Overview

Para-aminobenzoic acid (PABA) is a chemical that occurs naturally in the body. It is also found in several foods including grains, eggs, milk, and meat.

PABA is part of the folic acid molecule. It was once considered a B vitamin but is now considered a nonessential nutrient. PABA is used as a sunscreen because it can block ultraviolet (UV) radiation to the skin.

People use PABA for sunburn protection and for a disease that causes curved, painful erections (Peyronie disease). It is also used for hardening of skin and connective tissue (scleroderma), aging skin, infertility, and many other conditions, but there is no good scientific evidence to support these uses.

Uses & Effectiveness

Effective for

  • Sunburn. Applying PABA to the skin prevents sunburn. PABA is an FDA-approved sunscreen.

Possibly Effective for

  • A disease that causes curved, painful erections (Peyronie disease). Taking PABA by mouth improves symptoms of Peyronie disease. PABA is FDA-approved for use in this condition.

Possibly Ineffective for

  • Hardening of skin and connective tissue (scleroderma). Taking PABA by mouth doesn't seem to improve scleroderma. Although PABA is FDA-approved for scleroderma, there is only limited evidence that it is effective.

There is interest in using PABA for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: PABA is possibly safe when used appropriately. It's FDA-approved for use and generally well-tolerated. Side effects might include nausea, vomiting, upset stomach, anorexia, and rash. PABA is possibly unsafe when used in high doses. Taking more than 12 grams daily can cause serious side effects, including liver and kidney problems.

When applied to the skin: PABA is likely safe. It's FDA-approved for use and generally well-tolerated.

Special Precautions and Warnings

When taken by mouth: PABA is possibly safe when used appropriately. It's FDA-approved for use and generally well-tolerated. Side effects might include nausea, vomiting, upset stomach, anorexia, and rash. PABA is possibly unsafe when used in high doses. Taking more than 12 grams daily can cause serious side effects, including liver and kidney problems.

When applied to the skin: PABA is likely safe. It's FDA-approved for use and generally well-tolerated.

Pregnancy and breast-feeding: PABA is likely safe when applied to the skin during pregnancy or breast-feeding. But there isn't enough reliable information to know if PABA is safe to take by mouth when pregnant or breast-feeding. Stay on the safe side and avoid use.

Children: PABA is likely safe when applied to the skin for children. PABA is possibly safe for children when taken by mouth in doses of 220 mg/kg daily or less. But PABA is possibly unsafe when taken by mouth in higher doses.

Kidney disease: PABA might build up in the kidneys and make kidney disease worse.

Interactions

    Moderate Interaction

    Be cautious with this combination

  • Antibiotics (Sulfonamide antibiotics) interacts with Para-Aminobenzoic Acid (PABA)

    PABA can decrease the effectiveness of certain antibiotics called sulfonamides.

  • Cortisone interacts with Para-Aminobenzoic Acid (PABA)

    The body breaks down cortisone to get rid of it. 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.

  • Dapsone (Avlosulfon) interacts with Para-Aminobenzoic Acid (PABA)

    Dapsone is used as an antibiotic. PABA might decrease the effectiveness of dapsone for treating infections.

Dosing

PABA has most often been used by adults in doses of 12 grams by mouth daily in 4 to 6 divided doses. It has also been used by children in doses depending on weight. Potassium salt formulations of PABA are most common. PABA is also used in sunscreens applied to the skin.
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