The Complete Ingredient Breakdown: PABA

What is PABA?

PABA (Para-Aminobenzoic Acid) is an organic compound that was once considered part of the B-vitamin complex (sometimes called vitamin Bx or vitamin B10) but is no longer classified as a vitamin for humans. While it serves important functions in bacteria and some organisms, humans do not have an established nutritional requirement for PABA, though it may have specific therapeutic applications.

Chemical Nature:

• Aromatic amine and carboxylic acid
• Chemical formula: C₇H₇NO₂
• White crystalline substance
• Member of the para-aminobenzoic acid family
• Precursor compound in some organisms
• Not synthesized by humans in meaningful amounts

Historical Context:

• Once considered: vitamin B10 or Bx
• Reclassified: not essential for humans
• Essential: for bacteria (folate synthesis)
• Still included: in some B-complex supplements
• Popular in: 1940s-1950s for various conditions
• Research declined: after reclassification

Forms:

PABA (Free Form):

• Standard supplemental form
• Pure para-aminobenzoic acid
• Most common in supplements
• Oral and topical applications

Potassium PABA (Potaba):

• Prescription form in some countries
• Used for: fibrotic conditions (Peyronie's disease, scleroderma)
• Better absorbed: than free PABA
• FDA-approved: for specific conditions
• Higher doses: typically used

PABA Esters:

• Used in: sunscreens and cosmetics
• Octyl dimethyl PABA, padimate O
• Topical only: not for oral supplementation
• Sun protection: UV absorption

Key Characteristics:

• Not essential for humans
• Component of folic acid structure (in bacteria)
• UV light absorber (sunscreen properties)
• Antioxidant properties
• Anti-fibrotic effects (mechanism unclear)
• Melanin production involvement
• Generally recognized as safe (GRAS) at low doses

Primary Functions & Benefits

Functions in Bacteria (Not Humans):

Folate Synthesis:

• Bacteria require: PABA to synthesize folate
• Humans: obtain folate from diet (don't synthesize it)
• Sulfa drugs work: by blocking bacterial PABA use
• No role: in human folate metabolism

Proposed Functions in Humans (Limited Evidence):

Skin Pigmentation:

• May affect: melanin production
• Proposed: for vitiligo (repigmentation)
• Mechanism: unclear
• Evidence: weak and conflicting

Antioxidant Activity:

• Free radical scavenging: some in vitro evidence
• Practical significance: unclear
• Other antioxidants: more potent

Connective Tissue Effects:

• Anti-fibrotic: mechanism unknown
• Used for: Peyronie's disease, scleroderma
• Evidence: mixed and limited
• Potassium PABA: prescription form for these conditions

UV Protection (Topical):

• UVB absorption: used in older sunscreens
• Less common now: other ingredients preferred
• PABA esters: still used in some products

Historical and Proposed Benefits (Largely Unproven):

Hair Graying Prevention:

• Popular belief: restores hair color
• Scientific evidence: essentially none
• Mechanism: theoretically related to melanin
• Not supported: by modern research
• Anecdotal only

Vitiligo (Skin Depigmentation):

• Some old studies: suggested benefit
• Modern research: conflicting results
• Mechanism: proposed melanin production
• Not first-line: treatment
• Limited evidence

Peyronie's Disease:

• Fibrous plaque: in penis causing curvature
• Potassium PABA: FDA-approved treatment
• Evidence: mixed, some benefit in some studies
• Mechanism: unknown (anti-fibrotic proposed)
• High doses required: 12g daily
• Other treatments: often preferred

Scleroderma:

• Skin thickening: autoimmune condition
• Potassium PABA: used historically
• Evidence: weak and dated
• Not standard: treatment today
• Better options: available

Arthritis:

• Historical use: for joint inflammation
• No solid evidence
• Not recommended

Hair Loss:

• Claimed benefit: hair growth
• No scientific support
• Mechanism: unclear
• Not effective

Modern Understanding:

Limited Essential Role:

• Not a vitamin: for humans
• Not required: in diet
• Body doesn't use: PABA to make folate (unlike bacteria)
• Therapeutic uses: very specific and limited
• Most claims: not evidence-based

Recommended Daily Amounts

No RDA or Adequate Intake:

• Not classified: as essential nutrient
• No established: dietary reference intakes
• No deficiency: syndrome in humans
• No recommended: daily amount

Typical Supplemental Doses:

General Supplementation (Not Recommended for Most):

• B-complex: 25-100 mg (if included)
• No established need: for routine supplementation
• Historical use: not supported by modern evidence

Therapeutic Doses (Specific Conditions):

Peyronie's Disease (Potassium PABA):

• Prescription dose: 12,000 mg (12g) daily
• Divided: 3g four times daily
• Duration: 3-6 months minimum
• Medical supervision: required
• High dose: specific to this condition

Vitiligo (Historical, Not Standard):

• Doses used: 100-400 mg daily (sometimes higher)
• Often with: topical application
• Evidence: weak
• Not recommended: as primary treatment

Scleroderma (Historical):

• Potassium PABA: 12g daily (prescription)
• No longer: standard treatment
• Better options: available

Upper Limit:

• No official UL: established
• High doses: can cause side effects (see toxicity section)
• 8,000 mg daily: increased risk of adverse effects
• Prescription doses: require medical supervision

No Established Nutritional Need:

• Humans: don't require dietary PABA
• Supplementation: not necessary for general health
• Specific conditions: may have limited therapeutic use
• Most people: should not take PABA supplements

Food Sources

PABA in Foods (Generally Low Amounts):

Some Natural Occurrence:

• Whole grains: trace amounts
• Liver and organ meats: small amounts
• Mushrooms: minimal
• Yeast: some content
• Spinach and other greens: trace amounts

Quantification Difficult:

• Not typically: measured in food databases
• Amounts: very small
• Not significant: dietary source
• Not nutritionally: relevant for humans

Gut Bacteria Production:

• Intestinal bacteria: produce some PABA
• Absorption: uncertain
• Significance: unclear for human health
• Not relied upon: for any essential function

No Dietary Requirement:

• Humans: don't need PABA from food
• No deficiency: from lack of dietary PABA
• Food content: not nutritionally important
• Supplementation: only for specific therapeutic use

Supplementation Guidelines

General Recommendation: Not Needed for Most People

Who Might Consider:

• Peyronie's disease: prescription potassium PABA under medical care
• Specific fibrotic conditions: medical supervision required
• Historical therapeutic use: limited modern support
• Most people: no benefit from supplementation

Types of Supplements:

PABA (Free Acid):

• Standard supplement form
• Found in: some B-complex formulas
• Doses: typically 25-500 mg
• No established benefit: for general population
• May cause: GI upset even at moderate doses

Potassium PABA (Potaba - Prescription):

• FDA-approved: for Peyronie's disease and scleroderma
• High doses: 12g daily typical
• Prescription only: in the US
• Medical supervision: required
• Better absorbed: than free PABA
• More expensive

Topical PABA (Sunscreen Ingredient):

• PABA or PABA esters
• UVB protection
• Less common: now (other ingredients preferred)
• Can cause: allergic reactions in some people
• Stains clothing: yellow

Form Selection (If Using):

Not Recommended for General Use:

• No nutritional need
• Limited therapeutic applications
• Side effects: possible even at moderate doses
• Other options: usually better for claimed benefits

If Prescribed for Peyronie's Disease:

• Potassium PABA: prescription form
• Medical supervision: essential
• High doses: 12g daily
• Monitoring: for side effects and liver function

Dosing Considerations:

Not for Routine Supplementation:

• No benefit: for general health
• Not a vitamin: despite historical classification
• Can cause: side effects
• Avoid: unless specific medical reason

Therapeutic Use (Medical Supervision):

• Start low: assess tolerance
• Divide doses: throughout day with meals
• Medical monitoring: essential for high doses
• Liver function: monitor periodically
• Duration: condition-specific

Timing & Administration:

• With meals: reduces GI upset
• Divided doses: for high amounts (Peyronie's treatment)
• Consistent timing: for therapeutic use
• Not applicable: to most people (shouldn't be taking it)

Synergistic Supplements

Limited Evidence for Combinations:

B-Complex Vitamins:

• Historically included: with other B vitamins
• No synergy: established
• No benefit: to combining
• B-complex without PABA: perfectly adequate

Folate:

• No relationship: in humans (unlike bacteria)
• PABA doesn't: contribute to human folate status
• Historical confusion: from bacterial metabolism

Vitamin C:

• Sometimes combined: in old formulations
• No evidence: of synergy
• Both antioxidants: but PABA weak

For Specific Conditions (Historical, Limited Evidence):

Vitiligo (Not Recommended):

• Sometimes combined: with copper, vitamin C
• Weak evidence: for any combination
• Modern treatments: superior

Peyronie's Disease:

• Potassium PABA: often used alone
• Some combine: with vitamin E (limited evidence)
• Coenzyme Q10: sometimes added (no strong evidence)
• Medical management: varies by provider

No Established Synergies:

• PABA unique: in having no clear nutritional role
• Combinations: not evidence-based
• Most people: should avoid PABA entirely

Interactions & What NOT to Take

Drug Interactions:

Sulfonamide Antibiotics (Sulfa Drugs):

• Antagonistic: PABA blocks sulfa drug action
• Mechanism: sulfa drugs work by blocking bacterial PABA use
• PABA supplementation: reduces antibiotic effectiveness
• AVOID: PABA if on sulfa antibiotics
• Examples: sulfamethoxazole, sulfasalazine, sulfadiazine
• Critical interaction: can lead to treatment failure

Methotrexate:

• May interfere: with methotrexate action
• Theoretical: both affect folate pathways (in bacteria)
• Avoid: PABA if on methotrexate
• Medical consultation: required

Aspirin and NSAIDs:

• May increase: PABA toxicity risk
• Liver stress: both can affect liver
• Monitor: liver function if combining

Other Medications:

• Limited data: on most interactions
• Medical consultation: advised for any medication use
• High-dose PABA: more likely to interact

Conditions Requiring Caution:

Kidney Disease:

• PABA excreted: by kidneys
• Impaired clearance: in kidney disease
• Accumulation risk: with renal impairment
• Avoid: in kidney disease

Liver Disease:

• High doses: can affect liver function
• Monitor: liver enzymes
• Avoid: in active liver disease
• Potassium PABA: requires monitoring

Folate Metabolism Disorders:

• Theoretical concerns: though PABA doesn't affect human folate directly
• Medical supervision: advised

Nutrient Interactions:

No Established Interactions:

• PABA isolated: from normal nutrient metabolism
• No known: vitamin or mineral interactions
• Exception: sulfa drug interference (pharmaceutical, not nutrient)

Who Should Take PABA

Very Few People Should Take PABA:

Not Recommended for General Population:

• Not essential: for humans
• No health benefits: for most people
• Potential side effects: without clear benefit
• Better alternatives: for claimed uses

Specific Medical Conditions (Prescription Required):

Peyronie's Disease:

• Potassium PABA: FDA-approved treatment
• Prescription form: medical supervision
• Dose: 12g daily
• Evidence: mixed but some benefit shown
• Alternative treatments: available
• Medical decision: with urologist

Scleroderma (Historical, Rarely Used Now):

• Potassium PABA: used historically
• Evidence: weak
• Not standard: treatment today
• Better options: available
• If used: medical supervision required

Who Might Have Considered It Historically (No Longer Recommended):

Vitiligo:

• Old studies: suggested possible benefit
• Modern evidence: weak and conflicting
• Not first-line: treatment
• Better options: phototherapy, topical steroids, newer therapies

Hair Graying:

• Popular belief: prevents or reverses gray hair
• No scientific evidence
• Mechanism: theoretically related to melanin
• Not effective: based on research

General "Anti-Aging":

• Historical marketing: as anti-aging compound
• No evidence: for anti-aging effects
• Not recommended

Bottom Line on Who Should Take:

• Almost nobody: for routine supplementation
• Prescription use: Peyronie's disease (limited)
• Medical supervision: always required for therapeutic doses
• Alternatives: usually better for claimed benefits

Who Should AVOID or Use Caution

Absolute Contraindications:

People on Sulfa Antibiotics:

• PABA antagonizes: antibiotic action
• Can cause: treatment failure
• Serious infections: could worsen
• Absolutely avoid: while on sulfa drugs
• Examples: Bactrim (sulfamethoxazole), sulfasalazine

Kidney Disease:

• Impaired excretion: accumulation risk
• Higher toxicity: risk
• Avoid entirely

Liver Disease:

• High doses: can damage liver
• Active liver disease: contraindication
• Monitor closely: if any liver issues

Use Extreme Caution:

Pregnant Women:

• Safety: not well-established
• No known benefits: during pregnancy
• Potential risks: unknown
• Avoid: unless specifically prescribed

Breastfeeding Women:

• Transfer to milk: unknown
• No established benefits
• Avoid: to be safe

Children:

• No pediatric: indications
• Safety data: limited
• Not recommended

Elderly:

• Higher risk: side effects
• Kidney function: often reduced
• Medication interactions: more common
• Avoid: unless medically indicated

Medical Conditions:

Diabetes:

• May affect: blood sugar (some reports)
• Monitor closely: if using
• Better avoided

Autoimmune Conditions:

• Unclear effects: on immune function
• Medical supervision: if considering

Medication Users:

Multiple Medications:

• Limited interaction data
• Potential: for unknown interactions
• Avoid: unless specifically indicated
• Medical consultation: essential

General Population:

Most People Should Avoid:

• No nutritional need
• Potential side effects
• No clear benefits
• Better alternatives: for any claimed use

Deficiency Symptoms

No Human Deficiency Syndrome:

Not Essential:

• Humans: don't require PABA
• No deficiency: disease in humans
• Not needed: for any essential function
• Historical misclassification: as vitamin

Bacterial Deficiency:

• Bacteria need: PABA for folate synthesis
• Humans: get folate from diet
• Sulfa drugs: exploit bacterial PABA dependence
• Not relevant: to human nutrition

No Symptoms from Low PABA:

• Humans on: PABA-free diet show no deficiency
• No adverse effects: from lack of PABA
• Body doesn't: use PABA for essential processes
• Supplementation: unnecessary

Historical Claims (Unsupported):

• Gray hair: claimed as deficiency symptom (false)
• Fatigue: not related to PABA
• Skin issues: not from PABA deficiency
• Joint problems: unrelated to PABA

Bottom Line:

• No such thing: as PABA deficiency in humans
• Symptoms attributed: historically were misattributed
• Don't need: to worry about PABA intake
• Focus on: actual essential nutrients

Toxicity Symptoms

PABA Can Cause Significant Side Effects:

Common Side Effects (Moderate Doses, 1-8g daily):

Gastrointestinal:

• Nausea and vomiting: very common
• Abdominal pain: cramping
• Diarrhea: frequent
• Loss of appetite
• Dyspepsia: indigestion

Skin:

• Rash: various types
• Itching: pruritus
• Hyperpigmentation: darkening of skin (ironic given vitiligo use)

Serious Adverse Effects (High Doses, >8-12g daily):

Liver Toxicity:

• Elevated liver enzymes: ALT, AST
• Hepatitis: inflammation
• Liver damage: in some cases
• Jaundice: rare but possible
• Requires: immediate medical attention
• Monitor: liver function with high doses

Hypoglycemia:

• Low blood sugar: especially with high doses
• Mechanism: unclear
• Symptoms: shakiness, sweating, confusion
• More common: in diabetics
• Dangerous: can be severe

Hematologic:

• Fever: drug-induced
• Leukopenia: low white blood cells (rare)
• Agranulocytosis: severe (very rare)

Kidney Effects:

• Crystalluria: crystals in urine
• Kidney stones: possible
• Acute kidney injury: rare

Neurological:

• Vitamin B deficiency: from high-dose PABA (mechanism unclear)
• Neuropathy: rare

Allergic Reactions:

Skin Reactions:

• Contact dermatitis: from topical PABA (sunscreens)
• Allergic rash
• Photoallergy: sun-induced reaction

Anaphylaxis:

• Rare: but possible
• Severe allergic reaction
• Medical emergency

Drug Interaction Toxicity:

With Sulfa Drugs:

• Treatment failure: of infection
• Can be dangerous: for serious infections

Dose-Dependent:</p>

• Low doses (25-100 mg): usually well-tolerated
• Moderate doses (1-8g): GI upset common
• High doses (>8g): liver toxicity risk
• Very high doses (12g+): requires monitoring, multiple side effects common

Prescription Use (Potassium PABA):

• 12g daily: for Peyronie's disease
• Frequent side effects: GI upset, rash
• Monitoring required: liver function, blood sugar
• Many discontinue: due to side effects

Bottom Line on Toxicity:

• Not benign: significant side effects possible
• High doses: particularly problematic
• Liver toxicity: serious concern
• Risk-benefit: poor for most uses
• Medical supervision: essential for therapeutic doses

Testing & Monitoring

No Routine Testing for PABA Levels:

• Not measured: in standard clinical practice
• No deficiency: to test for
• Blood levels: not clinically relevant
• Not useful: for health assessment

Monitoring If Using Therapeutically:

Before Starting High-Dose PABA:

• Liver function: baseline ALT, AST, bilirubin
• Kidney function: creatinine, BUN
• Blood glucose: especially if diabetic
• Complete blood count: baseline

During High-Dose Treatment:

• Liver function: monthly for first 3 months, then every 3 months
• Blood glucose: regularly, especially if diabetic
• Kidney function: periodically
• CBC: if symptoms suggest hematologic issues
• Discontinue: if liver enzymes >3x normal

Clinical Monitoring:

• Side effects: nausea, rash, other symptoms
• Efficacy: for condition being treated
• Compliance: given high pill burden and side effects

Condition-Specific Monitoring:

Peyronie's Disease:

• Penile curvature: assess improvement
• Plaque size: physical exam, ultrasound
• Sexual function: questionnaires
• Duration: 3-6 months minimum before assessing

Liver Toxicity Surveillance:

• Critical: with high doses
• Stop immediately: if significant elevation
• Most cases: reversible with discontinuation

For General Population:

• No monitoring: needed (shouldn't be taking PABA)
• No blood tests: required for PABA status

Special Considerations

Historical Context and Modern Understanding

Once Considered a Vitamin:

• 1940s-1950s: classified as vitamin Bx or B10
• Reclassified: when found not essential for humans
• Bacteria require: PABA for folate synthesis
• Humans obtain: folate from diet
• Confusion: led to decades of inappropriate use

Declining Use:

• Popular historically: for many conditions
• Evidence lacking: for most claims
• Modern medicine: rarely uses PABA
• Exceptions: narrow prescription use (Peyronie's)

Peyronie's Disease Treatment

What is Peyronie's Disease:

• Fibrous plaque: in penis
• Causes: curvature, pain, erectile dysfunction
• Affects: 3-9% of men
• Often spontaneous: improvement in early stages

Potassium PABA Treatment:

• FDA-approved: for this indication
• Mechanism: unknown (proposed anti-fibrotic)
• Dose: 12g daily (very high)
• Duration: 3-6 months minimum
• Efficacy: mixed evidence, modest benefit in some studies
• Side effects: common (GI, rash)
• Not first-line: many other treatments available

Modern Alternatives Often Preferred:

• Intralesional collagenase: FDA-approved, more effective
• Verapamil injections
• Interferon injections
• Surgery: for severe cases
• Vacuum devices, traction therapy
• Pentoxifylline: oral alternative

PABA Use Declining:

• Newer treatments: more effective
• High pill burden: 12g = many pills daily
• Side effects: frequent
• Cost: can be expensive
• Compliance: difficult

Scleroderma (Historical Use)

What is Scleroderma:

• Autoimmune condition: skin and connective tissue
• Skin thickening: fibrosis
• Can affect: internal organs
• Serious condition: requires expert care

Historical PABA Use:

• Potassium PABA: used in 1950s-1980s
• Proposed: anti-fibrotic effect
• Evidence: weak, dated studies
• No longer standard: treatment

Modern Treatment:

• Immunosuppressants: methotrexate, mycophenolate
• Biologics: tocilizumab, rituximab
• Vasodilators: for vascular symptoms
• Physical therapy
• PABA: rarely used today

Vitiligo (Weak Evidence)

What is Vitiligo:

• Loss of skin pigmentation: autoimmune destruction of melanocytes
• White patches: on skin
• Affects: 0.5-2% of population
• Not dangerous: but cosmetic and psychological impact

PABA Historical Use:

• 1940s-1970s: popular for vitiligo
• Proposed: stimulates melanin production
• Oral and topical: both used
• Evidence: weak and conflicting

Modern Treatments Much Better:

• Topical corticosteroids
• Topical calcineurin inhibitors
• Phototherapy: narrowband UVB
• Excimer laser
• JAK inhibitors: newer, promising (ruxolitinib cream)
• Skin grafting: for stable patches
• PABA: not recommended

Gray Hair Prevention (Myth)

Popular Belief:

• PABA prevents or reverses: gray hair
• Theory: related to melanin production
• Widely marketed: historically

Scientific Reality:

• No evidence: PABA affects hair color
• Graying: primarily genetic, age-related
• Melanocyte activity: decreases with age
• PABA doesn't: restore melanocytes
• Studies: show no benefit
• Anecdotal reports: placebo effect

Modern Understanding:

• Gray hair: complex process
• Genetics: primary determinant
• Oxidative stress: contributes
• No proven: supplements to prevent graying
• Focus on: overall health, not PABA

Topical PABA in Sunscreens

Historical Use:

• Popular sunscreen ingredient: 1970s-1980s
• UVB absorption: effective sun protection
• SPF ratings: PABA-based sunscreens

Declined in Popularity:

• Skin irritation: common
• Allergic reactions: frequent
• Stains clothing: yellow discoloration
• Better alternatives: developed

Modern Sunscreens:

• Avobenzone, oxybenzone: more common chemicals
• Zinc oxide, titanium dioxide: physical blockers
• PABA rarely used: in modern formulations
• PABA esters: sometimes still used (padimate O)

If Allergic to PABA:

• Avoid: PABA-containing sunscreens
• Check labels: for PABA or PABA esters
• Many options: PABA-free sunscreens widely available

Lack of Modern Research

Research Declining:

• Peak interest: 1940s-1970s
• Reclassification: reduced funding
• Limited therapeutic use: little incentive
• Modern studies: rare

Most Evidence:

• Old studies: 1950s-1970s methodology
• Poor quality: by modern standards
• Conflicting results: common
• Hard to interpret: decades later

Current Status:

• Orphaned compound: little research interest
• Prescription use: narrow (Peyronie's)
• Supplement use: declining
• Future research: unlikely

Summary & Key Takeaways

PABA (Para-Aminobenzoic Acid) is a compound once considered a B vitamin but now known to be non-essential for humans. While it has narrow prescription use for Peyronie's disease and was historically used for various conditions, most therapeutic claims lack solid evidence. PABA can cause significant side effects, especially at high doses, including liver toxicity and GI distress. The vast majority of people should avoid PABA supplementation as it offers no benefits and poses potential risks.

Critical Points:

• Not a vitamin: for humans (despite historical classification)
• Not essential: no dietary requirement
• No deficiency: syndrome in humans
• Limited therapeutic use: Peyronie's disease (prescription only)
• Significant side effects: especially at high doses
• Liver toxicity: serious concern with high doses
• Most claims: unproven (gray hair, vitiligo, general health)
• Blocks sulfa antibiotics: dangerous interaction

Bottom Line for Most People:

DO NOT TAKE PABA:

• Not essential: for health
• No benefits: for general population
• Can cause: side effects
• Liver toxicity: risk
• Better alternatives: for any claimed use
• Exception: prescription for Peyronie's disease (medical supervision)

Historical vs. Modern Understanding:

Historical Claims (Mostly Unsupported):

• Gray hair prevention: NO EVIDENCE
• Vitiligo treatment: WEAK EVIDENCE, better options available
• Hair growth: NO EVIDENCE
• Anti-aging: NO EVIDENCE
• General health: NO BENEFITS
• "Vitamin" status: INCORRECT

Modern Medical Use (Very Limited):

• Peyronie's disease: FDA-approved (potassium PABA, 12g daily, prescription)
• Evidence: MIXED, modest benefit in some studies
• Side effects: COMMON (GI upset, rash, liver issues)
• Alternatives: OFTEN PREFERRED (newer treatments more effective)

Critical Safety Points:

Contraindications:

• Sulfa antibiotics: ABSOLUTE CONTRAINDICATION (blocks antibiotic action)
• Kidney disease: AVOID (impaired excretion)
• Liver disease: AVOID (hepatotoxicity risk)
• Pregnancy/breastfeeding: AVOID (safety unknown)
• General population: NOT RECOMMENDED

Side Effects:

• Common: nausea, vomiting, diarrhea, abdominal pain, rash
• Serious: liver toxicity, hypoglycemia, kidney damage
• Dose-dependent: higher doses = more side effects
• Monitoring required: liver function with high doses

Drug Interactions:

• Sulfa drugs: CRITICAL INTERACTION (treatment failure)
• Methotrexate: may interfere
• Aspirin/NSAIDs: may increase toxicity
• Limited data: on most other interactions

If Prescribed for Peyronie's Disease:

• Form: Potassium PABA (prescription)
• Dose: 12,000 mg (12g) daily divided doses
• Duration: 3-6 months minimum
• Monitoring: liver function monthly initially
• Side effects: expect GI upset, rash common
• Compliance: difficult (high pill burden)
• Alternatives: discuss with urologist (newer treatments may be better)

For Claimed Benefits:

Gray Hair:

• Evidence: NONE
• Recommendation: DON'T TAKE
• Reality: Genetics determine graying

Vitiligo:

• Evidence: WEAK, outdated
• Recommendation: Use modern treatments (phototherapy, topical steroids, JAK inhibitors)
• PABA: Not recommended

Hair Growth:

• Evidence: NONE
• Recommendation: DON'T TAKE
• Better options: Minoxidil, finasteride (proven)

General Health/Anti-Aging:

• Evidence: NONE
• Recommendation: DON'T TAKE
• Focus on: Actual essential nutrients (vitamins, minerals)

Comparison to Real Vitamins:

• Vitamin B12: ESSENTIAL, prevents anemia, nerve damage
• Folate: ESSENTIAL, prevents birth defects
• Vitamin C: ESSENTIAL, prevents scurvy
• PABA: NOT ESSENTIAL, prevents nothing, no health benefits for most people

Why PABA Persists in Some Supplements:

• Historical inertia: "B-complex" formulas from decades ago
• Marketing: "complete B-complex" claims
• Ignorance: manufacturers unaware it's not needed
• Tradition: "always been in the formula"
• Recommendation: Choose B-complex WITHOUT PABA

Historical Interest vs. Current Reality:

• 1940s-1970s: Popular supplement, considered vitamin
• 1980s-1990s: Reclassified, use declining
• 2000s-Present: Rarely used except narrow prescription use
• Future: Likely to become even more obscure

Bottom Line: PABA is not a vitamin and offers no health benefits to the vast majority of people. It can cause significant side effects, especially liver toxicity at high doses. The only legitimate modern use is prescription potassium PABA for Peyronie's disease, where evidence is mixed and newer alternatives are often preferred. Historical claims about gray hair prevention, vitiligo treatment, and general health benefits are unsupported by modern science. Most people should actively avoid PABA supplements. If you see PABA in a B-complex formula, choose a different formula without it. If prescribed for Peyronie's disease, understand it requires very high doses (12g daily), causes frequent side effects, and needs liver function monitoring. This is a compound whose time has passed - it made sense when we thought it was a vitamin, but modern science shows it's not essential and usually not beneficial.