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PABA (Para-Aminobenzoic Acid)

PAB-uh / pair-uh ah-MEE-noh ben-ZOH-ik AS-id

Vitamin

A compound once called a B vitamin that is part of folic acid. It's used in some sunscreens and studied for skin conditions, but is not essential in the diet.

PABA is like a building block that bacteria use to make their version of folic acid. Sulfonamide antibiotics work by slipping a fake PABA into the bacteria's assembly line, jamming their folate production.

What it does in the body

  • Component of folate molecular structure (pteroic acid moiety)
  • UV light absorption (topical photoprotection, historical use)
  • Substrate for bacterial folate synthesis in the gut
  • Investigated for fibrotic conditions (scleroderma, Peyronie's disease) — mechanism unclear
  • Potential role in hair pigmentation (limited evidence for reversing gray hair)

How much you need (Daily Value)

GroupRecommendedSource
Adult maleNo established DRI — not recognized as essentialN/A
Adult femaleNo established DRIN/A
PregnancyNo established DRIN/A
ChildrenNo established DRIN/A
Older adultsNo established DRIN/A

Richest food sources

FoodAmountWhere
Liver (various)0.5-1.0 mg per 100gglobal
Whole grains0.3-0.5 mg per 100gglobal
Eggs0.07 mg per eggglobal
Brewer's yeastHigh but variable amountsglobal
Spinach0.06 mg per 100gglobal
MushroomsSmall amountsglobal

If you don't get enough

Mild: Not applicable — PABA is not considered an essential human nutrient

Moderate: Not applicable

Severe: Not applicable — humans do not require preformed PABA. However, PABA deficiency in bacteria prevents their folate synthesis (basis for sulfonamide antibiotics)

Time to onset: Not applicable for humans

Too much

Upper limit: No established UL; supplementation above 400 mg/day not recommended without medical supervision

High doses (>8g/day): hepatotoxicity, nausea, vomiting, diarrhea, anorexia, fever, skin rash. Can interfere with sulfonamide antibiotic efficacy.

How well you absorb it

Rapidly absorbed from the GI tract; excreted primarily via the kidneys as acetylated metabolite

Helped by: Normal GI function

Hindered by: Sulfonamide antibiotics (competitive antagonists)

Cooking & storage

PABA is relatively heat-stable. Normal cooking does not significantly affect PABA content in foods.

Did you know. PABA is no longer classified as a vitamin by any major health organization. Its primary modern relevance is as a historical sunscreen ingredient (now largely replaced by safer alternatives) and as the pharmacological target of sulfonamide antibiotics.

Educational reference only. Nutrient needs vary with age, sex, health, and medication. Not medical or dietary advice. See our full disclaimer.
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Evidence grades: A — meta-analyses / large trials; B — cohort studies & guidelines; C — expert consensus. Links open in a new tab.

CPABA and its derivatives in sunscreen formulations — Dermatologic Therapy, 2013
CPotassium para-aminobenzoate (Potaba) in Peyronie's disease — Journal of Urology, 2005
BSulfonamides and PABA: mechanism of antibacterial action — Pharmacology & Therapeutics, 2010