Yes, tretinoin reduces pigmentation in 2 ways:
1. By renewing cells
Pigmentation occurs when a section of the skin is darker than the surrounding skin. This section can be a dot, small, or large area.
Before understanding how exactly tretinoin can affect pigmentation by renewing cells, we must understand what causes facial pigmentation.
A bit of back story about pigmentation cause…
Pigmentation is nothing but the accumulation of excess melanin.
Melanin is a pigment found in the skin. It has two important functions:
When skin gets inflammed, its defence mechanism kicks in. The skin starts producing more melanin, which is vital in defending the skin.
Once melanin offers a certain level of protection, it can’t offer any more. But the skin does not know this. It will continue producing melanin as long as the skin stays inflammed, so this means it can overproduce melanin.
But this overproduction does not happen to everyone. In lighter skin tones, the amount of melanin the skin produces is usually less than what the skin needs. So, there is no overproduction in this case. However, in dark skin tones, the skin has the ability to produce more melanin. This is the case where an overproduction of melanin occurs.
Some of the excess (overproduced) melanin the skin produces reaches the top layer and settles in the cells there. These deposits are usually concentrated and more intensely coloured than the rest of the skin.
Some of this excess melanin settles in skin cells below the topmost layer. Though these deposits are not in the topmost layer, they are still visible to the naked eye because they have an intense colour.
Returning to the excess melanin deposits in the cells in the visible layer, this is where the ingredient tretinoin can make an impact. Let’s find out how…
How tretinoin helps…
Cells from the top layer of the skin fall off regularly and are replaced by younger cells that travel to the top layer from the deeper layers of the skin. The frequency with which this replacement happens is called cellular turnover.
Higher cellular turnover means rough and dull skin. If the cellular turnover is low, the skin is very soft. Babies have a low cellular turnover rate.
As the skin ages, cellular turnover takes longer. One main reason for this is that not enough new cells are forming in the skin’s deeper layers. This is where tretinoin can help.
Tretinoin increases the formation of new cells in the deeper layers of skin. As the number of new cells increases, they replace older cells faster.
As the old cells fall off, the excess melanin inside them also disappears.
2. By inhibiting tyrosinase enzyme
Tyrosinase is an enzyme found in the skin that helps produce the pigment melanin.
As mentioned in the earlier section, when skin gets inflammed, skin’s defence mechanism kicks in. One of the first things that happens when this kicks in is that this enzyme gets stimulated. This enzyme gets hyper. It gets into action mode and starts helping in melanin production. But after a certain amount of melanin has been produced, any melanin after that amount is just excess. However, the enzyme tyrosinase does not know this. It continues to stay hyper as long as the skin is inflammed.
The excess melanin that this enzyme helps produce results in pigmentation.
Ingredients like tretinoin are tyrosinase inhibitors. Tretinoin interferes with the activity of the enzyme and reduces its activity. It calms it down and makes it less hyper. This results in lower production of excess melanin. Less excess melanin means less pigmentation.
How much tretinoin do we need?
Tretinoin can be used up to 0.1%. But it is important to start at much lower concentrations…from, say, 0.025% or 0.05%, and gradually get to 0.1%.
