PABA

📋 Quick facts

Description: PABA — chemical UV filter (UVB); largely phased out due to allergy and sensitization concerns.

All Functions: chemical UV filter (UVB); largely phased out due to allergy and sensitization concerns

Quick Facts:

• Category: sunscreen
• Regulatory Note: Prohibited in the EU

Proven Benefits At A Glance:

• PABA is a chemical sunscreen ingredient that was popular after World War II but has been largely phased out
• It was found to be a common skin sensitizer and could trigger cross-reactions with similar chemicals
• Prolonged PABA exposure has been linked to autoimmune responses including systemic lupus erythematosus and dermatomyositis
• In animal studies, PABA showed promise in slowing UV-induced tumor development
• A synthetic PABA derivative (ethylhexyl dimethyl PABA) used in modern sunscreens has raised toxicity concerns in research

⚗️ Chemical Overview

P-aminobenzoic acid appears as colorless crystals that discolor on exposure to light and air. (NTP, 1992) 4-aminobenzoic acid is an aminobenzoic acid in which the amino group is para to the carboxy group. It has a role as an allergen, a plant metabolite and an Escherichia coli metabolite. It is functionally related to a benzoic acid. It is a conjugate base of a 4-carboxyanilinium. It is a conjugate acid of a 4-aminobenzoate. It is a tautomer of a 4-ammoniobenzoate. A member of the vitamin B complex. It used to be common in sunscreening agents until found to also be a sensitizer. The potassium salt is used therapeutically in fibrotic skin disorders.

Source(s): ChEBI, CAMEO Chemicals, DrugBank, via PubChem

📊 Comedogenicity

🛡️ Safety rating

Safety tier is a starting heuristic from regulatory status and comedogenic rating, not a dermatological verdict — see our Terms for the full disclaimer. Research confidence reflects how many real cited studies back this ingredient, not the strength of their findings.

🌍 Regulatory Status

💧 Skin Type Compatibility

⚠️ Don’t Combine With

📚 Research & Evidence

🔬 The Science

PABA, or para-aminobenzoic acid, has a complicated history in skincare. Originally embraced as a sunscreen hero in the post-World War II era, dermatologists gradually recognized serious problems. According to *Australasian Journal of Dermatology* (1999), PABA turned out to be a fairly common skin sensitizer—meaning it frequently triggered allergic contact reactions. More concerning, it could cross-sensitize with chemically similar compounds both through skin contact and when taken as systemic medications. Extended PABA exposure raised another red flag: #1: it was associated with autoimmune responses, particularly systemic lupus erythematosus and dermatomyositis. These complications were serious enough that dermatological societies in Australia discussed them formally in 1964 and 1965, ultimately contributing to PABA’s gradual withdrawal from sunscreen products.

On the beneficial side, animal research suggested real photoprotective potential. A study in *Archives of Dermatological Research* (1990) tested a 5% PABA solution on hairless mice exposed to UVB radiation. #2: PABA significantly delayed tumor development time and reduced both overall tumor yield and carcinoma yield (with statistical significance, p < 0.05). Interestingly, #3: skin thickness in PABA-protected mice matched untreated controls, whereas unprotected UV-exposed skin became significantly thicker, suggesting PABA prevented some UV damage at a tissue level. Today's concern centers on ethylhexyl dimethyl PABA, an oil-soluble derivative commonly used in modern sunscreens (typically at 0.5–2.0% concentration). According to *Toxicology Research* (2019), animal studies have identified toxicity to the testis, epididymis, spleen, and liver.

Laboratory tests on human skin cells showed #4: ethylhexyl dimethyl PABA inhibited cell growth and DNA synthesis at low doses and halted the cell cycle in melanoma cells. Most significantly, #5: this compound showed increased mutagenicity (ability to cause genetic mutations) when exposed to sunlight, raising concern that it could paradoxically increase sun-induced cancer risk despite blocking UVB. The same source notes clinical human data remain limited. Risk assessment calculations suggested a safety margin of 180 for maximum-use scenarios, though the presence of mutagenic potential under sun exposure remains a concern requiring further investigation.

📄 Related Research

Matched by search — not necessarily verified support for every statement above.

• Mackie BS et al. (1999). The PABA story. Australas J Dermatol.
• Marmelzat J et al. (1980). Photodermatitis with PABA. Contact Dermatitis.
• Gasparro FP (1986). PABA: friend or foe?. Photodermatol.
• Flindt-Hansen H et al. (1990). The inhibiting effect of PABA on photocarcinogenesis. Arch Dermatol Res.
• Sung CR et al. (2019). Risk Assessment of Ethylhexyl Dimethyl PABA in Cosmetics. Toxicol Res.

🧴 Products Containing PABA

• Delia, Delia Cosmetics Cameleo Blond Moyen 7.0
• Maui Moisture Curl quench + coconut oil conditioner
• Netto Memory Fix Gel Coiffant
• Lovea Lait protecteur hydratant au Monoï de Tahiti SPF 30
• Auchan, Auchan Beauty Kids Spray solaire Water resistant UVA Kids
• Revuele Daily face cream, sunprotect
• Rituals… The Ritual of Ayurveda Nourishing Ultra-Shine Shampoo