The skin is made up of layers, split by the epidermis at the top and the dermis that is deeper underneath. Excess melanin caused by hyperpigmentation, damage or injuries can be found within either layer.
Successful skin lightening will depend on two things:

– The cause of the hyperpigmentation

– The depth of the excess pigmentation (where the excess melanin sits within the skin’s layers)

How deep is the excess melanin?

The skin is made up of layers, split by the epidermis and the dermis. The epidermis is the top layer while the dermis sits deeper underneath. Excess melanin caused by hyperpigmentation can be found within either layer.

While the depth of the excess melanin would depend on the specific cause, it can sometimes be difficult to know how deep the hyperpigmentation is. However, the below can be looked at as a general guide.

Depth of excess melanin in the skin

Type of pigmentation Surface (i.e Epidermal) Deep (i.e Dermal)
Brown birthmarks, cafe au lait spots No Yes
Normal tanning Yes No
Prolonged tanning Yes Yes
Age spots No Yes
Melasma* Yes Yes
Caused by injuries
(burns, cuts, abrasions, etc)*
Yes Yes

* Types of pigmentation with Yes in both columns simply indicate that melanin depths would vary case-by-case.

Q: What does this mean?
A: It means the choice of skin lightening treatments is critical to successful skin lightening.

As expected, cases of hyperpigmentation found in the top layer only (known as epidermal melanin) are much easier to treat. Epidermal hyperpigmentation are also responsive to over-the-counter skin lightening creams and lotions like those containing kojic acid or hydroquinone, while dermal (deep) cases do not respond to these treatments at all. Dermal or deep hyperpigmentation requires more invasive skin lightening treatments or changes made from within, if changes are to be seen.

See the following diagram to understand this further. Compare the distribution and placement of excess melanin-containing melanosomes between normal skin against both epidermal and dermal hyperpigmentation. Melanin-containing melanosomes are indicated by dots.

Epidermal versus (deeper) dermal hyperpigmentation. The distribution of melanin is indicated by the gray and black dots.

This also explains why some skin lightening treatments work well for some and not at all for others

The pursuit of lightening excess skin hyperpigmentation can prove to be frustrating as many will inevitably find that what works for someone else will not necessarily work for them. This leads to disappointment and confusion, and many will chase one skin lightening cream after another in the hope of finding one that works.

If this sounds familiar, it is likely that the reason for your stubborn hyperpigmentation is that it is simply buried deeper within your dermis, where skin lightening creams and lotions cannot penetrate.