Nail polish is a very common cosmetic beauty product used to create semipermanent, attractively-colored nails. Historically, there have been many changes in the components of nail polish, from beeswax and essential oils to the chemically-based solutions that are widely used today. However, the effects of some nail polishes and their components are not very widely known, and can result in unwanted problems that appear to have an unknown source. While many people use nail polish frequently with few symptoms, others may experience harsher symptoms.
One of the more severe effects of nail polish use can be allergic contact dermatitis. Symptoms of this can include cracked and dry skin, itch, rash, or leathery appearances in areas with direct contact to the irritant, which could be compared to an allergic reaction to poison ivy. In cases like this, certain chemicals in nail polish, such as tosylamide and formaldehyde resin have been traced back to reactions on the face and hands.
Additionally certain chemicals existing in many polishes can have a more systemic effect. Triphenyl phosphate (TPHP) levels were measured in a study assessing the use of a brand of nail polish with 0.97% TPHP by weight on TPHP levels in urine. The results of this study showed that ten to fourteen hours after painting, the subjects showed an increase in TPHP by about seven times the original amount. This study also clarified that the TPHP traveled most effectively through skin and nail contact than inhalation alone. TPHP exposure is associated with negative impacts in the reproductive system and endocrine system, mental toxicity, and metabolic function. Phalates, which have similar systemic effects to TPHP, have also been shown to appear in larger quantities in urine of nail polish users.
Older nail polish also has the tendency to promote bacterial growth and spread. A study by Wynd et. al. examined the number of bacterial colonies on the cleaned fingernails of operating room nurses that had either freshly painted or old, chipped nail polish. They found a statistically greater number of bacterial colonies on those with old, chipped nail polish.
On a more superficial level, extensive use of nail polish can result in yellowish or orange discoloration of the nail that typically goes away in about two weeks, but may require the nail to grow out to completely disappear. Another common issue is white spots on the nails which can be mistaken as a symptom for a different condition.
While this may mostly have listed the negative effects of nail polish, there are also positive effects. For example, it was found that dark opaque nail polish served as a sun protectant of 500 spf or greater, which could be useful for those who are more susceptible to sun damage, such as chemotherapy patients. Others may not be as directly related to health, but are nevertheless positive such as happiness with one's appearance or the psychological benefits of performing self care rituals. At the end of the day, it is your choice to decide if nail polish use is worth it for you, it is just better for that decision to be informed.
References
https://onlinelibrary.wiley.com/doi/10.1111/j.1473-2165.2005.00313.x
https://www.sciencedirect.com/science/article/abs/pii/S0001209207633286" Assessed and Endorsed by the MedReport Medical Review Board