Skin pigmentation is a very common dermatological condition that cuts across race, colour and skin type.

Most of the times the issue with skin pigmentation produces a lot of psychological effects  for persons involved, and these sort of conditions are quite challenging to treat as there are different causes for pigmentation and triggers for the process of melanogenesis (process by which melanin is formed).

The Good news however, is , the process by which pigmentation  occurs in the skin follows certain fairly  established pathways that eventually end up or result as complexion discolouration and there are cosmetic agents (cosmeceuticals) that can be utilised to  work through these pathways to depigment the skin

So here are the various pathways through which depigmentation can occur in skin:

  1. Direct inhibition of Tyrosinase activity, as well as the affecting the profileration of other enzymes involved  in the melanogenesis process.

Tyrosinase is the major enzyme involved in the process of melanin  synthesis and without it the process will be halted completely.

  1. Controlling the activity of the melanoctyes, which are the body cells that are responsible for production of melanin

  2. Alteration of constitutive and facultative pigmentation. Constutuitve skin colour is defined as the basal, genetically determined coloration  of the skin in the absence of any external factors such as sunlight. Facultative skin colour develops following exposure to stimulant such as sunlight

  3. Down regulation of melanosome transfer to keratinocytes.

So basically the melanocytes, which are the body cells responsible for producing melanin enclose organelles called the melanosomes, within which melanin pigments are synthesised, which are then transported to the keratinocytes ( upper layers of the skin ) from the melanocytes by means of projectile cells called dendrites.

The ability of the keratinocyte to incorporate and accumulate these melanin pigments determine the extent and degree of skin pigmentation.

In other  to treat complexion coloration issues, it’s important that you use active ingredients ( skin lightening Products),that have the ability to:

  •  Reduce, inhibit, or control the process that leads to excessive production of melanin in the skin
  •  Control the transfer of melanin to the keratinocytes, which  is the surface of the skin.
  •  Deal with current pigmentation on the epidermis

As mentioned earlier, skin lightning agents work in different pathways and are grouped together according to their mechanism of action

  •  Agents that prevent the transcription of the major enzyme tyrosinase
  • Agents that inhibits the action of the Tyrosinase so that, so that the reaction that will produce melanin pigments is hindered.
  • Agents that work to prevent the transfer of melanin pigments to the keratinocytes

So they all walk through different pathways to achieve different results.


Hydroquinone for a long time has been the gold standard for skin lightening and treating coloration issues in the skin. Unfortunately, hydroquinone has a lot of negative side effects that has made it become quite unpopular for  treating this condition,  while it has great potential to actually produce results,  it has equally more damaging side effects that override whatever benefits  may be derived from using it.

Hydroquinone inhibits tyrosine  by binding the copper ions at the active site of the enzyme. However  the process by which hydroquinone reduces skin pigmentation also leads to the production of Reactive oxygen species ROS (free radicals) and Quinones, which damage the skin cells  making it  very toxic to the skin  especially when used for long time.

Some of the common side effects of hydroquinone include:

  •  Exogenous ochronosis
  • Cataracts.
  • Pigmented colloid millia
  • Sclera
  • Nail discoloration.
  • Loss of elasticity of the skin
  • Impaired wound healing.
  • Exuding an offensive fish odour

However, a lot of improvement has been made in this area to produce more natural and safer skin lightening agents can help deal with hyperpigmentation issues with less toxic side effects. And some of them include  Kojic Acid, Arbutin, Azelaic Acid, Resveratrol  Licorice extract,Vitamin C, Niacinamide etc.

Agents that Inhibit Tyrosinase activity

Of all of these cosmeceuticals mentioned  above, Kojic Acid, Azelaic acid, and Arbutin work by inhibiting tyrosinase  activity in the  skin without affecting the skin function unlike hydroquinone making them relatively safer.

Tranexamic Acid is another active that works by reducing the activity of the other enzymes apart from tyrosinase responsible for melanin production in the skin safely without affecting the cell functions.

Agents that intercept cell signalling functions

Other skin lightening agents like vitamin C, Vitamin E and certain plant extracts work as antioxidants. So antioxidants  work in a bipartite manner in the skin lightening process

  1. They are  involved in arresting or neutralising the effects of free radicals on the skin. This helps with depigmentation by providing an alternative pathway for the skin to deal with oxidative stress without signalling for the melanosomes to deployed to affected areas, which will lead to pigmentation of the affected areas ,as would normally happen if the antioxidants were not present in the skin.
    Vitamin C is highly unstable, but there are more stable derivatives of vitamin C, that are more commonly used in cosmetics for skin lightening purposes, and the combination of Vitamins C&E have really good documented results in dealing with sun induced skin discolouration.
  2. Vitamin C also has the ability to  attach itself to active sites of the tyrosinase thereby inhibiting its activity

Agents  to deal with pigmentation issues present on  the skin surface by means of exfoliation

Exfoliating agents help to resurface surface of the skin by accelerating the turnover of epidermal cells, thereby dispersing melanin pigment, resulting in skin depigmentation.

Chemical agents used to exfoliate the skin stimulate the removal of the pigmented upper layer of the epidermis to remove skin discolouration.

Some examples of these group of ingredients include Alpha hydroxy acids, which are weak organic acids found in fruits, milk sugars and plants. Alpha hydroxy acids are commonly used as peeling agents to treat dry skin, acne and improve improve skin color or complexion.

Some examples of Alpha hydroxy acids that can be used for this purpose, include lactic acid and glycolic acid.

Another group of acids called Beta Hydroxy Acids common of which is the Salicylic acid which is a plant product and it helps to desquamate (slough off), the surface of the skin by penetrating and dissolving into the intercellular matrix of the stratum corneum as a result of its lipid soluble structure.

Agents that  hinder the transfer of melanin cells to the keratinocytes .

When melanin cells are produced in the melanosomes ,they need to be transported to the keratinocytes, where they will be assimilated and incorporated into the keratinocytes, at which is the point skin coloration becomes visible.

There are a group of skincare products or cosmeceuticals that help to either hinder that transportation process ,inhibit or reduce it so that the incidence of skin discoloration is not as proficient as it should be, so that the  process of melanin synthesis, that has been going on within the skin all this while, does not manifest itself on the surface of the skin where it’s actually clearly noticeable.

Because the efficiency of “Melanosomonal” transfer from Melanocytes to  keratinocytes, followed by melanosome precessing in the recipient keratinocytes plays a critical role in skin pigmentation, without successful transfer of melanosomes to keratinocytes, the skin can appear easily unpigmented.

A popular skincare ingredient  that is very useful for this sort of activity is Niacinamide. Topical niacinamide is described  to have several benefits on ageing skin but not limited to improve barrier function, improved appearance of photo aged facial skin and reduction of sebum production.

Additionally, Niacinamide is believed to influence the transfer of melanosomes from melanocytes to keratinocytes.

Multifunctional actives

Some actives are really special because like the antioxidants they tend to work through more than one path way in depigmenting the skin.

One of such very important depigmenting agent is the Licorice extract obtained from the roots of a Chinese plant.
Licorice extract  helps to influence pigmentation, by removing epidermal melanin, inhibiting the biosynthesis of melanin and inhibits in the activity of tyrosine is in dosage dependent manner,

Another all in one group of actives are Retinoids , these are a common treatment option used to ameliorate acne, photodamage and PIH. The mechanism of action likely involves the inhibition of tyrosinase, the dispersion of keratinocyte pigmented granules, reduction in pigment transfer and a reduction in corneocyte cohesion with an associated acceleration of epidermal turnover

So having done this very short review on the modes and mechanisms  that some depigmenting agents and cosmeceuticals work in in dealing with the issue of  complexion discoloration, we have to note that it will help us broaden our knowledge on how they work.

When  using skin lightening agents to deal with skin pigmentation,  we need to  be aware that most of the times, using one particular active might not be enough to produce the kind of effects that we desire to see.

For instance if you’re using skin lightening agents that works only to help to prevent production of melanin, and you already have pigmentation issues on your skin,  those kind of agents will not necessarily do anything to deal with the current pigmentation issues on your skin they might rather help to prevent further or increased pigmentation on your skin.

So it’s  a good idea to combine skin pigmetnation actives that work on different pathways in order to produce a synergetic effect that will be faster and more effective than using only one active or more than one active that act on the same pathway.

For instance, combining  agents that work at the basal layer inhibiting tyrosinase activity with ones that helps to inhibit, or control the transfer of melanosomes to the keratinocytes and ones that help to work on the surface of the skin dealing with already accumulated melanin on the skin’s surface would be a perfect combination for effective pigmentation treatment.

With this sort of synergy, more improved, advanced skin  depigmentation  can be realised without the use of hydroquinone to obtain safer  ways of removing skin pigmentation.