PABA (Para-Aminobenzoic Acid)
Summary
PABA is sold as a supplement, but the trials used its potassium salt (Potaba) at 12 g a day. In 75 men with early Peyronie's disease, 12 months shrank plaques and stopped curvature worsening more often than placebo (grade C). In 146 people with scleroderma it did not help the skin. Acute hepatitis has been reported.
Key facts
- An aminobenzoic acid; its potassium salt (aminobenzoate potassium, Potaba) is the form tested in trials[1][2]
- Response (plaque or curvature) 74.3% on 12 g a day vs 50.0% on placebo after 12 months; plaques shrank, curvature did not worsen[1]
- 12 g a day for 48 weeks did not change skin thickening or mobility versus placebo; more people stopped for side effects[2]
- Acute liver injury has been reported in at least six people taking potassium PABA; in the most recent report it resolved after stopping[3]
- 2 graded human outcomes on this page
- October 11, 2026
How it works
ProposedPotassium PABA is proposed to have antifibrotic effects on connective tissue; how it acts on Peyronie's plaques is not established.[1]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Scleroderma | Grade C | No effect | RCT · n = 146 · 1994 | 1 row |
| Peyronie's disease | Grade C | Improved | RCT · n = 75 · 2005 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Skin thickening and mobility in scleroderma | No effect | Grade C | RCT · n = 146 · 1994 Adults with longstanding, stable scleroderma Form: Aminobenzoate potassium · Dose: 12 g/day · Duration: 48 weeks No difference from placebo on any outcome; 76 of 146 completed; 18 vs 6 people withdrew for side effects, mostly stomach upset and headache. | 8151563 (opens PubMed)Source [2] |
| Plaque size and curvature in early Peyronie's disease | Improved | Grade C | RCT · n = 75 · 2005 Men with Peyronie's disease under 12 months, non-calcified plaque (103 randomized) Form: Potassium para-aminobenzoate (Potaba) · Dose: 12 g/day (3 g four times a day) · Duration: 12 months Responders 74.3% vs 50.0% on placebo; mean plaque size fell from 259 to 142 mm²; existing curvature did not improve but new or worsening curvature was less common. Pain relief did not differ. | 15774254 (opens PubMed)Source [1] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Aminobenzoate potassium (Potaba) | Varies[1] | No absorption comparison with plain PABA in our sources.[1] | Withdrawals for stomach upset and headache were more common than on placebo at 12 g a day; rare acute hepatitis.[2][3] | Peyronie's disease, scleroderma (12 g/day) |
| Para-aminobenzoic acid (supplement form) | Varies[1] | No human trials of plain PABA supplements in our sources.[1] | No trial data for plain PABA in our sources.[1] | Not tested in the trials we cite |
Studied doses
Doses studied in human trials ranged from 12 g of potassium aminobenzoate a day, for 48 weeks to 12 months.[1][2]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Liver disease or abnormal liver tests
- Acute hepatitis has been reported with potassium PABA; in the latest reported case it resolved about 4 months after stopping.[3]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Liver safety
Reported with the prescription potassium salt at high doses.
- Acute hepatitis
- A 2008 report added a case to five earlier ones of acute liver injury with potassium PABA; the patient recovered fully 4 months after stopping.[3]
Frequently asked questions
Is PABA a vitamin?
It is sometimes marketed as “vitamin Bx”, but the human trials tested it as a high-dose drug (the potassium salt), not as a nutrient.[1][2]
Does PABA help Peyronie's disease?
In one placebo-controlled trial, 12 g a day of potassium PABA for 12 months shrank plaques and kept curvature from worsening more often; it did not straighten existing curvature.[1]
Are PABA supplements the same as Potaba?
Potaba is the potassium salt used in the trials, at 12 g a day. Plain PABA supplements have not been tested in those trials.[1][2]
Is PABA safe for the liver?
Acute liver injury has been reported in at least six people taking potassium PABA. Stopping it is the recommended response.[3]
Sources
- [1]Potassium paraaminobenzoate (POTABA) in the treatment of Peyronie's disease: a prospective, placebo-controlled, randomized study.. Eur Urol, 2005. RCT
- [2]Comparison of aminobenzoate potassium and placebo in the treatment of scleroderma.. J Rheumatol, 1994. RCT
- [3]Acute hepatitis associated with treatment of Peyronie's disease with potassium para-aminobenzoate (Potaba).. J Sex Med, 2008. review
What changed
- First draft. Every PMID checked against NCBI E-utilities (title, year and journal taken from the PubMed record) and abstracts read for each cited row. No single-ingredient PABA product was listed by Supersmart US on 2026-10-11, so no product card is shown. Self-reviewed in a second strict pass, then checked by an independent adversarial fact-check against the PubMed abstracts and live product pages. No credentialed medical reviewer yet.