What constitutes our overall natural skin tone?
Our natural skin tone is derived from the basic melanin content of our skin, which is genetically inherited without any influence from external factors.
What is melanin and what does it do?
Melanin is the protein that gives our skin its natural colour and is found within our epidermis. There are two different types of melanin found in the skin, the darker eumelanin and the lighter pheomelanin. Different types, amounts and distributions of melanin contribute to variations in our skin tone.
In addition to giving skin its colour, melanin also has vital protective properties, helping to protects against free radical damage from pollution, inflammation and UV rays.
If we all have melanin, why are there different skin tones?
This is due to there being two different types of melanin present in the skin, but also size and number of the melanosomes (which deliver melanin to the surrounding cells).
The most common type is eumelanin. Eumelanin is a darker pigment that comes in shades of browns and blacks. Eumelanin is a large, dense, oblong molecule. It has a UV-protective quality and is more reactive to external stimuli such as trauma and inflammation to skin.
Pheomelanin is the second type of melanin. This smaller, lighter-coloured melanin comes in shades of yellows and reds. This type is like grains of sand in comparison to the bigger jellybean-like eumelanin molecules and it makes up the natural skin colour of people with lighter tones. Pheomelanin has little to no UV protection and is not as reactive as eumelanin.
Remember that most people have both types of melanin present in their skin, in varying quantities and distributions. Even lighter toned people may have inherited genes that have potential for increased eumelanin production and larger melanosomes.
Why and how does our skin tone change by external factors?
In simplest terms, tanning is darkening of the skin through exposure to ultraviolet (UV) light. When UV radiation hits our skin, it senses that it is being injured, so it tries to protect itself by producing more melanin in an attempt to block out harmful rays and prevent further injury.
The ratio between these two types of pigment is what makes the difference in each person's ability to tan. The skin of people with a higher amount of eumelanin will darken faster when exposed to the sun and so they will be slightly more protected from burns. But you must still always wear SPF!
Why does a tan fade over time too?
Cells in the epidermis are constantly reproducing and pushing older cells upward toward the uppermost layer of the skin, also called the horny layer (dead epidermis), where they are sloughed off in about one month. As your skin replaces its cells, the cells laden with melanin are removed. So, the tanning process must continue with the new cells.
Why is hyperpigmentation (darker patches on our skin) more of a problem in darker tones?
In those with deeper-toned skin, the melanocytes (cells that produce melanin) are larger and more active. These melanocytes are buddies with Langerhans cells, which are immune cells that get triggered by inflammatory activators. When these cells get going, the melanocytes join in too, producing more melanin.
Once this melanin is packaged in melanosomes and delivered into keratinocytes (outer layer of the epidermis), our skin kicks off the cell turnover process. During this process, enzymes gobble up the melanosome membrane at different speeds. Since eumelanin doesn't dissolve as quickly as pheomelanin, it sticks around longer, making the dead skin cells (corneocytes) of deeper-toned people contain eumelanin. This can make the skin look uneven or darker, with more hyperpigmentation.
What are the implications of this for skincare?
The size and solubility of melanin contributes to how it responds to topical ingredients, which is important to know when making decisions about skin care. So, for example, degrading excess melanin when treating hyperpigmentation is more easily achieved when targeting the small, soluble pheomelanin versus the dense, insoluble eumelanin. This is one reason why treating hyperpigmentation can be more challenging in melanin rich tones and may require more patience. Harsher treatments, seem like they will work faster, but are definitely not the solution and can make the problem much worse for people with deeper toned skin!
Skin conditions can also manifest differently on different tones because of differences in physiology and so, it’s important to train the brain to know what these are and the eye to recognise them. For instance, inflammation is the most overlooked condition in deeper tones, because it doesn’t always appear as redness in the skin, but perhaps tingling, warmth or slight discolouration. If ignored, it can rapidly turn in to pigmentation and worse.
Taking care not to inflame the skin with harsh ingredients is also important, so as not to damage the barrier and trigger an overproduction of the highly reactive eumelanin. Myths that deeper tones are more resilient, don’t need as much protection, require harsher treatments, or that lightening skin is more attractive, can all result in barrier disruption and a vicious cycle of problems that end up diminishing the skin’s natural glow.
How do I know what my skin tone and potential to melanin reactivity is?
Created in 1975, the Fitzpatrick scale is the most common scale used to determine skin photo type, which is the potential for skin sensitivity and hyperpigmentation due to UV exposure and inflammation. Categorised as types 1-6, this scale does not equate to specific races, but Skin Reactivity probability. It has limitations such as indicating the melanoma risk in deeper tones. It is best used in conjunction with systems such as the Lancer Ethnicity scale, as knowing ethnicity will also give insight to potential melanin reactivity.
In conclusion
Embracing the science of melanin is key to nurturing healthy, radiant skin. By understanding its properties and nuances, we can unlock the secrets to effective skincare tailored to individual needs!
