PABA
At a glance
- Best for
- Adults with Peyronie's disease considering potassium para-aminobenzoate (POTABA) under clinician supervision
- Typical dose
- 25–500 mg/day for supplements; 4–12 g/day for POTABA prescription use in fibrotic disease
- Time to effect
- Months (fibrotic conditions); not established for other uses
- Main caution
- Antagonizes sulfonamide antibiotics — must not be taken concurrently with sulfamethoxazole, dapsone, or sulfasalazine
What is it
Para-aminobenzoic acid (PABA, 4-aminobenzoic acid) is a benzoic acid derivative bearing an amino group at the para position (C 7 H 7 NO 2 ). It is an intermediate in bacterial, plant, and fungal folate biosynthesis, where it is condensed with pterin to form dihydropteroate; the antifolate sulfonamide antibiotics are structural analogs that competitively block this step. PABA is not a vitamin for humans because we do not synthesize folate and obtain it preformed in our diet; it was historically classified as a B-complex vitamin under the now-obsolete designations 'vitamin Bx' or 'vitamin B10' and remains marketed as a vitamin-like supplement. Topically, PABA was widely used as a UVB-absorbing sunscreen agent until allergic and staining reactions led to its replacement by other UV filters.
Is it worth it for you?
Worth considering if…
- You have Peyronie's disease and are under urologist supervision considering POTABA as an adjunct
- You understand that evidence is weak and that high-dose use requires medical oversight
Probably skip if…
- You are taking any sulfonamide antibiotic (sulfamethoxazole-TMP, dapsone, sulfasalazine) — direct antagonism
- You have renal or hepatic impairment — high-dose PABA is hepatotoxic and contraindicated
- You are pregnant or breastfeeding
- You are buying it for hair color restoration or vitiligo — no credible evidence supports this use
- You are buying it as a sunscreen — topical PABA is largely obsolete due to allergy and staining
Evidence at a glance
| Goal | Evidence | Effect | Best fit | Time |
|---|---|---|---|---|
| Peyronie's disease (potassium para-aminobenzoate) | Limited Evidence | Modest reduction in plaque size and pain in older RCT; small effect | Men with Peyronie's disease, under urologist supervision | Months |
| scleroderma and fibrotic skin disorders | Mixed Evidence | Not consistently demonstrated | Adults with scleroderma or morphea under specialist care | Months |
Evidence for 2 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Peyronie's disease (potassium para-aminobenzoate)
Disease adjunctPotassium para-aminobenzoate (POTABA) at 3–12 g/day has been used for Peyronie's disease based on the hypothesis that PABA may reduce fibrosis through modulation of oxidative stress and TGF-beta signaling. One older RCT found modest reduction in plaque size and penile pain. Evidence is limited to small, older studies with methodological limitations. POTABA at therapeutic doses requires medical supervision due to hepatotoxicity risk and GI burden.
Bottom line: Weak but not absent evidence — only consider under urologist supervision; self-dosing at therapeutic levels is not appropriate.
scleroderma and fibrotic skin disorders
Disease adjunctPABA and POTABA have been tried in scleroderma and other fibrosing skin conditions based on the same anti-fibrotic hypothesis as Peyronie's disease. Clinical trial results have been inconsistent and methodologically weak. No modern, adequately powered RCT has established efficacy. This use is largely historical and not part of current rheumatology treatment guidelines.
Bottom line: Not supported by current evidence — this is a historical use without modern clinical backing.
Evidence is mixed
The few available trials are old, small, and of poor quality; results have not been reproduced in contemporary study designs.
How to take it
- Typical dose
- 25–500 mg/day for supplements; 4–12 g/day for POTABA prescription (under physician supervision only)
- Timing
- With meals in divided doses to reduce GI upset at higher doses
- With food
- With food
- Split dosing
- Higher POTABA doses split into 4–6 doses throughout the day
- How long to try
- Peyronie's POTABA trials ran 3–12 months; shorter supplement use has no defined endpoint
What to track
- Penile plaque or curvature change if using for Peyronie's (under urologist care)
- Liver function tests at high doses
- Signs of allergy or skin changes
- Concurrent antibiotic prescriptions — stop PABA if sulfa antibiotic is prescribed
Safety
Common side effects
Nausea and vomiting at high doses, Anorexia, Skin rash, Fever
Serious risks
- Hepatic toxicity (rare but documented at high doses, including jaundice and severe hepatitis)
- Leukopenia at high doses
- Hemolysis in G6PD deficiency
- Contact dermatitis and photoallergy with topical use
Who should avoid it
- Anyone on sulfonamide antibiotics (sulfamethoxazole-TMP, dapsone, sulfasalazine) — direct antagonism reduces antibiotic efficacy
- People with renal or hepatic impairment
- People with G6PD deficiency
- Pregnant or breastfeeding women
Pregnancy & breastfeeding
Avoid during pregnancy and breastfeeding — insufficient safety data and potential fetal concern.
Interactions
PABA is a structural analog of sulfonamides and competitively reverses their mechanism — reduces or eliminates antimicrobial efficacy
High-dose PABA may theoretically affect coagulation parameters; monitor if combining
Choosing a product
Look for
- Dose in mg clearly stated
- Third-party tested — high-dose PABA is not a typical OTC supplement scenario
- Medical supervision required for POTABA therapeutic doses
Be skeptical of
- 'Restores hair color'
- 'Treats vitiligo'
- 'Sun protection supplement'
- 'Reverses aging skin'
References by claim
Track PABA with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.