Your dark spot isn't just a dark spot: there are three types, and each is treated differently
by BelénShare
Not all dark spots are the same, even though the eye tends to group them into a single category. Behind the same dark tone, completely different processes can be at play, each with its own origin, depth and pace of improvement.
That is why the same spot reappears every summer in the same part of the cheek, while another one fades with a product and a third barely responds to anything. Treating all of them with the same protocol is, in practice, the most frequent cause of frustration with these treatments.
Understanding exactly what happens when a dark spot forms, and which part of that process can actually be treated, completely changes the expectations with which any brightening routine begins.
Producing melanin is only half the story
When a dark spot appears, it is usually assumed that the problem is producing too much melanin. The other half is clearing that pigment away, and it is precisely this part that changes with age.
It is produced in the melanocyte. When the skin receives ultraviolet radiation or experiences inflammation, the surrounding keratinocytes send signals that make the melanocyte increase that production. The melanin is then transferred to the keratinocytes, where it acts as natural protection against sun damage (Yuan and Jin, 2018).
It is cleared through epidermal turnover. Melanin disappears when those keratinocytes rise to the surface and shed. In young skin this happens quickly, but from around age 40 turnover slows down and the pigment stays visible for longer.
Sometimes it gets trapped in the dermis. In some dark spots, part of the melanin crosses the basement membrane and reaches the dermis. There, no cell turnover exists that can clear it, and its disappearance depends on much slower tissue clean-up mechanisms.
Three types of dark spots, three different behaviours
These three account for most of the cases that appear from the age of forty onward.
| Type | What causes it | Why it comes back | What it responds to |
|---|---|---|---|
| Solar lentigo | Sun damage accumulated over years. | The melanocyte population in that area is stably altered, so the same spot pigments again every summer. | Strict sun protection, retinoids and azelaic acid. |
| Melasma | Interaction between hormones, ultraviolet radiation and visible light. | Has a dermal component (altered basement membrane, more vascularisation), which responds less well and explains the relapse. | Tinted sun protection, tranexamic acid, azelaic acid and niacinamide. |
| Post-inflammatory hyperpigmentation | Inflammation from acne, hair removal or aesthetic procedures. | On skin with slow turnover it takes months to fade, and longer still if the pigment reached the dermis. | Treating the inflammation as early as possible and avoiding procedures that irritate the skin again. |
Why sun protection is not just about avoiding sunburn
Ultraviolet radiation is not the only thing responsible for a dark spot getting darker.
Conventional sunscreens cover little of that range. Formulations containing iron oxides protect against visible-light-induced pigmentation better than an untinted mineral sunscreen (Lyons et al., 2021).
Ideas worth reconsidering
Exfoliating more does not clear things up faster. On skin with slow turnover, an aggressive procedure causes inflammation, and inflammation produces new pigment. With dark spots, consistency pays off more than intensity.
An untinted sunscreen is not enough if melasma is present. It blocks UV rays, but barely acts on visible light, one of the main reasons melasma gets worse.
Switching products every month makes it impossible to know if something is working. A brightening ingredient acts on pigment that must leave through epidermal turnover. Twelve to sixteen weeks is the reasonable minimum for judging the result.
Which active ingredient works on each type of dark spot
| Active ingredient | What it acts on |
|---|---|
| Azelaic acid | Inhibits tyrosinase activity and has anti-inflammatory properties; a good option when there is an inflammatory component. |
| Tranexamic acid | Modulates signalling pathways involved in melanogenesis and in the inflammation associated with melasma. |
| Niacinamide | Reduces the transfer of melanosomes from the melanocyte to the keratinocyte, which supports a more even tone. |
| Retinoids | Support epidermal turnover, which helps pigment that has already formed to clear away sooner. |
| Tinted sun protection | Covers the visible-light range that conventional sunscreens let through. |
When skin needs something beyond topical skincare
The active ingredients above work mainly on the surface of the skin. Photobiomodulation acts through a different pathway: certain LED light wavelengths are absorbed by mitochondrial photoreceptors, specifically cytochrome c oxidase, and increase ATP production inside the fibroblast, supporting collagen and elastin synthesis from within.
The Silicone LED Mask does not act on melanin. Its red and infrared wavelengths are not absorbed by the chromophores of melanin; instead, they act directly on the water and collagen in the skin. That is why its main mechanism is to stimulate the fibroblast, not to lighten pigment. Even so, in the independent efficacy test carried out on women over 40, an 18.6% improvement in dark spot colouration was also recorded after eight weeks of use, an effect associated with the overall improvement in skin quality, not with a direct action on pigment.
There is also no scientific evidence that red or infrared light, at these energy levels, causes hyperpigmentation. In very exceptional cases, on skin that is already sensitised (from sun erythema, from aggressive skincare, or in higher phototypes), irritation or a change in pigmentation could appear; if that happens, the right thing to do is to stop using it and consult your dermatologist.
It is added as a complement to sun protection and brightening actives, not as a substitute: it is applied to clean, dry skin, and everyday skincare is left for after the session, when it absorbs better.
The device has five intensity levels, and can be used directly at level 5 without going through the earlier ones. Ten minutes a day is enough, and short daily sessions pay off more than long, spaced-out use. As an initial protocol, 3 to 5 sessions a week for 3 or 4 weeks, followed by 1 to 2 maintenance sessions a week, or daily if preferred. It is not recommended during pregnancy, as no studies are available, and the use of red and infrared light is not recommended before the age of 25.
When a dark spot needs a medical check
Nothing above replaces a dermatological assessment. It is worth consulting a professional as soon as possible if any of these signs appear.
- It noticeably changes shape, colour, size or border. This is the sign that most often calls for a check-up.
- It bleeds, itches or hurts for no clear reason. A simple pigment spot does not usually cause these symptoms.
- It appears suddenly and does not match your usual pattern. Not every new dark spot has a sun or hormonal origin.
- It raises any doubt at all, however small. When in doubt, the right thing to do is ask before starting a treatment.
Frequently asked questions
Why does the same dark spot always come back in the same place?
Because cumulative exposure stably alters the melanocyte population in that area, which responds more intensely than the surrounding tissue to the same sun exposure.
How long does it take to see improvement?
At least twelve weeks, and up to sixteen in many cases, because the pigment has to leave through natural epidermal turnover. Judging the result before that time makes it impossible to know if the treatment is working.
Is melasma treated the same way as a sun-induced dark spot?
No. Melasma has a dermal component that responds less well to treatment, so it usually needs tinted sun protection and actives such as tranexamic acid, in addition to what already works for solar lentigo.
Does the LED mask lighten dark spots?
Not directly: its wavelengths are not absorbed by the chromophores of melanin, but by the water and collagen in the skin. In the efficacy test, an associated improvement in colouration was recorded, linked to the overall improvement in the skin, always as a complement to sun protection and brightening actives, never as a substitute.
Can I combine a retinoid and azelaic acid?
They are usually well tolerated together if introduced gradually. If any irritation persists, it is best to space out their use or consult your dermatologist.
Quick glossary
- Melanocyte
- The cell responsible for producing melanin, the pigment behind skin colour.
- Melanosome
- A structure inside the melanocyte where melanin is produced and stored before being transferred to the keratinocyte.
- Melasma
- Hyperpigmentation with a dermal component, associated with hormones, ultraviolet radiation and visible light.
- Post-inflammatory hyperpigmentation
- A dark spot that appears after skin inflammation, such as acne or an injury.
- Tinted sun protection
- Sunscreen containing iron oxides, which also covers the visible-light range.
In summary
Each dark spot has a different origin. One lives in the epidermis and responds relatively quickly to cell turnover; another has a dermal component that makes it more resistant and more prone to returning. That difference in depth is what decides whether a topical treatment can reach it or not, and why two dark spots that look the same can need completely different routines.
The SKINVITY team
Scientific references
The following references correspond to the general scientific evidence on skin pigmentation cited in this article, not to an efficacy test of a SKINVITY device unless expressly stated.
- Yuan XH, Jin ZH. Paracrine regulation of melanogenesis. Br J Dermatol. 2018;178(3):632-639.
- Dumbuya H, Grimes PE, Lynch S, et al. Impact of iron oxide-containing formulations against visible light-induced skin pigmentation. J Drugs Dermatol. 2020;19(7):712-717.
- Lyons AB, Trullas C, Kohli I, Hamzavi IH, Lim HW. Photoprotection beyond ultraviolet radiation: a review of tinted sunscreens. J Am Acad Dermatol. 2021;84(5):1393-1397.