Health ConditionsAndrogenetic alopecia (AGA), or male-pattern hair loss (MPHL), is a genetically determined progressive process that causes a gradual conversion of terminal hair into vellus hair. It is the most common nonscarring alopecia and is characterised by distinct gradual patterned hair loss. Male androgenetic alopecia is the most common cause of hair loss in men. The hair loss is progressive. Gradual conversion of terminal hairs into vellus hairs occurs in a highly reproducible pattern, denudes the scalp, and leads to baldness.
Androgenetic alopecia affects at least half of white men by the age of 50 years. This androgen-dependent hair loss may commence during puberty, and up to 80% of European men experience some degree of MPHL during their lifetime. It affects approximately 30% of men by the age of 30, 50% of men by age 50, and 57% of men by age 60. Caucasian individuals are most notably more affected, followed by Asians and African Americans, and subsequently by Native American and Inuit populations.
Hair loss from androgenetic alopecia in men is progressive and occurs typically in a characteristic pattern, beginning with recession of the frontal hairline and hair loss in the vertex or crown and progressing to complete loss of hair over the frontal and vertex scalp regions. In the most severe form of androgenetic alopecia in men, hair may be present only in a ring around the head in the temporal, parietal, and occipital regions of the scalp. This progression is characterized most often by the 7 categories of the Hamilton-Norwood scale, which assists in the diagnosis and monitoring of hair loss.
Hair loss typically begins with bitemporal recession of the frontal hairline, followed by diffuse hair thinning at the vertex, and eventual complete loss of hair at the center of the vertex. The bald patch at the vertex subsequently joins the frontal receding hairline, leaving an island of hair on the frontal scalp.
Pattern hair loss is classified as a form of non-scarring hair loss. Although the condition is considered a noninflammatory form of hair loss, a superficial, perifollicular, inflammatory infiltrate is noted at times. A mildly increased telogen-to-anagen ratio is often observed.
The process of hair loss occurs at the level of the hair follicles by "miniaturization," through which the hair follicle becomes progressively smaller both in depth and circumference, and the hair shaft produced becomes shorter and thinner. Excessive DHT shrinks hair follicles, replacing terminal hairs with vellus hairs. Excessive activation of the androgen receptor (AR) results in the miniaturisation of the follicles, shortening the anagen phase of the hair cycle. The hair shafts become thinner and shorter and may not penetrate the epidermis.
One theory holds that androgens change the length of anagen and telogen phases, so that a normal ratio of anagen to telogen ratio of approximately 9:1 can become approximately 2:1 or less in MPHL. Patients with androgenetic alopecia have a reduction in the terminal-to-vellus hair ratio, normally about 4:1. Following miniaturization of the follicles, fibrous tracts remain.
Testosterone is converted by type 2, 5-alpha reductase (SRD5A2) into dihydrotestosterone (DHT), leading to AGA. Both testosterone and DHT predominantly bind to intracellular androgen receptors, primarily located within the dermal papilla and hair bulb, with DHT exhibiting approximately five times greater affinity. DHT interacts with the androgen receptors in vulnerable scalp hair follicles to stimulate the genes responsible for follicular miniaturization.
Testosterone is converted to DHT by an enzyme, 5-alpha reductase (5AR). Men who have a congenital deficiency of 5AR (type II) do not experience male pattern baldness. Androgen receptors (ARs) in hair follicles bind to DHT, changing protein shape, and initiating a signalling cascade. Occipital hairs are less sensitive due to AR methylation, protecting them from miniaturization and loss.
AGA susceptibility is primarily influenced by hereditary factors, contributing to around 80% of the predisposition to baldness. AGA follows a polygenic model, characterized by varying expression levels, which accounts for the diverse range of clinical phenotypes and initial variations observed in individuals affected by this condition. Modifications of the androgen receptor (AR) genes on the Xq12 chromosome lead to AGA, through increased AR gene activity in hair follicles triggered by dihydrotestosterone (DHT) binding.
Researchers suspect that variants in several genes play a role in androgenetic alopecia. However, scientific studies have confirmed only that variations in one gene, the AR gene, are involved in this condition. The AR gene provides instructions for making a protein called an androgen receptor. Androgen receptors allow the body to respond appropriately to DHT and other androgens. Studies suggest that variations in the AR gene result in androgen receptors that are more easily stimulated by androgens than normal, leading to increased activity of the receptors in hair follicles.
This condition is characterized by a polygenic nature with varying penetrance degrees, influenced by maternal and paternal genes. A familial predisposition towards androgenetic alopecia exists, with sons having 5 to 6 times higher relative risk if their fathers experienced balding. To date, molecular genetic studies have identified 389 associated genomic regions, have implicated numerous genes in these regions, and suggested pathways that are likely to contribute to key pathophysiological mechanisms in MPHL.
While some degree of androgen-dependent hair loss is universal after puberty, the prevalence of alopecia of sufficient severity to warrant a diagnosis of balding increases with advancing age. The prevalence increases with advancing age; however, the age of onset and rate of progression are variable.
Since there are epigenetic influences, that is, environmental effects, that can retard or accelerate hair loss, even genetically identical twins may manifest different degrees of hair loss. Epigenetic factors, that is, environmental influences that impact one's genes, have been shown to affect hair loss. The most studied example is smoking or nicotine exposure, which has been proven to accelerate AGA hair loss.
Smoking may lead to hair loss by vasoconstriction, by forming DNA adducts, free radical damage to hair follicle, by enhancing senescence and hormonal effects. Data available show that there is a significant association between smoking and AGA. However, studies demonstrating the benefit of avoidance of smoking in improving hair loss are lacking. Furthermore, large controlled studies with histological documentation are still unavailable to affirm the findings. Heavy smokers (≥10 cigarettes per day) had almost three times an increased risk of having a moderate/severe alopecia (OR: 2.56; 95% CI: 1.27–5.16) in comparison with those who never smoked.
Androgenetic alopecia and its association with the metabolic syndrome (MetS) have received increasing interest since 1972, when the first link between cardiovascular risk factors and hair loss was raised. Many studies have investigated the relationship among AGA and MetS and its individual components, particularly in men, where a disproportionately large number of these studies supports this association. AGA has also been associated with other metabolic-related conditions, including coronary artery disease, polycystic ovary syndrome, and Cushing syndrome, as well as several nutritional deficiencies, all of which have led to many clinicians advocating for the screening of MetS and cardiovascular risk factors in patients who present with AGA.
Both males aged 40–91 and younger male patients of early onset androgenetic alopecia (before the age of 35) had a higher likelihood of metabolic syndrome and insulin resistance. With younger males, studies found metabolic syndrome to be at approximately a 4× increased frequency, which is deemed clinically significant. Abdominal obesity, hypertension, and lowered high-density lipoprotein were also significantly higher for younger groups.
Furthermore, patients with androgenetic alopecia had significantly poorer metabolic profiles, such as body mass index, waist circumference, fasting glucose, blood lipids, and blood pressure.
Some research has found evidence for the role of oxidative stress in hair loss, the microbiome of the scalp, genetics, and circulating androgens, particularly dihydrotestosterone. Other mechanisms such as chronic inflammation and several hormones or vitamins like aldosterone, insulin, or vitamin D have been implicated in the pathogenesis of androgenetic alopecia.
Androgenetic alopecia in men has been associated with several other medical conditions, including coronary heart disease and enlargement of the prostate. The morbidity of male androgenetic alopecia is predominantly psychological, although it is associated with a slight increased risk of melanoma and non-melanoma skin cancer of the scalp.
Micronutrients are major elements in the normal hair follicle cycle, playing a role in cellular turnover, a frequent occurrence in the matrix cells in the follicle bulb that are rapidly dividing. The findings suggest that deficiencies or imbalances in these micronutrients may contribute to the pathogenesis of AGA and represent modifiable risk factors for hair loss prevention and treatment. Vitamin B, vitamin D, iron, and zinc appear to play critical roles in hair growth and maintenance. Importantly, however, nutritional deficiency typically triggers telogen effluvium, a diffuse shedding pattern where follicles prematurely enter the resting phase, rather than the patterned recession characteristic of androgenetic alopecia. This distinction is clinically critical.
Scientific Evidence: The role of vitamin D receptor (VDR) has been well established and extensively studied in the hair cycle. Its deficiency is also closely linked to several types of alopecia, including alopecia areata, telogen effluvium, and androgenetic alopecia. A 2024 Frontiers in Nutrition systematic review and meta-analysis found that 51.94% of alopecia areata patients, 50.38% of female pattern hair loss patients, 47.38% of male androgenetic alopecia patients, and 53.51% of telogen effluvium patients had vitamin D deficiency.
Vitamin D acts through the vitamin D receptor (VDR) found in the outer root sheath, hair matrix, and dermal papilla. When VDR activity is insufficient, follicles can stall in the resting phase. However, correcting serum vitamin D deficiency alone may not restore hair growth if VDR function within the follicle is impaired.
One case-control study (50 cases, 50 controls) showed a significant correlation between vitamin D deficiency and the severity of androgenetic alopecia, suggesting that vitamin D may play a role in the premature onset of androgenetic alopecia. However, the authors noted that further studies on a larger population and the effect of vitamin D supplementation on the progression of androgenetic alopecia are required to validate the findings. Although it is unknown whether deficient vitamin D levels in the blood would lead to deficient vitamin D in the tissue, and whether this would lead to VDR dysfunction, numerous studies have linked vitamin D deficiency to the pathogenesis of various alopecia disorders. While these studies demonstrate varying degrees of association between vitamin D deficiency and alopecia, there is still debate over the causality and consistency of findings.
Scientific Evidence: Androgenetic alopecia has been associated with lower iron and vitamin D levels. Iron deficiency impairs the proliferation of hair matrix cells due to high ferritin demand. Some studies indicate that various hair follicle genes are regulated by iron. Supplemental iron, in patients with AGA, alopecia areata, and telogen effluvium with documented deficiency of iron, has been recommended with a Grade D recommendation, meaning evidence remains limited.
Scientific Evidence: Zinc plays a role in the hedgehog signaling pathway, which is essential for hair morphogenesis. A 2025 systematic review found that deficiencies in zinc, copper, magnesium, selenium, vitamins B12, E, D, and folic acid were all associated with androgenetic alopecia progression, suggesting zinc's role is often part of a broader nutritional picture rather than an isolated deficiency. There is inadequate data to recommend supplementation of zinc in the management of androgenetic alopecia. Notably, excess zinc supplementation can paradoxically exacerbate hair loss and interfere with copper absorption.
Scientific Evidence: Biotin, as a cofactor of carboxylase enzyme, plays a role in cell signaling and gene regulation. Despite heavy commercial promotion, biotin supplementation is not recommended in the management of telogen effluvium, alopecia areata, or AGA (Grade D recommendation) in the absence of confirmed deficiency. Large double-blind placebo-controlled trials are required to determine the effect of specific micronutrient supplementation on hair growth in those with both micronutrient deficiency and non-scarring alopecia.
Scientific Evidence: Deficiencies or imbalances in specific vitamins and minerals, especially vitamin B, vitamin D, iron, selenium, and zinc, are involved in the pathogenesis of AGA and may represent modifiable risk factors for the treatment and prevention of this condition. However, the current evidence is not entirely consistent, with some studies reporting no significant associations. There is inadequate data to recommend supplementation of folic acid, riboflavin, and vitamin B12 for hair loss.
Scientific Evidence: Selenium is a cofactor of glutathione peroxidase, which is a potent antioxidant. Its association with androgenetic alopecia has been noted in the same 2025 systematic review alongside other micronutrients, but evidence specific to AGA remains preliminary and no supplementation recommendations have been established outside of documented deficiency.
Scientific Evidence: Both lower and increased vitamin A levels can result in telogen effluvium, but lower levels are associated with hair breakage. The relationship of vitamin A specifically to androgenetic alopecia is less well-characterized than for vitamin D or iron. Excess vitamin A is a known potential cause of hair shedding, and evidence regarding its supplementation in the absence of deficiency for AGA is not established.
Scientific Evidence: Vitamin C enhances intestinal iron absorption. Animal studies show the role of vitamin C in the hair follicle cycle by increasing insulin-like growth factor-1 in dermal papilla, promoting hair shaft elongation. Direct human clinical evidence for vitamin C supplementation in androgenetic alopecia specifically remains sparse, and its role is primarily indirect, via iron absorption enhancement.
A range of plant-derived substances have been studied in relation to androgenetic alopecia, primarily through their ability to inhibit 5-alpha reductase, reduce inflammation, or improve scalp microcirculation. The following entries distinguish traditional from scientific use.
Traditional Use: Herbal therapies have been used to treat baldness since ancient times in the Ayurveda, Chinese, and Unani traditional medicinal systems. Serenoa repens (saw palmetto), a berry extract derived from the American dwarf palm native to the southeastern United States, has a documented history of use in traditional herbalism for urogenital and hair-related conditions.
Scientific Evidence: Saw palmetto, a botanical extract with antiandrogenic properties, has gained commercial popularity for its purported benefits on hair regrowth. Five randomized clinical trials (RCTs) and 2 prospective cohort studies demonstrated positive effects of topical and oral supplements containing saw palmetto (100–320 mg) among patients with androgenetic alopecia and telogen effluvium. A 60% improvement in overall hair quality, 27% improvement in total hair count, increased hair density in 83.3% of patients, and stabilized disease progression among 52% were noted with use of various topical and oral saw palmetto-containing supplements.
In one specific 16-week double-blind, placebo-controlled trial, 80 healthy male and female subjects aged 18–50 years were randomly allocated to receive either 400 mg capsules of a standardized saw palmetto oil or a topical formulation containing 20% saw palmetto oil, or respective placebos, once daily. The evidence as a whole is considered preliminary: the trials are generally small, heterogeneous in design, and not all used standardized extracts. Saw palmetto's 5-alpha reductase inhibition is weaker than pharmaceutical inhibitors such as finasteride.
Traditional Use: Rosemary has centuries of use in Mediterranean traditional medicine. Rosemary has long been used in traditional medicine. Its application to the scalp for hair promotion appears in folk remedy traditions across Europe and the Mediterranean region.
Scientific Evidence: Rosmarinus officinalis contains prominent antiandrogenic properties, which have been demonstrated in several studies. One study attributed the potent antiandrogenic effect to 12-methoxycarnosic acid primarily. Moreover, a randomized comparative trial conducted in 2015 showed rosemary oil to be comparable in effect to 2% minoxidil for the treatment of androgenetic alopecia.
In this 2015 randomized trial (Panahi et al., SKINmed), the clinical efficacy of rosemary oil was investigated in the treatment of androgenetic alopecia and compared with minoxidil 2%. Patients with AGA were randomly assigned to rosemary oil (n = 50) or minoxidil 2% (n = 50) for a period of 6 months. No significant change was observed in the mean hair count at the 3-month endpoint in either group. In contrast, both groups experienced a significant increase in hair count at the 6-month endpoint compared with the baseline and 3-month endpoint. The trial was limited to 100 participants, and rosemary oil was compared only to a 2% (lower-strength) minoxidil formulation. The finding has not yet been replicated in large independent trials. Clinical studies show promising outcomes, but responses vary, and large-scale, long-term trials are lacking.
Traditional Use: Pumpkin seed preparations have traditional uses in Ayurvedic, Chinese, and folk European medicine for various conditions. Pumpkin plant has been used in many countries throughout history for its known effect as antioxidant, anti-inflammatory, and antimicrobial properties.
Scientific Evidence: The mechanism of action of pumpkin seed oil in reducing hair loss is attributed to the inhibitory effects of β-sitosterol and linolenic acid on 5α-reductase, and decreasing IL-6 activity. Pumpkin seed oil has been shown to block the action of 5-alpha reductase and to have antiandrogenic effects on rats. A 6-month randomized trial (Cho 2014) demonstrated that pumpkin seed oil showed significant hair count increases versus placebo. This is the primary human clinical study on oral pumpkin seed oil; this study, which reported promising results with oral administration, was critiqued for incomplete research data, specifically lacking information on its effect on frontal AGA, which is crucial for early treatment stages. Overall, the evidence is promising but preliminary, resting on a small number of trials.
Traditional Use: Green tea (Camellia sinensis) has millennia of use in East Asian traditional medicine for a wide range of conditions. Its topical or internal use specifically for hair was part of traditional Chinese and Japanese wellness practices.
Scientific Evidence: Epigallocatechin gallate (EGCG) is a major polyphenolic constituent of green tea that features hair growth stimulation through enhancing the proliferation and preventing apoptosis of dermal papilla cells, in addition to selective inhibition of 5-alpha-reductase which converts testosterone to dihydrotestosterone. Several studies have reported that the polyphenols in green tea might be useful for treating AGA by inhibiting 5α-reductase activity. However, EGCG contains epigallocatechin-3-gallate, which inhibits 5-alpha reductase in laboratory studies. Clinical evidence in humans is more limited. Most current evidence for EGCG in AGA is from in vitro and animal studies; well-controlled human clinical trials are lacking.
Traditional Use: Phytosterol-containing plant foods and extracts (including pumpkin seeds, saw palmetto, and nettle root) have traditional use across various herbal systems.
Scientific Evidence: β-sitosterol is the active phytosterol in saw palmetto and pumpkin seed oil believed to contribute to 5-alpha reductase inhibition. It is rarely studied in isolation for AGA in humans; its clinical data is embedded in the wider literature on pumpkin seed oil and saw palmetto. This is among a broader group of natural DHT-related compounds including saw palmetto, pygeum, beta-sitosterol, nettle root, quercetin, pumpkin seed oil, green tea (EGCG), licorice root, flaxseed, curcumin, astaxanthin, resveratrol, L-carnitine, spearmint, and reishi mushroom that have attracted research interest, though clinical evidence for most of them in AGA remains sparse or absent.
Traditional Use: Pygeum bark has been used for centuries in traditional African medicine for urogenital complaints.
Scientific Evidence: Pygeum bark extract is primarily studied for prostate health, but its 5-alpha reductase inhibition has led to interest in hair loss applications. Dedicated human clinical trials of pygeum specifically for androgenetic alopecia are largely absent from the literature; its inclusion in hair-loss supplement reviews is based on its shared mechanistic profile with finasteride rather than direct AGA trial data.
Dietary changes, such as reducing pro-inflammatory foods (like trans and saturated fats) and increasing anti-inflammatory options (fruits and vegetables), can help prevent hair loss and mitigate its psychological impacts. Research published in Frontiers in Nutrition (2024) found an association between androgenic alopecia and higher dietary inflammatory index scores, suggesting that diets with high pro-inflammatory potential may be associated with increased AGA risk.
A study from Italy (Fortes et al.) concluded that overweight and smoking are associated with increased severity of androgenetic alopecia. Insulin resistance-induced sex hormone binding globulin (SHBG) suppression, hepatic inflammation, and oxidative stress may represent a common mechanistic axis linking metabolic dysfunction and AGA.
Lifestyle factors like diet and exercise modulate these pathways, offering potential therapeutic avenues. Direct clinical evidence on exercise specifically reducing AGA severity in controlled human trials is not yet well established, but the connection is plausible through the metabolic pathways linking insulin resistance, SHBG, and androgen availability.
As noted above, smoking may lead to hair loss by vasoconstriction, by forming DNA adducts, free radical damage to hair follicle, by enhancing senescence and hormonal effects. The association between smoking and AGA severity is well-supported in the available observational literature, though intervention evidence remains limited.
Hair fiber is composed primarily of keratin proteins. Adequate dietary protein and essential amino acid intake are broadly considered necessary for normal hair growth by dermatological authorities. However, specific controlled trials on protein supplementation in androgenetic alopecia are limited. The micronutrient review literature generally frames protein adequacy as a prerequisite for hair follicle function rather than a distinct treatment variable for AGA.
The role of nutrition and diet in treating hair loss represents a dynamic and growing area of inquiry. Large double-blind placebo-controlled trials are required to determine the effect of specific micronutrient supplementation on hair growth in those with both micronutrient deficiency and non-scarring alopecia, to establish any association between hair loss and micronutrient deficiency. For most patients, nutritional deficiency is a contributing or aggravating factor in AGA, not the primary cause.
Beta-sitosterol is a plant sterol found in saw palmetto and pumpkin seed oil that competitively inhibits 5α-reductase, reducing DHT conversion. An early double-blind RCT (Prager 2002, Journal of Alternative and Complementary Medicine, n=19 men with AGA) showed 60% of treated patients rated as 'improved' versus 11% for placebo at 5 months. It is the key active constituent underlying pumpkin seed oil's documented AGA efficacy.
Topical caffeine inhibits phosphodiesterase, raises cyclic AMP in follicular keratinocytes, and counteracts DHT-induced growth suppression, prolonging the anagen phase. A 2025 double-blind, placebo-controlled 24-week RCT (Celleno et al., PMC12359291) with a caffeine-containing shampoo showed significantly fewer hairs pulled (−2.8 vs +0.6, P<0.001) and improved phototrichogram parameters in male AGA versus placebo.
Curcumin downregulates androgen receptor expression in hair follicle cells and reduces scalp inflammation via NF-κB suppression, countering DHT-driven follicular miniaturization. It is a core ingredient of Nutrafol, evaluated in AGA clinical trials. The 2025 Frontiers in Nutrition systematic review (10.3389/fnut.2025.1719711) identifies curcumin among dietary supplements with evidence for AGA benefit.
EGCG, the major catechin of green tea, selectively inhibits 5α-reductase and stimulates dermal papilla cell proliferation and survival. PMC reviews (PMC11549889, PMC9963650) and a 2025 Frontiers in Nutrition systematic review confirm EGCG among phytochemicals with documented beneficial effects in AGA. In vitro and preclinical studies consistently support its DHT-reducing and follicle-promoting mechanisms.
The same 2015 Phytotherapy Research study by Shin HS et al. specifically modeled androgenic (male pattern) alopecia using DHT induction. Forsythiaside A outperformed finasteride in protecting hair follicles from DHT-induced damage in vitro and in vivo. This is the same scientific evidence as for Hair Loss above, specifically applicable to the androgen-dependent mechanism of male pattern hair loss.
Panax ginseng (red ginseng) ginsenosides inhibit 5α-reductase, stimulate dermal papilla cell proliferation, and improve scalp microcirculation. PMC reviews (PMC9963650, PMC11549889) cite red ginseng extract among phytochemicals with documented beneficial effects in AGA. A clinical study showed significant improvement in hair density with topical red ginseng application in AGA patients over 90–270 days.
Green tea (Camellia sinensis) polyphenols—primarily EGCG—inhibit 5α-reductase and stimulate dermal papilla cell proliferation relevant to AGA. Preclinical studies and multiple PMC systematic reviews (PMC9963650, PMC11549889) confirm hair growth-promoting effects, and green tea components appear in multiple evidence-based combination AGA supplement trials.
L-cystine is the disulfide form of cysteine essential for keratin biosynthesis and hair shaft structural integrity. A 2025 double-blind, placebo-controlled RCT (Piquero-Casals et al., Skin Appendage Disorders, n=80) with an oral supplement combining L-cystine, Serenoa repens, Cucurbita pepo, and Pygeum africanum showed significant hair density increases (+9.9 hairs/cm² at 3 months) and improved hair volume in AGA patients over 6 months.
Topical melatonin (0.1% solution) exhibits antioxidant and mild anti-androgenic properties. Five clinical studies (Fischer et al., Int J Trichology, 2012) showed positive effects on hair density and anagen phase in men and women with AGA. A 2025 network meta-analysis ranked topical melatonin as the highest-performing non-conventional AGA treatment after 5% minoxidil (SUCRA=61.9%).
Androgenetic alopecia (AGA) is explicitly listed in WebMD as a traditional use for oriental arborvitae, and multiple recent scientific studies have investigated P. orientalis for AGA-specific mechanisms. Studies have demonstrated activity against DHT-mediated follicle miniaturization pathways and UV-induced damage in AGA hair samples. Traditional Chinese medicine classics recognize the plant for hair darkening and regeneration.
Topical procyanidin B2 (from apple and grape polyphenol extract) promotes hair follicle cell proliferation via Wnt/β-catenin signaling and VEGF upregulation. Multiple Japanese RCTs (Takahashi 1998, Kamimura 2000/2002) demonstrated significant increases in terminal hair count versus placebo at 6 months. Topical procyanidin 0.7% was included in the 2025 network meta-analysis of male AGA trials as one of nine active comparators.
Pumpkin seed oil (Cucurbita pepo) contains beta-sitosterol and linoleic acid that inhibit 5α-reductase, reducing scalp DHT and IL-6-mediated inflammation. A landmark 24-week double-blind, placebo-controlled RCT (Cho 2014, PMC4017725, n=76 men with AGA) showed a 40% mean increase in hair count at 400 mg/day versus 10% for placebo (P<0.001). A 16-week RCT (PMC10648974, 2023) also confirmed significant improvements in hair density and anagen/telogen ratio.
Pygeum africanum (Prunus africana) bark extract contains phytosterols including beta-sitosterol with anti-androgenic and anti-inflammatory properties relevant to AGA. A 2025 double-blind, placebo-controlled RCT (Piquero-Casals et al., Skin Appendage Disorders, n=80, 6 months) testing an oral supplement combining Pygeum africanum, Serenoa repens, Cucurbita pepo, and L-cystine showed significant improvement in hair density (+9.9 hairs/cm² at 3 months) in AGA patients. Pygeum primarily features in combination AGA formulations.
Topical rosemary oil (Rosmarinus officinalis) enhances microcapillary perfusion and modulates prostaglandin E2 and leukotriene B4, prolonging the anagen phase. A randomized comparative trial (Panahi 2015, n=100) showed rosemary oil equaled 2% minoxidil in significant hair count increases at 6 months, with less scalp itching. A 2025 network meta-analysis confirmed topical rosemary as one of the best-evidenced non-conventional treatments for male AGA.
Saw palmetto (Serenoa repens) lipidosterolic extract inhibits both type I and II 5α-reductase, reducing DHT-driven follicular miniaturization in androgenetic alopecia (AGA). Multiple RCTs and a 2020 systematic review of 5 RCTs confirm improvements in hair density and count in men with AGA. Effects are smaller than finasteride but the tolerability profile is favorable.
An in vitro study demonstrated that L-threonate inhibits DHT-induced DKK1 (Dickkopf-1) expression in human hair dermal papilla cells. DKK1 is a key mediator of androgen-driven hair follicle miniaturization in androgenic alopecia. This is cell-culture evidence only, with no human clinical trials.
Tocotrienols are vitamin E isomers with potent antioxidant activity that reduce scalp lipid peroxidation associated with alopecia. A randomized, placebo-controlled trial (Beoy et al., 2010, PMC3819075; n=38) demonstrated a statistically significant 34.5% increase in hair count after 8 months of 100 mg/day mixed tocotrienols versus 0.1% decrease with placebo. The 2025 Frontiers in Nutrition systematic review cites this RCT for AGA.
Biotin (vitamin B7) is essential for keratin biosynthesis and widely used in AGA combination therapies. A 2024 PMC review (PMC11324195) documents its inclusion in compounded topical formulations with minoxidil, finasteride, and caffeine that promoted normal hair growth in male AGA. A 2024 systematic review (PubMed 39440586) identifies vitamin B deficiency as associated with increased AGA risk.
Vitamin D3 regulates hair follicle cycling via vitamin D receptor (VDR) signaling; VDR mutations cause alopecia. A 2024 systematic review (PubMed 39440586, 49 studies) identified vitamin D as one of four critical micronutrients whose deficiency is consistently associated with AGA risk and whose supplementation shows potential benefit for hair growth.
Zinc is a cofactor for 5α-reductase and enzymes involved in hair follicle cycling and keratin synthesis. A 2024 systematic review (PubMed 39440586, 49 studies) found zinc deficiency consistently associated with increased AGA risk, with supplementation showing potential benefit. A 2014 Journal of Drugs in Dermatology review identifies zinc among the best-evidenced supplemental treatments for AGA.
Horsetail (Equisetum arvense) has been used in European folk medicine as a hair-strengthening tonic due to its high silica content supporting keratin cross-linking. A 2018 placebo-controlled study (Pekmezci, n=120 AGA/TE subjects) using a multi-herb formula including Equisetum arvense leaf extract showed significantly reduced hair loss versus placebo. It is included in a 2025 registered RCT for AGA combination supplementation.
Stinging nettle (Urtica dioica) has centuries of use in European folk medicine and Ayurvedic traditions as a hair tonic to reduce loss and promote growth. In vitro studies show nettle root extract inhibits 5α-reductase and interferes with DHT-receptor binding. A 2018 placebo-controlled study (Pekmezci, n=120) using a multi-herb formula including Urtica dioica root extract showed significantly reduced hair loss in AGA subjects over 6 months.
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