Sources we trust
The 80+ places every score is sourced from.
SupplementScore is independent. Every rating, dose, and safety classification is derived from the regulators, peer-reviewed databases, professional societies, and research institutions below — never from manufacturer literature, sponsored content, or affiliate networks.
27,000+
Studies reviewed
80+
Trusted sources
$0
Industry funding
781
Supplements tracked
Peer-reviewed literature & citation databases
Where the underlying primary research is found, indexed, and graded.
PubMed ↗
Primary citation source
NCBI’s 35-million-citation biomedical database. Every supplement’s evidence base is checked against PubMed via the eUtils API. Citation counts on supplement pages are live-fetched here.
Cochrane Library ↗
Systematic reviews
Gold-standard meta-analyses. When a Cochrane review exists for a supplement, it is treated as the primary evidence anchor regardless of how many individual RCTs disagree.
Embase ↗
European literature
Elsevier’s biomedical database with stronger European trial coverage than PubMed alone. Used for cross-checking when a Cochrane review references trials we couldn’t find on PubMed.
ClinicalTrials.gov ↗
US trial registry
NIH/NLM registry of FDA-regulated clinical studies worldwide. Used to verify trial design, sponsor, completion status, and posted vs published outcomes.
WHO ICTRP ↗
Global trial registry
International Clinical Trials Registry Platform. Aggregates ClinicalTrials.gov plus 17 national registries (EU CTR, JPRN, ChiCTR, ISRCTN, etc.).
PROSPERO ↗
Systematic review registry
University of York registry of prospectively registered systematic reviews. Used to identify in-progress reviews on emerging topics.
bioRxiv / medRxiv ↗
Preprint servers
Cold Spring Harbor preprint repositories. Used cautiously — preprints are flagged as such and never the sole basis for a tier classification.
Google Scholar ↗
Citation cross-check
Used for backward citation tracing and grey-literature checks. Findings are validated against PubMed/Embase before being used as evidence.
Drug, compound & nutrient databases
Structured chemistry, mechanism-of-action, and drug-supplement interaction data.
DrugBank ↗
Drug-supplement interactions
University of Alberta’s structured drug interaction database. Primary source for the per-pair severity, mechanism, and CYP/P-gp pathway annotations in our 149 explicit drug-supplement pairs.
ChEMBL ↗
Bioactivity data
EMBL-EBI’s manually curated bioactivity database. Used for IC50/EC50/Ki receptor-binding data when mechanism claims need verification.
PubChem ↗
Chemical structure
NIH’s open chemistry database. Used for structural identity, isomer disambiguation, and physicochemical properties of supplement molecules.
RxNorm / RxNav ↗
Drug nomenclature
NLM’s standardized drug naming. Used to resolve brand → generic mappings (e.g., Lipitor → atorvastatin) for the 226 specific drugs in the interaction engine.
openFDA SPL ↗
Drug labels (structured)
FDA Structured Product Labels API. Source of the “Drug Interactions” section text mined for ~20,000 prescription labels — the substrate of our auto-extracted candidate pair list.
USDA FoodData Central ↗
Nutrient composition
USDA’s authoritative food/nutrient database. Used to cross-reference RDA/AI satisfaction from diet vs. supplement-only sourcing.
Adverse-event & pharmacovigilance
Real-world safety signals — what reaches emergency rooms and poison control.
openFDA FAERS ↗
FDA Adverse Event Reports
Programmatic access to the FDA Adverse Event Reporting System. Queried by supplement name to surface real-world safety signals against background reporting rates.
FDA MedWatch ↗
US safety alerts
FDA safety communications, recalls, and warning letters. The MedWatch RSS feed is monitored to trigger out-of-cycle reviews on flagged supplements.
EudraVigilance ↗
EU adverse events
European Medicines Agency’s public ADR portal. Cross-referenced against FAERS for transatlantic confirmation of safety signals.
UK Yellow Card ↗
UK pharmacovigilance
MHRA’s patient + clinician spontaneous reporting scheme. Includes a herbal-remedy-specific reporting category since 2003.
AAPCC NPDS ↗
US poison control
American Association of Poison Control Centers’ National Poison Data System. Quoted in Tier-4 risk articles (e.g., melatonin pediatric ER visits).
National regulators
Recall notices, monograph databases, and enforcement actions across 12 jurisdictions.
FDA ↗
United States
Recall notices, warning letters, MedWatch adverse events, and authorized health claims (e.g. psyllium, oat beta-glucan). Reviewed weekly.
EMA ↗
European Union
European Medicines Agency. Source for EU-specific safety reviews, herbal monograph database, and pharmacovigilance signals.
EFSA ↗
EU food safety
European Food Safety Authority. Source for EU health claims, novel-food approvals, and tolerable upper intake levels (ULs).
MHRA ↗
United Kingdom
Yellow Card scheme reports and Traditional Herbal Registration scheme. Cross-referenced against FDA and EMA actions.
BfArM ↗
Germany
German federal regulator. Source for several Tier-4 classifications where Germany has acted ahead of FDA (e.g. greater celandine, kava withdrawals).
TGA ↗
Australia
Therapeutic Goods Administration. Australia regulates supplements more strictly than the US; TGA actions are an early signal for new safety concerns.
Health Canada NHPD ↗
Canada
Natural Health Products Database — license numbers and authorized claims for ~75,000 products marketed in Canada.
ANSM ↗
France
Agence nationale de sécurité du médicament. Source for French-specific herbal contraindications and pharmacovigilance bulletins.
PMDA ↗
Japan
Pharmaceuticals and Medical Devices Agency. Source for kampo (Japanese herbal medicine) data and the Foods with Function Claims regulatory pathway.
Medsafe ↗
New Zealand
NZ Medicines and Medical Devices Safety Authority. Cross-referenced for southern-hemisphere safety signals.
Swissmedic ↗
Switzerland
Swiss therapeutic-products regulator. Notable for stricter herbal medicine standards (Phytotherapeutika) than EU defaults.
CDC ↗
US public health
MMWR and poison center surveillance data. Cited for outbreak reports (e.g. kava poisoning calls, kratom co-use trends).
US health, nutrition & integrative-medicine agencies
The first place we look for an authoritative consumer-facing fact sheet on a nutrient or herb.
NIH ODS ↗
NIH Office of Dietary Supplements
Authoritative fact sheets on ~80 supplements, plus the Dietary Supplement Label Database (DSLD) for product-level ingredient verification.
NCCIH ↗
Complementary & integrative health
National Center for Complementary and Integrative Health. Clinical digest series and herbal monographs covering ~120 botanicals.
NIH NHLBI / NIDDK / NIAMS ↗
NIH institutes
Disease-specific institutes (heart/lung/blood, diabetes/digestive/kidney, arthritis/musculoskeletal/skin) provide condition-area guidelines.
NHANES ↗
Population intake data
CDC’s National Health and Nutrition Examination Survey. Source for “90% of Americans don’t hit AI for choline”-style claims.
Linus Pauling Institute ↗
Oregon State Univ.
Micronutrient Information Center — clinically-oriented reviews on vitamins, minerals, and a growing set of phytochemicals. Useful evidence layer above NIH ODS.
National Academies (IOM) ↗
DRI / RDA / UL setting
National Academies of Sciences, Engineering, and Medicine. Sets the Dietary Reference Intakes (RDA, AI, UL) referenced by every dose calculator on the site.
Botanical & herbal monograph systems
Where the clinical-grade evidence on a specific herb is collated and reviewed.
WHO Monographs on Selected Medicinal Plants ↗
Global
Five published volumes covering ~150 plants with extensive evidence reviews and contraindications. Treated as the international starting point for any traditional-use herbal entry.
ESCOP Monographs ↗
European Phytotherapy
European Scientific Cooperative on Phytotherapy. Best-quality consolidated European evidence reviews on ~80 herbs.
German Commission E ↗
Germany — historical reference
Germany’s 1978-94 herbal monograph project — the first systematic regulatory review of botanicals globally. Still cited heavily where modern monographs don’t exist.
EMA HMPC monographs ↗
EU regulatory
European Medicines Agency Committee on Herbal Medicinal Products. ~150 herbal entries with regulatory-grade safety + efficacy reviews.
American Botanical Council ↗
HerbalGram
Independent non-profit; HerbalGram + HerbClip publications. Source for the Botanical Adulterants Prevention Program data we cite on quality-fraud articles.
MSKCC About Herbs ↗
Memorial Sloan Kettering
MSKCC’s integrative-medicine herb database. Particularly authoritative on herb-chemo interactions and oncology contraindications.
Independent supplement-specific evidence
Curated tertiary sources we cross-check against — not primary, but useful triangulation.
Examine.com ↗
Supplement research
Independent, ad-free supplement evidence database. Used for cross-checking effect sizes and identifying recently-published studies.
Natural Medicines (TRC) ↗
Drug interactions
Therapeutic Research Center’s clinical reference. Industry standard for supplement-drug interaction grading.
ConsumerLab ↗
Independent product testing
Independent third-party testing of supplement quality, dose accuracy, and contamination. Cited in our quality-fraud articles.
MedlinePlus ↗
NLM consumer reference
National Library of Medicine’s consumer-facing herbal database. Used as a sanity check for plain-language framing.
Quality, purity & third-party certification
Bodies that test and verify what’s actually in the bottle.
USP ↗
United States Pharmacopeia
Sets the official compositional and quality standards for medicines and supplements in the US (USP-NF). Products carrying the USP Verified mark have been audited for identity, potency, and purity.
NSF International ↗
Independent certifier
Third-party testing for label accuracy, contamination, and GMP compliance. The NSF mark is one of the strongest off-label-quality signals.
NSF Certified for Sport ↗
Banned-substance screening
NSF’s sport-specific program tests every lot against the WADA banned-substance list. Required for many professional and NCAA athletes.
Informed Sport / Informed Choice ↗
LGC Group certification
UK-based banned-substance certification used by most Premier League and Olympic teams. Tests every batch.
European Pharmacopoeia ↗
EU quality standards
EDQM’s Ph. Eur. monographs — the official quality benchmarks across all EMA jurisdictions. Useful when US/EU pharmacopoeia standards diverge.
Top-tier journals
Recent meta-analyses or RCTs in any of these trigger an automatic re-review of the affected entry.
NEJM ↗
Top general medical
New England Journal of Medicine. Tier-1 evidence anchor (impact factor ~96).
The Lancet ↗
Top general medical
Plus the family of specialty journals (Lancet Diabetes, Oncology, Healthy Longevity, etc.).
JAMA ↗
Top general medical
JAMA + JAMA Internal Medicine, Cardiology, Network Open. Used heavily for supplement+CV outcome trials (e.g., omega-3, vitamin D).
BMJ ↗
Top general medical
British Medical Journal. Often the first venue for skeptical reanalyses of widely-prescribed supplements.
Annals of Internal Medicine ↗
ACP journal
American College of Physicians. Strong source for guideline-grade synthesis and clinical practice editorials.
Nature Medicine ↗
Top translational
Heavy in mechanism + biomarker-driven trials (e.g., NMN, urolithin A, GlyNAC).
AJCN ↗
Nutrition
American Journal of Clinical Nutrition (ASN). Primary venue for vitamin/mineral RCTs and intake studies.
Nutrients ↗
Open access nutrition
MDPI’s open-access nutrition journal. High volume; we filter for systematic reviews and avoid single-arm pilots.
JISSN ↗
Sports nutrition
Journal of the International Society of Sports Nutrition. Source for ISSN position stands on creatine, β-alanine, citrulline, sodium bicarb, etc.
Advances in Nutrition ↗
Review-focused
ASN’s review-only journal. Useful for narrative consolidations.
Professional societies & guidelines
Where the “what should clinicians actually do” consensus lives.
AAP ↗
Pediatrics
American Academy of Pediatrics. Primary source for pediatric vitamin D drops, iron in infant formula, fluoride supplementation, and pediatric melatonin guidance.
ACOG ↗
OB-GYN
American College of Obstetricians and Gynecologists. Prenatal vitamin, folate, choline, omega-3, and pregnancy contraindication guidance.
AHA ↗
Cardiology
American Heart Association scientific statements on omega-3, vitamin D, plant sterols, dietary patterns.
ACC ↗
Cardiology guidelines
American College of Cardiology guidelines (often joint with AHA). Source for lipid + BP management context.
ADA ↗
Diabetes
American Diabetes Association Standards of Care. Cited for B12/metformin, supplement-glycemic interaction guidance.
ASN ↗
Nutrition
American Society for Nutrition. Position statements on intake adequacy, fortification policy, and supplement-specific claims.
AND ↗
Dietetics
Academy of Nutrition and Dietetics. Practitioner-facing guidance on real-world supplement use.
AASLD ↗
Hepatology
American Association for the Study of Liver Diseases. Source for the DILI Network and guidance on hepatotoxic supplements.
ACR ↗
Rheumatology
American College of Rheumatology guidelines on glucocorticoid-induced osteoporosis (calcium/D protocols) and DMARD-supplement interactions.
USPSTF ↗
Preventive medicine
US Preventive Services Task Force. Independent grade-A/B/C/D recommendations on supplements for primary prevention (e.g., multivitamins, β-carotene, vitamin D for falls).
Sport & banned-substance authorities
If a supplement appears on any of these lists, drug-tested athletes must avoid it.
WADA ↗
World Anti-Doping Agency
WADA Prohibited List. The global standard cited by Olympic and most international sport federations.
USADA Supplement 411 ↗
US Anti-Doping
USADA’s supplement risk education. Identifies high-risk supplement categories (pre-workouts, weight loss, sexual enhancement) for athlete-flagged warnings.
NCAA banned substances ↗
NCAA
College sport banned-substance list. Slightly different from WADA in stimulants and peptide hormones; cross-referenced for college-athlete-targeted articles.
DEA Diversion ↗
US controlled substances
Drug Enforcement Administration scheduling decisions. Cited where supplements have been administratively scheduled (e.g., Phenibut, kratom analog actions).
Research institutions
Academic centres whose translational research and editorial commentary we lean on.
Harvard T.H. Chan School of Public Health ↗
Public health nutrition
The Nutrition Source — public-health-grade synthesis on supplements and dietary patterns. Frequently quoted on multivitamin and antioxidant questions.
Johns Hopkins Bloomberg ↗
Public health
Strong on evidence synthesis methods (Cochrane US satellite + JHU EPC).
Stanford Medicine ↗
Clinical research
Cited heavily on metabolomics, longevity-related trials, and clinical-trial methodology critiques.
Mayo Clinic ↗
Clinical reference
Mayo’s patient-facing supplement reference is heavily cross-checked against primary literature; strong on drug-supplement interactions.
Cleveland Clinic ↗
Clinical reference
Cardiology and integrative medicine programs — cited on CoQ10, omega-3, and vitamin D contexts.
Karolinska Institutet ↗
Sweden
European-tier translational centre. Strong on iron, B12, and large Scandinavian-cohort observational data.
Oxford CEBM ↗
Evidence-based medicine
Centre for Evidence-Based Medicine. Source for EBM methodology and the Levels of Evidence we lean on for tier classification.
Critical-appraisal frameworks
The methodological tools we apply to every cited study before crediting it as evidence.
GRADE ↗
Evidence grading
Grading of Recommendations Assessment, Development and Evaluation. The four-level (high/moderate/low/very low) framework Cochrane uses; we map our A/B/C/D study grades onto GRADE outputs.
Cochrane RoB 2 ↗
Risk-of-bias for RCTs
Cochrane’s revised Risk of Bias tool. Used to flag selection, performance, detection, attrition, and reporting biases on individual RCTs we cite.
AMSTAR-2 ↗
Systematic review appraisal
A MeaSurement Tool to Assess systematic Reviews. Applied to non-Cochrane systematic reviews before they’re used as a tier-anchor.
CONSORT ↗
RCT reporting
Consolidated Standards of Reporting Trials. Used to identify when RCT methodology was likely sound vs likely opaque.
PRISMA ↗
Systematic review reporting
The reporting standard for systematic reviews and meta-analyses. We require PRISMA-flow disclosure for any review we use as a primary anchor.
What we explicitly do NOT use
Manufacturer literature, affiliate-driven supplement review sites, nutritional industry trade publications, celebrity-endorsed product pages, retailer product pages, multilevel-marketing materials, and influencer/podcast claims are explicitly excluded as primary sources. They may be cited in an article only as evidence of a marketing claim being analyzed.
See the methodology page for how these sources are weighted in the composite score, and the funder policy for how each cited paper is tagged with a funding source and conflict-of-interest flag.