1. Parabens

Commonly used as preservatives, they have been linked to hormone disruption and skin irritation.

2. Phthalates

These can interfere with hormone function and are found in products like fragrances, nail polish, and hair sprays.

3. Sodium Lauryl Sulfate (SLS)

Often used as a foaming agent, it can strip the skin of natural oils, leading to dryness and irritation.

4. Formaldehyde

Used as a preservative, it can cause skin irritation and has been classified as a human carcinogen.

5. Toluene

Found in nail polish, it's linked to reproductive issues and may affect the nervous system.

6. Mineral Oil

Derived from petroleum, it can clog pores and potentially lead to acne or skin irritation.

7. Triclosan

Commonly found in antibacterial products, it can disrupt hormone regulation.

8. Oxybenzone

Often used in sunscreens, it's a potential hormone disruptor and has been associated with coral reef damage.

9. Synthetic Fragrances

These can contain a mix of potentially harmful chemicals that may cause allergies or skin irritation.

10. Retinyl Palmitate

A form of vitamin A that, when exposed to sunlight, can increase skin sensitivity and potentially lead to skin damage.

11. Propylene Glycol

A humectant that can cause skin irritation, especially in high concentrations.

12. DEA (Diethanolamine), MEA (Monoethanolamine), TEA (Triethanolamine)

These can react to form carcinogens and may cause skin and eye irritation.

13. Ethoxylated Ingredients

Ingredients like PEGs (Polyethylene Glycols) can be contaminated with harmful chemicals like 1,4-dioxane, a possible carcinogen.

14. Hydroquinone

Used for skin lightening, it can cause skin irritation and may have links to cancer.

15. Methylisothiazolinone

A preservative that can cause allergic reactions and skin irritation.

16. Aluminum Compounds

Often found in antiperspirants, they may be linked to breast cancer and neurotoxicity.

17. Benzalkonium Chloride

An antimicrobial agent that can cause skin and eye irritation.

18. Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT)

Synthetic antioxidants that may be linked to skin irritation and hormone disruption.

19. Coal Tar

Used in dandruff shampoos and products for psoriasis, it's a known carcinogen.

20. Lead

Sometimes found in lip products, it can be harmful if ingested and has been linked to health issues.

21. PEG Compounds

Used as thickeners, solvents, and softeners, they can be contaminated with toxins.

22. Siloxanes

Used in skincare and haircare products, they can accumulate in the body and potentially disrupt hormone function.

23. Formaldehyde-Releasing Preservatives

These release small amounts of formaldehyde over time, which can cause skin irritation and allergic reactions.

24. Methylchloroisothiazolinone

Another preservative that can cause allergic reactions and skin irritation.

25. Paraffin

Similar to mineral oil, it can clog pores and lead to breakouts.

26. Quaternium-15

A preservative that releases formaldehyde and can cause skin irritation.

27. Sunscreen Chemicals

Some chemical sunscreens like avobenzone and octinoxate can cause skin irritation and have been associated with hormone disruption.

28. Sodium Hydroxymethylglycinate

A preservative that can cause allergic reactions.

29. EDTA (Ethylenediaminetetraacetic Acid)

While considered safe in low concentrations, it can cause skin irritation in some individuals.

30. PEG-40 Hydrogenated Castor Oil

May contain impurities that are harmful to the skin.

31. Sulfates

Apart from SLS, other sulfates like sodium laureth sulfate (SLES) can also cause skin irritation and dryness.

32. Petrolatum

Another derivative of petroleum that can potentially clog pores.

33. Thimerosal

A preservative containing mercury that can cause allergic reactions.

34. Phenoxyethanol

While generally considered safe in low concentrations, it can cause skin irritation in some individuals.

35. Polyacrylamide

Used in some skincare products, it can be contaminated with acrylamide, a probable carcinogen.

36. Synthetic Colors

These can cause skin irritation and allergies.

37. Boric Acid and Sodium Borate

Often found in moisturizers and makeup, they can disrupt hormone function.

38. DEHP (Di(2-ethylhexyl)phthalate)

Used in some nail products, it's a potential endocrine disruptor.

39. Hydroquinone

Used for skin lightening, it can cause skin irritation and may have links to cancer.

40. Hydrogen Peroxide

While sometimes used for acne treatment, it can cause skin irritation and damage.

41. Imidazolidinyl Urea

A preservative that releases formaldehyde and can cause skin irritation.

42. Nano Particles

These tiny particles can penetrate the skin and potentially cause cellular damage.

43. Oxybenzone

Found in some sunscreens, it's a potential hormone disruptor and can cause allergic reactions.

44. Resorcinol

Found in hair dyes and acne treatments, it can cause skin irritation.

45. Retinol (Vitamin A)

In high concentrations, it can cause skin irritation and increase sensitivity to sunlight.

46. Silicone

While not inherently harmful, it can cause buildup on the skin and potentially clog pores.

47. Talc

A common ingredient in powders, it can irritate the skin and potentially contain asbestos.

48. Toluene

Found in nail polish, it's linked to reproductive issues and may affect the nervous system.

49. Urea

While used as a moisturizer, it can cause skin irritation in some individuals.

50. Zinc Formaldehyde Sulfoxylate

Found in dandruff shampoos, it can cause skin irritation.

Remember, everyone's skin reacts differently, so what might be irritating for some could be harmless for others. It's always a good idea to patch test new products and consult with a dermatologist if you have specific skin concerns or sensitivities.