Parabens are synthetic chemicals (made by humans using methods different from methods nature uses) that are used as preservatives in beverages, foods, drugs, and cosmetics.

There are many different types of parabens such as methyl-, ethyl-, propyl-, isopropyl-, butyl- and isobutylparaben. There are "longer chain" parabens and "shorter chain" parabens. Animal studies have shown long chain parabens to be associated with more negative health outcomes than short chain parabens.

Parabens can enter the body by ingestion or absorption through the skin, and they have a half life of less than 24 hours, meaning they are out of the body quickly. However, regular application or ingestion of paraben-containing products could result in chronic, low levels of paraben in the body. 

In U.S. population studies, parabens have been detected in the urine of most people, indicating that most of the U.S. population is exposed to parabens. However, this widespread detection does not imply negative health effects. In fact, the safety of parabens is controversial. 

On the one hand, they protect people from developing illnesses caused by harmful bacteria and mold in contaminated products. On the other hand, they have been found to be associated with endocrine disruption, carcinogenicity (being cancer-causing), and reproductive toxicity in cell and animal studies. 

Based on current research, these negative outcomes are not high enough to result in banning or heavily regulating parabens. However, they do present legitimate concerns that justify ongoing research about the safety of parabens, and efforts have been made to regulate some parabens to some extent.

In 2006, the United Nations Food and Agriculture Organization (FAO) and World Health Organization (WHO) brought together a joint expert meeting to assess the safety of food additives (such as parabens) and decide on their acceptable daily intake levels – known as ADIs – based on what are known as “toxicological risks”. 

Cell and animal study results raised concerns about negative reproductive and estrogenic (related to or caused by an estrogen) effects of parabens. Out of precaution, the committee established an ADI for methyl- and ethyl- parabens at 0-10 mg per kilogram of body weight. 

An ADI was not established for propylparaben, meaning there is no acceptable daily intake level. This is because it is a longer chain paraben, which, as mentioned above, is associated with more negative reproductive health effects in male rats and mice compared to shorter chain parabens (such as methyl- and ethyl- parabens). 

It is worth making clear, however, that these studies were limited to animals. As a result, the committee acknowledged that the way that it is unclear how these study results apply to human health. This has remained the consensus among most experts, because to date, there have been no human studies showing harmful effects. 

In addition, humans are exposed to thousands of chemicals, directly and indirectly, every day. As a result, isolating the impact of a chemical or combination of chemicals on a biologic effect is very difficult to do in research.

Finally, it's also important to note that existing research suggests that parabens may have a negative environmental effect. For instance, there are data that suggest that parabens are linked to coral bleaching and parabens have been detected in have been detected in surface waters, fish, and sediment.

A combination of high quality cell, animal, environmental, and human studies are needed to better understand the toxicology of parabens on human and environmental health. Until further research shows that parabens demonstrate a clear human health risk, they remain generally recognized as safe to human health. 

At this time, parabens have no clear adverse effects to human health. However, some consumers are understandably concerned about their exposure to parabens due to some research findings that indicate negative health impacts in animals. Consumers who are concerned can read ingredient labels for words with “paraben” to avoid paraben-containing products.