Hyperpigmentation in Summer: Why Dark Spots Get Worse and How to Prevent It

If you spend time and money working on hyperpigmentation — post-acne marks, sun spots, melasma, uneven skin tone — and then notice in June and July that all your progress seems to reverse, you are not imagining it.

UV exposure is the single biggest trigger for hyperpigmentation. Here is why, and what to do about it.

How UV triggers dark spots

Melanocytes — the cells responsible for producing melanin, our skin's natural pigment — are activated by UV radiation. This is the body's protective response: produce more melanin to absorb UV and protect the deeper layers of skin from damage.

In skin that is prone to hyperpigmentation, this response is dysregulated. Melanocytes overproduce melanin in specific areas, creating patches and spots that are noticeably darker than the surrounding skin.

Every time UV light reaches those areas — even incidentally, through windows or on overcast days — the melanocytes are stimulated again. Dark spots that have faded over winter can deepen significantly with just a few weeks of unprotected sun exposure.

Melasma and sun: a particularly difficult relationship

Melasma — the deeper, more diffuse pigmentation disorder often triggered by hormonal changes or pregnancy — is notoriously UV-sensitive. Even small amounts of UV exposure can trigger significant darkening in melasma-prone skin.

For melasma, SPF 50 worn every day (not just on sunny days) is the most important management strategy. More so than any brightening serum or treatment.

The summer pigmentation toolkit

SPF 50, every morning, without exception. This is the foundation. Every other strategy builds on it.

Vitamin C in the morning. L-ascorbic acid (the active form of vitamin C) simultaneously neutralises the free radical damage caused by UV exposure and interferes with melanin synthesis — meaning it both prevents new pigmentation and fades existing marks. Apply before SPF for maximum effect.

Niacinamide. This form of vitamin B3 inhibits the transfer of melanin to skin cells, reducing the appearance of existing pigmentation. It is gentle enough for daily use and well tolerated by most skin types.

Avoid heat triggers. Heat — even without UV — can stimulate melanocyte activity in melasma-prone skin. This means avoiding prolonged steam, very hot showers, and excessive heat exposure in summer.

What not to do

Using hydroxy acids or retinol without SPF will worsen pigmentation, not improve it
Attempting to 'even out' skin tone by tanning will temporarily mask spots but ultimately create more
Skipping SPF on cloudy days — UVA is present regardless of cloud cover

The realistic expectation

With consistent SPF use and a good vitamin C, pigmentation can stabilise and gradually fade over the summer months rather than worsen. Without SPF, even the most effective brightening routine will fight a losing battle.

Protect first. Treat second.