What is methylparaben

Methylparaben also known as methyl paraben, belongs to a larger group known as “parabens” that include similar substances such as ethylparaben, propylparaben, isopropylparaben and butylparaben, among many others. All of them are actually parahydroxybenzoates or esters of parahydroxybenzoic acid also known as 4-hydroxybenzoic acid. Parabens are found in plants in the form of p-hydroxybenzoic acid (PHBA), a chemical that breaks down to become parabens in order to protect the plant. Methylparaben is a 4-hydroxybenzoate ester resulting from the formal condensation of the carboxy group of 4-hydroxybenzoic acid with methanol ¹. Methylparaben is a stable, non-volatile compound that is the most frequently used antimicrobial preservative in foods, drugs and cosmetics. Methylparaben also occurs naturally in several fruits, particularly in blueberries ¹. Interestingly, it is believed that the mechanism of action of methylparaben—like other parabens—is by interfering with cellular membrane transfer processes as well as by inhibition of the synthesis of DNA, RNA, and enzymes in bacterial cells ².

Parabens are antimicrobial preservatives that are allowed for use in a wide variety of personal care products, cosmetic products, in foods and in beverage processing to prevent the growth of microbes ³. Parabens are used to preserve the shelf life of many cosmetic and personal care products. Cosmetics that may contain parabens include makeup, moisturizers, hair care products, and shaving products, among others ⁴.  Many major brands of deodorants do not currently contain parabens, although some may. Used as a preservation agent, it has been proved to help beauty products enhance their qualities. Moreover, products containing methylparaben are much longer-lasting and their qualities are kept intact for a longer time as well.

Part of methylparaben popularity stems from its capacity to effectively absorb into the human skin. Consequently, it is used in combination with most other beauty ingredients, especially in the manufacturing of body lotions, emollients and other creams. Despite methylparaben highly effective anti-fungal properties, this substance is most often considered non-irritating and even safer than other similar products.

Centers for Disease Control and Prevention (CDC) scientists measured parabens in the urine of more than 2,548 participants aged six years and older who took part in the National Health and Nutrition Examination Survey (NHANES) during 2005–2006 ⁵. By measuring these chemicals in urine, scientists can estimate the amount of parabens that has entered people’s bodies. CDC scientists found methylparaben and propylparaben in the urine of most of the people tested, indicating widespread exposure to these parabens in the U.S. population. In adults younger than age 60, non-Hispanic blacks had higher levels of methyl paraben than non-Hispanic whites. Females had several-fold higher concentrations of methylparaben and propylparabens than males, which likely reflect the greater use of products containing parabens ⁵. Finding a measurable amount of parabens in urine does not imply that they cause an adverse health effect ⁵.

Methylparaben uses

Methylparaben has a role as a plant metabolite, an antimicrobial food preservative, a neuroprotective agent and an antifungal agent ¹. Preservatives may be used in cosmetics to prevent the growth of harmful bacteria and mold, in order to protect both the products and consumers. Parabens are the most frequently used antimicrobial preservatives that are allowed for use in foods, drugs, cosmetics and toiletries ⁶. The parabens used most commonly in cosmetics are methylparaben, propylparaben, butylparaben, and ethylparaben ⁴. Product ingredient labels typically list more than one paraben in a product, and parabens are often used in combination with other types of preservatives to better protect against a broad range of microorganisms ⁴. The shorter chain parabens methylparaben and ethylparaben are often used in combination with other parabens. The longer chain parabens are often used by themselves.

Methylparaben in food

In addition to its natural occurrence in some fruits and vegetables, parabens may also be added to food for preservation. Typical food products that contain parabens for preservation include beer, sauces, desserts, soft drinks, jams, pickles, frozen dairy products, processed vegetables, and flavoring syrups. The Scientific Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food concluded that a group ADI (Acceptable Daily Intake) of 0-10 mg/kg body weight per day could now be established for methylparaben and ethylparaben and their sodium salts ⁶. However, the panel considered that propylparaben could not be included in this group ADI (Acceptable Daily Intake) due to recent research demonstrating its effects on certain reproductive parameters in rats. While the presence of propyl paraben in the diet is limited and unlikely to represent a risk to consumers, the panel was unable to recommend a specific ADI for propyl paraben based on current evidence ⁶.

Parabens in cosmetics

Methylparaben is frequently used as a preservative in cosmetics to prevent the growth of potentially harmful bacteria and mold in products that would otherwise be susceptible to microbial growth ⁷. Parabens are usually easy to identify by their name, such as methylparaben, propylparaben, butylparaben, or ethylparaben. Cosmetics that may contain parabens include makeup, moisturizers, hair care products, and shaving products, among others. Many major brands of deodorants do not currently contain parabens, although some may. Safety questions about the use of parabens in cosmetics center around parabens’ potential to act like estrogen, a hormone that can be associated with the development of breast cancer. Studies have shown, however, that parabens have significantly less estrogenic activity than the body’s naturally occurring estrogen. Parabens have not been shown to be harmful as used in cosmetics, where they are present only in very small amounts.

Is methylparaben bad?

A handful of studies have been used to support the claim that methylparaben may produce estrogen mimicking in the body (endocrine disrupting chemical) ⁸, ⁹. Some research has focused on parabens, which are preservatives used in some deodorants and antiperspirants, that have been shown to mimic the activity of estrogen in the body’s cells ¹⁰. Methylparaben and its safety has caused a lot of controversy, especially after a study revealed that they may have been a link between certain cases of breast cancer and the excessive use of methylparaben in pharmaceutical and cosmetic products ¹¹, ¹². This affirmation stems from the fact that parabens imitate the function of estrogen and may lead to the creation of excessive breast tissue ¹³. It has been reported that parabens are found in breast tumors, but there is no evidence that they cause breast cancer. However, the current evidence isn’t strong enough for the U.S. Food and Drug Administration (FDA) or Cosmetic Ingredient Review Panel to recommend discontinuing its use in products ¹⁴. In 2006, the industry-led Cosmetic Ingredient Review, in a partnership with the U.S. Food and Drug Administration (FDA), determined that there was no need to change Cosmetic Ingredient Review’s original conclusion from 1984 that parabens are safe for use in cosmetics ¹⁵. The FDA allows single or multiple parabens to be added to food or food packaging as antimicrobials to prevent food spoilage ⁵. This is also the case in the EU, where skincare and body care ingredients are highly regulated. The scientific consensus on parabens is that they are safe for their indicated uses. Moreover, research into parabens as a class of ingredients is being continually studied and updated regularly.

Methylparaben may be responsible for sensitivity and irritation in some people. It is generally recommended that people with allergic skin types or those who are prone to eczema or dermatitis avoid products with methylparaben.

The controversial nature of these ingredients has meant that there has been a respectable amount of research into the safety of parabens. Given the controversy most jurisdictions have limited the use of parabens to low concentrations, for example in the EU, the use of butylparaben is limited to 0.4%. The typical concentration of parabens used in cosmetics is 0.01 to 0.3 percent.

What is known about the relationship between antiperspirants or deodorants and breast cancer?

Aluminum-based compounds are used as the active ingredient in antiperspirants. These compounds form a temporary “plug” within the sweat duct that stops the flow of sweat to the skin’s surface. Some research suggests that aluminum-containing underarm antiperspirants, which are applied frequently and left on the skin near the breast, may be absorbed by the skin and have estrogen-like (hormonal) effects ¹⁶. Because estrogen can promote the growth of breast cancer cells, some scientists have suggested that the aluminum-based compounds in antiperspirants may contribute to the development of breast cancer ¹⁶. In addition, it has been suggested that aluminum may have direct activity in breast tissue ¹⁷. However, no studies to date have confirmed any substantial adverse effects of aluminum that could contribute to increased breast cancer risks. A 2014 review concluded there was no clear evidence showing that the use of aluminum-containing underarm antiperspirants or cosmetics increases the risk of breast cancer ¹⁸.

Only a few studies have investigated a possible relationship between breast cancer and underarm antiperspirants or deodorants. One study, published in 2002 ¹⁹, did not show any increase in risk for breast cancer among women who reported using an underarm antiperspirant or deodorant. The results also showed no increase in breast cancer risk among women who reported using a blade (nonelectric) razor and an underarm antiperspirant or deodorant, or among women who reported using an underarm antiperspirant or deodorant within 1 hour of shaving with a blade razor. These conclusions were based on interviews with 813 women with breast cancer and 793 women with no history of breast cancer.

A subsequent study, published in 2006 ²⁰, also found no association between antiperspirant use and breast cancer risk, although it included only 54 women with breast cancer and 50 women without breast cancer.

A 2003 retrospective cohort study ²¹ examining the frequency of underarm shaving and antiperspirant/deodorant use among 437 breast cancer survivors reported younger age at breast cancer diagnosis for women who used antiperspirants/deodorants frequently or who started using them together with shaving at an earlier age. Because of the retrospective nature of the study, the results are not conclusive. Because studies of antiperspirants and deodorants and breast cancer have provided conflicting results, additional research would be needed to determine whether a relationship exists ²².

Is methylparaben safe?

At this time, scientists do not have information showing that parabens as they are used in cosmetics have any link to breast cancer or other health problems. Parabens are reported to cause contact dermatitis reactions in some individuals on skin exposure ¹. Parabens have been implicated in numerous cases of contact sensitivity associated with skin exposure; however, the mechanism of this sensitivity is unknown. Sensitization has occurred when medications containing parabens have been applied to damaged or broken skin. Allergic reactions to ingested parabens have been reported, although rigorous evidence of the allergenicity of ingested paraben is lacking ¹. Some parabens are more likely to cause irritation and sensitivity than others such as methylparaben. Therefore, if you are using a large number of paraben-containing products, then you may be exposing your skin to higher-than-normal levels of the ingredient. This may slightly increase the risk of irritation. If you have sensitive skin it may be useful to become familiar with common preservatives in order to reduce this risk.

Acute toxicity studies in animals indicate that methylparaben is practically non-toxic by both oral and parenteral routes ²³. In a population with normal skin, methylparaben is practically non-irritating and non-sensitizing ²³. In chronic administration studies, no-observed-effect levels (NOEL) as high as 1050 mg/kg have been reported and a no-observed-adverse-effect level (NOAEL) in the rat of 5700 mg/kg is posited. Methylparaben did increase chromosomal aberrations in a Chinese hamster ovary cell assay. Methylparaben was noncarcinogenic when injected subcutaneously in mice or rats or when administered intravaginally in rats ²³. Methylparaben was nonteratogenic in rabbits, rats, mice, and hamsters. It is not embryotoxic. Methylparaben failed to produce any effect in uterotrophic assays in two laboratories, but did produce an effect in other studies from another laboratory. In one in vitro study, sperm were not viable at concentrations as low as 6 mg/mL methylparaben, but an in vivo study of 0.1% or 1.0% methylparaben in the diet of mice reported no spermatotoxic effects ²³. Methylparaben was studied using rats at levels in the diet up to an estimated mean dose of 1141.1 mg/kg per day with no adverse testicular effects ²³.

Medaka vitellogenin assays and DNA microarray analysis were carried out for methylparaben and found induction of significant vitellogenin in male medaka at 630 ug/L of methylparaben, while the expression levels of genes encoding proteins such as choriogenin and vitellogenin increased for concentrations at 10ug/L of methylparaben ¹.

Methylparaben and ethylparaben, in increasing concentrations, were studied for their effect on the oral mucous membrane of 39 subjects ²⁴. They described toxic limit concentrations for methylparaben and ethylparaben of 5 and 10%, respectively. One subject had a reaction of the oral mucous membrane to methylparaben ²⁴. As constituents of antibacterial ointments, dermatological preparations, and proprietary lotions and skin creams, parabens are recognized causes of severe and intractable contact dermatitis ²⁵. All parabens are capable of sensitizing skin and inducing cutaneous allergic responses, although incidence of such reactions is low ²⁶.

Are there safer alternatives to parabens?

Creating safe and effective products without preservatives isn’t really an option. The risk of contamination is high when dealing with water-based formulations and not including a preservative can limit how safe and how effective your product will be. However, given the rumors around the safety of parabens, many brands have replaced parabens with alternatives. There are some issues with this. Newer preservatives aren’t as well researched as parabens. This means that the health implications are somewhat unknown, particularly their long term side effects. In fact, many of these alternatives including the ‘natural’ ones tend to cause more irritation to the skin and don’t work as well in preserving the formulation. This increases the risk that your product may become contaminated with mold, bacteria and fungi. It also reduces the shelf-life of the product, creating more waste. Both ‘natural’ and synthetic alternatives to parabens are more likely to irritate the skin and cause sensitivity and allergic reactions. Just because it is paraben-free doesn’t make it safer.

One way that may help to reduce the amount of preservatives needed in a formulation is through packaging design. Packaging design may reduce the amount of exposure to contaminants, such as vacuum sealed products or pumps. However, packaging design does not stop the product from degrading and becoming rancid.

Methylparaben side effects

Methylparaben when used in the eye region occasionally cause redness and swelling of eyelids from allergic contact dermatitis ²⁷. All parabens are capable of sensitizing skin and inducing cutaneous allergic responses, particularly in sensitive or irritated skin, although incidence of such reactions is low ²⁶.

Parabens are used because they are gentle and non-irritating. However, like any ingredient some people may be more likely to experience irritation than others. It is generally recommended that hyper-sensitive skin types such as those prone to eczema or dermatitis or those with broken skin avoid the use of parabens if they find them to be irritating.

Parabens are also more likely to irritate the skin when it is broken such as if you have a wound or cut on the skin. If your skin is broken, it is best to avoid the use of parabens in that area.

Another concern with parabens and other parabens is the possibility of an allergic reaction. However, the actual incidence of allergy and true allergic contact dermatitis to parabens is very low, less than 2 percent.

Like many skincare ingredients, parabens can cause irritation and sensitization when used on inflamed or damaged skin such as skin types experiencing dermatitis and eczema.

This is why parabens are never used to preserve topical hydrocortisone creams or antibiotic ointments which are used on damaged or inflamed skin. Generally, parabens don’t irritate the skin or cause allergy for normal skin types.

References

1. Methylparaben. https://pubchem.ncbi.nlm.nih.gov/compound/Methylparaben
2. N. Valkova, F. Lépine, L. Valeanu, M. Dupont, L. Labrie, J.-G. Bisaillon, R. Beaudet, F. Shareck, and R. Villemur, Hydrolysis of 4-hydroxybenzoic acid esters (parabens) and their aerobic transformation into phenol by the resistant Enterobacter cloacae strain EM, Appl. Environ. Microbiol., 67, 2404–2409 (2001).
3. Parabens as Urinary Biomarkers of Exposure in Humans. Environmental Health Perspectives volume 114, number 12, December 2006. https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp.9413
4. Parabens in Cosmetics. https://www.fda.gov/cosmetics/cosmetic-ingredients/parabens-cosmetics
5. Parabens Factsheet. https://www.cdc.gov/biomonitoring/Parabens_FactSheet.html
6. EFSA advises on the safety of paraben usage in food. https://www.efsa.europa.eu/en/news/efsa-advises-safety-paraben-usage-food
7. Cosmetics Safety Q&A: Parabens. https://www.fda.gov/cosmetics/resources-consumers-cosmetics/cosmetics-safety-qa-parabens
8. Janjua NR, Mortensen GK, Andersson AM, Kongshoj B, Skakkebaek NE, Wulf HC. Systemic uptake of diethyl phthalate, dibutyl phthalate, and butyl paraben following whole-body topical application and reproductive and thyroid hormone levels in humans. Environ Sci Technol. 2007 Aug 1;41(15):5564-70. doi: 10.1021/es0628755
9. Janjua NR, Frederiksen H, Skakkebaek NE, Wulf HC, Andersson AM. Urinary excretion of phthalates and paraben after repeated whole-body topical application in humans. Int J Androl. 2008 Apr;31(2):118-30. doi: 10.1111/j.1365-2605.2007.00841.x.
10. Final amended report on the safety assessment of Methylparaben, Ethylparaben, Propylparaben, Isopropylparaben, Butylparaben, Isobutylparaben, and Benzylparaben as used in cosmetic products. International Journal of Toxicology 2008; 27 Suppl 4:1-82. https://journals.sagepub.com/doi/pdf/10.1177/109158180802704s01
11. Darbre PD, Aljarrah A, Miller WR, Coldham NG, Sauer MJ, Pope GS. Concentrations of parabens in human breast tumours. J Appl Toxicol. 2004 Jan-Feb;24(1):5-13. doi: 10.1002/jat.958
12. Darbre PD. Environmental oestrogens, cosmetics and breast cancer. Best Pract Res Clin Endocrinol Metab. 2006 Mar;20(1):121-43. doi: 10.1016/j.beem.2005.09.007
13. Darbre, P.D. Underarm antiperspirants/deodorants and breast cancer. Breast Cancer Res 11, S5 (2009). https://doi.org/10.1186/bcr2424
14. http://www.cir-safety.org/sites/default/files/paraben_build.pdf
15. https://ntp.niehs.nih.gov/ntp/htdocs/chem_background/exsumpdf/butylparaben_508.pdf
16. Darbre PD. Aluminium, antiperspirants and breast cancer. J Inorg Biochem. 2005 Sep;99(9):1912-9. doi: 10.1016/j.jinorgbio.2005.06.001
17. Darbre PD, Mannello F, Exley C. Aluminium and breast cancer: Sources of exposure, tissue measurements and mechanisms of toxicological actions on breast biology. J Inorg Biochem. 2013 Nov;128:257-61. doi: 10.1016/j.jinorgbio.2013.07.005
18. Willhite, C. C., Karyakina, N. A., Yokel, R. A., Yenugadhati, N., Wisniewski, T. M., Arnold, I. M., Momoli, F., & Krewski, D. (2014). Systematic review of potential health risks posed by pharmaceutical, occupational and consumer exposures to metallic and nanoscale aluminum, aluminum oxides, aluminum hydroxide and its soluble salts. Critical reviews in toxicology, 44 Suppl 4(Suppl 4), 1–80. https://doi.org/10.3109/10408444.2014.934439
19. Mirick DK, Davis S, Thomas DB. Antiperspirant use and the risk of breast cancer. J Natl Cancer Inst. 2002 Oct 16;94(20):1578-80. doi: 10.1093/jnci/94.20.1578
20. Fakri S, Al-Azzawi A, Al-Tawil N. Antiperspirant use as a risk factor for breast cancer in Iraq. East Mediterr Health J. 2006 May-Jul;12(3-4):478-82. https://applications.emro.who.int/emhj/1203_4/12_3-4_2006_478_482.pdf
21. McGrath KG. An earlier age of breast cancer diagnosis related to more frequent use of antiperspirants/deodorants and underarm shaving. Eur J Cancer Prev. 2003 Dec;12(6):479-85. doi: 10.1097/00008469-200312000-00006
22. Dieterich, M., Stubert, J., Reimer, T., Erickson, N., & Berling, A. (2014). Influence of lifestyle factors on breast cancer risk. Breast care (Basel, Switzerland), 9(6), 407–414. https://doi.org/10.1159/000369571
23. Methylparaben. https://pubchem.ncbi.nlm.nih.gov/source/hsdb/1184
24. Cosmetic Ingredient Review; Final Amended Report on the Safety Assessment of Methylparaben, Ethylparaben, Propylparaben, Isopropylparaben, Butylparaben, Isobutylparaben, and Benzylparaben as used in Cosmetic Products p 57. Int J Toxicol 27 Suppl 4: 1-82 (2008).
25. Gilman, A. G., L. S. Goodman, and A. Gilman. (eds.). Goodman and Gilman’s The Pharmacological Basis of Therapeutics. 6th ed. New York: Macmillan Publishing Co., Inc. 1980., p. 969
26. Osol, A. and J.E. Hoover, et al. (eds.). Remington’s Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1096
27. Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 695