Skin Pigmentation Causes Explained: Hormones, Medications, Sun Exposure, and Melasma

Skin pigmentation changes can feel frustrating and confusing, especially when dark patches or uneven tone appear without an obvious cause. Pigmentation concerns — including melasma, sun spots, and post-inflammatory hyperpigmentation — develop when melanocytes produce excess melanin in response to internal and external triggers. Hormonal shifts, certain medications, inflammation, and sun exposure can all influence how much pigment your skin produces and where it appears. Understanding these root causes is key to managing pigmentation effectively and preventing it from returning. By taking an inside-out approach that supports overall health alongside targeted skin care, it’s possible to achieve clearer, more even-looking skin over time.

Close-up of facial melasma showing hormonal pigmentation on the cheek

How Hormonal Changes Affect Skin Pigmentation

Melasma is strongly linked to hormonal fluctuations, which is why it often appears during pregnancy, while taking oral contraceptives, or during hormone replacement therapy. Changes in oestrogen and progesterone levels can increase the sensitivity of melanocytes — the pigment-producing cells in the skin.

When these hormones rise or fluctuate, melanocytes may become overstimulated and produce excess melanin, leading to the development of darker patches.

The liver plays an important supporting role in maintaining hormone balance. Although it does not produce hormones, it is responsible for processing and clearing excess hormones from the body. If these pathways are sluggish, hormones can recirculate rather than being efficiently eliminated, which may contribute to ongoing pigment stimulation.

Environmental compounds known as xenoestrogens can further add to the hormonal load. Found in some plastics, pesticides, and personal care products, these chemicals can mimic oestrogen in the body and interfere with natural hormone balance.

Supporting healthy hormone metabolism through balanced nutrition, hydration, and reducing exposure to endocrine-disrupting chemicals may help create a more stable internal environment, making hormonally driven pigmentation easier to manage.

How Medications and Other Factors Influence Skin Pigmentation

While hormones play a major role in skin pigmentation changes, certain medications and lifestyle factors can also make the skin more prone to developing dark spots and hyperpigmentation. Some medications increase the skin’s sensitivity to light or influence internal pathways linked to melanin production. These can include hormonal contraceptives, hormone replacement therapy, and medications that affect mood, inflammation, or immune function.

Inflammation is another important contributor to uneven skin pigmentation.

When the skin or body is under stress — whether from gut imbalance, chronic stress, illness, or skin barrier damage — melanocytes can become more reactive. This can lead to post-inflammatory hyperpigmentation, where dark marks remain after acne, irritation, or skin injury.

Genetics also influence how easily pigmentation develops. Some people naturally have more active melanocytes or are more prone to developing pigmentation and dark patches in response to triggers. Those with medium to deeper skin tones may notice pigmentation appears more easily or lingers for longer.

A weakened skin barrier can further worsen hyperpigmentation. Over-exfoliation, harsh skincare products, or untreated inflammation leave the skin more vulnerable to environmental triggers, increasing the likelihood of uneven pigment forming.

Certain medications, environmental toxins, and ongoing inflammation can also place extra demand on the liver, which is responsible for processing hormones, chemicals, and metabolic by-products. When the liver is under increased stress, this can contribute to a higher overall inflammatory load in the body. In facial mapping approaches such as Osmosis Skin Mapping, pigmentation or congestion in areas associated with liver function is sometimes viewed as a reflection of internal detoxification pathways needing additional support. While skin changes are not a diagnostic tool, they can provide helpful insight into patterns of internal stress that may be influencing pigmentation.

Addressing these underlying factors — calming inflammation, strengthening the skin barrier, supporting detoxification pathways, and being mindful of medication-related photosensitivity — can significantly improve how the skin responds to pigmentation treatment and help reduce the appearance of dark spots over time.

The Sun’s Role in Worsening Pigmentation

Sun exposure is one of the biggest external triggers for melasma and other forms of hyperpigmentation. Ultraviolet (UV) radiation stimulates melanocytes, the cells responsible for producing melanin. In skin that is already hormonally sensitised, this response becomes exaggerated, leading to the formation of darker, uneven patches.

Even small amounts of daily sun exposure — such as driving, walking outdoors, or sitting near windows — can worsen pigmentation over time. UV rays penetrate the skin and activate pigment production, while heat from the sun can further increase melanocyte activity, making melasma more persistent and difficult to fade.

It’s not just UV light that plays a role. Visible light (including blue light from screens and daylight) has also been shown to stimulate skin pigmentation, particularly in those prone to melasma or darker skin tones. This means consistent daily protection is essential, not just during long periods in direct sunlight.

Because hyper-pigmentation is triggered internally but activated externally, sun protection becomes one of the most important steps in managing pigmentation. Wearing a broad-spectrum SPF, reapplying throughout the day, and using protective measures such as hats and shade can significantly reduce flare-ups and help other treatments work more effectively.

Sunscreen and hat use are essential for preventing upper lip melasma and sun-induced pigmentation.

Why an Inside-Out Approach Works Best

Skin Pigmentation concerns like melasma and other forms of hyperpigmentation are rarely just surface-level issues. While topical treatments are important, long-term improvement happens when we address the internal factors that influence melanin production in the first place.

Hormonal balance, liver repair and detoxification pathways, inflammation levels, gut health, and stress all affect how reactive melanocytes become. When the body is under internal strain, pigment cells are more easily triggered, and dark patches can return quickly — even after successful treatment.

Supporting the body from within helps create a more stable environment for the skin. Nourishing whole foods, adequate hydration, healthy digestion, stress regulation, and targeted supplementation (when appropriate) can all help reduce inflammatory load and improve how the skin responds to treatment.

At the same time, strengthening the skin barrier is essential. A resilient barrier reduces inflammation, improves tolerance to active ingredients, and helps protect against environmental triggers that worsen pigmentation.

At SWAN, pigmentation is treated through a personalised inside-out protocol that combines advanced topical skin therapy with internal support for hormones, liver repair & detoxification, and skin barrier repair. This includes professional treatments and homecare guided by the science-based approach of Osmosis Skincare, alongside nutrition and lifestyle strategies tailored to your body’s needs.

By combining internal support with professional treatments and consistent sun protection, pigmentation can be managed more effectively and results are more likely to last. This integrated approach not only helps fade existing dark spots but also reduces the likelihood of new pigmentation forming.

Daily sunscreen and wearing a hat can help reduce sun-induced pigmentation and dark spots.

Simple Home Care Tips to Support Pigmentation

While professional treatments make a big difference, your daily routine plays an essential role in managing skin pigmentation and preventing dark spots from returning.

✔ Wear sunscreen every day Choose a broad-spectrum SPF and reapply if you’re outdoors. Pigmentation can worsen with even small amounts of UV and visible light exposure.

✔ Protect your skin from heat and sun Hats, shade, and avoiding peak sun hours can help reduce pigment stimulation, especially if you’re prone to melasma.

✔ Strengthen your skin barrier Use gentle, nourishing skincare rather than over-exfoliating. A healthy barrier reduces inflammation and makes pigment easier to treat.

✔ Be mindful of internal triggers Balanced meals, good hydration, stress management, and supporting digestion all help reduce the internal stress that can make pigmentation worse.

✔ Avoid picking or irritating the skin Inflammation from breakouts or overuse of active products can lead to post-inflammatory hyperpigmentation.

Pigmentation is complex, and what works for one person may not work for another. A personalised approach that considers your skin, health history, and lifestyle gives the best long-term results.

If you’re struggling with melasma or ongoing pigmentation, a personalised consultation can help uncover the triggers affecting your skin and create a treatment plan tailored to you.

Book a skin consultation at SWAN Skin Wellbeing and Nutrition to start your inside-out journey toward clearer, more even skin.