Hyperpigmentation: A Nutrition and Natural-Health Reference
1. Definition and Overview
Hyperpigmentation is a condition characterized by the darkening of an area of the skin or nails due to an excess production of melanin, the pigment responsible for skin color. Increased pigmentation results from an increase in melanin production and/or the number of melanocytes. It can also be secondary to exogenous substances or extravasation of chemicals deposited in the skin.
Hyperpigmentation is associated with numerous dermatological disorders and can present in various forms, such as melasma, post-inflammatory hyperpigmentation, and lentigines. It tends to be more prevalent and persistent in individuals with darker skin tones, who have more active melanocytes and are thus more prone to uneven pigmentation.
Disorders of hyperpigmentation are common and, depending on the extent and location of involvement, can affect the quality of life and pose a significant psychologic burden for patients. Patients' physical appearance, psychological health, and social functioning are all impacted by a sizable number of skin conditions that cause pigmentary abnormalities.
2. Clinical Presentation
Hyperpigmentation may be localized, as in the case of post-inflammatory hyperpigmentation or melasma, or more diffuse in its presentation. Diffuse hyperpigmentation tends to be associated with metabolic causes, certain medications, malignancy, or autoimmune or infectious etiologies.
Epidermal hyperpigmentation appears light to dark brown, whereas dermal hyperpigmentation may have a blue-gray coloration due to the Tyndall effect. Researchers have subdivided hyperpigmentation disorders into epidermal, dermal, or mixed epidermal-dermal disorders based on the location of pigment deposition, along with disorders of hyperpigmentation of the mucosa and nails.
Melasma consists of dark brown, roughly symmetric patches of hyperpigmentation with irregular borders on the face — usually on the forehead, temples, cheeks, cutaneous upper lip, or nose — and occurs primarily in pregnant women (melasma gravidarum, also called the mask of pregnancy) and in women taking oral contraceptives. Focal linear hyperpigmentation is commonly due to phytophotodermatitis, a phototoxic reaction that results from ultraviolet (UV) light combined with psoralens (specifically furocoumarins) in plants such as limes, parsley, and celery.
3. Body Systems Involved
3.1 The Skin and Melanocyte-Keratinocyte Unit
Melanocytes are pigment-producing, neural crest-derived cells that reside in the basal layer of the skin. In normal skin, roughly every tenth cell in the basal layer is a melanocyte, and each melanocyte communicates with 30–40 neighbouring keratinocytes.
Melanosomes are unique organelles located in the cytoplasm of melanocytes, which contain key enzymes regulating the production of pigments such as tyrosinase (TYR), tyrosinase-related protein-1 (TYRP-1) and tyrosinase-related protein-2 (TYRP-2). Activation of the transcription factor microphthalmia-associated transcription factor (MITF) results in the upregulation of the expression of key genes such as TYR, TYRP-1 and TYRP-2, and promotes melanogenesis in melanocytes.
Sequential enzymatic reactions within the melanocytes convert the amino acid tyrosine into either form of melanin: eumelanin and pheomelanin. Keratinocytes residing in the skin epidermis release various paracrine signals — including α-melanocyte stimulating hormone (αMSH), adrenocorticotropic hormones (ACTH), stem cell factor (SCF), and endothelin-1 (ET-1) — that trigger melanogenesis in the neighbouring melanocytes. The αMSH, being the major signal, binds to the receptor MC1R on melanocytes, which in turn activates the cAMP/CREB key signaling cascade to trigger the transcriptional activation of key genes of the melanogenesis pathway, including MITF, tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase (DCT).
Mature melanosomes can migrate from the perinuclear region to the dendrites of the melanocyte, and in the epidermis, melanocytes are associated with 30 to 40 keratinocytes through dendrites, transferring mature melanosomes into the cytoplasm of keratinocytes.
3.2 Oxidative Stress Pathways
In response to signals from cytokines, infection, UV radiation, cosmetics, and drugs, melanocytes and keratinocytes produce reactive oxygen species (ROS), including superoxide anion, peroxides, hydroxyl radicals, and singlet oxygen, in the process of activating NADPH oxidases, the mitochondrial electron transport chain, nitric oxide synthases, and other enzymes. Oxidative stress, significantly present in both vitiligo and melasma, triggers inflammatory cascades and melanogenesis, making antioxidants a promising therapeutic avenue.
In melasma, serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), and blood glutathione are significantly higher than those of controls.
3.3 Endocrine and Hormonal Systems
Various factors, such as UV radiation, inflammation, hormones, and free radicals, induce the secretion of α-MSH in keratinocytes; this hormone enhances the function of the α-MSH–MC1R signaling pathway and promotes melanogenesis. Hyperpigmentation or hypermelanosis disorders due to environmental stressors, such as hormonal imbalance, can also affect melanin or pigmentation levels in the skin.
4. Contributing and Associated Factors
4.1 Ultraviolet Radiation
It is widely understood that sun exposure is a contributing factor in the formation and appearance of hyperpigmentation disorders and that photoprotection should be paramount to the management of these conditions. Chronic exposure to UV rays affects the function of melanocytes, leading to irregular melanin production which is evident in solar lentigines (age spots), melasma, and additional types of hyperpigmentation.
4.2 Inflammation and Post-Inflammatory Hyperpigmentation (PIH)
Post-inflammatory hyperpigmentation (PIH) represents the sequelae of various cutaneous disorders, including infections, allergic reactions, mechanical injuries, reactions to medications, phototoxic eruptions, trauma (e.g., burns), inflammatory diseases (e.g., lichen planus, lupus erythematosus and atopic dermatitis), as well as reactions to devices including electromagnetic devices such as lasers and microdermabrasion.
PIH is a pathophysiologic response to cutaneous inflammation. Melanocytes can be stimulated by the inflammatory process to synthesize and secrete more melanin, or the number of melanocytes can increase in the epidermis, leading to hyperpigmentation of the skin. PIH can also occur when inflammation disrupts the basal cell layer, causing melanin pigment to be released and subsequently trapped by macrophages in the papillary dermis.
4.3 Hormonal and Endocrine Factors
Hyperpigmentation is associated with Addison's disease and other sources of adrenal insufficiency, in which hormones that stimulate melanin synthesis are frequently elevated; acanthosis nigricans, or hyperpigmentation of intertriginous areas associated with insulin resistance; and patchy hyperpigmentation often found in pregnant women (melasma). Melasma occurs primarily in pregnant women and in women taking oral contraceptives and is more prevalent among and lasts longer in people with dark skin.
4.4 Systemic Diseases and Metabolic Conditions
Hyperpigmentation related to systemic disorders includes metabolism/enzyme disorders (hemochromatosis, Wilson's disease, Gaucher's disease, Niemann-Pick's disease, amyloidosis, ochronosis, acanthosis nigricans, and porphyria cutanea tarda), endocrine disorders (Addison's disease, Cushing syndrome, and hyperthyroidism), nutritional disorders (pellagra, vitamin B12 deficiency, folic acid deficiency, vagabond's disease, and prurigo pigmentosa), mastocytosis, collagen diseases, liver dysfunction, and kidney dysfunction. Hyperpigmentation can also be related with infectious diseases (measles, syphilis, and Malassezia furfur) and syndromes including von Recklinghausen's disease, McCune-Albright syndrome, and Bloom syndrome.
4.5 Genetic Factors
Human skin pigmentation and melanin synthesis are incredibly variable, and are impacted by genetics, UV exposure, and some drugs. The etiology of hyperpigmentation disorders emphasizes the role of genetics, environmental factors, and inflammatory responses in their development.
4.6 Medications and Exogenous Substances
Diffuse hyperpigmentation can result from medications and also has systemic and neoplastic causes (especially lung carcinomas and melanoma with systemic involvement). Certain drugs and heavy metals can also cause hyperpigmentation.
4.7 Lifestyle Factors
Lack of sleep, use of contact lenses, alcohol overuse, excessive consumption of soda or caffeine, and smoking are lifestyle factors that can contribute to the development of periorbital hyperpigmentation; the etiology seems to stem from various factors including genetics, sun exposure, allergies, facial anatomy — specifically orbital hollowing — and vasculature.
5. Nutritional Deficiencies Associated with Hyperpigmentation
5.1 Vitamin B12 Deficiency
Skin pigmentation is a common manifestation in nutritional deficiencies and is frequently associated with deficiency of vitamin B12. Published case reports in PMC document a well-characterized clinical pattern: serum vitamin B12 levels can be reduced to levels such as 132 pg/mL (reference range 197–771 pg/mL), with peripheral blood smear showing normocytic anemia and hyper-segmented neutrophils, leading to a diagnosis of vitamin B12 deficiency manifesting as cutaneous pigmentation.
Treatment with intramuscular vitamin B12 (cyanocobalamin) injections followed by oral supplementation raised serum B12 levels and resulted in marked improvement of cutaneous hyperpigmentation by 3 months, while neurological symptoms improved within 4–6 weeks.
However, the relationship is not universal for all forms of hyperpigmentation. A case-control study examining 51 women with melasma versus 51 controls found that comparing the frequency of vitamin B12 deficiency between the case and controls revealed a nonsignificant association between melasma and vitamin B12 deficiency. Mean levels of ferritin, hemoglobin, MCV, iron, vitamin B12, TIBC, and folate were not statistically different between groups. This illustrates that vitamin B12 deficiency hyperpigmentation is a distinct clinical entity, separable from hormonally-driven melasma.
5.2 Folate (Vitamin B9) Deficiency
Folate assists with red blood cell development and skin cell regeneration. Folic acid deficiency is listed among the nutritional disorders associated with hyperpigmentation, though current clinical evidence linking isolated dietary folate deficiency as a direct driver of skin hyperpigmentation is limited to case-series and mechanistic observations.
5.3 Pellagra (Niacin/Vitamin B3 Deficiency)
Pellagra — a niacin deficiency disease — is among the recognized nutritional disorders associated with hyperpigmentation. Pellagra classically manifests with the triad of dermatitis (including photosensitive hyperpigmentation), diarrhea, and dementia, and has been described in populations with severe dietary niacin and tryptophan deficiency.
5.4 Iron and Other Mineral Considerations
Evidence has suggested that hyperpigmentation can occur as a result of iron deficiency anemia and vitamin B12 deficiency. In the case-control study of melasma patients referenced above, the women in the melasma group had a higher frequency of below-normal range ferritin and serum iron compared to the control group, though these differences did not reach statistical significance as independent predictors.
6. Nutrients, Herbs, and Natural Ingredients
The following section distinguishes between traditional (historical and ethnobotanical) use and scientific evidence. Review of the literature has revealed few clinical trials that evaluated the treatment of hyperpigmentation with natural ingredients. Despite their increasing use, many lack in-vivo and/or in-vitro studies to validate their efficacy. Where evidence exists, study type, population, outcome, and limitations are described.
6.1 Ascorbic Acid (Vitamin C)
Traditional Use: Vitamin C–rich plant foods (citrus, rosehips, amla/Indian gooseberry) have long been used in Ayurvedic and traditional Chinese medicine for skin brightening and complexion improvement, administered both topically and orally.
Scientific Evidence: Vitamin C is a naturally occurring antioxidant that interacts with copper ions at the tyrosinase active site and acts as a reducing agent at various oxidative steps of melanin formation, hence inhibiting melanogenesis. The reduced tyrosinase activity mediated by vitamin C appears to be caused by antioxidant activity, not by direct inhibition of tyrosinase activity. Topical vitamin C products derived from fruits and vegetables are unstable, resulting in questionable efficacy.
For melasma, vitamin C was among those ingredients showing promise in reducing pigmentation, with vitamin C displaying significant effects in meta-analysis. The evidence base, while growing, consists largely of small trials; larger rigorous randomized controlled trials (RCTs) are still needed to establish optimal formulations, doses, and duration.
6.2 Niacinamide (Nicotinamide / Vitamin B3)
Traditional Use: Niacinamide does not have a classical ethnobotanical history as a skin-lightening agent per se; its topical use for hyperpigmentation is a modern cosmeceutical development from biochemical research.
Scientific Evidence: Supplementation of nicotinamide restores the cellular NAD+ pool and mitochondrial energetics, attenuates oxidative stress and inflammatory response, enhances extracellular matrix and skin barrier, and inhibits the pigmentation process in the skin. Rather than blocking pigment production, niacinamide interferes with pigment delivery — specifically the transfer of melanosomes from melanocytes into the keratinocytes visible on the surface.
Clinical trials using 2% niacinamide have shown that it significantly reduces the total area of hyperpigmentation and increases skin lightness after 4 weeks of treatment. A clinical trial involving 24 women with hyperpigmented axillae compared emulsions containing 4% nicotinamide or 0.05% desonide (a low-potency corticosteroid) applied for 9 weeks; both nicotinamide and desonide improved skin lightness compared with placebo, and the former was slightly less effective than the latter. Niacinamide has shown clinical efficacy in treating facial and axillary hyperpigmentation in two separate RCTs.
6.3 Kojic Acid
Traditional Use: Kojic acid is a naturally occurring fungal metabolite produced during the fermentation of certain foods (sake, soy sauce, rice wine) in East Asian food traditions. Its skin-lightening properties were first noted in Japan. It is not a classical herbal remedy but emerged from observation of traditional fermentation processes.
Scientific Evidence: Kojic acid is a tyrosinase inhibitor. A preliminary study conducted on 12 patients with post-acne skin reported that kojic acid reduces skin discoloration by increasing skin brightness in 75% of patients tested, reducing skin contrast in approximately 83%, and increasing skin homogeneity in approximately 67% of patients. This study was small and preliminary in design. Controlled trials on treating hyperpigmentation are lacking; however, several studies have shown that arbutin is less effective than kojic acid for hyperpigmentation. The overall evidence base for topical kojic acid consists primarily of small comparative studies, and larger, well-controlled trials are needed.
6.4 Licorice Root (Glycyrrhiza glabra)
Traditional Use: Licorice root has been used for millennia in traditional Chinese medicine, Ayurveda, and ancient Greek medicine. In many Asian traditions, it was applied topically or consumed as a decoction for skin complaints and as a general tonic. Glycyrrhiza glabra, commonly known as licorice root, has long been used in both traditional and modern medicine due to its active compounds such as glabridin, which possesses antioxidant and tyrosinase-inhibiting properties.
Scientific Evidence: Licorice extract contains liquiritin, which disperses melanin, and glabridin, an ROS scavenger and tyrosinase inhibitor. Licorice extract improves hyperpigmentation by dispersing the melanin, inhibiting melanin biosynthesis, and inhibiting cyclooxygenase activity, thereby decreasing free radical production.
Multiple RCTs show that licorice extract components have clinical efficacy in treating melasma and UVR-induced pigmentation. In vitro studies have shown that glabridin has 16 times the skin lightening effects of hydroquinone. In a single-center, double-blind clinical study of 18 subjects comparing the efficacy of a hydroquinone-free formula containing glabridin, there was a significant reduction in ultraviolet-induced hyperpigmentation compared with both the negative control and 4% hydroquinone cream. Furthermore, in a single-blinded study comparing the efficacy of belides, emblica, and licorice 7% to 2% hydroquinone in the treatment of melasma, the degree of depigmentation in both groups was not statistically different. Evidence is encouraging but limited by small sample sizes and heterogeneous formulations.
6.5 Arbutin (from Bearberry and Other Plants)
Traditional Use: Arbutin is a glycoside naturally found in bearberry (Arctostaphylos uva-ursi), cranberry, and pear skin. Bearberry has been used in traditional European and Native American herbal medicine as a urinary antiseptic; its skin-lightening potential is a modern cosmeceutical application.
Scientific Evidence: Arbutin functions as a tyrosinase inhibitor. In a single RCT, aloesin was found effective at treating UVR-induced pigmentation both independently and synergistically with arbutin. The overall clinical evidence base for arbutin alone remains limited; controlled trials on treating hyperpigmentation are lacking, and several studies have shown that arbutin is less effective than kojic acid for hyperpigmentation.
6.6 Ellagic Acid
Traditional Use: Ellagic acid is a polyphenol present in pomegranates, strawberries, raspberries, grapes, and walnuts — all of which have traditional use in various healing traditions for skin health. Its isolation and specific application to hyperpigmentation is a contemporary development.
Scientific Evidence: Various plant-derived flavonoids still under investigation include catechin conjugated with gallic acid (from green tea leaves) and ellagic acid (from green tea, eucalyptus, strawberry, and others). Ellagic acid is a tyrosinase inhibitor that can successfully treat melasma, as well as hyperpigmentation and dark spots. A 2026 pilot observational study tested a sunscreen formulation containing ellagic acid, niacinamide, and Polypodium leucotomos extract in 20 women with melasma or sun-induced hyperpigmentation over 12 weeks; baseline MASI scores decreased by 44% from baseline (p = 0.0001). This pilot proof-of-concept study suggested the combination may reduce melasma severity with excellent tolerability; however, the findings warrant confirmation in larger controlled trials. The evidence is preliminary and confounded by the multi-ingredient formulations used in most studies.
6.7 Soy (Glycine max)
Traditional Use: Soy-based products including soymilk, tofu, and fermented preparations have been dietary staples in East Asian cultures for thousands of years and have been applied topically in certain traditional cosmetic preparations.
Scientific Evidence: Soy contains active ingredients including isoflavones, vitamin E, and serine protease inhibitors — soybean trypsin inhibitor (STI) and Bowman-Birk protease inhibitor (BBI). The BBI and STI components inhibit the PAR-2 pathway, which mediates melanosome transfer from melanocytes to keratinocytes. Several skin care products containing soy are available to improve hyperpigmentation; skin lightening benefit can be seen after 12 weeks of twice daily application, and the de-pigmenting effect of soymilk is reversible, with daily topical treatments for 7 months showing no adverse effects. Of the Asian botanical ingredients reviewed in one evidence-based analysis, soy and licorice had the most clinical evidence supporting their efficacy, while all other ingredients were supported by in vitro studies only.
6.8 Green Tea (Camellia sinensis) and Epigallocatechin Gallate (EGCG)
Traditional Use: Green tea has been consumed in China, Japan, and Korea for over two millennia. Traditional Chinese medicine employed it for its anti-inflammatory and "clearing" properties, including for skin conditions. Topical preparations from green tea infusions represent an extension of these traditions.
Scientific Evidence: Green tea extracts contain polyphenolic compounds that act on various biochemical pathways, causing anti-inflammatory, antioxidant, and anti-carcinogenic effects; epigallocatechin-3-gallate (EGCG) is the main active ingredient. Studies have shown that green tea extracts cause in vitro inhibition of mushroom tyrosinase, which may be responsible for the de-pigmenting effect; however, more in vivo studies are needed to substantiate this action. Evidence for green tea's effect on human skin hyperpigmentation remains largely in vitro and preclinical; clinical RCT data specific to hyperpigmentation are limited.
6.9 Turmeric (Curcuma longa)
Traditional Use: Turmeric has been used in Ayurvedic and South and Southeast Asian traditional medicine for thousands of years. Topical turmeric pastes (combined with milk, yogurt, or honey) have traditionally been applied to the skin to improve complexion and reduce blemishes. Oral consumption as a spice and tonic is integral to South Asian culinary traditions.
Scientific Evidence: Evidence-based data support the clinical utility of turmeric as one of several natural compounds for the treatment of hyperpigmentation, though evidence quality is variable. In vitro data indicate that curcumin, turmeric's principal bioactive polyphenol, inhibits tyrosinase activity and has potent antioxidant effects. The systematic review of clinical studies found few clinical trials that evaluated the treatment of hyperpigmentation with natural ingredients including turmeric specifically. Clinical evidence for oral or topical curcumin/turmeric in hyperpigmentation remains preliminary, with most supportive data coming from in vitro and animal studies.
6.10 Aloesin (from Aloe vera)
Traditional Use: Aloe vera gel has been used for millennia across African, Mediterranean, and Asian cultures as a topical remedy for burns, skin wounds, and inflammatory skin conditions.
Scientific Evidence: Aloesin is a natural derivative of aloe vera that inhibits tyrosinase at non-cytotoxic concentrations and is a competitive inhibitor of DOPA oxidation and a non-competitive inhibitor of tyrosine hydroxylase activity. In a single RCT, aloesin was found effective at treating UVR-induced pigmentation both independently and synergistically with arbutin. Aloesin remains an experimental product and is not widely available clinically.
6.11 Mulberry (Morus alba)
Traditional Use: White mulberry root bark (Morus alba root bark extract) has been used in traditional Chinese medicine as a skin-brightening ingredient in topical preparations for centuries, appearing in classical formularies for facial cosmetics.
Scientific Evidence: Mulberry is an ROS scavenger with tyrosinase and other melanogenesis-inhibitory properties; one RCT showed that 7% mulberry extract is beneficial in treating melasma. Clinical evidence is promising but limited to small single trials; larger replication studies are needed.
6.12 Polypodium Leucotomos (Calaguala Fern)
Traditional Use: Polypodium leucotomos is a tropical American fern used in traditional Central American medicine for inflammatory skin and atopic conditions.
Scientific Evidence: The aqueous extract of the fern Polypodium leucotomos (PLE) has demonstrated antioxidant and photoprotective activities and has been used for the treatment of several pigmentary disorders. Based on a review of relevant literature including the results of a randomized, placebo-controlled study, the oral administration of Polypodium leucotomos significantly improved the severity of melasma in women. A double-blind, placebo-controlled pilot trial in Asian patients (N=40) treated with topical 4% hydroquinone plus either oral PLE or placebo for 12 weeks found an average improvement of Melasma Area and Severity Index (mMASI) score in both groups compared to baseline. No controlled studies have assessed the efficacy of Polypodium leucotomos specifically for post-inflammatory hyperpigmentation; however, no adverse events have been associated with its use. Evidence is promising but limited by small sample sizes and concurrent use of other interventions in most trials.
6.13 Azelaic Acid
Traditional Use: Azelaic acid is a naturally occurring dicarboxylic acid found in grains such as wheat, rye, and barley. It is produced by Malassezia furfur (a yeast naturally present on skin). Its skin-lightening properties were identified via scientific investigation rather than through classical herbal tradition.
Scientific Evidence: Two RCTs showed that azelaic acid (AzA) can be used to treat melasma and PIH. Azelaic acid functions as a tyrosinase inhibitor and has additional anti-inflammatory properties. Azelaic acid is among the natural ingredients that act via tyrosinase inhibition to reduce pigmentation. The clinical evidence for azelaic acid in hyperpigmentation is among the stronger of the naturally derived agents reviewed in the systematic literature.
6.14 Vitamin E (Tocopherol)
Traditional Use: Vitamin E–rich plant oils (wheat germ, sunflower, almond) have been applied topically in various folk healing traditions for wound healing and skin nutrition. Its specific use for hyperpigmentation is a modern application.
Scientific Evidence: Alpha-tocopheryl ferulate (α-TF), a derivative of vitamin E, has been shown to effectively inhibit melanin production in both melanoma cells and normal melanocytes, offering a protective effect against UV-induced hyperpigmentation; it also prevents oxidative DNA damage. Vitamin E has a strong antioxidative effect in human melanocytes by scavenging free radicals, stabilizing carotenoids, and protecting against UVA-induced oxidative damage, thereby inhibiting excessive melanin production and helping to prevent DNA damage caused by oxidative stress. Nonenzymatic antioxidants including vitamin C, vitamin E, coenzyme Q10, carotenoids, glutathione, and ubiquinol represent the cellular defense arsenal against ROS in the skin. Clinical RCT evidence for vitamin E as a standalone agent for hyperpigmentation in humans is limited.
6.15 Carotenoids (Beta-Carotene, Lutein, Zeaxanthin)
Traditional Use: Carotenoid-rich foods — carrots, pumpkin, paprika, tomatoes, leafy greens — have been recognized in many traditional health systems as "skin foods," valued for their ability to impart a healthy complexion. Their specific effects on hyperpigmentation were not isolated in pre-scientific traditions.
Scientific Evidence: Carotenoids possess the ability to quench singlet oxygen, protect against UV-induced ROS generation, and decrease antioxidant enzyme activities and membrane perturbation. Topical application of beta-carotene lotion decreases melasma intensity index and lesion size. A randomized, double-blinded, placebo-controlled clinical trial compared subjects with oral lutein/zeaxanthin treatment to a placebo group; results revealed skin lightening effects within the treated cohort, which may be related to tyrosinase inhibition and increased antioxidant capacity; however, oral lutein/zeaxanthin treatment had minimal effects in terms of PIH and long-term UV exposure. Evidence is preliminary; effects observed are modest and formulation-dependent.
7. Dietary and Lifestyle Factors
7.1 Sun Exposure and Photoprotection
The physiopathology of melasma includes a complex interaction between genetics, sex hormones, and sun exposure. Oxidative stress induced by UVA and visible light may play a role in the pathophysiology of melasma by altering the dermal component. Photoprotection through broadband sunscreens is widely established as the cornerstone of managing photoaccentuated hyperpigmentation.
7.2 Antioxidant-Rich Diet
ROS are produced through external factors such as UV exposure and during melanogenesis; oxidative stress in melasma represents the multifactorial damage of melanocytes as deficient antioxidative mechanisms. The dietary antioxidant defense system — encompassing vitamins C and E, carotenoids, polyphenols, and glutathione precursors — has been discussed in the literature as a potential modifier of this oxidative burden.
7.3 Hormonal Modulators in Diet
Melasma is caused by focal hypermelanogenesis triggered through multiple factors, including a genetic predisposition, sun exposure, hormonal stimuli, increased vascularity, and skin inflammation. Dietary phytoestrogens (from soy and legumes), which interact with estrogen receptors, have been discussed in this context; however, clinical evidence directly linking dietary phytoestrogen intake to changes in hormonally driven melasma in humans is not well established in the current literature.
7.4 Inflammation-Modifying Diet
Pro-inflammatory dietary patterns may perpetuate conditions that promote PIH. Hyperpigmentation disorders are influenced by numerous endogenous and exogenous factors impacting melanocyte activity and melanin production. Dietary strategies targeting systemic inflammation through the reduction of refined carbohydrates, processed foods, and a higher intake of omega-3 fatty acids and polyphenol-rich vegetables are discussed in broader dermatological nutrition literature; however, human interventional evidence specific to hyperpigmentation reduction is not yet conclusive.
7.5 Lifestyle and Sleep
Lack of sleep, alcohol overuse, excessive consumption of soda or caffeine, and smoking are lifestyle factors that can contribute to the development of periorbital hyperpigmentation. Chronic psychological stress, through its effects on cortisol and catecholamine pathways, has also been hypothesized to promote melanogenesis. Catecholamines can promote melanogenesis through the cAMP/PKA pathway, while also mediating melanogenesis through the activation of PKC-β pathways by α1 and β2 adrenergic receptors.
8. Evidence Summary and Limitations
Systematic searches of PubMed and SCOPUS databases for clinical studies evaluating the use of different natural products in treating hyperpigmentation revealed few clinical trials. Despite limited evidence-based research, several natural ingredients did show efficacy as depigmenting agents, including azelaic acid, soy, lignin peroxidase, ascorbic acid iontophoresis, arbutin, ellagic acid, and licorice.
Most trials reviewed are small (commonly fewer than 30 subjects), of short duration, conducted in single centers, and often use combination formulations that make it difficult to attribute effects to any single ingredient. The literature reveals relatively few clinical studies — including six RCTs — that evaluated the topical management of hyperpigmentation using natural ingredients specifically in defined populations. Many potentially active botanical compounds have been investigated only in vitro or in animal models and have not yet been validated in rigorous human clinical trials. Characterizing evidence as "promising" or "preliminary" is therefore appropriate for the majority of agents described in this article, with the exceptions of niacinamide, azelaic acid, and licorice, which have the most consistently supportive clinical evidence base.
References
Go back