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Longer Stronger Hair & Nails

Applied Nutrition
4.8
★ ★ ★ ★ ★
(2048 ratings)
Copper 2 mg
PABA 30 mg
Vitamin A 7500 IU
Biotin 2500 mcg
Zinc 15 mg
Horsetail 200 mg
Collagen 60 mg
Product Image
Score69
A well-targeted biotin and mineral formula for hair and nails, with weak collagen dosing and incomplete horsetail and bioflavonoid disclosure as the main limits.
How scoring works
Quantity:60 Liquid(s) • (30 servings)
Goals:
Nail Health
Hair Health
Skin Health

Score 69

A well-targeted biotin and mineral formula for hair and nails, with weak collagen dosing and incomplete horsetail and bioflavonoid disclosure as the main limits.
How scoring works
$15.99($0.53 per serving)
iHerb
$ 15.99
Amazon
$ 0.00
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Analysis

Biotin at 2,500 mcg, zinc citrate, copper chelate, vitamin C, and horsetail align well with normal hair and nail structure. The formula is most relevant when one of these nutrients is inadequate, while changes would appear gradually as new hair and nail tissue grows.

Mineral form quality is a strength, and the 15 mg zinc amount is paired with 2 mg copper. Horsetail identifies the species but not the plant part or silica yield, so its active contribution cannot be confirmed.

Hydrolyzed collagen sounds useful but reaches only 60 mg, far below a meaningful oral collagen serving. The product has some secondary skin and immune relevance, yet it lacks the collagen depth, vitamin D, selenium, and eye-specific nutrients needed for broader goals.

Who is it for
  • Adults seeking a hair-and-nail supplement with useful zinc and copper forms
  • People whose diet may be low in biotin, zinc, or vitamin C
  • Users willing to disclose high-dose biotin before laboratory testing
Best for
  • Nail growth and resilience when nutrient intake is inadequate
  • Hair-focused micronutrient support
  • Combining biotin with zinc, copper, vitamin C, and horsetail

Pros

  • Provides 2,500 mcg biotin at a clearly stated amount
  • Uses well-absorbed zinc citrate
  • Pairs 15 mg zinc with 2 mg chelated copper
  • Includes vitamin C and a species-identified horsetail extract
  • Active amounts are mostly disclosed

Cons

  • The 60 mg collagen amount is only a token addition
  • Collagen source, type, and amino acid profile are not disclosed
  • Horsetail does not state plant part or active silica yield
  • The bioflavonoid complex hides individual ingredients and amounts
  • The formula has little direct value for bone, digestive, or testosterone goals

Warnings

  • Biotin at 2,500 mcg can distort thyroid, hormone, and cardiac troponin blood tests; disclose use to the laboratory and ordering clinician before testing.
  • Preformed vitamin A as retinyl palmitate should be counted with other supplements, and people who are pregnant or could become pregnant should avoid excessive intake.
  • PABA can interfere with sulfonamide antibiotics, so concurrent use should be reviewed with the prescriber.
  • The undisclosed bioflavonoid complex prevents complete screening for personal sensitivities and medicine interactions.

Nutrient quality

74 High impact

The nutrient and botanical combination is strongly aligned with hair and nail support. Token collagen and an opaque bioflavonoid complex add more label appeal than functional depth.

Ingredient transparency

64 Moderate impact

Most actives have stated amounts, but components of the antioxidant bioflavonoid complex are not individually quantified. A complete inactive-ingredient list is absent.

Customer satisfaction

73 High impact

Feedback volume is substantial enough to stabilize the aggregate signal. No complaint text is supplied, so repeated negative themes cannot be assessed.

Value for money

67 High impact

The serving offers reasonable value for the meaningful biotin, zinc, copper, and vitamin amounts. Token collagen and an opaque bioflavonoid blend weaken the value of the extras.

Report analysis

Goals

Nail Health
Nail Health
Impact
Highest effect
A- Goal FitB+ Strength of SupportA- CoverageB+ Formula Quality
Collagen · 60 mgBiotin · 2500 mcgHorsetail · 200 mg

Biotin, zinc citrate, horsetail, vitamin C, and hydrolyzed collagen create a strongly nail-focused formula. The expected benefit is greatest when the relevant nutrient intake is inadequate.

Collagen is only a trace amount and the horsetail extract does not disclose active silica yield. Nails grow slowly, so any change would appear in new nail over time rather than repair the existing plate.

Study evidence
Biotin Supportive 8 studies
Collagen Supportive 4 studies
Horsetail Not classified

No linked studies yet.

Vitamin C Supportive 1 study
Zinc No effect 1 study
Hair Health
Hair Health
Impact
High effect
B Goal FitC+ Strength of SupportB CoverageB Formula Quality
Biotin · 2500 mcgZinc · 15 mgVitamin C · 100 mgCollagen · 60 mg

Biotin at 2,500 mcg, zinc citrate, chelated copper, horsetail, gotu kola, and collagen provide a directly targeted hair-and-nail profile. The collagen amount is only 60 mg, and horsetail does not disclose its silica yield, so structural support is weaker than the label suggests.

The combination covers nutritional, connective-tissue, and circulation-related pathways with generally clear amounts. High-dose biotin may distort thyroid, hormone, or cardiac troponin blood tests, so it should be disclosed before laboratory testing.

Study evidence
Biotin Supportive 4 studies
Collagen Supportive 3 studies
Copper Adverse 4 studies
Horsetail Not classified

No linked studies yet.

Zinc Supportive 22 studies
Skin Health
Skin Health
Impact
High effect
B- Goal FitC+ Strength of SupportC+ CoverageB- Formula Quality
Zinc · 15 mgVitamin C · 100 mgCollagen · 60 mgCopper · 2 mg

Vitamin A, vitamin C, zinc, copper, and silica-related horsetail support turnover, collagen synthesis, and tissue integrity. Hydrolyzed collagen is included, but its amount is far below a meaningful oral collagen serving.

The formula is relevant to skin despite being marketed mainly for hair and nails. The 2,500 mcg biotin amount can distort thyroid, hormone, or cardiac troponin blood tests and should be disclosed before laboratory testing.

Study evidence
Biotin Supportive 10 studies
Collagen Supportive 62 studies
Copper Supportive 16 studies
Vitamin A Supportive 106 studies
Vitamin C Supportive 53 studies
Zinc Supportive 66 studies
Immunity
Immunity
Impact
Moderate effect
C+ Goal FitB- Strength of SupportC- CoverageD- Formula Quality
Vitamin C · 100 mgZinc · 15 mgVitamin A · 7500 IU

Vitamin A, vitamin C, and zinc provide a modest foundation for barrier and immune-cell support. Zinc citrate is supplied at a useful maintenance amount.

The formula lacks vitamin D and selenium, leaving important immune pathways uncovered. Most of its botanicals, collagen, and biotin are aimed at hair and nail support rather than the selected goal.

Study evidence
Vitamin A Supportive 107 studies
Vitamin C Supportive 53 studies
Zinc Supportive 73 studies
Vision Support
Vision Support
Impact
Moderate effect
C Goal FitB- Strength of SupportD+ CoverageD Formula Quality
Zinc · 15 mgVitamin C · 100 mgCopper · 2 mgVitamin A · 7500 IU

Vitamin A, vitamin C, zinc, and copper provide basic nutrients that also matter for normal visual function and antioxidant defense. The hair and nail formula is not designed around ocular outcomes.

Vitamin A is substantial and delivered in a softgel, while zinc and copper use good organic forms. Lutein, zeaxanthin, DHA, vitamin E, and a broader retinal antioxidant system are absent.

Study evidence
Copper Supportive 7 studies
Vitamin A Supportive 65 studies
Vitamin C Disputed 24 studies
Zinc Supportive 39 studies
General Health
General Health
Impact
Moderate effect
C Goal FitC Strength of SupportD+ CoverageC+ Formula Quality
Collagen · 60 mgZinc · 15 mgVitamin C · 100 mg

Zinc citrate, vitamin C, copper, and vitamin A provide some useful micronutrient support. The formula remains focused on hair and nail needs rather than broad daily resilience.

Only a trace amount of hydrolyzed collagen is supplied, and the bioflavonoid complex is not individually disclosed. Good zinc and copper forms improve coherence, but they do not compensate for the very small collagen amount.

Study evidence
Collagen Supportive 31 studies
Vitamin C Supportive 56 studies
Zinc Supportive 60 studies

Ingredients

IngredientAmount per serving
Vitamin A (Vitamin A Palmitate)
 7500 IU
Vitamin C (Ascorbic Acid)
 100 mg
Biotin
2500 mcg
Calcium (Calcium Carbonate)
 20 mg
Zinc (Zinc Citrate)
 15 mg
Copper (Copper Amino Acid Chelate)
 2 mg
Horsetail (Equisetum arvense) extract (Silica)
 200 mg
Gotu Kola extract (Triterpenes)
 120 mg
hydrolyzed Collagen
60 mg
PABA
30 mg
Antioxidant Bioflavonoid Complex
80 mg
Adults 18–50
Report overview
Copper (Copper Amino Acid Chelate) · 2 mg OverallScore87
A+ Active Ingredient Quality & BioavailabilityA- Dose, Safety & Label TransparencyC+ Value

The copper amino acid chelate is a highly absorbable form with clear label disclosure. The copper amount matches the collection target. The zinc-to-copper balance falls outside the preferred range, though both minerals are present. The serving cost is reasonable for a broader multi-ingredient formula.

View ingredientView products
PABA · 30 mg OverallScore82
A Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyD- Value

PABA is clearly named in a standard form, though no pharmaceutical-grade or high-purity claim is supplied, and the delivery format suits the dose. The clearly disclosed 30 mg amount suits a high-potency B-complex, and no targeted additives appear in the supplied ingredient data. PABA-specific cost efficiency is weak, so the broader formula must carry most of the value.

View ingredientView products
Vitamin A (Vitamin A Palmitate) · 7500 IU OverallScore80
C- Active Ingredient Quality & BioavailabilityA+ Dose, Safety & Label TransparencyB+ Value

Preformed retinyl palmitate supplies all vitamin A, so long-term intake is less self-regulated than carotenoid conversion. The liquid softgel provides a favorable fat-based delivery format. The dose is within the preferred range and the cost efficiency is good.

View ingredientView products
Loading alternative details
75 Performance

Longer Stronger Hair and Nails

Irwin Naturals
Longer Stronger Hair and Nails improves the hair-focused design through buffered vitamin C, useful mineral forms, biotin, horsetail, amino acids, and flax oil. Lysine and proline are modest and horsetail lacks silica standardization, but the formula avoids the original's substantial preformed vitamin A and token collagen.
72 Performance

Hair Volume

New Nordic
Hair Volume offers a clearer hair-focused blend of biotin, apple procyanidins, zinc, copper, horsetail, and methionine. Zinc oxide and copper sulfate are basic forms and concentrated biotin may interfere with laboratory tests, but the formula avoids the original's substantial preformed vitamin A and token collagen.
67 Performance

Hair/Skin/Nails Ultra

Pure Encapsulations
Hair/Skin/Nails Ultra provides specialized nutrient forms and broader structural support through zinc, copper, PABA, and collagen. Several amounts weaken confidence and value and the listed biotin should be verified, but the formula is more structurally focused than the original's token collagen serving.
78 Budget

Hair Skin & Nails

Nature Made
Hair Skin & Nails is the only clearly hair-focused candidate with a lower serving cost, using biotin, beta-carotene, vitamin C, zinc, and copper. It avoids the original's substantial preformed vitamin A and token collagen, but oxide minerals weaken absorption quality and high biotin may interfere with laboratory tests.
74 Value

Longer Stronger Hair and Nails

Irwin Naturals
Longer Stronger Hair and Nails provides better practical value through buffered vitamin C, useful mineral forms, biotin, horsetail, amino acids, and flax oil at a serving cost close to the original. Lysine and proline are modest and horsetail lacks full silica detail, while concentrated biotin may interfere with laboratory tests.
74 Value

Hair Volume

New Nordic
Hair Volume balances quality and cost with biotin, apple procyanidins, zinc, copper, horsetail, cysteine, and methionine in a focused hair formula. Basic mineral forms and modest amino-acid amounts limit depth, but it avoids the original's substantial preformed vitamin A and token collagen.
81 Value

Hair Skin & Nails Collagen Plus Formula

Life Extension
Hair Skin & Nails Collagen Plus Formula offers stronger value through substantial collagen peptides and keratin rather than the original's token collagen amount. Biotin and supporting nutrients add breadth, although basic mineral forms and low silicon temper the otherwise focused formula.
Report alternatives

Sources

Published studies used for the product analysis and the top-ranked studies for each ingredient and goal.

  1. The Role of Sesbania grandiflora-Derived Biotin and Bambusa arundinacea-Derived Silica Extracts in Promoting Hair, Skin, and Nail Health: A Randomized, Double-Blind, Placebo-Controlled Clinical Study.
    Patel MN; Maheshvari J; Patel N · Cureus · 2025
    Randomized trial105 participantsHair Health Nail Health Skin Health forBiotin
  2. The Infatuation With Biotin Supplementation: Is There Truth Behind Its Rising Popularity? A Comparative Analysis of Clinical Efficacy versus Social Popularity.
    Soleymani T; Lo Sicco K; Shapiro J · Journal of drugs in dermatology : JDD · 2018
    Narrative reviewHair Health forBiotin
  3. Hair Loss and Zinc Deficiency: A Cross-Sectional Study.
    Liran O; Vered S; Cohen B; Shapiro Ben David S; Nakhleh A; Rahamim-Cohen D; Azuri J; Adler L · Healthcare (Basel, Switzerland) · 2025
    Cross-sectional study23,975 participantsHair Health forZinc
  4. The effects of minoxidil, 1% pyrithione zinc and a combination of both on hair density: a randomized controlled trial.
    Berger RS; Fu JL; Smiles KA; Turner CB; Schnell BM; Werchowski KM; Lammers KM · The British journal of dermatology · 2003
    Randomized trial200 participantsHair Health forZinc
  5. Trace element levels in alopecia areata.
    Bhat YJ; Manzoor S; Khan AR; Qayoom S · Indian journal of dermatology, venereology and leprology · 2009
    Case-control study100 participantsHair Health forCopper
  6. Biotin for the treatment of nail disease: what is the evidence?
    Lipner SR; Scher RK · The Journal of dermatological treatment · 2018
    Narrative reviewNail Health forBiotin
  7. Vitamins and minerals: their role in nail health and disease.
    Scheinfeld N; Dahdah MJ; Scher R · Journal of drugs in dermatology : JDD · 2007
    Narrative reviewNail Health forZinc Nail Health forBiotin
  8. A double-blind, placebo-controlled, randomised, clinical study on the effectiveness of collagen peptide on osteoarthritis.
    Kumar S; Sugihara F; Suzuki K; Inoue N; Venkateswarathirukumara S · Journal of the science of food and agriculture · 2015
    Randomized trialGeneral Health forCollagen
  9. Efficacy and safety of native type II collagen in modulating knee osteoarthritis symptoms: a randomised, double-blind, placebo-controlled trial.
    Luo C; Su W; Song Y; Srivastava S · Journal of experimental orthopaedics · 2023
    Randomized trial101 participantsGeneral Health forCollagen
  10. Healing Process, Pain, and Health-Related Quality of Life in Patients with Venous Leg Ulcers Treated with Fish Collagen Gel: A 12-Week Randomized Single-Center Study.
    Mościcka P; Cwajda-Białasik J; Szewczyk MT; Jawień A · International journal of environmental research and public health · 2022
    Randomized trial100 participantsGeneral Health forCollagen
  11. Efficacy and Safety of Dietary Undenatured Type II Collagen on Joint and Motor Function in Healthy Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study.
    Shiojima Y; Takahashi M; Takahashi R; Maruyama K; Moriyama H; Bagchi D; Bagchi M; Akanuma M · Journal of the American Nutrition Association · 2023
    Randomized trial64 participantsGeneral Health forCollagen
  12. The use of a collagen matrix in hard-to-heal venous leg ulcers.
    Romanelli M; Mulder G; Paggi B; Macchia M; Panduri S; Dini V · Journal of wound care · 2016
    Randomized trial40 participantsGeneral Health forCollagen
  13. Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective studies.
    Aune D; Keum N; Giovannucci E; Fadnes LT; Boffetta P; Greenwood DC; Tonstad S; Vatten LJ; Riboli E; Norat T · The American journal of clinical nutrition · 2019
    Meta-analysis69 studies pooledGeneral Health forVitamin C
  14. Scientific Opinion on the substantiation of a health claim related to vitamin C and increasing non haem iron absorption pursuant to Article 14 of Regulation (EC) No 1924/2006.
    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) · EFSA journal. European Food Safety Authority · 2026
    Guideline / consensusGeneral Health forVitamin C
  15. Vitamin C Depletion and All-Cause Mortality in Renal Transplant Recipients.
    Sotomayor CG; Eisenga MF; Gomes Neto AW; Ozyilmaz A; Gans ROB; Jong WHA; Zelle DM; Berger SP; Gaillard CAJM; Navis GJ; Bakker SJ · Nutrients · 2018
    Cohort study598 participantsGeneral Health forVitamin C
  16. Associations of Serum Biomarkers of Fruit and Vegetable Intake With the Risk of Cause-Specific Mortality and All-Cause Mortality: A National Prospective Cohort Study.
    Pu L; Zhang R; Wang X; Zhao T; Sun H; Han L · Frontiers in nutrition · 2022
    Cohort study12,530 participantsGeneral Health forVitamin C
  17. Relation between plasma ascorbic acid and mortality in men and women in EPIC-Norfolk prospective study: a prospective population study. European Prospective Investigation into Cancer and Nutrition.
    Khaw KT; Bingham S; Welch A; Luben R; Wareham N; Oakes S; Day N · Lancet (London, England) · 2001
    Cohort study19,496 participantsGeneral Health forVitamin C
  18. Effectiveness of sodium bicarbonate and zinc chloride mouthwashes in the treatment of oral mucositis and quality of life in patients with cancer under chemotherapy.
    Mohammadi F; Oshvandi K; Kamallan SR; Khazaei S; Ranjbar H; Ahmadi-Motamayel F; Gillespie M; Jenabi E; Vafaei SY · Nursing open · 2022
    Randomized trial144 participantsGeneral Health forZinc
  19. Zinc supplementation in young children with acute diarrhea in India.
    Sazawal S; Black RE; Bhan MK; Bhandari N; Sinha A; Jalla S · The New England journal of medicine · 1995
    Randomized trial937 participantsGeneral Health forZinc
  20. Associations of mortality with ocular disorders and an intervention of high-dose antioxidants and zinc in the Age-Related Eye Disease Study: AREDS Report No. 13.
    Clemons TE; Kurinij N; Sperduto RD; AREDS Research Group · Archives of ophthalmology (Chicago, Ill. : 1960) · 2004
    Randomized trial4,753 participantsGeneral Health forZinc
  21. Effects of zinc and probiotic co-supplementation on inflammation, gastrointestinal symptoms, quality of life, and mood in irritable bowel syndrome patients.
    Rezazadegan M; Soheilipour M; Amani R · Scientific reports · 2026
    Randomized trial84 participantsGeneral Health forZinc
  22. Effect of zinc sulfate supplementation on premenstrual syndrome and health-related quality of life: Clinical randomized controlled trial.
    Siahbazi S; Behboudi-Gandevani S; Moghaddam-Banaem L; Montazeri A · The journal of obstetrics and gynaecology research · 2018
    Randomized trial142 participantsGeneral Health forZinc
  23. Low serum biotinidase activity in children with valproic acid monotherapy.
    Schulpis KH; Karikas GA; Tjamouranis J; Regoutas S; Tsakiris S · Epilepsia · 2001
    Clinical trial125 participantsHair Health Skin Health forBiotin
  24. Vitamins A, B, C, and D: A Short Review for the Dermatologist.
    Coerdt KM; Goggins CA; Khachemoune A · Alternative therapies in health and medicine · 2021
    Narrative reviewHair Health forBiotin
  25. Low-Molecular-Weight Collagen Peptide Supplementation Improves Cellulite Severity, Skin Elasticity, and Hair Shaft Diameter: A Clinical Study with Pharmacokinetic Evaluation.
    Hwang S; Won J; Kim S; Kang W; Park M · Journal of medicinal food · 2026
    Randomized trial114 participantsHair Health forCollagen
  26. Calcium and Vitamin D Supplementation with and Without Collagen on Bone Density and Skin Elasticity in Menopausal Women-A Randomized Controlled Study.
    Duangjai A; Srivilai J; Nangola S; Amornlerdpison D · Clinics and practice · 2025
    Randomized trialHair Health forCollagen
  27. Dietary Collagen Supplementation as a Strategy for Skin Health: A Narrative Review of Clinical Effects on Skin, Hair, Nails, and Wound Healing.
    Biełach-Bazyluk A; Jurga M; Flisiak I; Zbroch E · Nutrients · 2026
    Narrative reviewHair Health forCollagen
  28. Menkes disease and response to copper histidine: An Indian case series.
    Yoganathan S; Sudhakar SV; Arunachal G; Thomas M; Subramanian A; George R; Danda S · Annals of Indian Academy of Neurology · 2022
    Case series4 participantsHair Health forCopper
  29. UV damage to hair and the effect of antioxidants and metal chelators.
    Millington KR; Marsh JM · International journal of cosmetic science · 2021
    In vitro / ex vivo studyHair Health forCopper
  30. Preserving fibre health: reducing oxidative stress throughout the life of the hair fibre.
    Marsh JM; Davis MG; Lucas RL; Reilman R; Styczynski PB; Li C; Mamak M; McComb DW; Williams RE; Godfrey S; Navqi KR; Chechik V · International journal of cosmetic science · 2016
    In vitro / ex vivo studyHair Health forCopper
  31. Incubatory environment of the scalp impacts pre-emergent hair to affect post-emergent hair cuticle integrity.
    Schwartz JR; Henry JP; Kerr KM; Flagler MJ; Page SH; Redman-Furey N · Journal of cosmetic dermatology · 2018
    Randomized trialHair Health forZinc
  32. A comparison of hair quality and cosmetic acceptance following the use of two anti-dandruff shampoos.
    Draelos ZD; Kenneally DC; Hodges LT; Billhimer W; Copas M; Margraf C · The journal of investigative dermatology. Symposium proceedings · 2006
    Randomized trial40 participantsHair Health forZinc
  33. BMI and levels of zinc, copper in hair, serum and urine of Turkish male patients with androgenetic alopecia.
    Ozturk P; Kurutas E; Ataseven A; Dokur N; Gumusalan Y; Gorur A; Tamer L; Inaloz S · Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS) · 2015
    Case-control study216 participantsHair Health forZinc
  34. Analysis of serum zinc and copper concentrations in hair loss.
    Kil MS; Kim CW; Kim SS · Annals of dermatology · 2013
    Case-control study342 participantsHair Health forZinc
  35. Depressed immune response to tetanus in children with vitamin A deficiency.
    Semba RD; Muhilal; Scott AL; Natadisastra G; Wirasasmita S; Mele L; Ridwan E; West KP; Sommer A · The Journal of nutrition · 1992
    Randomized trial236 participantsImmunity forVitamin A
  36. Impact of a single megadose of vitamin A at delivery on breastmilk of mothers and morbidity of their infants.
    Roy SK; Islam A; Molla A; Akramuzzaman SM; Jahan F; Fuchs G · European journal of clinical nutrition · 1997
    Randomized trial50 participantsImmunity forVitamin A
  37. Vitamin A supplementation reduces measles morbidity in young African children: a randomized, placebo-controlled, double-blind trial.
    Coutsoudis A; Broughton M; Coovadia HM · The American journal of clinical nutrition · 1991
    Randomized trial60 participantsImmunity forVitamin A
  38. Vitamin A supplementation enhances specific IgG antibody levels and total lymphocyte numbers while improving morbidity in measles.
    Coutsoudis A; Kiepiela P; Coovadia HM; Broughton M · The Pediatric infectious disease journal · 1992
    Randomized trial60 participantsImmunity forVitamin A
  39. Vitamin A supplementation reduces the monocyte chemoattractant protein-1 intestinal immune response of Mexican children.
    Long KZ; Santos JI; Estrada Garcia T; Haas M; Firestone M; Bhagwat J; Dupont HL; Hertzmark E; Rosado JL; Nanthakumar NN · The Journal of nutrition · 2006
    Randomized trial127 participantsImmunity forVitamin A
  40. Vitamin C and contribution to the normal function of the immune system: evaluation of a health claim pursuant to Article 14 of Regulation (EC) No 1924/2006.
    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) · EFSA journal. European Food Safety Authority · 2026
    Guideline / consensusImmunity forVitamin C
  41. Therapeutic effects of high-dose vitamin C supplementation in patients with COVID-19: a meta-analysis.
    Sun L; Zhao JH; Fan WY; Feng B; Liu WW; Chen RQ; Ban C; Dang AG; Wang M; Luo KT; Zhou GY; Yu FF; Ba Y · Nutrition reviews · 2024
    Meta-analysis2,334 participants14 studies pooledImmunity forVitamin C
  42. Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis.
    Abioye AI; Bromage S; Fawzi W · BMJ global health · 2021
    Meta-analysisImmunity forVitamin C
  43. New evidence for antioxidant properties of vitamin C.
    Vojdani A; Bazargan M; Vojdani E; Wright J · Cancer detection and prevention · 2001
    Randomized trial20 participantsImmunity forVitamin C
  44. Enhanced Vitamin C Delivery: A Systematic Literature Review Assessing the Efficacy and Safety of Alternative Supplement Forms in Healthy Adults.
    Calder PC; Kreider RB; McKay DL · Nutrients · 2025
    Systematic review13 studies pooledImmunity forVitamin C
  45. Nutrient supplementation for prevention of viral respiratory tract infections in healthy subjects: A systematic review and meta-analysis.
    Vlieg-Boerstra B; de Jong N; Meyer R; Agostoni C; De Cosmi V; Grimshaw K; Milani GP; Muraro A; Oude Elberink H; Pali-Schöll I; Roduit C; Sasaki M; Skypala I; Sokolowska M; van Splunter M; Untersmayr E; Venter C; O'Mahony L; Nwaru BI · Allergy · 2022
    Meta-analysis199,055 participants115 studies pooledImmunity forZinc
  46. Zinc supplementation reduces the incidence of acute lower respiratory infections in infants and preschool children: a double-blind, controlled trial.
    Sazawal S; Black RE; Jalla S; Mazumdar S; Sinha A; Bhan MK · Pediatrics · 1998
    Randomized trial609 participantsImmunity forZinc
  47. A randomized controlled trial of zinc supplementation in the treatment of acute respiratory tract infection in Thai children.
    Rerksuppaphol S; Rerksuppaphol L · Pediatric reports · 2020
    Randomized trial64 participantsImmunity forZinc
  48. The effect of zinc and vitamin A supplementation on immune response in an older population.
    Fortes C; Forastiere F; Agabiti N; Fano V; Pacifici R; Virgili F; Piras G; Guidi L; Bartoloni C; Tricerri A; Zuccaro P; Ebrahim S; Perucci CA · Journal of the American Geriatrics Society · 1998
    Randomized trial136 participantsImmunity forZinc
  49. The role of specific nutrients in preventing immune system and blood cell disorders: an umbrella review.
    Vecchietti A; Strano P; Minutolo G; Grieco V; Cappuccio G; Granvillano G; Confalonieri L; Briganti GL; Raso E; Chimienti M; Pellegrini M; Mercogliano M; Spatari G; Lugli C; Urbano T; Lorenzon A · Journal of preventive medicine and hygiene · 2026
    Systematic review13 studies pooledImmunity forZinc
  50. Treatment of brittle fingernails and onychoschizia with biotin: scanning electron microscopy.
    Colombo VE; Gerber F; Bronhofer M; Floersheim GL · Journal of the American Academy of Dermatology · 1991
    Other32 participantsNail Health forBiotin
  51. Treatment of brittle nail with a hydroxypropyl chitosan-based lacquer, alone or in combination with oral biotin: A randomized, assessor-blinded trial.
    Chiavetta A; Mazzurco S; Secolo MP; Tomarchio G; Milani M · Dermatologic therapy · 2020
    Randomized trial50 participantsNail Health forBiotin
  52. Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails.
    Hexsel D; Zague V; Schunck M; Siega C; Camozzato FO; Oesser S · Journal of cosmetic dermatology · 2018
    Single-arm trial25 participantsNail Health forCollagen
  53. Influence of collagen peptide supplementation on visible signs of skin and nail health and -aging in an East Asian population: A double blind, randomized, placebo-controlled trial.
    Vleminckx S; Virgilio N; Asserin J; Prawitt J; Silva CIF · Journal of cosmetic dermatology · 2024
    Randomized trial85 participantsNail Health forCollagen
  54. Nail Supplements: When, How, and Why?
    Zaraa I; Richert B · Skin appendage disorders · 2026
    Narrative reviewNail Health forCollagen
  55. Expanding the COL7A1 mutation database: novel and recurrent mutations and unusual genotype-phenotype constellations in 41 patients with dystrophic epidermolysis bullosa.
    Kern JS; Kohlhase J; Bruckner-Tuderman L; Has C · The Journal of investigative dermatology · 2006
    Observational study41 participantsNail Health forCollagen
  56. Vitamin C Deficiency in Inflammatory Bowel Disease: The Forgotten Micronutrient.
    Dunleavy KA; Ungaro RC; Manning L; Gold S; Novak J; Colombel JF · Crohn's & colitis 360 · 2023
    Other20 participantsNail Health forVitamin C
  57. Evaluation of biophysical skin parameters and hair changes in patients with acne vulgaris treated with isotretinoin, and the effect of biotin use on these parameters.
    Aksac SE; Bilgili SG; Yavuz GO; Yavuz IH; Aksac M; Karadag AS · International journal of dermatology · 2021
    Non-randomized trial60 participantsSkin Health forBiotin
  58. Generalized seborrhoeic dermatitis. Clinical and therapeutic data of 25 patients.
    Messaritakis J; Kattamis C; Karabula C; Matsaniotis N · Archives of disease in childhood · 1976
    Non-randomized trial25 participantsSkin Health forBiotin
  59. Holocarboxylase synthetase deficiency: novel clinical and molecular findings.
    Tammachote R; Janklat S; Tongkobpetch S; Suphapeetiporn K; Shotelersuk V · Clinical genetics · 2010
    Case series4 participantsSkin Health forBiotin
  60. Exploring the Impact of Hydrolyzed Collagen Oral Supplementation on Skin Rejuvenation: A Systematic Review and Meta-Analysis.
    Dewi DAR; Arimuko A; Norawati L; Yenny SW; Setiasih NL; Perdiyana A; Arkania N; Nadhira F; Wiliantari N · Cureus · 2024
    Meta-analysis967 participants14 studies pooledSkin Health forCollagen
  61. Effects of collagen-based supplements on skin's hydration and elasticity: A systematic review and meta-analysis.
    Danessa G; Notario D; Regina R · Indian journal of dermatology, venereology and leprology · 2025
    Meta-analysis646 participants10 studies pooledSkin Health forCollagen
  62. Oral intake of collagen peptide NS improves hydration, elasticity, desquamation, and wrinkling in human skin: a randomized, double-blinded, placebo-controlled study.
    Lee M; Kim E; Ahn H; Son S; Lee H · Food & function · 2023
    Randomized trial100 participantsSkin Health forCollagen
  63. Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study.
    Kim DU; Chung HC; Choi J; Sakai Y; Lee BY · Nutrients · 2018
    Randomized trial64 participantsSkin Health forCollagen
  64. Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis.
    de Miranda RB; Weimer P; Rossi RC · International journal of dermatology · 2021
    Meta-analysis1,125 participants19 studies pooledSkin Health forCollagen
  65. Noninferiority of Copper Dressings Than Negative Pressure Wound Therapy in Healing Diabetic Wounds: A Randomized Clinical Trial.
    Melamed E; Dabbah J; Israel T; Kan I; Pinzur MS; Roth T; Borkow G · Advances in wound care · 2026
    Randomized trialSkin Health forCopper
  66. Improvement of facial skin characteristics using copper oxide containing pillowcases: a double-blind, placebo-controlled, parallel, randomized study.
    Borkow G; Gabbay J; Lyakhovitsky A; Huszar M · International journal of cosmetic science · 2010
    Randomized trial57 participantsSkin Health forCopper
  67. Radially Electrospun Fibrous Membrane Incorporated with Copper Peroxide Nanodots Capable of Self-Catalyzed Chemodynamic Therapy for Angiogenesis and Healing Acceleration of Diabetic Wounds.
    Huang Y; Qi L; Liu Z; Jiang Y; Wang J; Liu L; Li Y; Zhang L; Feng G · ACS applied materials & interfaces · 2023
    Animal experimentSkin Health forCopper
  68. Engineering copper nanoparticle/polysaccharide-immobilized cotton gauze for accelerated healing of Staphylococcus aureus-infected dermal wounds.
    Sahoo M; Banerjee T; Virkar S; Das S; Biswas S; Mitra D · Journal of materials chemistry. B · 2026
    Animal experimentSkin Health forCopper
  69. Stimulation of Healing of Non-Infected Stagnated Diabetic Wounds by Copper Oxide-Impregnated Wound Dressings.
    Melamed E; Rovitsky A; Roth T; Assa L; Borkow G · Medicina (Kaunas, Lithuania) · 2021
    Single-arm trialSkin Health forCopper
  70. Efficacy and Tolerability of Topical 0.1% Stabilized Bioactive Retinol for Photoaging: A Vehicle-Controlled Integrated Analysis.
    Farris P; Berson D; Bhatia N; Goldberg D; Lain E; Mariwalla K; Zeichner J; Miller D; McGuire T; Kizoulis M · Journal of drugs in dermatology : JDD · 2024
    Meta-analysis471 participants6 studies pooledSkin Health forVitamin A
  71. Tensile properties and contours of aging facial skin. A controlled double-blind comparative study of the effects of retinol, melibiose-lactose and their association.
    Piérard-Franchimont C; Castelli D; Cromphaut IV; Bertin C; Ries G; Cauwenbergh G; Piérard GE · Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI) · 2016
    Randomized trial120 participantsSkin Health forVitamin A
  72. Antiaging action of retinol: from molecular to clinical.
    Bellemère G; Stamatas GN; Bruère V; Bertin C; Issachar N; Oddos T · Skin pharmacology and physiology · 2009
    Randomized trial48 participantsSkin Health forVitamin A
  73. An Updated Review of Topical Tretinoin in Dermatology: From Acne and Photoaging to Skin Cancer.
    Balado-Simó P; Morgado-Carrasco D; Gómez-Armayones S; López-Ferrer A; Barco D; Ferrándiz-Pulido C; Podlipnik S · Journal of clinical medicine · 2025
    Narrative reviewSkin Health forVitamin A
  74. Novel Cyclized Hexapeptide-9 Outperforms Retinol Against Skin Aging: A Randomized, Double-Blinded, Active- and Vehicle-Controlled Clinical Trial.
    Chang H; Tao K; Yang Y; Wang Y; Ge M; Wang X; Tang S; Yu H · Journal of cosmetic dermatology · 2025
    Randomized trialSkin Health forVitamin A
  75. Evaluation of the anti-wrinkle effect of an ascorbic acid-loaded dissolving microneedle patch via a double-blind, placebo-controlled clinical study.
    Lee C; Yang H; Kim S; Kim M; Kang H; Kim N; An S; Koh J; Jung H · International journal of cosmetic science · 2017
    Randomized trial23 participantsSkin Health forVitamin C
  76. Comparative Study on the Outcome of Periorbital Wrinkles Treated with Laser-Assisted Delivery of Vitamin C or Vitamin C Plus Growth Factors: A Randomized, Double-blind, Clinical Trial.
    Machado BHB; Frame J; Zhang J; Najlah M · Aesthetic plastic surgery · 2021
    Randomized trial149 participantsSkin Health forVitamin C
  77. Randomized trial of topical ascorbic acid in DMSO versus imiquimod for the treatment of basal cell carcinoma.
    Burke B; Bailie JE · Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie · 2022
    Randomized trial25 participantsSkin Health forVitamin C
  78. Vitamin C improves healing of foot ulcers: a randomised, double-blind, placebo-controlled trial.
    Gunton JE; Girgis CM; Lau T; Vicaretti M; Begg L; Flood V · The British journal of nutrition · 2022
    Randomized trial16 participantsSkin Health forVitamin C
  79. Dietary nutrient intakes and skin-aging appearance among middle-aged American women.
    Cosgrove MC; Franco OH; Granger SP; Murray PG; Mayes AE · The American journal of clinical nutrition · 2007
    Cross-sectional study4,025 participantsSkin Health forVitamin C
  80. Sex-related differences in response to zinc pyrithione shampoo vs. non-anti-dandruff shampoo.
    Collins LZ; Baines FL; Matheson JR; Turner GA; Diao Y; Li Y; Pi Y · International journal of cosmetic science · 2019
    Meta-analysis2,088 participants20 studies pooledSkin Health forZinc
  81. Maintenance of an Acidic Skin Surface with a Novel Zinc Lactobionate Emollient Preparation Improves Skin Barrier Function in Patients with Atopic Dermatitis.
    Andrew PV; Pinnock A; Poyner A; Brown K; Chittock J; Kay LJ; Cork MJ; Danby SG · Dermatology and therapy · 2024
    Cohort study23 participantsSkin Health forZinc
  82. Spatial expression of metallothionein, matrix metalloproteinase-1 and Ki-67 in human epidermal wounds treated with zinc and determined by quantitative immunohistochemistry: A randomised double-blind trial.
    Ågren MS; Chafranska L; Eriksen JO; Forman JL; Bjerrum MJ; Schjerling P; Larsen HF; Cottarelli E; Jorgensen LN; Gjerdrum LMR · European journal of cell biology · 2021
    Randomized trial30 participantsSkin Health forZinc
  83. A pilot trial using topical regular crystalline insulin vs. aqueous zinc solution for uncomplicated cutaneous wound healing: Impact on quality of life.
    Attia EA; Belal DM; El Samahy MH; El Hamamsy MH · Wound repair and regeneration : official publication of the Wound Healing Society [and] the European Tissue Repair Society · 2014
    Randomized trial90 participantsSkin Health forZinc
  84. Evidence-Based Nutritional Interventions in Wound Care.
    Saeg F; Orazi R; Bowers GM; Janis JE · Plastic and reconstructive surgery · 2021
    Systematic review2,339 participants36 studies pooledSkin Health forZinc
  85. What did we learn in 35 years of research on nutrition and supplements for age-related macular degeneration: a systematic review.
    Pameijer EM; Heus P; Damen JAA; Spijker R; Hooft L; Ringens PJ; Imhof SM; van Leeuwen R · Acta ophthalmologica · 2023
    Systematic review27 studies pooledVision Support forCopper
  86. Dietary Nutrient Intake and Progression to Late Age-Related Macular Degeneration in the Age-Related Eye Disease Studies 1 and 2.
    Agrón E; Mares J; Clemons TE; Swaroop A; Chew EY; Keenan TDL; AREDS and AREDS2 Research Groups · Ophthalmology · 2021
    Cohort study8,242 participantsVision Support forCopper
  87. Association between late age-related macular degeneration and dietary intake of copper, iron, zinc and selenium: a 2005-2008 NHANES cross-sectional observational study.
    Lu Y; Li C; Liu Y; Wu T; Lu P · BMC ophthalmology · 2025
    Observational study4,996 participantsVision Support forCopper
  88. Associations between dietary nutrient intake and the risk of multiple age-related ocular diseases: evidence from longitudinal analysis.
    Yang Y; Zou H · The journal of nutrition, health & aging · 2026
    Cohort study103,192 participantsVision Support forCopper
  89. Dietary habits and dietary nutrient intake in patients with age-related macular degeneration: A case-control study.
    Šalková Kráľová J; Kolář P; Kapounová Z; Veselý P; Derflerová Brázdová Z · Central European journal of public health · 2023
    Case-control study151 participantsVision Support forCopper
  90. A randomized trial of vitamin A and vitamin E supplementation for retinitis pigmentosa.
    Berson EL; Rosner B; Sandberg MA; Hayes KC; Nicholson BW; Weigel-DiFranco C; Willett W · Archives of ophthalmology (Chicago, Ill. : 1960) · 1993
    Randomized trial601 participantsVision Support forVitamin A
  91. Efficacy and safety of retinol palmitate ophthalmic solution in the treatment of dry eye: a Japanese Phase II clinical trial.
    Toshida H; Funaki T; Ono K; Tabuchi N; Watanabe S; Seki T; Otake H; Kato T; Ebihara N; Murakami A · Drug design, development and therapy · 2018
    Randomized trial66 participantsVision Support forVitamin A
  92. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age.
    Imdad A; Mayo-Wilson E; Haykal MR; Regan A; Sidhu J; Smith A; Bhutta ZA · The Cochrane database of systematic reviews · 2022
    Meta-analysis1,223,856 participants47 studies pooledVision Support forVitamin A
  93. Vitamin A supplementation improves retinal function in infants at risk of retinopathy of prematurity.
    Mactier H; McCulloch DL; Hamilton R; Galloway P; Bradnam MS; Young D; Lavy T; Farrell L; Weaver LT · The Journal of pediatrics · 2012
    Randomized trial89 participantsVision Support forVitamin A
  94. Effect of short-term, high-dose retinol on dark adaptation in aging and early age-related maculopathy.
    Owsley C; McGwin G; Jackson GR; Heimburger DC; Piyathilake CJ; Klein R; White MF; Kallies K · Investigative ophthalmology & visual science · 2006
    Randomized trial104 participantsVision Support forVitamin A
  95. Role of Oral Vitamin 'C' on Astigmatic Errors in Phacoemulsification.
    Mohan S; Sah K; Khattri M; Ahmad L; Sachan SK · Current eye research · 2021
    Randomized trial400 participantsVision Support forVitamin C
  96. Ascorbic acid metabolites are involved in intraocular pressure control in the general population.
    Hysi PG; Khawaja AP; Menni C; Tamraz B; Wareham N; Khaw KT; Foster PJ; Benet LZ; Spector TD; Hammond CJ · Redox biology · 2019
    Observational studyVision Support forVitamin C
  97. Nutritional modulation of cataract.
    Weikel KA; Garber C; Baburins A; Taylor A · Nutrition reviews · 2014
    Narrative reviewVision Support forVitamin C
  98. Dietary n-3 Fatty Acid, α-Tocopherol, Zinc, vitamin D, vitamin C, and β-carotene are Associated with Age-Related Macular Degeneration in Japan.
    Aoki A; Inoue M; Nguyen E; Obata R; Kadonosono K; Shinkai S; Hashimoto H; Sasaki S; Yanagi Y · Scientific reports · 2017
    Case-control study530 participantsVision Support forVitamin C
  99. Adherence to a Mediterranean diet, lifestyle and age-related macular degeneration: the Coimbra Eye Study - report 3.
    Raimundo M; Mira F; Cachulo MDL; Barreto P; Ribeiro L; Farinha C; Laíns I; Nunes S; Alves D; Figueira J; Merle BM; Delcourt C; Santos L; Silva R · Acta ophthalmologica · 2019
    Case-control study883 participantsVision Support forVitamin C
  100. Antioxidant vitamin and mineral supplements for age-related macular degeneration.
    Evans JR · The Cochrane database of systematic reviews · 2002
    Systematic review170 participants7 studies pooledVision Support forZinc
  101. Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration.
    Evans JR; Lawrenson JG · The Cochrane database of systematic reviews · 2023
    Meta-analysis3,790 participants5 studies pooledVision Support forZinc
  102. Oral zinc in macular degeneration.
    Newsome DA; Swartz M; Leone NC; Elston RC; Miller E · Archives of ophthalmology (Chicago, Ill. : 1960) · 1988
    Randomized trial151 participantsVision Support forZinc
  103. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8.
    Age-Related Eye Disease Study Research Group · Archives of ophthalmology (Chicago, Ill. : 1960) · 2001
    Randomized trial3,640 participantsVision Support forZinc
  104. Effect of vitamin A and zinc supplementation on the nutriture of children in Northeast Thailand.
    Udomkesmalee E; Dhanamitta S; Sirisinha S; Charoenkiatkul S; Tuntipopipat S; Banjong O; Rojroongwasinkul N; Kramer TR; Smith JC · The American journal of clinical nutrition · 1992
    Randomized trial133 participantsVision Support forZinc