Dose is important. Some children who took doses of PABA greater than 220 mg/kg/day died.

Pregnancy and breast-feeding: PABA seems to be safe when applied to the skin during pregnancy or breast-feeding. But don’t take PABA by mouth until more is known about the safety of oral use.

Kidney disease: PABA might build up in the kidneys making kidney disease worse. Don’t use it if you have kidney problems.

PARA-AMINOBENZOIC ACID (PABA) Interactions What is this?

Major Interaction Do not take this combination

  • Antibiotics (Sulfonamide antibiotics) interacts with PARA-AMINOBENZOIC ACID (PABA)

    Para-aminobenzoic acid (PABA) can decrease the effectiveness of certain antibiotics called sulfonamides.

    Some of these antibiotics include sulfamethoxazole (Gantanol), sulfasalazine (Azulfidine), sulfisoxazole (Gantrisin), and trimethoprim/sulfamethoxazole (Bactrim, Septra).

  • Dapsone (Avlosulfon) interacts with PARA-AMINOBENZOIC ACID (PABA)

    Dapsone (Avlosulfon) is used as an antibiotic. Para-aminobenzoic acid (PABA) might decrease the effectiveness of dapsone (Avlosulfon) for treating infections.

Moderate Interaction Be cautious with this combination

  • Cortisone (Cortisone Acetate) interacts with PARA-AMINOBENZOIC ACID (PABA)

    The body breaks down cortisone to get rid of it. Para-aminobenzoic acid (PABA) might decrease how quickly the body breaks down cortisone. Taking PABA by mouth and getting a cortisone shot might increase the effects and side effects of cortisone.


The following doses have been studied in scientific research:


  • To prevent sunburn: PABA sunscreens come in concentrations of 1% to 15%.

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