What is PABA (para-aminobenzoic acid)?

PABA is a non-essential compound once grouped with B vitamins. It occurs in some foods and has been used in topical products for UVB absorption.

What is PABA used for?

Topically, PABA can act as a UVB-absorbing sunscreen ingredient. Orally, it has been studied mainly for certain fibrotic conditions such as Peyronie’s disease and scleroderma, but it is not generally recommended for routine supplementation.

What is a typical PABA dosage?

Oral PABA dosing in studies and medical use has ranged widely, from hundreds of milligrams to high doses in grams per day. Dosing should be individualized and medically supervised, especially at higher intakes.

What are the risks and side effects of PABA?

High-dose oral PABA can cause gastrointestinal upset and other adverse effects, and topical use may trigger skin irritation or allergic reactions in some people. It may also interact with certain medications, so check with a clinician before use.

Who should avoid PABA?

People with a history of allergy to PABA-containing products should avoid it. Those who are pregnant or breastfeeding, have significant medical conditions, or take prescription medications should use PABA only with medical guidance.

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PABA (para-
aminobenzoic acid)

Limited research available·3/10

A higher score indicates better study conditions, but not necessarily effectiveness.

PABA (para-aminobenzoic acid) is a non-essential compound used for skin health and certain fibrotic diseases, but carries significant risks at high doses.

Anti-inflammatory Joint Healt Skin Health

dose range

400–12000 mg

Divided doses (2–4 times daily)

Consumption

Take with food to reduce GI discomfort. Only use high doses under medical supervision.

Not fat-soluble.

Best time

For conditions such as scleroderma or Peyronie's disease, dosing is typically spread through the day.

Description

Para-aminobenzoic acid (PABA) was once thought to be a B-vitamin but is non-essential for humans. It is found in some foods and previously used in sunscreens for UV protection. Today, oral PABA is mainly studied for its effects on skin disorders and fibrotic conditions, though it is not generally recommended for routine supplementation.

benefits

Main effects with level of evidence

Limited

Note on evidence

Evidence for oral supplementation is limited to small clinical trials, primarily related to scleroderma and Peyronie’s disease; benefits for general skin health are not established.

Topical photoprotection from UVB radiation

Strong

PABA is effective as a UVB-absorbing ingredient in topical sunscreen formulations, contributing to protection against sunburn when applied to the skin.

Particularly relevant for: Individuals seeking sun protection

2 · PubMed

Adjunct therapy in Peyronie’s disease

Limited

High-dose oral PABA has shown some improvement in symptoms (plaque size, curvature) in men with Peyronie's disease, based on small clinical trials.

Particularly relevant for: Men with Peyronie's disease under medical care

3 · PubMed

Support in scleroderma and related fibrotic disorders

Limited

Oral PABA has been used at high doses to help soften the skin and reduce fibrosis in scleroderma, with mixed efficacy reported in small studies.

Particularly relevant for: People with scleroderma under specialist care

4 · NIH

Safety & Information

Important safety information & known risks

For educational purposes only • not medical advice

When taken orally, PABA is generally well-tolerated in low doses but can cause serious side effects at higher doses.

warning notices

Gastrointestinal side effects (nausea, vomiting, appetite loss) occur at higher doses.
Allergic reactions and skin rashes are possible, even with topical use.
High-dose or long-term use may cause liver damage and blood abnormalities.
Safety in children, pregnancy, and breastfeeding is not established.
Avoid use during pregnancy and breastfeeding due to insufficient safety data.
Do not use with sulfonamide antibiotics; effectiveness of antibiotics may be reduced.
High daily doses (above 8 g) may cause liver toxicity and should only be taken under medical supervision.
Discontinue and seek medical advice if allergic reactions (rash, itching, breathing difficulties) or jaundice occur.

Known interactions with medications

Sulfonamide antibiotics
Other hepatotoxic drugs

Contraindications / special precautions

Pregnancy
Breastfeeding
Use with sulfonamide antibiotics
Liver disease

interactions

Important interactions between active ingredient ↔ supplement / medication / food

Notable interaction with sulfonamide antibiotics; may also increase risk of adverse effects with other hepatotoxic drugs.

Reduces the effectiveness of sulfonamide antibiotics.

drug · Sulfonamide antibiotics

AvoidStrong

Why

PABA competes with sulfonamides for incorporation into bacterial folate synthesis, antagonizing the antibiotic effect.

recommendation

Do not use PABA supplements during sulfonamide antibiotic therapy.

1 · WebMD

Potential increased risk of liver toxicity when combined with other hepatotoxic substances.

drug · Other hepatotoxic drugs

CautionLimited

Why

High-dose PABA is associated with hepatotoxicity, which may be additive.

recommendation

Avoid high-dose PABA if using other medications that can affect the liver.

1 · WebMD

mechanisms of action

Brief explanations of how it works

UVB Absorption and Free Radical Protection (topical use)

PABA absorbs UVB radiation, helping prevent DNA damage in skin cells when used as a sunscreen ingredient.

2 · PubMed

Inhibition of Collagen Cross-Linking

PABA at high doses may alter collagen synthesis, reducing abnormal fibrosis in conditions like Peyronie’s disease and scleroderma.

3 · PubMed 4 · NIH

Sources & References

Primary literature and reviews on which these statements are based

4 sources

WebMD

General background, safety, and dosing information.

PubMed

Review of PABA use in photoprotection and dermatological applications.

PubMed

Clinical trial of PABA for Peyronie’s disease.

NIH

Double-blind trial on PABA's effect in scleroderma.

Last updated: February 7, 2026

This information is for educational purposes only and does not replace medical advice.

PABA (para-
aminobenzoic acid)

Description

benefits

Topical photoprotection from UVB radiation

Adjunct therapy in Peyronie’s disease

Support in scleroderma and related fibrotic disorders

Safety & Information

interactions

Reduces the effectiveness of sulfonamide antibiotics.

Potential increased risk of liver toxicity when combined with other hepatotoxic substances.

mechanisms of action

UVB Absorption and Free Radical Protection (topical use)

Inhibition of Collagen Cross-Linking

Sources & References

Amino Acids & Derivatives

Other categories

Safety & Information

interactions

Reduces the effectiveness of sulfonamide antibiotics.

Potential increased risk of liver toxicity when combined with other hepatotoxic substances.

mechanisms of action

UVB Absorption and Free Radical Protection (topical use)

Inhibition of Collagen Cross-Linking

Sources & References