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Skin concerns · Dark spots

Not every dark spot has the same cause.

Sun spots, melasma, post-acne marks and freckles are all made of the same pigment, melanin, yet each is set off by something different. Once you know which kind you have, you also know what is likely to help, how long fading takes and why the spot may come back.

Identify your spot Recommended products
Is a mole or spot changing? Read this first.
Prof. Dr. Ömer Tahir Günkara · Yıldız Technical University Why do dark spots form? The sun's UV rays and DNA damage

The melanin factory

A dark spot is the last link in a five-step production line.

Pigment-producing cells called melanocytes sit in the lowest layer of the epidermis. When they receive a signal, they make melanin and hand it out in small packages to the cells above. If too much pigment collects in one place, a spot shows. Each active ingredient works on a different link in this chain, which is why it pays to build your routine around the steps.

UV and visible light Epidermis Basal layer Melanocyte Melanosome: pigment package Keratinocyte Visible spot Shedding
Side-view drawing of the skin's upper layer. On the left, rays of sunlight strike the surface (1). In the basal layer below, a star-shaped melanocyte receives a signal (2) and produces melanin inside it (3). The melanocyte's branches pass pigment packages to the surrounding keratinocytes (4). The pigment-laden cells move upwards and, on the right, form a brown spot at the surface, where the topmost cells are shed (5).

  1. Trigger

    UV rays, visible light, hormonal changes and inflammation send melanocytes a “protect the skin” signal. In deeper skin tones, visible light can also cause pigmentation that lingers.[1,2]

    What works here

    Sunscreen

    A broad-spectrum sunscreen filters UV, and a tinted formula with iron oxides also holds back part of the visible light.[3]

    In the Longos range: Your own sunscreen; Detox & Blue Light adds antioxidant support.

  2. Signal

    UV causes oxidative stress in skin cells: damage done by free radicals. This stress raises levels of signalling molecules such as α-MSH, which stimulate pigment production. Melanocytes receive the message through a receptor called MC1R.[1]

    What works here

    Antioxidants

    In a lab study, the vitamin C derivative 3-O-Ethyl Ascorbic Acid suppressed the free-radical-driven α-MSH signal in skin cells exposed to UVA.[4]

    In the Longos range: Brightening and Detox & Blue Light

  3. Production

    Inside the melanocyte, the enzyme tyrosinase turns the amino acid tyrosine into melanin, step by step. This enzyme sets the pace of production.[1]

    What works here

    Vitamin C

    Vitamin C interacts with the copper ions at the core of tyrosinase, slowing the enzyme down and reducing melanin production.[4,5]

    In the Longos range: Brightening: 3-O-Ethyl Ascorbic Acid and Kakadu plum

  4. Transfer

    Melanin travels in packages called melanosomes, passed along the melanocyte's branches to the surrounding keratinocytes. A spot becomes visible when pigment builds up in these cells.[1]

    What works here

    Niacinamide

    In cells grown in the lab (cell culture), niacinamide, a form of vitamin B3, reduced the transfer of pigment packages by 35 to 68%.[6]

    In the Longos range: Not in Longos serums; included here as general information.

  5. Surface

    Pigment-laden cells move upwards and are eventually shed. In young adults, the journey through the skin's outermost layer takes about 20 days; later in life, it takes more than 10 days longer.[7]

    What works here

    Retinoids and fruit acids

    Retinoids, derivatives of vitamin A, speed up cell turnover: in tissue samples (biopsies) taken from spots where tretinoin was applied, pigment in the epidermis fell by 35%. Fruit acids (AHAs) help surface cells shed gently.[8]

    In the Longos range: Midnight Repair: HPR · Brightening: finger lime (AHA)

Niacinamide and tretinoin, a prescription retinoid, are mentioned as general information; neither is an ingredient of Longos serums. The HPR in Midnight Repair is a gentle ester from the retinoid family; most of the retinoid evidence on dark spots comes from tretinoin studies.

Identify your spot

Which type is yours? Follow the clues.

Answer three questions: when did the spot appear, is it symmetrical on both sides of your face, and does it fade in winter? Your answers point to one of the types below. If you're unsure, or the spot is changing, show it to a dermatologist.

Sun spots

Solar lentigo

Face illustration: brown spots of different sizes with well-defined edges, scattered across the forehead, nose, temples and cheeks.

How common it is

More common with age: the Leiden study found a strong link between sun spots and age.[9]

What it looks like
Flat, light to dark brown spots with well-defined edges, often called age spots. They become more numerous with age and don't fade in winter.
Where it appears
Cheeks, forehead, nose, backs of the hands, arms, shoulders and décolletage.
Why it happens
Sun exposure that adds up over the years. In the Leiden study of 962 people, sun spots increased markedly with age and were linked to total time spent in the sun and to sunburn before the age of 20.[9]
What helps
Daily sunscreen, vitamin C and a retinoid. With prescription tretinoin, facial spots lightened within 10 months in 20 of 24 people; among the 28 who used a placebo cream, the figure was 8.[8]
How long it takes
Months. In the same study, the first difference was measured in month 1. Spots that cleared completely took 8 months on average, and they did not return over the following 6 months.[8]

TipApply sunscreen to the backs of your hands too: sun spots appear on the hands and arms as well as the face.

The skin analysis in the app doesn't tell you which type of spot you have; it uses the skin tone score to track differences in tone from week to week.

How the skin analysis measures

Safety check

If a spot is changing, start with a dermatologist's examination.

Most spots are harmless. If a mole or spot is changing, show it to a dermatologist before you try to fade it. Dermatologists use a five-letter checklist for exactly this.[17]

  1. A: Uneven shapeAsymmetry

    The two halves of the spot don't match.

  2. B: Ragged edgesBorder

    The edges are irregular, notched or blurred.

  3. C: Mixed coloursColour

    The same spot shows more than one shade: brown, black, red, white or blue.

  4. D: SizeDiameter

    Wider than 6 millimetres, roughly the size of the eraser on the end of a pencil.[17]

  5. E: ChangeEvolving

    Its size, shape, colour or surface is changing; it itches, feels tender or bleeds.

See a dermatologist promptly if:

  • A mole or spot has changed in recent weeks or months
  • It bleeds, crusts over or looks like a sore that won't heal
  • It itches or hurts when you touch it
  • A spot you took for melasma or an acne mark keeps growing despite regular care

This list is not meant for diagnosis; it helps you recognise when it's time to see a specialist. The skin analysis in the app is not a substitute for a medical diagnosis either.

Why do they come back?

A faded spot can return with its trigger.

Melanocytes respond to a trigger every time it shows up. When a spot fades, production has slowed, not stopped; once the trigger returns, it speeds up again. That is why, in caring for dark spots, protection comes before brightening ingredients.

Sun Visible light Heat Hormones Irritation

Melanocytes produce again

  • 01SunThe most important trigger for melasma. Melasma darkens in summer and right after strong sun, and lightens in winter; a few sunny days can undo weeks of fading.[10]
  • 02Visible lightIn 20 volunteers with brown to dark skin (skin types IV to VI), visible light caused darker, longer-lasting pigmentation than UVA1, the long-wave part of UVA. In medium to olive skin (skin types III to IV), blue-violet light (415 nm) caused darkening that lasted up to 3 months, while red light (630 nm) did not increase pigment.[2,18]
  • 03HeatHeat is also cited as an accelerator of melasma: stoves, ovens, saunas, hot steam. Sunscreen doesn't block heat, so the answer is to keep your distance from the source.[14]
  • 04HormonesPregnancy and hormonal contraception are common starting points for melasma. Among the surveyed women who used a hormonal method, 25% said their melasma first appeared after starting it.[11]
  • 05IrritationHarsh peels, scrubbing and squeezing blemishes cause inflammation, and inflammation means new pigment.[15,16]

Melasma through the summer

With a tinted sunscreen, less of the melasma came back.[13]

MASI increase (median) Lower is better
  • Untinted cream with UV protection only +2.43
  • Tinted cream with iron oxides, against UV and short-wave visible light +0.45
39 people with melasma, over 6 months of spring and summer. Both creams had the same UV filters; only one contained iron oxides. MASI is a scale that scores how far the pigmentation spreads and how dark it is.

What about screen light?

At the same wavelengths, the blue light from phone and computer screens measured 100 to 1,000 times weaker than sunlight. In 12 people with melasma, one half of the face was exposed for 5 days to light equivalent to 8 hours a day of heavy screen use, and the spots showed no difference. The main source of visible light is the sun.[19]

The protection habit[13]

  • Broad-spectrum sunscreen every morning, whatever the weather
  • A tinted formula with iron oxides if you're prone to dark spots
  • Reapply every 2 hours outdoors
  • A hat, shade and sunglasses
  • Keep your face away from hot steam and oven heat

What to expect, and when

Fading a dark spot takes weeks, sometimes months.

Pigment-laden cells need time to reach the surface and shed, and that time grows longer with age. Measurements from studies show what you can expect, week by week.

  1. Week 3

    One renewal cycle

    In young adults, the skin's outermost layer renews in about 20 days; later in life, it takes more than 10 days longer. Allow at least one cycle before you look for the first change.[7]

  2. Week 4

    The first measurable difference

    In a study comparing a moisturiser with 5% niacinamide against a placebo moisturiser in the same people (18 participants), spots had decreased significantly more with niacinamide after 4 weeks. In the tretinoin study, too, the first difference was measured in month 1.[6,8]

  3. Week 8

    The first clear change in melasma

    In an 8-week study of 68 people with melasma, the group using an iron-oxide sunscreen improved 15% more on the spot score than the group using a product that protects against UV only. Both groups were also using hydroquinone.[3]

  4. Week 12

    Spots become less visible

    In 50 women who applied 5% niacinamide to one half of the face twice a day, the look of spots, fine lines and sallowness had decreased after 12 weeks.[20]

  5. Week 16

    Where vitamin C stands

    In a group of 16 women who applied 5% vitamin C to one half of the face and 4% hydroquinone to the other, the women's own ratings favoured the hydroquinone side: good or very good results for 93%, against 62.5% for vitamin C. Colour measurements showed no significant difference between the sides, and side effects occurred in 1 of 16 women on the vitamin C side, compared with 11 on the hydroquinone side.[12]

  6. Month 6

    Getting through summer

    With melasma, the real test is the summer months. In people using a tinted sunscreen with iron oxides, less of the melasma came back over 6 months.[13]

  7. Month 10

    The outcome for sun spots

    Facial sun spots lightened in 83% of those using tretinoin, compared with 29% in the placebo group. Spots that cleared completely did not return over the following 6 months.[8]

The studies used different products, doses and protocols. Tretinoin and hydroquinone are prescription products, and niacinamide is not in Longos serums; these results do not come from Longos products. Results vary from person to person.

What helps

Protect first, then brighten, then renew.

Dark spot care is built in three layers, and the order matters: without protection, every sunny day undoes the progress made with brightening ingredients. Longos serums and Longos Sense support one step in each layer; sun protection comes from your own sunscreen.

  1. 1 Every morning

    Protect

    A broad-spectrum sunscreen with SPF 30 or higher. If you're prone to dark spots or have melasma, choose a tinted formula with iron oxides. In Detox & Blue Light, Baikal skullcap root, cocoa and Epilobium extracts provide antioxidant support against environmental stress; they don't replace sunscreen.[3,13,16]

    Your own sunscreen + Detox & Blue Light

  2. 2 Morning or evening

    Brighten

    The 3-O-Ethyl Ascorbic Acid in Brightening is a more stable derivative of vitamin C and works at the tyrosinase step, which governs melanin production. Kakadu plum is a fruit rich in vitamin C, and the fruit acids in finger lime gently renew the surface.[4,5]

    Brightening + Longos Sense

  3. 3 Evening · start with 2 to 3 nights a week

    Renew

    The hydroxypinacolone retinoate (HPR) in Midnight Repair is a gentle ester from the retinoid family; by supporting cell renewal, it may help pigmented cells shed from the surface. The strongest retinoid evidence on dark spots comes from prescription tretinoin, and studies of HPR on dark spots are limited.[8]

    Midnight Repair

Longos Sense

Where does the device fit in?

Longos Sense works together with a serum; on its own, it doesn't fade spots. The Brightening protocol combines three modes, and the app adjusts the timing to your skin.

  • Red light

    The end of visible light that drives pigment is blue-violet; in one study, red light (630 nm) caused no increase in pigment.[18]

  • Radiofrequency

    Warms the skin gently and in a controlled way, in the same session as the serum. If you have melasma, check with your dermatologist before you start any mode that uses heat.[14]

  • Cryotherapy

    Part of the Brightening protocol; it cools the skin during the session.

  • Skin analysis

    The app scores differences in tone with the skin tone score; measure once a week in the same light to follow the change.

A woman without make-up holding Longos Sense against her cheek.
Where to start

For the first 12 weeks

  1. 1Sunscreen every morning: your choice of formula, tinted with iron oxides if you're prone to dark spots
  2. 2Brightening with Longos Sense, on the protocol the app recommends
  3. 3Midnight Repair: start with 2 to 3 evenings a week and build up as your skin adjusts
  4. 4A skin analysis every four weeks, in the same light
See the products
Hevi Feyza talks about her experience with Longos Sense for dark spots. Results vary from person to person.

Real user

Measure your spots to see how they change.

Spots change slowly, and a daily look in the mirror won't show the difference. Measuring your progress helps you stay patient.

  1. 01

    Same light

    Let daylight fall on your face from the front, and measure at the same time and in the same place each week.

  2. 02

    Clean face

    No make-up and no products on your skin; hair tied back, phone at face level.

  3. 03

    Skin tone score

    The app tracks differences in tone with a separate score, and every analysis is saved with its date.

  4. 04

    Once a week

    You can follow the change week by week in the History tab.

Explore the skin analysis

The skin analysis is not a medical diagnosis and does not identify the type of spot.

The Quantum Orbit Labs R&D team in white lab coats in the laboratory.
Our formulas are developed and measured together with university laboratories.

Lab measurement

Brightening responded more strongly with Longos Sense.

Brightening's response was measured electrochemically, in two steps, in the laboratories of Yıldız Technical University and Dokuz Eylül University: the serum on its own, then with the Longos Sense protocol. The result is read in microamperes (µA), a small unit of electric current. Under the same conditions, a higher current means a stronger response in the test medium.

+12.2%Increase measured with Longos Sense

Measurement protocol

  • Cold mode
  • Red LED
  • Radiofrequency

Measured values: 19,6 µA · 22 µA

  • Serum on its own Baseline
  • With Longos Sense +12.2%

AGON Biotechnology and Bioİzmir contributed to the scientific work. AGON Biotechnology develops biosensors and electrochemical measurement systems in the technology development zone of Dokuz Eylül University.[21]

These findings are controlled laboratory observations; they make no claim of medical diagnosis or treatment. The measurement was carried out in the laboratory, not on skin, and results on skin vary from person to person.

All lab measurements

Frequently asked

About caring for dark spots

Will a dark spot serum erase my spots completely?

It depends on the type of spot. Sun spots and post-acne marks can fade noticeably over time. Melasma, on the other hand, is chronic: even when it fades, it can return with its triggers. Cosmetic products help reduce the look of dark spots; to keep the results, you need daily sun protection.

Should I use vitamin C in the morning or the evening?

Either works. In the morning, apply it under your sunscreen. The 3-O-Ethyl Ascorbic Acid in Brightening is a more stable derivative than pure vitamin C. Because the formula also contains fruit acids, always wear sunscreen during the day.

Can I use a retinoid and vitamin C together?

Yes. Most people use them at different times of day: vitamin C in the morning, the retinoid in the evening. The HPR in Midnight Repair is a gentle retinoid ester, but start with 2 to 3 nights a week all the same. If you notice redness or stinging, use it less often, because irritation can cause spots too.

What can I do about dark spots during pregnancy?

Melasma is common in pregnancy, and the key step during this time is sun protection. Talk to your doctor before using products that contain retinoids (Midnight Repair included) or devices that work with light, heat or radiofrequency.

Do I need sunscreen in winter too?

If you're prone to dark spots, yes. Melasma may darken in summer, but UV and visible light reach your skin all year round. Protecting spots that have faded over the winter helps you go into summer with calmer skin.

Can Longos Sense fade dark spots on its own?

No. Longos Sense is a device that works together with a serum; in the lab measurement, Brightening's response increased when it was used with the device. The real work of dark spot care is done by daily protection and brightening ingredients; the device is one part of that routine.

References

Sources for the information on this page

Studies published in peer-reviewed journals, plus laboratory measurements by Quantum Orbit Labs. The numbers in square brackets in the text link to this list.

  1. 1.D'Mello SAN, Finlay GJ, Baguley BC, Askarian-Amiri ME. Signaling pathways in melanogenesis. International Journal of Molecular Sciences. 2016;17(7):1144. pmc.ncbi.nlm.nih.gov
  2. 2.Mahmoud BH, Ruvolo E, Hexsel CL et al. Impact of long-wavelength UVA and visible light on melanocompetent skin. Journal of Investigative Dermatology. 2010;130(8):2092-2097. pubmed.ncbi.nlm.nih.gov
  3. 3.Castanedo-Cazares JP, Hernandez-Blanco D, Carlos-Ortega B et al. Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial. Photodermatology, Photoimmunology & Photomedicine. 2014;30(1):35-42. pubmed.ncbi.nlm.nih.gov
  4. 4.Chen SJ, Hseu YC, Gowrisankar YV et al. The anti-melanogenic effects of 3-O-ethyl ascorbic acid via Nrf2-mediated α-MSH inhibition in UVA-irradiated keratinocytes and autophagy induction in melanocytes. Free Radical Biology and Medicine. 2021;173:151-169. pubmed.ncbi.nlm.nih.gov
  5. 5.Al-Niaimi F, Chiang NYZ. Topical vitamin C and the skin: mechanisms of action and clinical applications. Journal of Clinical and Aesthetic Dermatology. 2017;10(7):14-17. pmc.ncbi.nlm.nih.gov
  6. 6.Hakozaki T, Minwalla L, Zhuang J et al. The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer. British Journal of Dermatology. 2002;147(1):20-31. pubmed.ncbi.nlm.nih.gov
  7. 7.Grove GL, Kligman AM. Age-associated changes in human epidermal cell renewal. Journal of Gerontology. 1983;38(2):137-142. pubmed.ncbi.nlm.nih.gov
  8. 8.Rafal ES, Griffiths CEM, Ditre CM et al. Topical tretinoin (retinoic acid) treatment for liver spots associated with photodamage. New England Journal of Medicine. 1992;326(6):368-374. pubmed.ncbi.nlm.nih.gov
  9. 9.Bastiaens M, Hoefnagel J, Westendorp R et al. Solar lentigines are strongly related to sun exposure in contrast to ephelides. Pigment Cell Research. 2004;17(3):225-229. pubmed.ncbi.nlm.nih.gov
  10. 10.Handel AC, Miot LDB, Miot HA. Melasma: a clinical and epidemiological review. Anais Brasileiros de Dermatologia. 2014;89(5):771-782. pmc.ncbi.nlm.nih.gov
  11. 11.Ortonne JP, Arellano I, Berneburg M et al. A global survey of the role of ultraviolet radiation and hormonal influences in the development of melasma. Journal of the European Academy of Dermatology and Venereology. 2009;23(11):1254-1262. pubmed.ncbi.nlm.nih.gov
  12. 12.Espinal-Perez LE, Moncada B, Castanedo-Cazares JP. A double-blind randomized trial of 5% ascorbic acid vs. 4% hydroquinone in melasma. International Journal of Dermatology. 2004;43(8):604-607. pubmed.ncbi.nlm.nih.gov
  13. 13.Boukari F, Jourdan E, Fontas E et al. Prevention of melasma relapses with sunscreen combining protection against UV and short wavelengths of visible light: a prospective randomized comparative trial. Journal of the American Academy of Dermatology. 2015;72(1):189-190. pubmed.ncbi.nlm.nih.gov
  14. 14.Sarkar R, Jagadeesan S, Basavapura Madegowda S et al. Clinical and epidemiologic features of melasma: a multicentric cross-sectional study from India. International Journal of Dermatology. 2019;58(11):1305-1310. pubmed.ncbi.nlm.nih.gov
  15. 15.Abad-Casintahan F, Chow SKW, Goh CL et al. Frequency and characteristics of acne-related post-inflammatory hyperpigmentation. Journal of Dermatology. 2016;43(7):826-828. pubmed.ncbi.nlm.nih.gov
  16. 16.Davis EC, Callender VD. Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. Journal of Clinical and Aesthetic Dermatology. 2010;3(7):20-31. pmc.ncbi.nlm.nih.gov
  17. 17.Abbasi NR, Shaw HM, Rigel DS et al. Early diagnosis of cutaneous melanoma: revisiting the ABCD criteria. JAMA. 2004;292(22):2771-2776. pubmed.ncbi.nlm.nih.gov
  18. 18.Duteil L, Cardot-Leccia N, Queille-Roussel C et al. Differences in visible light-induced pigmentation according to wavelengths: a clinical and histological study in comparison with UVB exposure. Pigment Cell & Melanoma Research. 2014;27(5):822-826. pubmed.ncbi.nlm.nih.gov
  19. 19.Duteil L, Queille-Roussel C, Lacour JP et al. Short-term exposure to blue light emitted by electronic devices does not worsen melasma. Journal of the American Academy of Dermatology. 2020;83(3):913-914. pubmed.ncbi.nlm.nih.gov
  20. 20.Bissett DL, Oblong JE, Berge CA. Niacinamide: a B vitamin that improves aging facial skin appearance. Dermatologic Surgery. 2005;31(7 Pt 2):860-865. pubmed.ncbi.nlm.nih.gov
  21. 21.Quantum Orbit Labs. Electrochemical laboratory measurements of Longos Sense and the serums. Laboratories of Yıldız Technical University and Dokuz Eylül University, with contributions from AGON Biotechnology and Bioİzmir. quantumorbitlabs.com/en/clinical-evidence

Recommended products

For dark spot care

Longos Sense and three serums that work at different steps of dark spot care. Sunscreen isn't on this list: make a broad-spectrum sunscreen of your choice (a tinted formula if you're prone to dark spots) the first step of your routine every morning.

Longos Sense + 8 serums Longos Sense device and 8 serums

Longos Sense set

The red light, radiofrequency and cryotherapy of the Brightening protocol, in one device. The app measures your skin tone score and selects the Brightening protocol; the set includes all three serums on this page.

View the set
  • Brightening serum

    Start here · Brighten

    Brightening serum

    3-O-Ethyl Ascorbic Acid, Kakadu plum and finger lime. Works at the tyrosinase step and helps dark spots look less noticeable.

    Red light Radiofrequency Cryo

  • Detox & Blue Light serum

    Morning · Protection support

    Detox & Blue Light serum

    Baikal skullcap root, cocoa and Epilobium extracts. Antioxidant support against city and light stress; not a substitute for sunscreen.

    Ultrasonic

  • Midnight Repair serum

    Evening · Renew

    Midnight Repair serum

    The retinoid ester HPR, grape extract and sweet almond oil. Supports surface renewal overnight.

    Red light Radiofrequency

Your first step this week: tomorrow morning, whatever the weather, apply sunscreen to your face and the backs of your hands. On the same day, run the skin analysis in the app once on a clean face; your skin tone score becomes your starting point.

Start the skin analysis

The set's serums are pre-selected; swap any you like. You can pick the same serum more than once.