Table 1.

Common lightening agents for melasma

Name	Mechanism of action	Side effects	Reference
Hydroquinone	Tyrosinase inhibition	Erythema, irritation, exogenous ochronosis	De Caprio, 1999, Grimes, 2009, Nordlund et al., 2006, Tse, 2010
Azelaic acid	Tyrosinase inhibition	Stinging, burning, itching, dryness	Hashim et al., 2018, Schulte et al., 2015
Kojic acid	Tyrosinase inhibition	Irritation, contact dermatitis	Deo et al., 2013, Lajis et al., 2012, Monteiro et al., 2013
Ascorbic acid	Inhibition of reactive oxygen species	No significant adverse event	Al-Niaimi and Chiang, 2017, Pires et al., 2018
Retinoids	Downregulation of Tyrosinase	Irritant reaction, dryness, hyperpigmentation	Kang, 2005
Corticosteroid treatments	Antiinflammatory and nonselective inhibition of melanogenesis	Telangiectasias, epidermal atrophy, steroid-induced acne, striae, hypopigmentation	Menter, 2004
Niacinamide	Inhibition of melanasome transfer	Irritation	Bissett, 2002, Navarrete-Solís et al., 2011, Wohlrab and Kreft, 2014
Licorice	Melanin dispersion, tyrosinase inhibition	No significant adverse event	Picardo and Carrera, 2007; Videira et al., 2013
Undecylenoyl phenylalanine	Antagonist of α-melanocyte-stimulating hormone, β-adrenergic, stem cell receptors	No significant adverse event	Glowka et al., 2018, Olejnik et al., 2018
4-N-butylresorcinol	Tyrosinase inhibition, antioxidant, antiinflammatory	Mild erythema and itching	Huh et al., 2010; Wargniez et al., 2017
Soybean	Inhibits melanosome transfer to keratinocytes	No significant adverse event	Birk, 1985, Paine et al., 2001
Arbutin	Inhibition of tyrosinase	Skin irritation	Sarma et al., 2017
Glucosamine	Inhibition of tyrosinase activation	Skin rash	Niwano et al., 2018
Mequinol	Inhibition of tyrosinase	Skin irritation, redness, peeling	Keeling et al., 2008