Hydroquinone

Hydroquinone is a topical medication used to treat certain skin conditions that involve local hyperpigmentation of the skin, such as melasma, lentigines, age spots and even acne scars (deposition of fibrous tissue leads to a poor melanin production in the area).

Skin pigmentation is caused by melanin deposition in the skin, produced by specialized cells known as melanocytes, located in the stratum basale, the deepest layer of the epidermis (the outermost part of the skin).

Melanocytes synthesize melanin from an important amino acid, tyrosine. The conversion of tyrosine to skin pigmentation requires several enzymatic steps; hydroquinone targets tyrosine hydroxilase, which converts tyrosine to dihydroxyphenylalanine, the most immediate melanin precursor.^[10][11]

No. Steroids are anti-inflammatory that act on a genetic level, inhibiting the production of pro-inflammatory cytokines, leukocytes, neutrophils, etc. Hydroquinone, on the other hand, is a tyrosine hydroxylase blocker, leading to lower melanin synthesis.

Yes. Due to rising concerns among the medical community and the publication of research that linked hydroquinone to higher cancer risks in animals, the FDA banned the product for over-the-counter sale in 2020.^[12]

Medical concern about the potential short- and long-term consequences of prolonged skin contact with these cosmetic agents prompted a series of investigations. Research has shown that, hydroquinone has many serious side effects. Hydroquinone works by decreasing the production and increasing the degradation of melanin pigments in the skin. This increases the skin’s exposure to UVA and UVB rays, increasing the risk of skin cancer.^[13]

In terms of short-term effects, hydroquinone may cause a series of irritative and allergic reactions, such as dermatitis. This inflammation may lead to an altered balance of melanin deposition in the skin, causing hypo- or hyperpigmented areas in the skin (in other words, a post inflammatory hyperpigmentation).^[14]

Hydroquinone works by decreasing the production and increasing the degradation of melanin pigments in the skin. This increases the skin’s exposure to UVA and UVB rays, increasing the risk of skin cancer.^[15] Regulatory agencies in the U.S., Europe, Japan and other countries restrict the product use.

Hydroquinone works by decreasing the production and increasing the degradation of melanin pigments in the skin. This increases the skin’s exposure to UVA and UVB rays, increasing the risk of skin cancer.

Hydroquinone has been found to cause organ-system toxicity and respiratory tract irritation.

Organ-system toxicity: Hydroquinone is linked to a skin condition called ochronosis in which the skin (our largest organ) thickens and turns bluish-grey.^[16] Exposure of the eye can cause pigmentation and permanent corneal damage.^[17]

Respiratory Tract Irritation: Hydroquinone may be harmful if inhaled, causing irritation of the nose, throat and upper respiratory tract. A study on occupational exposure of hydroquinone showed that subjects exposed to hydroquinone had a higher prevalence of a cough and decreased lung capacity compared to their unexposed counterparts.^[18]

Not necessarily. You can easily protect your skin through preventive skin protection measures:

• Avoid prolonged sun exposure, particularly during the afternoon.
• Adequate use of mineral sunscreen lotions if needed.
• Avoid utilizing cosmetic products whose components you aren’t familiar with, as they may induce mild to severe irritative and allergic contact dermatitis symptoms.