Table 2.

List of existing cosmetic preservatives and their problems.

Preservative and Its Chemical Structure	Category	Toxic Effect	Cosmetics/Personal Care Products	References
Imidazolidinyl urea	Formaldehyde releaser	Carcinogenic	Eyeliners, mascara, eye shadows, foundation, shampoos, sunscreens, powders, tanning creams, make-up removers, concealers, moisturizing lotions, etc.	[27,28]
Diazolidinyl Urea	Formaldehyde releaser	Carcinogenic	Blush, eyeliners, eye shadows, lipsticks, foundation, face powders, concealers, moisturizers, hand wash, sunscreens, hair colorants, etc.	[28]
DMDM Hydantoin (Glydant)	Formaldehyde releaser	Carcinogenic, dermatitis	Exfoliants, shampoo, hair smoothing products, liquid soaps, creams, lotions, nail polish, nail glue, etc.	[29,30]
Sodiumhydroxymethyl glycinate (SHMG)	Formaldehyde releaser	Carcinogenic, skin irritant	Body sprays, baby wipes, cleaning agents, shampoo, soaps, hair conditioner, etc.	[28,31]
Quaternium-15	Formaldehyde releaser	Sensitization	Blush, bronzer, eye shadow, foundation, baby products (baby oil, shampoo, wash bath), shaving creams and gels, sunscreens, etc.	[28,32,33]
Benzalkonium chloride solution I.P (BAK)	Quaternary ammonium compound	Cytotoxicity, dry eye syndrome, pulmonary irritation, nasal mucosal damage, bacterial resistance, genotoxicity, apoptosis, leaching of eye lens, etc.	Deodorants and body spray, baby wipes, moisturizers, body washes, cleansers, etc.	[34,35,36,37,38,39,40,41,42]
BHA     BHT	Phenolic compounds	Endocrine disruptors, neurological problems, metabolic dysfunction, behavioral issues and may cause cancer	Lipstick, lip glosses, moisturizers, lotions, sunscreen, fragrance, clean and clear foaming face wash, face wash, soap, shampoo, deodorants, etc.	[28,43]
R = an alkyl group Methylparaben, Ethylparaben, Propylparaben, Isobutylparaben, Butylparaben	Paraben	Estrogenic effect and interfere with male reproductive functions, breast cancer, contact eczema, development of malignant melanoma, etc.	Creams, face powder, blusher, face pack, face scrub, nature’s facial kit, face wash, etc.	[28,43,44,45,46,47,48]
Triclosan and triclocarbans	Antimicrobial agent	Antibiotic resistance in bacteria, endocrine disruptor, neurotoxicity, skin sensitization, reproductive and developmental toxicity, genotoxicity, phototoxicity, carcinogenicity etc.	Foundation, lip gloss, mascara, body spray, perfume spray, medicated soaps, toothpaste, deodorants, hand wash, face wash, mouthwash, etc.	[28,49,50]
Kathon CG: 3: 1 mixture of 5-chloro-2-methyl-4-isothiazoline-2-1 and 2-methyl-4-isothiazolin-2-one	Isothiazolinones	Allergic contact dermatitis	Body washes, liquid soaps, conditioners, shampoos, wipes, etc.	[51,52]
Methylisothiazolinone, Methylchloroisothiazolinones	Isothiazolinones	Skin irritant	Shampoos, conditioner, liquid hand wash, soaps, face wash, etc.	[48,53,54,55,56]
Iodopropynylbutyl carbamate (IPBC)	Belongs to the carbamate family of biocides	Sensitization	Lip balm, lotions, hair dye, hair colorants, etc.	[32,52]
Methyldibromoglutaronitrile (MDBGN)		Contact allergy	Body lotion, hand lotion, facial lotion, sunscreen lotion, shower gels, etc.	[32,52]
Thiomersal	Mercurial	Kawasaki’s Disease, genotoxicity, apoptosis, cytotoxicity, neurotoxicity, neurodevelopmental and CVS disorders	Eye make-up products	[57,58,59,60,61,62,63,64,65]
Chlorobutanol	Alcohol	Not used in aerosol dispensers, cytotoxicity, retinal toxic, irritation	Face wash, creams mouthwashes, ointments, etc.	[66,67,68]
Benzyl Alcohol	Aromatic alcohol	Contact dermatitis, mucous membrane irritation, CNS depression lethargy, metabolic acidosis, toxicity on fatal development and respiratory abnormalities, etc.	Creams, baby lotion, sunscreen SPF 50, baby wipes, etc.	[69]
Ethylhexylglycerin	Glyceryl ether	Contact allergen and impairs membrane integrity, etc.	Baby cream, shower gel, moisturizing lotions, skin peels, face masks, body butter, shampoos, conditioner, etc.	[70,71,72]
Phenoxyethanol	Glycol ether	Allergic and skin irritation	Hand sanitizer, perfume, F-foundation, blush, lipstick, mascara, eye shadow, hand cream, hair color and spray, lip balm, nail polish, baby wipes, etc.	[73,74,75,76]
Chlorhexidine	Amidines	Ototoxic, nausea, stomach irritation, respiratory distress syndrome	Conditioner, creams, toothpaste, deodorants, antiperspirants, etc.	[77,78,79]
Ascorbic acid	Organic acid	Skin irritation	Anti-aging creams and skin toners, etc.	[80,81,82]
Benzoic acid	Organic acid	Carcinogenic, irritation, metabolic acidosis, asthma, convulsions, etc.	Face wash, shampoo, body wash creams, etc.	[83,84,85]
Sodium benzoate	Organic acid	Carcinogenic, irritation, metabolic acidosis, asthma, convulsions, etc.	Body cleanser, toothpaste, etc.	[83,84,85]
Citric acid	Organic acid (Alpha-hydroxy acid)	Sensitization and irritation, etc.	Facial kit, face wash, serum, scrubbers, baby facial toners, exfoliating, cleaning products, etc.	[86]
Sorbic acid	Organic acid (Monocarboxylic acid)	Itching and irritation, etc.	Body lotion, eye cream, anti-aging face serum, eyeshadow, cleansing wipes, bronze powder, skincare products, etc.	[87]
Climbazole	Antifungal agent	Skin irritation includes redness, rashes, and itching	Hair lotions, face creams, foot care products, and rinse-off shampoo, etc.	[88]
Hydroxyethoxyphenyl butanone		Slight ocular irritation	Rinse off, oral care, and leave-on cosmetic products	[89,90]
Dehyderoacetic acid (DHA)	Organic acid	Minimal eye irritation, allergic contact dermatitis	Shampoo, lotions, creams, mousses, sunscreens, baby care products, oral care products, foundations, powders, wipes, etc.	[91,92]
Erythorbic acid	Stereoisomer of ascorbic acid	Sensitization	Hair and nail products	[93]
Formaldehyde	Naturally occurring organic compound	Contact dermatitis, irritation and leukemia on prolonged exposure, etc.	Nail polishes, hair gels, soaps, lotions, makeup products, shampoos, etc.	[94]