Hyperpigmentation — including melasma, post-inflammatory hyperpigmentation (PIH), solar lentigines, and generalised uneven tone — is one of the more challenging skin concerns to treat effectively. Over-the-counter products often contain active ingredients at sub-therapeutic concentrations. Medical-grade and prescription treatments work through the same mechanisms but at clinically substantiated concentrations and with greater penetration.

Some ingredients discussed in this article, including tretinoin and hydroquinone 4%, are prescription-only medicines in the UK. This article is for educational purposes only. Always follow the guidance of your prescribing clinician.

What causes hyperpigmentation?

Hyperpigmentation occurs when melanocytes produce excess melanin in response to a trigger. The main triggers are:

• UV exposure — the primary driver of solar lentigines and a significant aggravating factor in melasma
• Inflammation — acne, injuries, or skin irritation trigger post-inflammatory hyperpigmentation (PIH)
• Hormonal changes — pregnancy, hormonal contraception, and other hormonal shifts are the primary drivers of melasma
• Cumulative sun damage — years of UV exposure manifest as age spots and generalised uneven tone

Types of hyperpigmentation

Melasma — symmetrical patches typically on the cheeks, forehead, and upper lip; hormonally triggered and often UV-aggravated. One of the more difficult types to treat and prone to recurrence.

Post-inflammatory hyperpigmentation (PIH) — dark marks left after acne, injuries, or inflammation. More common and more pronounced in darker skin tones.

Solar lentigines — flat brown spots from cumulative UV exposure.

Generalised uneven tone — diffuse dullness and patchiness from a combination of factors.

Key active ingredients

Prescription-only

Tretinoin — accelerates epidermal cell turnover, dispersing melanin granules and shedding pigmented cells faster. Also enhances penetration of co-applied brightening ingredients and inhibits melanogenesis. Available at 0.025%, 0.05%, and 0.1%. For a detailed comparison of strengths, see our guide to tretinoin strengths.

Hydroquinone 4% — inhibits tyrosinase, the enzyme responsible for melanin synthesis. The most effective topical melanin-inhibiting ingredient available. Should be used for 3–4 months at a time, with 2–3 month breaks, to reduce the risk of ochronosis with prolonged use. For guidance on combining tretinoin and hydroquinone, see our tretinoin and hydroquinone combination guide.

Non-prescription professional-grade actives

Vitamin C (L-ascorbic acid) — inhibits melanin production, neutralises free radicals that trigger pigmentation, and provides antioxidant photoprotection alongside SPF. Effective at 10–20% L-ascorbic acid at pH 3.5.

Niacinamide — inhibits melanosome transfer from melanocytes to keratinocytes, reducing pigmentation at the cellular level. Also reduces inflammation that triggers PIH and strengthens the skin barrier. Effective at 2–5%.

Azelaic acid — inhibits tyrosinase, reduces inflammation, and treats acne while preventing PIH. Well tolerated by sensitive skin and suitable for rosacea-related pigmentation. Effective at 10–20%.

Tranexamic acid — reduces melanin synthesis and is particularly effective for hormonal pigmentation and melasma. Available topically and, in some cases, orally (prescription).

Alpha arbutin — a gentler tyrosinase inhibitor, well tolerated with minimal irritation. Suitable for sensitive skin or as a maintenance ingredient.

Building a routine

Morning: protect and brighten

1. Gentle cleanser — mild, pH-balanced, no exfoliating actives in the morning
2. Vitamin C serum — 10–20% L-ascorbic acid applied to clean, dry skin provides antioxidant protection and active brightening throughout the day
3. Niacinamide or tranexamic acid serum (optional) — can be layered if skin tolerates it, or used at night instead
4. Moisturiser — lightweight, fragrance-free
5. Broad-spectrum SPF 50 — the single most important step in any hyperpigmentation routine. UV exposure directly stimulates melanin production and will counteract all other treatment progress. Reapply every 2 hours when outdoors.

Evening: treat and repair

Non-prescription routine:

1. Gentle cleanser
2. Azelaic acid 10–20% or alpha arbutin serum
3. Moisturiser

With prescription tretinoin:

1. Gentle cleanser
2. Wait 20–30 minutes until skin is completely dry
3. Tretinoin (pea-sized amount)
4. Wait 20 minutes (optional), then moisturiser

Full prescription protocol (tretinoin + hydroquinone):

1. Gentle cleanser
2. Hydroquinone 4% to pigmented areas (or full face as directed)
3. Wait 20–30 minutes until completely dry
4. Tretinoin (pea-sized amount)
5. Wait 20 minutes (optional), then moisturiser

For a detailed guide to the tretinoin and hydroquinone combination, including how to introduce it safely, see our combination guide.

What to expect: timeline

Weeks 1–4: Adjustment period. Possible irritation, dryness, and purging with tretinoin. Pigmentation may temporarily appear darker as surface melanin is brought up — this is expected.

Weeks 4–8: Irritation subsides as tolerance builds. Slight lightening of dark spots begins. Overall tone starts to even.

Weeks 8–12: Noticeable fading of hyperpigmentation. More even skin tone and improved texture.

Months 3–6: Significant reduction in hyperpigmentation. Maintenance becomes the focus.

6+ months: Maximum results achieved. Ongoing sun protection and maintenance treatment prevent recurrence.

Special considerations by type

Melasma

Melasma is hormonally driven and UV-aggravated, making it one of the more difficult types to treat and prone to recurrence. The tretinoin and hydroquinone combination is the most clinically substantiated approach. Tranexamic acid (topical or oral) can provide additional benefit. Strict, year-round sun protection is critical — UV exposure is the primary aggravating factor. Hormonal triggers (contraception, HRT) should be discussed with a clinician.

Post-inflammatory hyperpigmentation (PIH)

Treating the underlying cause (typically acne) is as important as treating the pigmentation itself. Avoid picking or squeezing blemishes — this significantly worsens PIH. Niacinamide and azelaic acid address both inflammation and pigmentation simultaneously. Tretinoin accelerates fading by increasing cell turnover.

Darker skin tones

Darker skin tones are more prone to PIH and require a more cautious approach to active ingredients — lower starting strengths, slower introduction, and avoidance of treatments that cause significant inflammation. Some laser treatments are not appropriate for darker skin tones and require an experienced practitioner.

When to seek a prescriber assessment

• Over-the-counter treatments have not produced meaningful results after 3–6 months
• You have melasma or suspected hormonal pigmentation
• Hyperpigmentation is severe, widespread, or worsening
• You want to access prescription-strength treatments (tretinoin, hydroquinone 4%)
• You are experiencing persistent irritation from current treatments

Frequently asked questions

What is the most effective treatment for hyperpigmentation?

The combination of prescription tretinoin and hydroquinone 4% is the most clinically substantiated topical treatment for hyperpigmentation and melasma. Both are prescription-only in the UK. For those not yet on prescription treatment, vitamin C, niacinamide, azelaic acid, and tranexamic acid are the most evidence-backed non-prescription options.

How long does it take to fade hyperpigmentation?

Meaningful improvement typically takes 8–12 weeks of consistent treatment. Significant fading of established hyperpigmentation usually requires 3–6 months. Melasma and deep pigmentation may take longer and are prone to recurrence without ongoing maintenance and sun protection.

Does SPF really make that much difference?

Yes — UV exposure directly stimulates melanin production and will counteract the effects of all other treatments. Daily broad-spectrum SPF 50 is not optional in any hyperpigmentation routine. It is the single most important step.

Can I use vitamin C and niacinamide together?

Yes. The historical concern that niacinamide and vitamin C interact to form nicotinic acid is not supported by evidence at the concentrations used in skincare. They can be used together or at different times of day.

What is ochronosis and how do I avoid it?

Ochronosis is a rare condition causing blue-black skin discolouration associated with prolonged, unsupervised use of high-concentration hydroquinone. It is avoided by using hydroquinone for 3–4 months at a time with 2–3 month breaks, and only under prescriber supervision. Contact your prescriber immediately if you notice blue-black discolouration.

Is tretinoin safe for darker skin tones?

Yes, but a more cautious approach is needed — lower starting strength, less frequent initial application, and careful monitoring for irritation-induced PIH. Discuss the appropriate protocol with your prescriber.

Can hyperpigmentation come back after treatment?

Yes, particularly melasma, which is hormonally driven and UV-aggravated. Ongoing sun protection and maintenance treatment are essential to prevent recurrence. Some patients require periodic treatment cycles rather than a single course.