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?

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.

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

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

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

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

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

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.

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

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.

1 Star
Refer to label instructions
PABA, a compound commonly found in B-complex vitamins, has been shown to repigment skin affected by 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.

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • Dapsone

    PABA (para-aminobenzoic acid) is a compound found in foods that is considered by some to be a member of the B-vitamin family. PABA may interfere with the activity of dapsone.4 Read supplement product labels for PABA content.

Reduce Side Effects

  • none

Support Medicine

  • none

Reduces Effectiveness

  • none

Potential Negative Interaction

  • Methotrexate

    PABA can increase methotrexate levels, activity, and side effects.5 The incidence and severity of this interaction remains unclear.

  • Sulfamethoxazole

    PABA may interfere with the activity of sulfamethoxazole. PABA should not be taken with this drug until more is known.

  • Sulfasalazine

    PABA may interfere with the activity of sulfasalazine. PABA should not be taken with this drug until more is known.

  • Trimethoprim/ Sulfamethoxazole

    PABA (para-aminobenzoic acid) may interfere with the action of sulfamethoxazole. It should not be taken together with trimethoprim/sulfamethoxazole.

Explanation Required

  • none

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

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.6 One report exists of vitiligo appearing after ingestion of large amounts of PABA7 and use of amounts over 20 grams per day in small children has resulted in deaths.8 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.9


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. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 88.

5. Holt GA. Food & Drug Interactions. Chicago: Precept Press, 1998, 170.

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

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

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

9. 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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