Studies cited from Pub Med + the (NIH) National Institute of Health:
Bisphenol-A (BPA) - it is reported that this chemical potentially causes breast cancer by destroying hormone functions, causing early puberty. High exposure in utero is associated with poor behavioral outcomes such as higher levels of anxiety, depression, hyperactivity, and aggressive behavior in children.
Flouride - Prenatal and childhood excessive fluoride exposures may impair the intelligence development of school children.
In a 2012 study, children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas
Fluoride readily crosses the placenta (Agency for Toxic Substances and Disease Registry 2003). Fluoride exposure to the developing brain, which is much more susceptible to injury caused by toxicants than is the mature brain, may possibly lead to permanent damage (Grandjean and Landrigan 2006). In response to the recommendation of the NRC (2006), the U.S. Department of Health and Human Services (DHHS) and the U.S. EPA recently announced that DHHS is proposing to change the recommended level of fluoride in drinking water to 0.7 mg/L from the currently recommended range of 0.7–1.2 mg/L, and the U.S. EPA is reviewing the maximum amount of fluoride allowed in drinking water, which currently is set at 4.0 mg/L (U.S. EPA 2011).
Fragrance - among the Top 5 known allergens. Can cause asthma and trigger asthma attacks. More than 95% of the chemicals in synthetic fragrances are derived from petrochemicals.
These chemicals include: benzene derivatives, aldehydes, phthalates, and other known toxins -all capable of causing cancer, birth defects, nervous-system disorders and allergies.
Formaldehyde - used as an anti-microbial agent in personal care products; dangers include: asthma, sensory irritation, tissue damage to upper respiratory tract, Leukemia + nasal cancer.
How to spot it - a human carcinogen that you will not "see" on the label, because it is a contaminant of the manufacturing process or formulation. Look out for ingredients: "Fragrance Quaternium," "DMDM Hydantoin," and "Ureas."
Methylisothiazolinone (MIT) - a chemical used in shampoo to prevent bacteria from developing, which may have detrimental effects on your nervous system (tremors, MS, etc).
Mineral Oil, Paraffin + Petrolatum - these products coat your skin like plastic, clogging pores and creating a build-up of toxins. They also slow cellular development, which can cause you to show earlier signs of aging, and are a suspected cause of cancer and disruption to hormonal activity.
Musk - used as fragrances, can accumulate in your body, and have been linked to skin irritation, hormone disruption, and cancer in laboratory studies.
Parabens - a chemical found in underarm deodorants and other cosmetics that has been shown to mimic the action of the female hormone estrogen, which can drive the growth of human breast tumors.
Phthalates - plasticizing ingredients shown to disrupt hormone activity, reduce sperm counts, and cause reproductive malformation. Also linked to liver + breast cancer, diabetes, and obesity.
Sodium Lauryl/Laureth Sulfate - The real problem with SLES/SLS is that the manufacturing process (ethoxylation) results in SLES/SLS being contaminated with 1,4 dioxane, a carcinogenic by-product. NIH found that at high exposures cells detached from each other and underwent cell death.
Toluene - made from petroleum or coal tar, and found in most synthetic fragrances. Chronic exposure linked to anemia, lowered blood cell count, liver or kidney damage, and may affect a developing fetus.