Parabens

Parabens are esters of para-hydroxybenzoic acid (see also benzoic acid), also called PHB esters. Parabens have an antimicrobial and antimycotic effect and are therefore widely used in pharmaceutical products, in cosmetics (almost every 4th cosmetic) as well as in various other cosmetics. food as preservatives (E 214 - E 219)

Products in which e.g. parabens are used are:

• Drugs for both external and internal treatment
• cosmetics such as creams, lotions, make-up, lipsticks, aftershave lotions, deodorants, soaps, sunscreens, depilatories, shampoos, toothpastes
• Food: Only methyl paraben and ethyl paraben and their sodium salts are permitted as preservatives in food. They are listed on foodstuffs under the numbers E 214 and 215 and E 218 and 219. Parabens can be detected in measurable but low concentrations in urine, serum and milk.
• Tobacco products: Parabens are also found in tobacco products. They are declared there (according to the currently valid tobacco regulation) as E 214 - E 217.
• Technical fat and oil products: In the technical field parabens are used to preserve oils, fats, glues, shoe polish.
• Cosmetics: Cosmetic products are mainly preserved by methyl and ethyl parabens. Propyl and butyl parabens are used less frequently.
• Due to lack of data, the very rarely used substances isopropyl, isobutyl, phenyl and pentyl parabens should be avoided completely.
• Benzyl paraben is not approved as a preservative in cosmetic products.

Safety of cosmetic product use: The use of parabens in cosmetic products has been associated in recent years with several relevant adverse reactions, including an increased risk of breast cancer.

Allergenicity: From an allergological point of view, it should be noted that parabens can enter the body not only via cosmetics and their long-term skin contact, but also via the gastrointestinal passage of drugs and food.

Parabens are frequently criticized for triggering allergies. Sensitizations against parabens are very rare despite their wide distribution; only very few allergic reactions to the approved parabens have been observed. Parabens do not appear in the hit list (findings in 1.0 million patients) of the 20 most frequent allergens of the IVDK, which is headed by nickel sulphate and fragrance mix.

However, less good results are obtained when parabens are replaced by other preservatives. Many of the other preservatives used in cosmetics have a much higher sensitizing potential. For example, the use of methylisothiazolinone (MI) is re-evaluated and prohibited for the preservation of products which remain on the skin.

Dermatologists confirm the good skin tolerance of parabens. Hence, based on a broad data base there is no reason to exchange parabens for other preservatives which have a considerably higher allergenic potential.

Hormonal efficacy (breast cancer risk): Parabens and breast cancer: Parabens have been suspected to be harmful to health in several cases, e.g. as inducers of breast cancer. The Federal Institute for Risk Assessment (BfR) has clarified in corresponding publications that parabens in cosmetic products do not pose a health risk when used as intended even on large surfaces. A causal relationship between breast cancer and parabens has not yet been scientifically proven.

It is undisputed that certain parabens have a certain hormonal activity so that they can be classified as xenoestrogens, the synthetic estrogens. It has also been shown that parabens can bind to oestrogen receptors in vitro. In various studies, however, the estrogen-like effect of parabens was by a factor of 1,000 to 1,000,000 less than that of 17-ß-oestradiol, the physiological hormone. Strongest effects were shown for butyl paraben while the ester methyl paraben which is most frequently used in cosmetic products showed the lowest estrogenic effect. However, a recent experimental work on ER+ mammary gland carcinoma cells showed stimulation by methyl paraben; another recent relevant experimental work showed stimulation of tumor cells by butyl paraben.

Overall assessment: The Federal Institute for Risk Assessment (BfR) summarised the status of the assessment of parabens in a statement in January 2011. According to this, methyl and ethyl parabens are considered safe in the permitted concentration range (up to 0.4%). The estrogenic potency is low. For butyl and propyl parabens, a maximum concentration of 0.19% is proposed because of their higher estrogenic potency. Up to this concentration the use is considered safe. The rarely used isopropyl, isobutyl, pentyl and phenyl paraben should be provisionally omitted because of the incomplete data available. However, the risk of carcinoma should be re-examined in the light of recent and relevant experimental data. The two preservatives propyl paraben and butyl paraben should no longer be contained in children's cosmetics used in diapers from April 2015 on. The basis is an evaluation of the preservatives by the Scientific Committee for Consumer Safety (SCCS) of the EU Commission. The ban also applies to all "diaper cosmetics" for children < 3 years of age.

Azzouz A et al (2016) Simultaneous determination of parabens, alkylphenols, phenylphenols, bisphenol A and triclosan in human urine, blood and breast milk by continuous solid-phase extraction and gas chromatography-mass spectrometry. J Pharm Biomed Anal 119:16-26.

Darbre PD et al(2004) Concentrations of parabens in human breast tumours. Journal of applied toxicology 24: 5-13

GD Gesellschaft für Dermopharmazie e.V.: Contact allergies to cosmetics (PDF; 17 kB) Press release of 4 April 2011.

Hines EP et al.(2015) Concentrations of environmental phenols and parabens in milk, urine and serum of lactating North Carolina women. Reprod Toxicol 54:120-128

BfR (2004) Paraben-containing deodorants and the development of breast cancer (13 February 2004)

Lillo MA et al (2016) Methylparaben stimulates tumor initiating cells in ER+ breast cancer models. J Appl Toxicol doi: 10.1002/jat.3374.

San S et al.(2016) Parabens and Human Epidermal Growth Factor Receptor Ligand Cross-Talk in Breast Cancer Cells. Environ Health Perspect 124:563-569

Directive 2006/52/EC of the European Parliament and of the Council of 5 July 2006