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Para-aminobenzoic acid (PABA) is a compound that is an essential nutrient for microorganisms and some animals, but has not been shown to be essential for people. PABA is considered by some to be a member of the vitamin B-complex, though its actions differ widely from other B vitamins.

What Are "Star" Ratings?

a7_3star   Reliable and relatively consistent scientific data showing a substantial health benefit.

a7_2star   Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

a7_1star   For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

This supplement has been used in connection with the following health conditions:

Used for Amount Why
Dermatitis Herpetiformis
Refer to label instructions 1 star   PABA in high amounts has been reported to reduce or eliminate the skin lesions of DH in one preliminary trial.

1 star  Dermatitis Herpetiformis

Para-aminobenzoic acid (PABA) in high amounts (9–24 grams per day) has been reported to reduce or eliminate the skin lesions of DH in one preliminary, clinical trial.1 With continued administration, people with DH remained symptom-free for as long as 30 months. Since supplementation with such large amounts of PABA has the potential to cause side effects, these amounts should be used only with medical supervision.

Used for Amount Why
Female Infertility
Refer to label instructions 1 star   Some women have achieved pregnancy after supplementing with PABA, which is believed to increase the ability of estrogen to facilitate fertility.

1 star  Female Infertility

Some previously infertile women have become pregnant after supplementing with PABA (para-aminobenzoic acid), 100 mg four times per day.2 PABA is believed to increase the ability of estrogen to facilitate fertility.

Used for Amount Why
Refer to label instructions 1 star   PABA, a compound commonly found in B-complex vitamins, has been shown to repigment skin affected by vitiligo.

1 star  Vitiligo

An early report described the use of PABA (para-aminobenzoic acid)—a compound commonly found in B-complex vitamins—for vitiligo. Consistent use of 100 mg of PABA three or four times per day, along with an injectable form of PABA and a variety of hormones tailored to individual needs, resulted, in many cases, in repigmentation of areas affected by vitiligo.3

How It Works

How to Use It

Small amounts of PABA are present in some B-complex vitamins and multivitamin formulas. The amount of PABA used in the studies described above ranged from 300 mg to 12 grams per day. Anyone taking more than 400 mg of PABA per day should consult a physician.

Where to Find It

PABA is found in grains and foods of animal origin.

Possible Deficiencies

Deficiencies of PABA have not been described in humans, and most nutritionists do not consider it an essential nutrient.

Best Form to Take

PABA is available as a nutritional supplement, but because it is mildly acidic, it can cause stomach irritation when taken in large amounts. The potassium salt of PABA, called Potaba®, which is available by prescription, tends to be better tolerated.


Interactions with Supplements, Foods, & Other Compounds

PABA interferes with sulfa drugs (a class of antibiotics) and therefore should not be taken when these medications are being used.

Interactions with Medicines

Certain medicines interact with this supplement.

May Be Beneficial: Some medicines may increase the need for this supplement.
Avoid: Some medicines interact with this supplement, so they should not be taken together.
Check: Some interactions between this supplement and certain medicines require more explanation. Click the link to see details.

Note: The following list only includes the generic or class name of a medicine. To find a specific brand name, use the Medicines Index.

May Be Beneficial: Dapsone
Avoid: Methotrexate
Avoid: Sulfamethoxazole
Avoid: Sulfasalazine
Avoid: Trimethoprim/ Sulfamethoxazole

Side Effects

Side Effects

No serious side effects have been reported with 300–400 mg per day. Larger amounts (such as 8 grams per day or more) may cause low blood sugar, rash, fever, and (on rare occasions) liver damage. One report exists of vitiligo appearing after ingestion of large amounts of PABA and use of amounts over 20 grams per day in small children has resulted in deaths. There is also a report of a death from toxic hepatitis in a person with lupus, who took as much as 48 grams per day for six days, followed by 8 grams per day for seven months.


1. Zarafonetis CJ, Johnwick EB, Kirkman LW, Curtis AC. Paraaminobenzoic acid in dermatitis herpetiformis. Arch Dermatol Syph 1951;63:115–32.

2. Sieve BF. The clinical effects of a new B-complex factor, para-aminobenzoic acid, on pigmentation and fertility. South Med Surg 1942;104:135–9.

3. Sieve BF. Further investigations in the treatment of vitiligo. Virginia Med Monthly 1945;Jan:6–17.

4. Kantor GR, Ratz JL. Liver toxicity from potassium para-aminobenzoate. J Am Acad Dermatol 1985;13:671–2.

5. Hughes CG. Oral PABA and vitiligo. J Am Acad Dermatol 1983;9:770 [letter].

6. Worobec S, LaChine A. Dangers of orally administered para-aminobenzoic acid. JAMA 1984;251:2348.

7. Zarafonetis CJD, Grekin RH, Curtis AC, et al. Further studies on the treatment of lupus erythematosus with sodium para-aminobenzoate. J Invest Dermatol 1948;11:359.

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