The Science-Backed Beauty Supplement (Continued)

Building on our comprehensive exploration of the clinical evidence supporting Ageless: Hair Skin & Nails, this continued research article delves deeper into additional human clinical trials and published studies that validate the remarkable efficacy of this multi-ingredient beauty supplement formulation.

Advanced Clinical Evidence: Human Studies Validating Individual Ingredients

The scientific foundation for beauty supplementation continues to expand with rigorous human clinical trials demonstrating that individual ingredients in Ageless work synergistically to produce measurable improvements in hair, skin, and nail health.

Biotin: Clinically Proven Hair and Nail Enhancement

New Clinical Findings

Recent clinical research has significantly expanded our understanding of biotin's direct effects on hair growth and strength. A comprehensive randomized, double-blind, placebo-controlled study incorporating biotin with silica demonstrated that the combination produced statistically significant increases in hair fall reduction, hair thickness, hair growth rate, and improvements in brittle nails through phototrichogram measurements.[110]

The study tracked multiple parameters over 90 days, measuring changes in hair fall using the 60-second hair comb test, hair thickness via phototrichogram technology, and PGA (Physician Global Assessment) scoring for nail conditions.[110] Results showed consistent improvements across all assessed parameters, with instruments like the CASALite Nova phototrichogram providing objective evidence of hair density and growth rate changes.[110]

L-Cysteine: Cellular Evidence of Hair Follicle Support

In Vitro Human Studies

Groundbreaking research on an L-cystine-containing hair-growth formulation (Panto[vi]gar®) demonstrated its protective effects against oxidative stress in human hair follicular keratinocytes (HHFKs).[27] The study specifically examined the four core compounds including L-cystine, establishing a central role for cysteine in supporting cellular processes critical to hair health.[27]

When cultured human hair follicular keratinocytes were treated with L-cystine and complementary compounds, researchers observed a remarkable 1.4–2.3-fold increase in metabolic activity, a 1.9–2.9-fold increase in DNA content, and a 3.6–41.0-fold increase in de novo DNA synthesis.[27] Most importantly, L-cystine was identified as crucial for suppressing expression of aging markers in keratinocytes, suggesting that adequate cysteine intake helps prevent premature hair aging.[27]

A separate clinical trial on L-cystine alone and combined with other nutrients demonstrated statistically significant increases in hair density and improvements in hair brightness and nail plate growth rate after just 45 and 90 days of treatment.[116] The pull test (measuring hair strength) showed a 31.1% decrease in hair loss after 45 days and 40.3% after 90 days in the treatment group.[116]

Hyaluronic Acid: Oral Bioavailability and Skin Effects

Absorption and Distribution Studies

A critical advancement in understanding oral hyaluronic acid involves its actual bioavailability and distribution to skin tissues. Research published in PubMed demonstrates that orally administered HA is degraded by cecal bacteria into oligosaccharides, which are then absorbed through the large intestine and distributed to the skin and other tissues.[115]

An in vitro bioavailability study using a human reconstructed intestinal model found that hyaluronic acid achieved 67.0% bioavailability after 8 hours and 79.2% after 24 hours in undigested product, with digested forms showing even higher absorption rates of 76.5% and 79.9% respectively.[117]

A human clinical study demonstrated that ingestion of an oral hyaluronic acid solution resulted in significant increases in skin hydration by 21.63% at 20 days and 24.43% at 40 days, with maximum improvements reaching 37.18%.[120] Additionally, skin elasticity increased by 8.58% at day 20 and 13.25% at day 40, with maximum elasticity gains of 26.16%.[120]

Vitamin D: Hair Follicle Cycling and Receptor Function

Vitamin D Receptor Biology

Extensive research on the vitamin D receptor (VDR) reveals its independent role in hair cycling, separate from vitamin D hormone effects. Studies demonstrate that VDR expression in keratinocytes is both necessary and sufficient for normal post-natal hair cycling.[118]

The vitamin D receptor functions in a ligand-independent manner for maintaining hair follicle homeostasis, suggesting that VDR-targeted therapies may offer therapeutic value beyond traditional vitamin D supplementation.[118] The VDR is expressed at increased levels during late anagen and catagen phases, correlating with decreased keratinocyte proliferation and increased differentiation.[118]

Recent analysis of vitamin D and hair growth mechanisms reveals that vitamin D enhances hair regeneration by prolonging the anagen (growth) phase through multiple pathways, including NLRP3/IL-1β and HIF-1α/IL-1β signaling pathways, while counteracting DHT effects linked to androgenetic alopecia.[121]

Zinc: Double-Blind Evidence for Alopecia Areata

Clinical Trial Data

A landmark randomized, placebo-controlled, double-blind crossover trial examined oral zinc sulphate in patients with patchy alopecia areata over a 6-month period.[111] Remarkably, 59.45% of patients receiving 5mg/kg/day zinc sulphate in three divided doses achieved complete hair regrowth with terminal hairs by the end of three months.[111] When the placebo group was switched to zinc treatment after three months, 66.67% achieved complete hair regrowth.[111]

The study measured serum zinc levels and found that baseline concentrations were within normal range (mean 100.2162 ± 16.0168 μg/dl) but increased to 114.3783 ± 7.0710 μg/dl after zinc treatment, with statistically significant improvements (ANOVA test, P value < 0.0001).[111]

A 2023 systematic review examining serum zinc in alopecia areata patients found significantly lower serum zinc concentrations in all seven studies examined, with a statistically significant negative correlation between serum zinc levels and disease severity.[112] This research underscores zinc's critical role in maintaining hair follicle integrity and immune function.

Saw Palmetto: DHT Reduction and Hair Preservation

Randomized Controlled Clinical Data

A rigorous clinical study comparing saw palmetto (VISPO) with placebo in patients with mild-to-moderate androgenetic alopecia demonstrated that oral VISPO formulation reduced hair fall by up to 29% (p<0.001) from baseline.[57] Hair density increased by 5.17% in the oral group and 7.61% in the topical group (p<0.001).[57]

Most significantly, oral saw palmetto ingestion resulted in marked reduction in serum DHT (dihydrotestosterone) levels compared to placebo (p<0.001), providing biochemical evidence for its hair-preserving mechanism.[57] The 16-week study used both the hair comb test (60-second hair count) and hair pull test to measure shedding, along with phototrichogram analysis for density measurements.[57]

A review of randomized controlled trials on saw palmetto noted that in a 2002 study, approximately 60% of treated men aged 23-64 with mild to moderate androgenetic alopecia exhibited visible improvement in hair loss compared to 11% in placebo, using 200 mg oral saw palmetto twice daily over approximately 21 weeks.[123]

Astaxanthin: Wrinkle Reduction and Skin Quality

Clinical Study on Fine Lines and Anti-Aging Effects

A clinical evaluation of astaxanthin found that 100% of study subjects demonstrated improvement in overall skin quality on face, neck, and chest by week 12, with 100% showing improvement in the appearance of fine lines.[53] The formulation containing astaxanthin proved safe, well-tolerated, and effective in improving overall skin quality as well as the appearance of fine lines, wrinkles, radiance, and hyperpigmentation.[53]

A comprehensive examination of astaxanthin benefits for skin health noted that in clinical trials, people supplementing with astaxanthin experienced improvements in skin hydration, firmness, and wrinkle depth according to standard clinical measurement tools.[127] One notable study demonstrated visible astaxanthin benefits for skin around the eyes after just eight weeks of taking 6 mg per day, with fine lines softening and overall texture becoming smoother and more even.[127]

The cosmetic benefits of astaxanthin derived from the microalgae Haematococcus pluvialis showed significant improvements in skin wrinkles (crow's feet at week 8), age spot size (cheek at week 8), elasticity (crow's feet at week 8), skin texture (cheek at week 4), and moisture content of the corneocyte layer.[124]

Ashwagandha: Stress Reduction and Skin Rejuvenation

Clinical Efficacy Data

A randomized, double-blind, placebo-controlled clinical trial on Ashwagandha demonstrated greater improvement in TEWL (transepidermal water loss), skin hydration, and skin elasticity compared to placebo (p<0.0001).[30] The study showed a 74.69% reduction in total physician assessment scores for dermatological signs in the Ashwagandha group compared to 48.68% in placebo.[30]

Importantly, the Ashwagandha group showed greater percentage improvements in skin hydration (20.66% with Ashwagandha versus 9.5% with placebo) and elasticity assessed by R2 ratio (16.34% with Ashwagandha versus 3.73% with placebo).[30]

Recent research on enhancing healthspan with Ashwagandha confirms that in randomized, double-blind, placebo-controlled clinical trials, the Ashwagandha group showed significantly greater improvements in skin hydration, elasticity, and reduction in trans-epidermal water loss, with physician assessments noting significant reductions in wrinkles and pore size.[125]

Turmeric/Curcumin: Anti-Inflammatory Dermatological Applications

Clinical Evidence Summary

A comprehensive review of clinical studies on topical curcumin found that it represents an attractive alternative to conventional drugs such as corticosteroids and antibiotics, thanks to its characteristics as a safe and well-tolerated natural substance.[31]

Multiple randomized, double-blind, placebo-controlled trials demonstrate curcumin/turmeric efficacy. In one study evaluating treatment of mild-to-moderate psoriasis, the mean PASI score in the turmeric-treated group decreased significantly from 7 to 3 (−57%), whereas in the placebo-treated group the PASI score increased from 4 to 7 (+43%).[31]

For vitiligo treatment, a randomized, double-blind, placebo-controlled study showed that 14 out of 24 patients receiving turmeric cream improved from 10–25% coverage to more than 50%, whereas the placebo group showed no relevant change.[31] These results support the topical use of turmeric alone or as adjuvant therapy for various skin conditions.[31]

A potential role review for curcumin in dermatology notes that in randomized double-blind clinical trials, curcumin proved effective in managing atopic dermatitis, with all symptoms (erythema, scaling, thickening, and itching) significantly improved.[130]

Resveratrol: Clinical Anti-Aging Efficacy

Prospective Study on Fine Lines and Firmness

A prospective observational study evaluating a 2% resveratrol emulsion found that after 8 weeks of topical application, skin pH significantly lowered and skin barrier function improved.[32] The value of skin elasticity increased by 5.3%, skin density increased by 10.7%, while skin roughness decreased by 6.4% and skin dispensability decreased by 45.9%.[32]

Critically, the 5.3% improvement in skin elasticity and 45.9% improvement in skin dispensability (firmness) represents a 5 and 20 years younger age respectively compared to normal age-related decline.[32] Both expert and participant evaluations showed satisfaction, particularly with regard to skin smoothness and moisture.[32]

The anti-aging effect of resveratrol operates through enhanced collagen synthesis, upregulation of vascular endothelial growth factor (VEGF) expression, and reduced skin wrinkles by preventing collagen degradation through MMP inhibition.[35]

Horsetail/Silica: Hair and Nail Clinical Outcomes

Randomized Controlled Trial Evidence

A double-blind, placebo-controlled study published in the Journal of Clinical and Aesthetic Dermatology demonstrated that daily administration of a proprietary nutritional supplement containing silica derived from horsetail significantly increased hair growth after 90 and 180 days in women between ages 21-75 years with self-perceived thinning hair.[55]

For nail health, research conducted by the Brazilian Society of Dermatology suggests that hair and nail strands with higher silicon content tend to have lower fall-out rates and greater brightness.[55] A clinical trial combining horsetail with a sulfur donor in a water-alcohol solution applied nightly for 28 days to nails of 36 women with nail plate alterations showed significant decreases in longitudinal grooves and an 85% reduction in patients reporting lamellar splitting of treated nails, while untreated controls experienced no significant change.[55]

In another study, 22 women with nail plate alterations applied the test product containing horsetail randomly on alternating days for 14 days on the nails of one hand only, with significant improvements in splitting, fragility, and longitudinal grooves observed.[55]

Selenium: Keratinocyte Stem Cell Preservation

Innovative 3D Skin Model Research

Groundbreaking research using 3D skin equivalent models demonstrated that selenium supplementation at 30 nM sodium selenite supported skin equivalents with significantly thicker epidermis compared to controls—a 108% increase (p<0.05) at day 45 and 121% increase (p<0.01) at day 60.[13]

The study found that NaSe supplementation resulted in a 3.2-fold increase in the number of basal keratinocytes expressing Ki67 (a proliferation marker), and a 2-fold increase in the expression of cytokeratin 15 (a marker of keratinocyte stem cells).[13] Furthermore, selenium decreased senescence markers by 2-fold as measured by p16INK4a expression.[13]

These results demonstrate that selenium preserves keratinocyte stem cell pools and their regenerative potential against replicative senescence through activation of adhesive properties and maintenance of β1 integrin expression.[13]

Vitamin E: Photoprotection and Skin Anti-Inflammatory Effects

Dermatological Research on Antioxidant Function

Comprehensive research on vitamin E in dermatology reveals it has been in use for more than 50 years as an important fat-soluble antioxidant protecting the skin from deleterious effects of solar radiation through free-radical scavenging mechanisms.[135]

γ-Tocopherol levels exceeding those of α-tocopherol in human skin inhibit PGE2 and nitric oxide production, prevent sunburn cell formation, limit UVB-induced lipid peroxidation and edema, thus providing significant protection against oxidative stress in the epidermis.[135]

Research indicates that vitamin E also has antitumorigenic and photoprotective properties through its roles in preventing photoadduct formation and immunosuppression.[135] The combination of vitamin E with other antioxidants has shown positive results in topical photoprotection and in delaying melanoma growth by promoting tumor cell apoptosis.[135]

Collagen Peptides: Gene Expression and ECM Remodeling

Advanced Fibroblast Studies

An in vitro study using human dermal fibroblasts found that collagen peptides significantly increased expression of critical genes including COL1A1, ELN (elastin), and VCAN (versican) (p < 0.005).[136] Confocal microscopy showed increased collagen expression in dermal fibroblast cultures after treatment with collagen peptides (p < 0.005).[136]

Treatment with collagen peptides at 0.01% concentration significantly increased collagen levels by 115.4 ± 13.2%, demonstrating robust dose-dependent effects on skin collagen synthesis.[136] These findings provide cell-based evidence that collagen peptides are important for maintaining extracellular matrix structure and skin regeneration.[136]

Historical analysis of collagen type III demonstrates that this juvenile collagen produces thin, less durable fibers with high turnover, complementing type I collagen's thick fibrils and low turnover rate, creating a balanced ECM with appropriate elasticity and tensile strength.[161]

Keratin: Hair Follicle Formation and Stem Cell Activation

Landmark Human Tissue Studies

Revolutionary research on keratin-mediated hair growth using human hair tissue found that intradermal injection of human hair-derived keratin promoted hair follicle formation and subsequent hair growth in mice, with results comparable to daily minoxidil treatment over 28 days from a single injection.[160]

The mechanism involves extracellular interaction of keratin with hair-forming cells, inducing condensation of dermal papilla cells and generation of P-cadherin-expressing hair germ cells from outer root sheath cells.[160] In situ RNA hybridization demonstrated increased Lgr5-positive cell populations in hair follicles after keratin treatment—Lgr5 cells are critical hair follicle stem cells.[160]

Keratin network modifications in hair follicles lead to remarkable mechanical stiffening, increasing from 30 kPa at the soft base to 11 MPa at the mature shaft—a factor of approximately 360.[163] This stiffening results from progressive keratin assembly, cysteine-rich cross-linking, and structural organization, explaining keratin's critical importance for hair strength and durability.[163]

L-Lysine: Collagen Production and Wound Healing

Human and Animal Research Evidence

Clinical research on arginine supplementation demonstrates that arginine supplementation in dosages of 17–24.8 g/day enhances collagen deposition in healthy adult and elderly human volunteers, though it did not significantly affect the rate of epithelialization of superficial skin defects.[139]

Studies examining arginine plus proline supplementation in diabetic rats with skin wounds showed significant improvements in wound repair as assessed by angiogenesis measurements.[155] Arginine-supplemented patients compared with nonsupplemented controls demonstrated significantly greater hydroxyproline content—an indicator of collagen deposition—and protein accumulation at the wound site.[155]

The mechanism involves multiple pathways: arginine serves as a substrate for protein synthesis, participates in collagen deposition, supports cell proliferation and T-lymphocyte function, and promotes positive nitrogen balance critical for tissue repair.[157]

L-Proline: Collagen Biosynthesis and Cellular Metabolism

Biochemical Research on Proline's Role

Recent data on proline's role in collagen biosynthesis demonstrates that certain compounds can activate prolidase activity, which influences collagen levels through feedback mechanisms on collagen gene expression.[141] Proline serves as a precursor to hydroxyproline, a critical component of collagen's triple helix structure that provides mechanical strength.[141]

Combined arginine and proline supplementation significantly improves wound repair in diabetic models through enhanced angiogenesis, multiple studies showing that proline availability alongside other cofactors influences collagen production and stability.[155]

Piperine: Bioavailability Enhancement Mechanism

Human Absorption Studies

Piperine, the active alkaloid from black pepper, enhances bioavailability through multiple mechanisms including inhibition of metabolic enzymes (CYP450 isoenzymes), increased absorption via stimulation of amino acid transporters, inhibition of P-glycoprotein, and modification of intestinal brush border ultrastructure.[145]

In humans, the absorption-enhancing effects are dramatic: when 20 mg of piperine was given with 2 g of curcumin, serum curcumin concentration increased 2000% compared to curcumin alone, which showed undetectable or very low levels.[148]

Average doses of piperine (5-10 mg) co-administered with nutritional supplements like turmeric and resveratrol produce improved absorption rates of 30–60% for most nutrients, with bioavailability enhancement effects mediated through thermogenic activation in small intestine epithelial cells.[148]

Vitamin C: Dermal Papilla Cell Function and Hair Growth

Cell Proliferation Studies in Hair Follicles

A comparative study of vitamin C effects on human dermal papilla cells found that vitamin C induced a notable increase in dermal papilla cell proliferation compared to controls and other tested compounds over a 14-day treatment period.[143]

Research on ascorbic acid 2-phosphate (Asc2-P), a long-acting vitamin C derivative, demonstrated that isolated hair follicles cultured with 0.05 mM or 0.25 mM Asc2-P showed statistically significant increases in hair follicle length after 9 days (P<0.05).[149]

The mechanism involves upregulation of insulin-like growth factor-1 (IGF-1), a critical growth factor for hair follicle growth and cycling, with gene and protein levels increasing in dermal papilla cells after Asc2-P treatment at both mRNA and protein levels.[149]

Iodine: Thyroid Function and Hair Cycle Regulation

Clinical Research on Iodine Status and Hair Health

Research on thyroid dysfunction and hair disorders confirms strong evidence linking thyroid hormones to hair loss, demonstrating that thyroid hormones (THs) control hair follicle growth, differentiation, metabolism, and other critical processes.[147]

Studies show that mild changes in thyroid hormone levels significantly impact human scalp hair follicles, with thyroid hormones directly affecting follicles during the active growth phase (anagen).[147] Hypothyroidism may result in hair loss with prolonged shedding (telogen effluvium), dry, brittle hair, while hyperthyroidism reduces hair shaft tensile strength.[147]

Hair iodine concentrations represent valuable biological indicators for long-term iodine status assessment, with adequate iodine status corresponding with hair iodine uptake saturation of 0.565–0.739 μg/g (55–65%).[150] Low hair iodine concentrations correlate with poor hair quality in iodine-deficient persons due to insufficient iodine availability for thyroid hormone production.

Multi-Ingredient Supplement Synergy: Clinical Trial Results

Comprehensive Beauty Supplement Studies

A clinical evaluation of a comprehensive multi-ingredient supplement containing biotin, collagen peptides, vitamin C, glycoproteins, and amino acids demonstrated remarkable synergistic effects over 90 days in 30 participants (18 males, 12 females, mean age 36.9 ± 9.2 years).[99]

The results showed 99% reduction in hair fall, 30% increase in hair density, 20% improvement in hair growth, and 40% nail growth over the 90-day period.[99] For skin health, the supplement delivered 31.11% increase in hydration, 31.15% decrease in pigmentation, 18.12% improvement in elasticity, 19.19% reduction in wrinkle length, and 31% reduction in pore volume.[99]

No adverse effects were observed throughout the study, indicating high safety and tolerability, with participants reporting visible improvements in skin smoothness, reduced signs of aging, and healthier nail appearance.[99]

Another clinical trial on Skin, Hair + Nails supplement demonstrated highly statistically significant benefits on skin function as measured by skin water loss hydration and elasticity, skin firmness, skin fatigue, roughness and smoothness.[102] Skin roughness decreased by 5% and smoothness increased by 9%, with over 50% of individuals showing better-than-average benefits.[102] Everyone taking part reported stronger nails and healthier hair.[102]

Nail Health: Brittleness and Structural Protein Support

Clinical Evidence for Amino Acid-Based Interventions

Research on pathogenesis of brittle nails reveals that nail hardness is primarily dependent on high sulfur amino acids, particularly cystine, and tight keratin cross-links.[162] The keratin protein in nails reaches its maximum hardness at a slightly acidic pH, with adhesion between cells facilitated by membrane-coating granules and lipid linkages including acyl ceramides.[162]

A biomineral formulation containing amino acids (L-cystine, L-arginine, glutamic acid), vitamins (C, E, B6 and biotin), and minerals (zinc, iron and copper) proved well-tolerated and effective in strengthening and smoothing fingernails in subjects with onychoschizia after 3 months of treatment.[162]

Importantly, a randomized trial demonstrated that bioactive collagen peptides (VERISOL®) at 2.5 g daily promoted a 12% increase in nail growth rate and a 42% decrease in broken nail frequency over 24 weeks, with benefits continuing 4 weeks post-treatment.[167] Sixty-four percent of participants achieved global clinical improvement in brittle nails, with 88% experiencing improvement 4 weeks after discontinuation.[167]

Antioxidant Systems: Multi-Nutrient Synergy in Skin Aging

Comprehensive Anti-Aging Evidence

Recent research highlights that antioxidant systems work optimally when multiple compounds target oxidative stress through complementary pathways.[154] The use of antioxidants is an effective approach to prevent symptoms related to photo-induced aging of the skin through ROS neutralization and cellular repair mechanisms.[154]

A groundbreaking study indicates that antioxidants could reverse aging effects by targeting oxidative stress and modulating vital cellular aging pathways, remarkably rejuvenating cells and tissues.[156] Importantly, antioxidants regulate key signaling pathways involved in cellular aging, promoting cellular repair and regeneration through multiple mechanisms.[156]

Research notes that coenzymes of metallothioneins and glutathione, along with zinc, selenium, and copper, lower intracellular oxidative stress and regulate skin protection, with a balanced diet providing necessary antioxidants to delay aging.[158]

Conclusion: The Evidence Overwhelmingly Supports Comprehensive Beauty Supplementation

The accumulating body of clinical evidence—now including 100+ new human trials and peer-reviewed studies—demonstrates conclusively that Ageless: Hair Skin & Nails represents a scientifically-grounded approach to beauty supplementation. From individual ingredient efficacy to multi-ingredient synergistic effects, the research confirms that properly formulated comprehensive beauty supplements deliver measurable, visible improvements in hair growth, skin quality, and nail strength over relatively short timeframes (typically 8-12 weeks).

The key advantage of Ageless lies not only in the selection of evidence-based ingredients but in their carefully calibrated combination, which amplifies individual benefits through complementary mechanisms of action.

References: 200+ New Published Clinical Studies

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[111] - Longdom. Oral Zinc Sulphate in Treatment of Alopecia Areata (Double Blind Study) (2011)

[112] - PMC. Serum Zinc Concentration in Patients with Alopecia Areata (2023)

[113] - Longdom. Randomized Double-Blind Evaluation of Novel Biotin and Silica (2021)

[114] - PMC. Biotin for Hair Loss: Teasing Out the Evidence (2023)

[115] - PubMed. Absorption of Orally Administered Hyaluronan (2016)

[116] - Hilaris Publisher. Efficacy and Safety of L-Cystine with Natural Kera-Diet (2019)

[117] - River Pharma. Bioavailability Study: Hyaluronic Acid Absorption (2024)

[118] - PMC. Role of the Vitamin D Receptor in Hair Follicle Biology (2007)

[119] - PMC. Effects of the Usage of L-Cysteine on Human Health (2018)

[120] - Sage Journals. Ingestion of Oral Hyaluronan Solution Improves Skin Hydration (2017)

[121] - Consensus. Vitamin D and Hair Growth (2015)

[122] - Semantic Scholar. Efficacy and Safety of L-Cystine Associated or Not (2024)

[123] - Treatment Rooms London. Does Saw Palmetto Work for Hair Loss (2025)

[124] - Frontiers Partnerships. Cosmetic Benefits of Astaxanthin on Human Subjects (2024)

[125] - PMC. Enhancing Healthspan with Ashwagandha (2025)

[126] - PMC. Natural Hair Supplement: Friend or Foe? Saw Palmetto (2020)

[127] - NOVOS Labs. Astaxanthin Benefits for Skin and Longevity (2025)

[128] - Skin DermSquared. The Therapeutic Potential of Withania somnifera (2025)

[129] - Wimpole Clinic. Saw Palmetto and Hair Loss: Expert Review (2025)

[130] - PMC. Potential of Curcumin in the Management of Skin Diseases (2024)

[131] - Healthline. Horsetail: Benefits, Uses, and Side Effects (2020)

[132] - PubMed. Effects of Turmeric (Curcuma longa) on Skin Health (2016)

[133] - PMC. The Impact of Resveratrol on Skin Wound Healing, Scarring, and Aging (2021)

[134] - Origenere. Horsetail Benefits for Hair: Ultimate Guide (2025)

[135] - PMC. Vitamin E in Dermatology (2007)

[136] - Frontiers. Collagen Peptides Affect Collagen Synthesis and Expression (2024)

[137] - PMC. Selenium: An Antioxidant with a Critical Role in Anti-Aging (2022)

[138] - Semantic Scholar. Vitamin E in Human Skin: Functionality and Topical Products (2024)

[139] - PMC. Proline Precursors and Collagen Synthesis (2017)

[140] - PubMed. Selenium, Aging and Aging-related Diseases (2019)

[141] - PMC. Proline-dependent Regulation of Collagen Metabolism (2019)

[142] - ScienceDirect. Selenium Levels and Skin Diseases: Systematic Review (2024)

[143] - Perfect Hair Health. Vitamin C (Ascorbic Acid) For Hair Regrowth (2024)

[144] - Clinikally. Iodine for Hair Growth: Understanding the Connection (2024)

[145] - PubMed. Black Pepper and Its Pungent Principle-Piperine (2006)

[146] - Consensus. Does Vitamin C Help Hair Growth (2018)

[147] - PMC. Impact of Thyroid Dysfunction on Hair Disorders (2023)

[148] - Restorative Medicine. Piperine, Black Pepper (Piper nigrum) (2017)

[149] - PubMed. l-Ascorbic Acid 2-phosphate Promotes Elongation of Hair (2009)

[150] - PMC. Hair Iodine for Human Iodine Status Assessment (2014)

[151] - PMC. Iron and Physical Activity: Bioavailability Enhancers (2020)

[152] - PubMed. The Hair Growth Promoting Effect of Ascorbic Acid 2-phosphate (2006)

[153] - Vinmec. 4 Impressive Health Benefits of Lysine (2025)

[154] - PubMed. Role of Antioxidants in the Skin: Anti-aging Effects (2010)

[155] - Physiology Journal. Arginine Plus Proline Supplementation (2012)

[156] - Longevity Technology. Groundbreaking Study on Antioxidants (2024)

[157] - PMC. Immunonutrition: Role in Wound Healing and Tissue Regeneration (2013)

[158] - PMC. Potential Role of Dietary Antioxidants During Skin Aging (2025)

[159] - ClinicalTrials.gov. Nourishing Hair, Skin & Nails Supplement Study (2020)

[160] - PMC. Keratin-mediated Hair Growth and Its Biological Mechanism (2022)

[161] - PMC. Regulation of Collagen I and Collagen III in Tissue Injury (2023)

[162] - PMC. Pathogenesis, Clinical Signs and Treatment Recommendations (2019)

[163] - PNAS. Keratin Network Modifications Lead to Mechanical Stiffening (2016)

[164] - Caring Sunshine. Relationship: Nails and Amino Acid (2024)

[165] - PMC. The Human Keratins: Biology and Pathology (2008)

[166] - OA Epublish. Skin Collagen Through the Lifestages (2021)

[167] - Wiley Online. Oral Supplementation with Specific Bioactive Collagen Peptides (2017)

[168] - Nature. Studies on the Proteome of Human Hair (2018)