Dark spot serum: how to choose the right one for your dark spots

On the shelf, all dark-spot serums make similar promises: "evens out", "brightens", "corrects". The active ingredients, however, are very different, and each works on a different point in the process that causes a spot to form. That's why the same serum may work well on a sun spot and do almost nothing for melasma. Choosing well requires two pieces of information: what type of spot you have and what is actually in the formula.

Article written by Elisa Avalle, founder of LeLang Skin Care and dermocosmetics specialist. Cover image generated with the support of artificial intelligence.

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Before the serum: what type of spot do you have?

Almost all facial spots are caused by an excess of melanin, but they do not all develop in the same way. The three most common situations respond differently to the same active ingredients:

Type of spot	How to identify it	What to expect from a serum
Solar lentigines	Brown spots with sharply defined edges on the cheekbones, forehead, and backs of the hands; they appear after years of sun exposure	They fade gradually; darker, older ones change very little
Post-inflammatory hyperpigmentation	Red or dark marks where a spot or irritation occurred	They respond well, especially when treated early
Melasma	Symmetrical patches on the cheeks, forehead, and upper lip; they worsen with sun, heat, and hormones	It improves but tends to return: long-term management is needed, often with a dermatologist

If you don't know which group you belong to, you'll find the differences explained in the guide to facial hyperpigmentation and in the in-depth articles on sun spots, post-acne marks, and melasma.

The active ingredients that matter in a dark spot serum

A dark spot forms in several stages: a signal (sun, inflammation, hormones) activates melanocytes, the enzyme tyrosinase produces melanin, the melanin is transferred to surface cells and remains there until they renew. Each active ingredient acts at one of these stages.

Active ingredient	Where it works	Who it is best suited for
Vitamin C and derivatives	It slows tyrosinase and neutralizes free radicals produced by the sun	Sun spots, dull complexion, prevention
Niacinamide	It reduces the transfer of melanin to surface cells	Almost all skin types, including oily and sensitive skin
Tranexamic acid	It reduces the inflammatory and vascular signals that activate melanocytes	Melasma, skin that reddens easily
Alpha-arbutin and kojic acid	They inhibit tyrosinase	Sun spots and post-inflammatory dark spots
Azelaic acid	It inhibits tyrosinase and calms inflammation	Acne-prone skin with dark marks
Exfoliants (glycolic acid, mandelic acid, enzymes)	They accelerate the turnover of pigment-containing cells	Superficial dark spots, thickened or dull skin
Retinoids	They accelerate cell renewal and improve pigment distribution	Mature skin with dark spots and signs of photoaging

Concentrations to know

There are precise references for some of these active ingredients. Niacinamide has the best data at around 4-5%. Pure ascorbic acid works at approximately 8 to 20% and only at an acidic pH, while stabilized derivatives each have their own effective concentration: how they compare is explained in the guide to the vitamin C serum. For alpha-arbutin and kojic acid, since 2024 European regulations have set limits in facial products: 2% for alpha-arbutin and 1% for kojic acid. Tranexamic acid is usually found in cosmetics at between 2 and 5%.

Hydroquinone, the traditional depigmenting agent, is not permitted in skincare cosmetics in Europe: it is found only in prescription preparations. A serum sold as a cosmetic that lists it, or products purchased outside controlled channels that contain it, should be avoided.

How to read the label

The large name on the packaging says little. The useful information is elsewhere:

1. Position in the INCI. Ingredients are listed in descending order of concentration down to 1%. An active that appears after fragrance and preservatives is present in a minimal amount.
2. The stated percentage. It is not mandatory, but a brand that provides it allows you to compare it with the references above.
3. Packaging. Vitamin C and retinoids degrade when exposed to air and light: opaque or airless bottles are preferable.
4. Fragrance. If your skin is reactive, check for parfum and allergens at the end of the INCI.

To learn how to read an ingredients list in a few minutes, see the guide on how to read the INCI.

The right dark-spot serum for your skin type

Oily or acne-prone skin

Here, dark spots are often post-inflammatory marks. Niacinamide, azelaic acid, and mandelic acid work well; mandelic acid exfoliates gently and helps control sebum. Lightweight, gel or watery textures are best.

Sensitive skin or skin that reddens easily

Well-tolerated actives such as niacinamide and tranexamic acid are preferable, as are stabilized vitamin C derivatives instead of pure ascorbic acid. High-concentration exfoliants should be introduced cautiously, once or twice a week in the evening. Irritating the skin is counterproductive: inflammation itself stimulates new dark spots.

Mature skin

Dark spots almost always occur alongside wrinkles and loss of firmness. The most sensible combination is vitamin C in the morning and a retinoid or exfoliant in the evening, used on alternate evenings. This is also the approach described in the guide to skin aging.

Morning or evening, and how long to wait

An effective routine for dark spots does not need many products: simply use each active at the right time.

1. Morning: cleanse, use an antioxidant serum with vitamin C, moisturizer if needed, and sunscreen.
2. Evening: cleanse, use a serum with niacinamide or tranexamic acid, or an exfoliant or retinoid on alternate evenings.
3. Do not layer exfoliants and retinoids on the same evening, especially at first.

The surface cells renew themselves in about four weeks, and several cycles are needed for the pigment to visibly diminish. The first honest comparison should be made after 8-12 weeks, using a photo taken in the same daylight as when you started.

Serum alone is not enough: sun protection

An anti-spot serum reduces melanin production; every exposure without protection reactivates it. That is why the result is lost after just a few weeks of unprotected sun exposure. You need a high SPF every morning, even in winter and in the city, reapplied if you spend time outdoors. With melasma, visible light also matters: a clinical study showed better results with filters that also shield this part of the spectrum, such as tinted ones.

Spot Defence is our SPF 50 sunscreen serum designed for those with uneven pigmentation: a lightweight texture to use every morning as the final step, with stabilized vitamin C and antioxidants that complement the filters. To choose protection based on your skin, see the guide to the best sunscreen.

How we designed it

In our line, the work on spots is divided between morning and evening, as described above. In the morning, the antioxidant serum contains 15% stabilized vitamin C (3-O-ethyl ascorbic acid) and 0.5% ferulic acid, together with vitamin E and hyaluronic acid.

In the evening, two or three times a week, use a gentle exfoliant with mandelic acid and papaya and pineapple enzymes, which accelerates the turnover of cells that retain pigment.

Those who prefer a ready-made routine can find cleanser, vitamin C, exfoliation, cream, and SPF 50 combined in the dedicated protocol.

When to see a dermatologist

A serum is the right choice for stable, already identified spots. You should see a doctor before starting if a spot has appeared recently, changes shape, color, or size, has irregular edges, bleeds, or itches. Extensive melasma, or melasma that does not respond after three months of a proper routine, also deserves a dermatological evaluation: there are treatments that a cosmetic product cannot replace.

The next step

The pharmacist at LeLang partner pharmacies and parapharmacies can help you identify the type of dark spot and choose the serum to add to your existing routine.

Sources for this article

1. Hakozaki T. et al. (2002). "The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer". British Journal of Dermatology, vol. 147, no. 1, pp. 20-31.
2. Pinnell S.R. et al. (2001). "Topical L-ascorbic acid: percutaneous absorption studies". Dermatologic Surgery, vol. 27, no. 2, pp. 137-142.
3. Castanedo-Cazares J.P. et al. (2014). "Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial". Photodermatology, Photoimmunology & Photomedicine, vol. 30, no. 1, pp. 35-42.
4. Commission Regulation (EU) 2024/996, amending Annex III of Regulation (EC) No 1223/2009 for alpha-arbutin, arbutin, kojic acid, and vitamin A.

Where to continue: Facial discoloration · Peels for dark spots · Hyperpigmentation

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