What ingredient in polish can cause allergic reactions in some clients?

Formaldehyde is a known allergen often found in nail products, particularly in polishes and hardeners, and it can trigger allergic reactions in some clients. This ingredient is used for its ability to help improve the durability and strength of the nail product. However, because it is a potent chemical, it can cause sensitivity in certain individuals, leading to symptoms such as redness, itching, or swelling upon exposure.

While toluene, acetone, and camphor can also cause reactions, they are typically associated more with irritation or toxicity rather than allergic reactions specifically. For example, toluene can lead to irritation and other adverse effects but is not as commonly linked to allergies as formaldehyde is. Acetone, mostly used as a solvent, might cause temporary drying or irritative effects, while camphor is generally used in small amounts and is known more for its strong scent and potential to cause respiratory effects if inhaled in large quantities. Therefore, formaldehyde distinctly stands out as the ingredient most likely to trigger allergic reactions in clients.