Hydroquinone, is a main agent for the whitening treatment.

  • It is the main ingredient for blocking or inhibiting the melanin synthesis in the bio pathway.
  • The hydroquinone inhibit the tyrosinase enzyme that helps to convert tyrosine into melanin.
  • The hydroquinone cream comes in various concentration of 2%, 4%, 8% and even higher.
  • The hydroquinone function as a powerful antioxidant.
  • It is normally used as a 2% cream in cosmetic as an OTC product in the USA. Anything higher than 4% need to be prescribed and normally used for small patches or areas.

The Clinic Laser & Cosmetic Surgery Ling, supervised by Dr David Ling, has been using this ingredient safely for skin whitening treatment over the past 20 years, together with the PRP, filler (such as Vampire lift), Botox and thread lift.

Hydrpquinone can be used together as a part of the formula for skin care products. The formula component ingredients are listed here includes:


Hydroquinone is the most effective blocking agent of melanin synthesis pathway.

Hydroquinone is the most effective blocking agent of the melanin synthesis pathway.


Tri-Luna Triple formulation

Hydroquinone, is normally used as a combination formula.

  • It is used together in combination with tretinoin 0.05% or o.1%.
  • Tretinoin is modified vitamin E that is also very effective for whitening because it also inhibit the tyrosine conversion into melanin.
  • When hydroquinone is used in higher concentration, alone, or together with tretinoin, both become an irritant, cause even more irritation.
  • So it is usually used together with cortisone.
  • The irritant effect of hydroquinone 4%, and also the tretenoin 0.1%, are suppressed by the anti-inflammatory effect of cortisone 2%.
  • Similarly, the skin thinning effect and damaging effect of cortisone is offset by the positive effect of tretinoin.

This is the tri-combination formula commonly used, such as the Tri-Luna cream.


Hydroquinone when used alone or combination with tretinoin, both help to prevent hormone-induced or sun-induced melasma.

Hydroquinone is a powerful inhibitor of melanin synthesis. Therefore, it brings about the lightening effct of skin tone. However, it does not bleach the skin but only lighten the skin. Hydroquinone can only disrupt the synthesis of melanin.

Negative side effects of triple ingredients cancel each other

The irritation/negative effects of hydroquinone and tretinoin are offset by cortisone. Similarly, the side effect of cortisone is offset/neutralised by the tretinoin.

Mechanism of action

The mechanism of action of hydroquinone is very well documented and peer reviewed. Its mechanism of action is by

  • inhibiting the tyrosinase enzyme.
  • It is most likely by a powerful non-reversible inhibition.
  • The compound is highly toxic to the melanocytes which is a pigment producing cell.
  • The compound studied previously is also possibly showing mutagenic tendency in animal cell.
  • According to the publication by –>
    • Thiele et al., which was published in 1997; and
    • another one by Donsing and Viyoch, published in 2008,
    • it confirms the mechanism of action, the action at the exact location along the metabolic pathways.


Side effect

The Side effects of hydroquinone includes the following:

  • Irritation, burning and stinging effect
  • Peeling and scaling effect,
  • Redness or erythema
  • Thinning of skin
  • Exogenous onchronosis:
    • which is a condition due to thinning of the skin,
    • as well as a loss of skin elasticity, and
    • impaired wound healing ability. Because of this reason, its use is rather restricted, especially when used in higher concentration, like above 2 %.
    • Moreover, it is only allowed to be used for smaller area such as freckle, age spots or sun damage blemishes.