Para-aminobenzoic acid — commonly known as PABA, and sometimes referred to informally as vitamin B10 — is a small organic molecule with an interesting and somewhat undeservedly overlooked role in human biochemistry. Technically, PABA is not a vitamin: it is not essential for human life in the way that vitamins are, and the body can produce limited amounts endogenously with the help of intestinal bacteria. Nevertheless, it is a biologically active compound that participates in several important processes, has a well-established history of topical and oral use, and appears in a range of B-complex supplement formulations. Understanding what PABA actually does — and separating this from older claims that have not stood up to scrutiny — provides a clearer picture of when and why it might be worth including in a nutritional programme.
What Is PABA and How Was It Discovered?
Para-aminobenzoic acid (PABA) is an aminobenzoic acid — an organic compound belonging to the broader family of aromatic acids. It was first synthesised by Fischer in 1863 and characterised in biological contexts in the early 20th century. PABA is structurally related to several important biological molecules: it is a precursor to folate in bacteria and plants (which synthesise their own folate from PABA), and it is the structural backbone of the anaesthetic procaine (novocaine) and related local anaesthetic compounds.
In humans, PABA is not a vitamin in the strict sense — there is no established deficiency disease, no set recommended dietary intake recognised by EFSA or other major regulatory bodies, and the body does not use PABA as a direct folate precursor (humans cannot synthesise folate and must obtain it from diet). Notably, sulfonamide antibiotics work precisely by mimicking PABA and blocking its use in bacterial folate synthesis — a mechanism that has no equivalent role in human cells. PABA's designation as "vitamin B10" is historical rather than current scientific classification.
PABA's Roles in the Body
Despite its non-essential status, PABA does participate in several biological processes in humans:
- Cofactor role in one-carbon metabolism — PABA is a component of folate as it exists in bacteria and plants, but in humans it functions more broadly as a participant in amino acid and protein metabolism, supporting pathways that intersect with B-vitamin activity
- Antifibrotic activity — the most clinically documented use of oral PABA is in the treatment of fibrotic skin conditions; potassium para-aminobenzoate (Potaba) has been studied and used clinically for conditions including scleroderma and Peyronie's disease, where it is thought to inhibit excess collagen deposition
- Support for skin and hair health — PABA is involved in protein metabolism pathways relevant to hair structure and skin integrity; some older research suggested a potential role in pigmentation maintenance, though the evidence for oral PABA reversing grey hair in healthy individuals is limited
- Intestinal and immune support — as a product of intestinal bacterial activity, PABA contributes to the metabolic milieu of the gut; its antibacterial properties have been noted historically, and its structural similarity to sulfonamides may have relevance for certain gut pathogens
- UV photoprotection (topical use) — PABA was among the first UV-absorbing compounds used in commercial sunscreens, effective at absorbing UVB radiation. However, topical PABA has largely been discontinued in modern sunscreen formulations due to its tendency to cause allergic contact dermatitis and to stain clothing
Dietary Sources of PABA
PABA is present in a range of foods, although it is generally not measured or listed in standard nutritional databases as it is not classified as an essential nutrient. Foods that contain meaningful amounts include:
- Organ meats — liver is among the richer animal sources
- Whole grains and wheat germ — among the better plant-based sources
- Brewer's yeast — historically used as a PABA source in nutritional contexts
- Mushrooms — contribute to PABA intake alongside other B-vitamin–adjacent compounds
- Leafy greens and sunflower seeds — provide trace amounts
- Meat and dairy — red meat, milk, and yogurt contain small quantities
Because the daily requirement is low — estimated at a few milligrams and not formally established — dietary deficiency in the traditional sense is rare in individuals eating a varied diet. PABA is also produced by intestinal bacteria, adding to endogenous supply. Explore our vitamin B collection for B-complex supplements that include PABA alongside the complete B-vitamin family.
Signs of PABA Insufficiency
Because PABA is not classified as an essential vitamin, the concept of "deficiency" is less well-defined than for vitamins with established requirements. However, insufficient PABA intake — particularly in the context of broader B-vitamin inadequacy — has been associated with some observable changes. These include premature greying and increased hair fragility, skin dryness and susceptibility to certain skin conditions, and fatigue or mood disturbances that overlap with general B-vitamin insufficiency symptoms. It is important to recognise that these signs are non-specific and far more likely to reflect deficiencies in folate, B12, biotin, or other B vitamins than a PABA shortfall specifically.
Antibiotic use — particularly sulfonamides and broad-spectrum antibiotics that alter gut flora — can reduce endogenous PABA production by disrupting intestinal bacteria. This is one context where paying attention to PABA intake through a B-complex supplement may have some rationale.
[tip:PABA is best absorbed in the presence of other B vitamins, vitamin C, and adequate dietary fat. Coffee and alcohol can reduce its absorption. Most B-complex formulations that include PABA provide it at doses of 25–100 mg — well within the range that has been studied without safety concerns for general supplementation use.]Dosage and Safety
No official recommended daily allowance for PABA has been established in the EU or by EFSA. Typical doses in B-complex supplements range from 10 mg to 100 mg per serving. At these levels, PABA is well tolerated by the vast majority of people. Higher doses — in the gram range used clinically for fibrotic conditions (Potaba is typically used at 12 g/day in divided doses under medical supervision) — carry a different safety profile, with the potential for gastrointestinal side effects and, at very high doses, hepatotoxicity.
For general dietary supplementation, PABA presents no significant safety concerns at the doses found in standard B-complex products. As with all supplements, it should be used thoughtfully and at appropriate doses. Pregnant women taking multiple supplements should be aware that B-vitamin content can overlap across products — checking total intake across all supplements being taken simultaneously is good practice.
[warning:High-dose PABA supplementation (gram-level doses used for fibrotic conditions) should only be undertaken under medical supervision. At such doses, PABA can cause nausea, anorexia, and in rare cases liver toxicity. Standard supplemental doses (25–100 mg) do not carry these risks. PABA-containing sunscreens have been associated with contact allergy; topical formulations are largely avoided in modern products. Individuals with allergy to sulfonamide drugs or local anaesthetics structurally related to PABA should exercise caution and consult a healthcare professional before supplementing.]PABA in the Context of the B-Vitamin Family
PABA's most practical supplementation context is as part of a comprehensive B-complex formulation — where its contributions to protein metabolism and skin/hair health complement the well-established actions of folate, B12, riboflavin, biotin, and pantothenic acid. While standalone PABA supplementation has its place for specific applications, most people interested in PABA's general health benefits will find that a full-spectrum B-complex covering all the B-vitamin–adjacent compounds is a more comprehensive and proportionate approach. Our hair, skin and nails supplements collection includes products specifically formulated to support the nutritional needs of skin and hair.
[products: now-foods-paba-500-mg-100-capsules]For comprehensive B-vitamin support including PABA alongside folate, B12, biotin, and the full B-complex family:
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