L'acide para-aminobenzoïque (PABA), exclu chez Typology.

Why does Typology not use para-aminobenzoic acid (PABA)?

Para-aminobenzoic acid is a first-generation UV filter used in sunscreen formulations. We decided to exclude it from our products at Typology. Why? Learn more below about controversies surrounding para-aminobenzoic acid.

What is para-aminobenzoic acid?

The para-aminobenzoic acid, also known as PABA and 4-aminobenzoic acid, is an organic molecule used since the 1940s to protect skin from ultraviolet rays emitted by the sun. 4-aminobenzoic acid acts mainly by absorbing UVB and has an absorption peak around 270 nm. PABA is a chemical filter whose mechanism of action relies on conjugated double bonds within its structure. These bonds absorb light energy and convert it into heat harmless to the skin.

Structure chimique de l'acide para-aminobenzoïque.
Chemical structure of para-aminobenzoic acid.
Source: PubChem.
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Para-aminobenzoic acid can protect skin from UVB rays, but it is esterified into Padimate O, another UV filter. It is more stable and offers better cosmetic compatibility. In regulatory terms, para-aminobenzoic acid is listed in Annex IV of Regulation (EC) No. 1223/2009, which lists the UV filters permitted in the European Union. PABA can also be used in the United States, at a maximum concentration of 15%, compared with 5% in Europe.

Physicochemical propertiesValues
Chemical formulaC7H7NO2
Molar mass137,14 g/mol
SolubilitySoluble in alcohol. Low solubility in water.
AppearanceWhite or pale yellow crystals
Physicochemical properties of para-aminobenzoic acid.

Para-aminobenzoic acid, a controversial ingredient.

4-aminobenzoic acid is falling out of use in skincare because its toxicological profile raises growing concerns about skin health. That is why at Typology we exclude this sun filter from our formulations. Para-aminobenzoic acid is associated with allergic and photoallergic reactions. Clinical studies have shown it can trigger these reactions in people with photodermatosis.

At a Norwegian dermatology clinic, 23 patients with redness or burning after sun exposure were examined. 48% had a positive skin test to PABA by direct contact or after UV irradiation. A broader Scandinavian study of 1,993 patients with suspected photodermatoses reported 44 allergic reactions to para-aminobenzoic acid, a 2.2% rate. These results suggest that this sunscreen filter may be a significant sensitizing agent in sensitive or photosensitive skin.

In addition, PABA appears to be able to penetrate the skin barrier. This is supported by several studies in vitro and in vivo. In a study with human volunteers, about 11.5% ± 6.3% of the applied PABA dose was recovered in the urine after 24 hours, indicating significant systemic absorption. The product was applied to healthy subjects’ forearms without occlusion, and the skin was rinsed 24 hours later. Despite this delayed removal, a substantial fraction of the molecule had already entered the body.

Note : Based on the review of scientific literature by the Scientific Committee on Consumer Safety, one of the independent scientific committees managed by the European Commission’s Directorate-General for Health and Consumers, PABA poses no mutagenic, carcinogenic, or teratogenic risks.

Does para-aminobenzoic acid present environmental issues?

Regarding the potential environmental effects of 4-aminobenzoic acid, these have been sparsely studied. According to available data, this sunscreen UV filter does not appear to be persistent but it would be toxic to aquatic organisms. For example, the 48-hour median lethal concentration (LC50) in aquatic invertebrates is about 10.03 mg/L, which means that at this concentration half of the exposed organisms do not survive the period. For fish, a 96-hour exposure reveals a much lower LC50 of around 1.041 mg/L, indicating higher toxicity for these organisms.

Data from the ECHA database (European Chemicals Agency) indicate that the environmental impact of para-aminobenzoic acid cannot be ignored.

Sources

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