Fiebre

Aloe vera has demonstrated in vitro stimulation of dermal papilla cell proliferation (~25%) and has been studied in hair loss RCTs as part of herbal combinations. A 2025 systematic review of 16 RCTs identified aloe vera among natural products with promising clinical efficacy for promoting hair growth. It also has a long traditional use in Ayurveda and folk medicine for scalp and hair health.

Azelaic acid is a naturally occurring dicarboxylic acid (found in grains) with demonstrated 5-alpha reductase inhibitory activity. It reduces DHT production in follicles and has been used in topical formulations for androgenetic alopecia. It is also synergistic with zinc and B6 in inhibiting 5-alpha reductase in vitro.

Beta-sitosterol is a phytosterol found in saw palmetto, pumpkin seed oil, and numerous plants. It inhibits 5-alpha reductase, reducing DHT levels linked to androgenetic alopecia. A randomized double-blind placebo-controlled trial demonstrated that a combination of saw palmetto and beta-sitosterol significantly improved hair density by blind expert assessment versus placebo.

Topical caffeine has been studied in human in vitro and clinical settings for androgenetic alopecia. It counteracts testosterone-induced suppression of hair follicle growth, stimulates hair shaft elongation in organ culture, and a clinical study found topical caffeine solution non-inferior to 5% minoxidil solution over 24 weeks. It is used in various topical hair loss products.

Camellia sinensis (the tea plant, source of green, white, oolong, and black tea) provides EGCG and other catechins that inhibit 5-alpha reductase and stimulate hair follicle dermal papilla cell proliferation. It is cited in systematic reviews of herbal RCTs for hair loss as a promising natural agent.

Capsaicin combined with isoflavones was evaluated in a double-blind placebo-controlled clinical trial and found to significantly improve total hair count in patients with alopecia areata, androgenetic alopecia, and alopecia totalis. The mechanism involves capsaicin-induced increase in IGF-1 production by sensory nerves, which promotes follicle growth.

Reduced catalase activity in scalp hair follicles leads to millimolar accumulation of H₂O₂, which bleaches hair from within and disrupts melanin synthesis. This mechanism underlies both age-related hair graying and is associated with androgenic alopecia. A pseudocatalase compound has been trialed in vitiligo and gray hair reversal.

Collagen peptides provide amino acids—particularly proline, glycine, and hydroxyproline—that support the dermal matrix surrounding hair follicles. A systematic review found collagen peptides improve the clinical appearance, strength, and brittleness of hair. Collagen also constitutes the connective tissue sheath anchoring follicles, and its degradation with aging is associated with follicle miniaturization.

Cystine, the oxidized dimer of cysteine, directly constitutes the disulfide crosslinks in hair keratin that determine shaft strength and integrity. Oral cystine supplementation—particularly in European combination products (cystine + B-vitamins)—has been evaluated in RCTs for diffuse hair loss with positive results in hair density and pull-test scores.

Cuscuta reflexa extracts have been studied in preclinical models for hair loss, demonstrating promotion of follicular proliferation and reduced hair loss in cyclophosphamide-induced alopecia in rats. Effects in testosterone-induced alopecia have also been reported. The genus is documented among traditional anti-hair-fall agents.

Eclipta alba (bhringraj) has been used in Ayurvedic and Chinese medicine for over 1,000 years to promote hair growth. Preclinical studies demonstrate its methanol extract induces anagen in telogen-phase follicles—outperforming minoxidil in animal models. Human observational studies report >75% reduction in hair loss. Eclipta alba is among the best-studied Ayurvedic hair botanicals.

EGCG, the major polyphenol of green tea, promotes hair growth by stimulating proliferation and inhibiting apoptosis of dermal papilla cells, and selectively inhibiting 5-alpha reductase. In vitro and in vivo studies confirm these mechanisms. A systematic review of 16 RCTs identified green tea among the natural products with meaningful evidence for hair loss.

A randomized, placebo-controlled clinical trial demonstrated successful treatment of low-to-moderate androgenetic alopecia with a fenugreek seed extract supplement in both men and women. A review of the evidence base for fenugreek in androgenetic alopecia confirms clinical and preclinical support, with topical and oral applications studied.

Forsythiaside A from Forsythia suspensa has been studied in a preclinical androgenic alopecia mouse model, showing significant protective effects on hair follicle density, thickness, and anagen/telogen ratio compared to both DHT-treated controls and finasteride. The compound inhibits DHT-induced apoptosis in human hair dermal papilla cells in vitro. No human clinical trials exist.

Panax ginseng and its ginsenosides have demonstrated hair growth-promoting effects by preventing apoptosis of dermal papilla cells, inhibiting 5-alpha reductase, and activating the Wnt/beta-catenin pathway. Korean red ginseng extract has been studied in RCTs for alopecia areata. A mini-review of ginseng RCTs in postmenopausal women reported 20–40% follicle proliferation via ginsenosides.

Ginsenosides are the primary bioactive saponins of Panax ginseng, directly responsible for its hair growth-promoting effects. They stimulate dermal papilla cell proliferation, inhibit 5-alpha reductase, suppress follicle apoptosis, and activate Wnt/beta-catenin and Shh/Gli pathways. RCTs using ginsenoside-standardized Korean red ginseng extract have shown efficacy in alopecia areata.

The 2024 clinical study documenting hair growth improvements in women with hair loss directly addresses hair loss as the study population. Traditional use of amla for preventing hair fall is one of its most extensively documented applications in Ayurvedic medicine.

Green tea (Camellia sinensis) and its principal catechin EGCG inhibit 5-alpha reductase, stimulate dermal papilla cell proliferation, and suppress TGF-beta-mediated follicle apoptosis. It appears in a 2025 systematic review of 16 RCTs for herbal hair remedies as one of the natural products showing promising clinical efficacy. Traditional use in East Asia for scalp and hair health is well-documented.

Impatiens balsamina has been used in traditional Chinese and Thai medicine for hair loss, and laboratory research has identified steroid 5-alpha reductase (5αR) inhibitory compounds within the plant. A bisnaphthoquinone derivative was identified as a testosterone 5α-reductase inhibitor (Ishiguro et al., 2000), directly relevant to androgenetic alopecia.

Hair loss (telogen effluvium) is a well-recognised manifestation of both hypothyroidism and hyperthyroidism, both of which can be caused by abnormal iodine status. Iodine deficiency reduces thyroid hormone synthesis, shifting hair follicles into telogen phase. Excessive iodine can paradoxically trigger hyperthyroidism and a different mechanism of follicular damage. Thyroid hormone receptors are directly expressed in hair follicles.

Iron deficiency is one of the best-established nutritional causes of hair loss, particularly telogen effluvium and diffuse alopecia in women. Low ferritin restricts oxygen delivery to the hair bulb, impairing follicle activity. Multiple systematic reviews confirm iron and ferritin deficiency are strongly associated with non-scarring alopecia, and clinical guidelines recommend supplementation in documented deficiency.

Isoflavones (phytoestrogens from soy and other legumes) have anti-androgenic properties including 5-alpha reductase inhibition and androgen receptor modulation. Combined with capsaicin, they significantly improved hair count in a double-blind RCT in alopecia patients. Equol (a soy isoflavone metabolite) specifically inhibits DHT binding to hair follicle receptors.

Keratin hydrolysate supplementation provides the structural protein substrate of the hair shaft, including key sulfur-containing amino acids cysteine and methionine. A systematic review noted solubilized keratin improves the clinical appearance, strength, and brittleness of hair. Keratin proteins also play a direct role in follicle structure and differentiation.

L-cysteine is the primary sulfur-containing amino acid in keratin and the rate-limiting substrate for hair shaft synthesis. A clinical trial included L-cysteine combined with medicinal yeast and pantothenic acid demonstrated benefits for diffuse hair loss. Cysteine deficiency contributes to weakened, brittle hair.

L-cystine (the oxidized dimer of cysteine) is the form of cysteine predominantly found incorporated into the hair shaft's disulfide bonds, directly constituting the structural integrity of keratin. Supplementation is traditionally linked to hair strength and thickness, and combination products containing L-cystine have been used in controlled trials for diffuse hair loss.

Lavender oil has demonstrated hair growth promotion in preclinical models, with topical application in mice showing significant increases in hair follicle number and depth comparable to minoxidil. Combined with rosemary oil, it showed statistically significant improvements in hair growth rate, thickness, density, and hair fall reduction in a 2025 RCT (PMC12256010).

Millet seed oil activates the β-catenin signaling pathway and promotes hair follicle proliferation in both animal models and human dermal papilla cells, suggesting therapeutic potential for androgenetic alopecia. The phytosterol miliacin in millet seed oil reduces telogen-phase hair density in clinical trials. These findings make millet seed oil a candidate treatment for hair loss.

MSM provides bioavailable organic sulfur necessary for keratin disulfide bond formation in the hair shaft—approximately 14% of cysteine in hair contains sulfur atoms that form these bonds. Preliminary clinical data suggest MSM at 1–3 g/day may improve hair thickness and growth rate within 8–12 weeks. Mechanistic rationale is strong, though large-scale RCTs are limited.

Omega-3 fatty acids (EPA and DHA) have anti-inflammatory effects that reduce perifollicular inflammation triggering catagen. A 2016 double-blind clinical trial found omega-3/omega-6 supplementation with antioxidants significantly reduced hair loss (89.9% improvement) and improved hair density in women with female pattern hair loss over 6 months.

Topical onion juice has been studied in a clinical trial for alopecia areata, showing hair regrowth in 86.9% of patients versus tap water controls at 8 weeks (Sharquie et al., 2002). The active components are believed to include sulfur compounds and quercetin with anti-inflammatory properties. However, the single published trial had methodological limitations and has not been replicated.

Multiple preclinical studies have established hair growth-promoting effects of P. orientalis leaf extract in human dermal papilla cell models and mouse models, supporting its potential for addressing hair loss broadly. TCM also records the plant as a classical remedy for alopecia. Mechanisms include ACK1 activation, Wnt/β-catenin pathway stimulation, and upregulation of hair growth factors.

Several clinical studies report that oral D-panthenol improved female pattern hair loss and male androgenetic alopecia. A PubMed case series (PMID 32255530) found marked improvement in 9 male androgenetic alopecia cases treated with dexpanthenol. In vitro work published in PMC confirmed D-panthenol promotes hair follicle cell growth by preventing senescence and apoptosis.

Peppermint oil has been shown in a controlled animal study to produce hair growth surpassing minoxidil 3%, with a 92% increase in hair follicle count versus 46% for minoxidil. It is proposed to promote hair growth by increasing dermal papilla thickness, follicle count, and scalp blood flow via vasodilation mediated by menthol.

Pine bark extract (particularly Pycnogenol from French maritime pine) is rich in procyanidins and phenolic acids that stimulate dermal papilla cell proliferation, improve scalp microcirculation, and provide antioxidant protection. A 6-month RCT found pine bark extract supplementation significantly increased hair density in women with thinning hair.

Procyanidin oligomers (from apple polyphenol extract and grape seed) selectively and intensively promote proliferation of hair epithelial cells in vitro and activate hair follicle growth in vivo. Topical apple procyanidin B-2 in clinical trials produced significant increases in hair count in men with androgenetic alopecia.

Pumpkin seed oil contains beta-sitosterol and linolenic acid, which inhibit 5-alpha reductase and reduce IL-6 activity, slowing DHT-related follicle miniaturization. A 2014 randomized double-blind placebo-controlled 24-week trial in 76 men with androgenetic alopecia found a 40% increase in mean hair count in the pumpkin seed oil group versus 10% in the placebo group. A separate RCT comparing topical pumpkin seed oil to minoxidil 5% foam in 60 women also demonstrated significant improvements in hair shaft diversity.

Pycnogenol (French maritime pine bark extract) is rich in procyanidins and phenolic acids. A pilot clinical trial in women found Pycnogenol supplementation over 6 months significantly increased hair density and hair growth scores. Its mechanisms include improved scalp microcirculation, antioxidant activity, and promotion of dermal papilla cell proliferation.

Rosemary oil (Salvia rosmarinus, formerly Rosmarinus officinalis) has demonstrated hair-regrowth efficacy comparable to 2% minoxidil in a 6-month randomized controlled trial. It is thought to enhance scalp microcirculation and inhibit 5-alpha reductase via its active constituent carnosic acid, which promotes nerve growth factor-driven follicle recovery. A 2025 double-blind three-arm RCT further confirmed significant improvements in hair growth rate, thickness, density, and reduced hair fall.

Saw palmetto (Serenoa repens) is the most researched natural botanical for androgenetic alopecia. Its fatty acids inhibit both Type I and Type II 5-alpha reductase, reducing DHT—the same mechanism as finasteride but at a more modest scale. A 2020 systematic review of five RCTs found 83.3% of patients showed increased hair density. A 2023 randomized placebo-controlled 16-week trial in 80 male subjects confirmed significant reductions in serum DHT and hair shedding.

Silicon supplementation has been shown to reduce hair brittleness and fragility, which are contributing factors to perceived hair loss and thinning. A higher silicon content in hair has been associated with lower rates of hair loss in observational data. Clinical studies demonstrate improvement in hair strand strength, though reversal of established hair loss or follicle-mediated alopecia has not been demonstrated.

Soy isoflavones (principally genistein and daidzein) inhibit 5-alpha reductase and have anti-androgenic effects relevant to androgenetic alopecia. Daidzein is metabolized by gut bacteria to equol, which specifically binds and sequesters DHT. Soy isoflavone-containing preparations have been studied in hair loss contexts including the capsaicin/isoflavone RCT showing improved hair count.

A 1998 randomized controlled trial (Archives of Dermatology) tested a topical blend including thyme essential oil for alopecia areata in 86 patients; the active group showed significantly better hair regrowth at seven months. Thyme contains apigenin, a bioflavonoid that downregulates TGF-beta in dermal papilla cells and may benefit androgenic alopecia preclinically. Evidence is limited to one small RCT where thyme was part of a multi-essential oil combination.

A randomized, placebo-controlled trial demonstrated that 100 mg/day mixed tocotrienols for 8 months increased hair count by 34.5% in volunteers with hair loss, compared to a slight decrease in the placebo group. The mechanism is attributed to tocotrienols' antioxidant activity reducing lipid peroxidation and oxidative stress in the scalp.

Biotin (vitamin B7) deficiency causes hair loss and brittle nails in humans; correcting deficiency restores hair growth. However, high-quality evidence does not support supplementation in individuals without documented biotin deficiency. A 2024 PubMed systematic review found no high-quality studies demonstrating efficacy of oral biotin for hair loss in non-deficient individuals.

Vitamin D receptors are expressed in hair follicles and play a role in regulating the hair cycle. Deficiency in vitamin D has been associated with alopecia areata and androgenetic alopecia in multiple studies. Clinical guidelines support supplementation in patients with documented vitamin D deficiency presenting with non-scarring hair loss.

Vitamin D3 (cholecalciferol) is the most bioavailable form of vitamin D, acting via follicular vitamin D receptors to regulate hair cycling. Deficiency is associated with alopecia areata and androgenetic alopecia. Clinical guidelines recommend correction of documented deficiency in patients with non-scarring hair loss.

Zinc is a critical cofactor for enzymes in the hair follicle and acts as an inhibitor of follicle apoptosis. Zinc deficiency is associated with hair loss, and a 2025 systematic review linked deficiencies in zinc—among other micronutrients—to androgenetic alopecia progression. Cross-sectional studies show elevated prevalence of zinc deficiency in patients with telogen effluvium.

Alpha-linolenic acid (ALA) is the plant-derived omega-3 fatty acid found in flaxseed, chia, and hemp oils. As a precursor to EPA and DHA, it contributes to anti-inflammatory eicosanoid metabolism that may reduce perifollicular inflammation in androgenetic alopecia. It is included in hair supplement formulations targeting omega-3 fatty acid support.

Apigenin is a flavonoid found in chamomile, parsley, and celery. It promotes hair growth in vitro and in vivo by promoting dermal papilla cell proliferation and has demonstrated ability to extend the anagen phase in mouse models by regulating the Wnt/beta-catenin pathway. It is studied as a potential anti-androgenic and anti-inflammatory hair-active flavonoid.

Ashwagandha (Withania somnifera) is a major Ayurvedic adaptogen with anti-stress and cortisol-lowering properties. Since chronic elevated cortisol is a known trigger for telogen effluvium, ashwagandha's stress-reduction effects are mechanistically relevant to stress-related hair loss. It is listed among hair-health ingredients in authoritative Ayurvedic and integrative medicine sources.

Biota seed is cited in TCM and herbal references as a topical hair tonic used to treat hair loss, and WebMD lists male-pattern baldness (androgenic alopecia) as a traditional indication for oriental arborvitae. However, WebMD explicitly states there is no good scientific evidence supporting this use. The evidence base is entirely traditional.

Birch leaves and birch sap have a documented traditional use for preventing and treating hair loss (alopecia). The anti-inflammatory and antimicrobial properties of birch constituents are considered relevant to scalp health. Birch leaves are described in traditional European herbal medicine as having anti-alopecia properties. No controlled clinical trials for birch and hair loss have been identified.

Chia seed is one of the richest plant sources of alpha-linolenic acid (ALA, ~60–65% of fat content), providing anti-inflammatory omega-3 fatty acids. It also contains antioxidant polyphenols, zinc, and protein that support hair follicle nutrition. Its use for hair health is primarily based on nutritional support and essential fatty acid provision.

Chinese fleeceflower (Polygonum multiflorum, He Shou Wu) has been used in Traditional Chinese Medicine for over a thousand years to nourish hair, prevent premature graying, and address hair loss, based on its role in tonifying kidney and liver. Scientific evidence from human clinical trials is limited, and the herb carries hepatotoxicity risk.

Copper is an essential cofactor for lysyl oxidase, which cross-links collagen and elastin in the follicle connective tissue, and for tyrosinase involved in melanin synthesis. Copper deficiency has been associated with hair loss and premature graying. Copper peptides (GHK-Cu) have demonstrated hair growth stimulation in preclinical models.

Curcumin, the principal bioactive polyphenol of turmeric, inhibits 5-alpha reductase and NF-kB-mediated scalp inflammation in preclinical models. It has a long traditional use in Ayurvedic medicine for scalp health. Some in vitro and animal data support its anti-androgenic and anti-inflammatory actions relevant to hair loss, though human clinical trials are limited.

Evening primrose oil is a rich source of gamma-linolenic acid (GLA, ~9%) and linoleic acid, fatty acids that support scalp barrier function and prostaglandin E1 synthesis with hair growth-promoting properties. It is used traditionally and in supplement formulations for hair loss, particularly for conditions associated with omega-6 fatty acid deficiency.

Flaxseed is a rich source of alpha-linolenic acid (omega-3) and lignans, both of which have been associated with hair health. Lignans in flaxseed (secoisolariciresinol diglucoside) can be converted by gut bacteria to enterolactone, a weak phytoestrogen that may modulate androgen activity relevant to androgenetic alopecia. Flaxseed is traditionally used in hair formulations.

Fo-ti (Polygonum multiflorum / He Shou Wu) has been used for centuries in Traditional Chinese Medicine to nourish the liver and kidney, tonify blood, and prevent premature graying and hair loss. Classical TCM texts document its use specifically for hair health. Scientific evidence in humans is limited, and the herb carries documented hepatotoxicity risk.

Folic acid (vitamin B9) is critical for DNA synthesis and rapid cell division in the hair matrix. Deficiency has been associated with hair loss and has been linked to androgenetic alopecia in systematic reviews. However, isolated RCT evidence for folic acid supplementation in hair loss is lacking, and clinical guidelines cite inadequate data for routine supplementation.

Genistein is the primary isoflavone from soy with anti-androgenic properties including 5-alpha reductase type II inhibition and androgen receptor modulation relevant to androgenetic alopecia. It is the precursor to equol (in gut-competent individuals) and contributes to the hair-protective effects of soy isoflavone supplementation.

Gamma-linolenic acid (GLA) is an omega-6 fatty acid found in borage oil, evening primrose oil, and black currant seed oil. It is a precursor to prostaglandin E1, which has hair growth-stimulating properties, and has been used traditionally and in supplement formulations for hair loss. Animal studies and preliminary human data suggest it may reduce androgenetic hair loss.

Grape seed extract provides oligomeric proanthocyanidins (OPCs) that promote hair follicle cell proliferation and are mechanistically similar to apple procyanidin B-2 (which has demonstrated hair count improvements in clinical trials). Grape seed OPCs improve scalp microcirculation and have antioxidant/anti-inflammatory properties relevant to hair health.

H. spicatum rhizome is traditionally used as a hair growth promoter and is classified in Ayurveda as 'keshya' (hair conditioner/promoter). It is cited in traditional indications for baldness treatment, and the essential oil has been used in hair oil formulations. A dedicated preclinical chemical examination and hair growth study evaluated rhizome oils.

Horsetail (Equisetum arvense) is rich in silica, the primary mineral used to strengthen hair structure and prevent thinning. It has a long history in European herbal medicine for hair and nail health. While silica's role in hair integrity is biologically supported, isolated clinical trials specifically for horsetail in hair loss are limited.

Indigo leaves are documented in Ayurveda for preventing hair loss and promoting hair regrowth, with formal recognition in Ayurvedic Pharmacopoeia formulations. The antimicrobial and anti-inflammatory properties address scalp conditions that contribute to hair loss. No controlled clinical trials exist.

L-methionine is a sulfur-containing essential amino acid that is a metabolic precursor to cysteine (via the transsulfuration pathway) and the universal methyl donor S-adenosylmethionine (SAM). As cysteine is the principal sulfur amino acid in hair keratin, methionine availability is foundational to keratin synthesis. It is included in hair supplement formulations and traditional hair nutrition protocols.

Luteolin is a flavonoid found in celery, parsley, and chamomile that inhibits 5-alpha reductase, reduces perifollicular inflammation, and has been shown to promote hair growth in mouse models. It acts via similar mechanisms to quercetin and other anti-androgenic flavonoids and is included in hair loss research as a naturally occurring DHT blocker.

Magnesium is an essential cofactor for hundreds of enzymatic reactions and participates in DNA synthesis and protein metabolism in hair follicle cells. A 2025 SAGE systematic review found magnesium deficiency associated with androgenetic alopecia progression alongside other micronutrient deficiencies. Direct clinical trials for isolated magnesium supplementation in hair loss are lacking.

Menthol, the primary active constituent of peppermint oil, promotes scalp vasodilation via TRPM8 channel activation, improving blood flow to hair follicles. It is widely used in scalp tonics and hair loss formulations based on this mechanistic basis and traditional practice, though isolated human RCTs are lacking.

Stinging nettle (Urtica dioica) has a long tradition of use in European herbal medicine for hair loss and scalp health. It contains compounds including beta-sitosterol and sterols that inhibit 5-alpha reductase in vitro. Human clinical trial evidence is limited, but it appears in Commission E and traditional monographs as a scalp-stimulating herb.

PABA has been used traditionally to prevent hair loss and to restore gray hair to its natural color. Clinical reports from the 1940s–1950s documented hair re-pigmentation in patients receiving PABA for other conditions such as scleroderma and dermatomyositis; the effect was reversible upon discontinuation. No controlled studies on hair loss prevention or restoration exist.

Prevention of premature hair graying and support of hair health are among the oldest traditional indications for Ligustrum lucidum in TCM. The 2020 Chinese Pharmacopoeia lists 'making the hair black' among its official functions. No clinical trial data for hair loss or graying exist.

Pygeum africanum (African plum tree) bark extract is used primarily for benign prostatic hyperplasia and contains beta-sitosterol and other phytosterols that inhibit 5-alpha reductase—the same mechanism implicated in androgenetic alopecia. Traditional and functional medicine practitioners use it for androgenic hair loss. Dedicated hair loss RCTs are absent; evidence is primarily mechanistic and traditional.

Quercetin is a flavonoid found in onions, capers, and many plant foods. It inhibits 5-alpha reductase and androgen receptor signaling in cell models, reduces DHT-induced follicle apoptosis, and has anti-inflammatory properties relevant to alopecia areata (quercetin is proposed as the active agent in onion juice's clinical effect). In vivo mouse studies show quercetin promotes hair growth.

Rehmannia is used in TCM as a hair tonic, particularly for premature greying and hair loss associated with kidney essence and blood deficiency. The Restorative Medicine monograph lists 'hair tonic (premature graying)' as a traditional indication. Its use for hair is linked to the TCM tenet that the kidney 'manifests in the hair.' Both traditional use and naturopathic clinical practice support this application.

Rehmannia is listed in TCM references as a hair tonic, specifically for premature greying of hair. The Restorative Medicine monograph includes 'hair tonic (premature graying)' as an indication. Prepared rehmannia is used traditionally in blood and essence-nourishing formulas for hair health.

Resveratrol is a stilbenoid polyphenol found in grapes, Japanese knotweed, and red wine. In cell models it inhibits 5-alpha reductase activity and promotes dermal papilla cell proliferation via Wnt/beta-catenin signaling. Animal studies show topical resveratrol extends the anagen phase. It is included in hair loss supplement formulations based on mechanistic and preclinical data.

A comprehensive PMC review (PMC5984022) reported 'considerable rates of recovery in cases suffering from alopecia when treated with hair-restoring preparations based on safflower.' Traditional use across Korean, Thai, and Indian medicine includes safflower for hair loss. No high-quality clinical trial evidence exists.

Selenium is an essential trace mineral incorporated into selenoproteins including thioredoxin reductase and glutathione peroxidase, which protect follicle cells from oxidative damage. Deficiency is associated with androgenetic alopecia in systematic reviews. However, excess selenium causes hair loss (selenosis), making the therapeutic window narrow.

Selenomethionine is the most bioavailable organic form of selenium found in plant foods. It supports the selenoprotein systems that protect hair follicle cells from oxidative damage. Selenium deficiency—correctable with selenomethionine—has been associated with androgenetic alopecia progression in systematic reviews.

Turmeric (Curcuma longa) provides curcumin and related curcuminoids that inhibit 5-alpha reductase and NF-kB-mediated inflammation implicated in androgenetic alopecia. Turmeric has an extended traditional use in Ayurvedic and Southeast Asian medicine for scalp conditions and hair health. Direct human RCT evidence for hair loss specifically is limited.

Thiamine (vitamin B1) is an essential coenzyme for energy metabolism in hair follicle cells and is included in European combination hair loss treatments alongside L-cystine and pantothenic acid. Clinical trials of L-cystine/thiamin/pantothenate combination products have shown benefit for diffuse alopecia.

Vitamin B12 deficiency can cause premature graying and diffuse hair loss by impairing DNA synthesis in rapidly dividing hair matrix cells. Population studies associate low B12 levels with hair loss, and a 2025 systematic review linked B12 deficiency to androgenetic alopecia progression. Supplementation is indicated only in documented deficiency.

Riboflavin (vitamin B2) is essential for electron transport and energy production in the rapidly dividing cells of the hair matrix. Deficiency is associated with hair changes and has been linked to androgenetic alopecia in systematic reviews. However, isolated human RCTs for riboflavin in hair loss are lacking.

Niacin (vitamin B3) is a vasodilator and essential coenzyme precursor (NAD+/NADP+) required for energy metabolism in rapidly dividing hair follicle cells. Deficiency (pellagra) causes hair and skin changes including alopecia. Niacinamide (the amide form) is used in scalp formulations to improve microcirculation and is often combined with other hair supplements.

Niacinamide (nicotinamide) is the amide form of niacin, a precursor to NAD+ required for follicle cell energy metabolism. It improves scalp microcirculation, has anti-inflammatory properties, and is included in topical hair loss formulations. Niacin deficiency causes alopecia as part of pellagra; niacinamide is used as a safer, non-flushing alternative in hair supplements.

Vitamin B5 (pantothenic acid) plays a key role in fatty acid synthesis, adrenal hormone production, and is involved in the metabolism of hair follicle cells. It is widely used in hair supplements and has a traditional role in hair health in European phytotherapy. Direct RCT evidence for isolated vitamin B5 in alopecia is limited, though combination products containing pantothenic acid have shown benefit.

Vitamin B6 (pyridoxine) is required for amino acid metabolism—including the synthesis of cysteine and methionine used in keratin production—and for normal hormonal balance including androgen metabolism. Deficiency has been associated with hair loss. It is widely incorporated in hair supplement formulations based on its role in follicle cell metabolism.

Folate (vitamin B9) is essential for DNA synthesis in rapidly dividing hair matrix cells. Deficiency has been linked to androgenetic alopecia progression in systematic reviews. Routine supplementation without documented deficiency is not currently supported by clinical guidelines.

5-methyltetrahydrofolate (5-MTHF) is the bioactive form of folate required for one-carbon metabolism and DNA synthesis in hair matrix cells. It is preferentially used in individuals with MTHFR polymorphisms who have impaired conversion of folic acid. The same evidence base supporting folate's role in hair loss applies to this more bioavailable form.

Vitamin C is essential for collagen synthesis required to maintain the integrity of the follicular connective tissue sheath, and enhances iron absorption—a key cofactor for hair loss prevention. As a potent antioxidant, it protects follicle cells from oxidative damage. It is a standard component of hair health nutrition and is used as a co-supplement with iron in hair loss management.

Vitamin E is a lipid-soluble antioxidant that protects scalp and follicle cell membranes from oxidative lipid peroxidation implicated in androgenetic alopecia and other hair loss types. A small 8-month RCT found tocotrienol supplementation significantly increased hair count by 34.5% versus placebo. Deficiency has been associated with hair loss in systematic reviews.

Multiple Native American groups, including the Cheyenne and Zuni, used yucca topically to stimulate hair growth and treat scalp conditions. These uses are documented in ethnobotanical records and clinical reference libraries. Yucca's saponins cleanse the scalp, and traditional accounts attribute hair-strengthening effects to the plant. No clinical trial has tested yucca for alopecia.