# Verified Supplement Data

> Evidence-based supplement comparison database. We chain clinical trial evidence to specific products, third-party certifications, and cost per clinically-effective daily dose.

## What This Site Provides

This site answers: "What specific supplement product should I buy for my condition/goal, at what dose, based on actual clinical evidence, and what will it cost me per day?"

Each comparison page includes:
- Clinical evidence from PubMed systematic reviews and meta-analyses
- Product label data verified against the NIH Dietary Supplement Label Database (DSLD)
- Third-party certification status (USP Verified, NSF Certified for Sport, ConsumerLab)
- Cost normalized to clinically-effective daily dose (not cost per pill)

## Magnesium Supplements

- [Best Magnesium Supplement Overall (2026)](https://verifiedsupplementdata.com/magnesium/best-overall/): Master buying guide with all forms, top products, decision matrix by goal, and specific product recommendations with pricing
- [Magnesium Supplement Guide](https://verifiedsupplementdata.com/magnesium/): Hub page — which magnesium form for which goal
- [All Magnesium Forms Compared](https://verifiedsupplementdata.com/magnesium/forms-compared/): 8 forms ranked by bioavailability, use case, and cost (glycinate, citrate, oxide, threonate, taurate, malate, chloride, sulfate)
- [Best Magnesium Glycinate for Sleep (2026)](https://verifiedsupplementdata.com/magnesium/best-for-sleep/): 6 products compared by evidence, certification, and cost per 400mg clinical dose
- [Magnesium Glycinate vs Citrate](https://verifiedsupplementdata.com/magnesium/glycinate-vs-citrate/): Head-to-head comparison with evidence for each form
- [Magnesium L-Threonate vs Glycinate](https://verifiedsupplementdata.com/magnesium/threonate-vs-glycinate/): Brain health (Magtein, BBB crossing, 2026 RCT) vs general wellness (sleep, anxiety, repletion). Only form shown to increase brain magnesium.
- [Magnesium Oxide vs Glycinate](https://verifiedsupplementdata.com/magnesium/oxide-vs-glycinate/): Cheap (~4% bioavailability) vs premium absorption. Why oxide fails for supplementation, the label illusion, and when to switch.
- [Magnesium Citrate vs Oxide](https://verifiedsupplementdata.com/magnesium/citrate-vs-oxide/): Both affordable but citrate absorbs dramatically better. Cost per absorbed dose, laxative effects, and when oxide is appropriate.
- [Best Magnesium for Anxiety](https://verifiedsupplementdata.com/magnesium/best-for-anxiety/): Systematic review + RCT evidence, GAD-7 score reduction, recommended form and dose
- [Magnesium for Muscle Cramps](https://verifiedsupplementdata.com/magnesium/best-for-muscle-cramps/): Honest Cochrane review findings (mostly negative) + nocturnal leg cramp exception
- [Magnesium Dosage Guide](https://verifiedsupplementdata.com/magnesium/dosage-guide/): NIH RDA, clinical trial doses by condition, elemental vs compound weight, timing
- [Signs of Magnesium Deficiency](https://verifiedsupplementdata.com/magnesium/deficiency-signs/): Symptoms, risk factors, testing limitations, prevalence data

## Symptom Pages
- [Always Tired](https://verifiedsupplementdata.com/symptoms/always-tired/): Nutrient deficiencies that cause constant fatigue — iron, B12, vitamin D, magnesium
- [Can't Sleep](https://verifiedsupplementdata.com/symptoms/cant-sleep/): Magnesium glycinate for insomnia (meta-analysis: -17 min sleep onset), magnesium vs melatonin comparison
- [Anxiety That Won't Go Away](https://verifiedsupplementdata.com/symptoms/anxiety-natural-relief/): Evidence-based supplements for anxiety, magnesium RCT evidence (GAD-7 -4.5, P<0.001)
- [Brain Fog](https://verifiedsupplementdata.com/symptoms/brain-fog/): B12, iron, vitamin D, magnesium L-threonate — the nutrient deficiencies behind mental cloudiness
- [Feeling Depressed](https://verifiedsupplementdata.com/symptoms/feeling-depressed/): Vitamin D, folate, B12, omega-3 — deficiencies that mimic or worsen depression
- [Hair Falling Out](https://verifiedsupplementdata.com/symptoms/hair-falling-out/): Iron deficiency (ferritin <30) is the #1 nutritional cause. Biotin evidence is weak (we're honest).
- [Tingling in Hands and Feet](https://verifiedsupplementdata.com/symptoms/tingling-hands-feet/): B12 neuropathy can start at "normal" levels. Methylcobalamin meta-analysis (15 RCTs).
- [Heart Palpitations](https://verifiedsupplementdata.com/symptoms/heart-palpitations/): Magnesium deficiency induced arrhythmias in 36% of women in controlled study. CoQ10 for afib.
- [Eye Twitching](https://verifiedsupplementdata.com/symptoms/eye-twitching/): Myokymia causes, magnesium connection, when to see a doctor
- [Leg Cramps at Night](https://verifiedsupplementdata.com/symptoms/leg-cramps-at-night/): Nocturnal leg cramp evidence (2021 RCT: P=0.01)
- [Heavy Periods and Iron Depletion](https://verifiedsupplementdata.com/symptoms/heavy-periods/): The vicious iron depletion cycle. Ferrous bisglycinate breaks it.
- [Restless Legs](https://verifiedsupplementdata.com/symptoms/restless-legs/): Iron and magnesium connection. Ferritin below 75 associated with RLS.
- [Afternoon Energy Crash](https://verifiedsupplementdata.com/symptoms/afternoon-crash/): When the 2pm wall is a nutrient deficiency, not blood sugar
- [Doctor Said Take Magnesium](https://verifiedsupplementdata.com/symptoms/doctor-recommended-magnesium/): Which magnesium to buy when your doctor recommends it
- [Hair Loss on GLP-1 (Ozempic/Wegovy)](https://verifiedsupplementdata.com/symptoms/glp1-hair-loss/): 25-33% experience telogen effluvium. Evidence-based protocol.

## Vitamin D Supplements
- [Vitamin D Supplement Guide](https://verifiedsupplementdata.com/vitamin-d/): Hub page — D2 vs D3, dosage controversy, K2 pairing, deficiency
- [Vitamin D2 vs D3](https://verifiedsupplementdata.com/vitamin-d/d2-vs-d3/): D3 is 2-3x more effective than D2 at raising blood levels (20-RCT meta-analysis). Head-to-head comparison, dosing, K2 co-supplementation
- [Vitamin D Deficiency Signs](https://verifiedsupplementdata.com/vitamin-d/deficiency-signs/): 42% of US adults are deficient. Symptoms, risk factors, blood test interpretation (25(OH)D levels), and correction protocol
- [Vitamin D Dosage Guide](https://verifiedsupplementdata.com/vitamin-d/dosage-guide/): 1,000 vs 2,000 vs 5,000 IU debate. Dosing by blood level, K2 co-supplementation guide, safety and toxicity thresholds
- [Vitamin D + K2](https://verifiedsupplementdata.com/vitamin-d/with-k2/): When K2 matters, MK-7 vs MK-4, dosing table, food sources, warfarin warning
- [Vitamin D3: 1,000 vs 5,000 IU](https://verifiedsupplementdata.com/vitamin-d/1000-vs-5000-iu/): The dose debate. 1,000 IU for maintenance, 5,000 IU for deficiency correction. Dosing by blood level, body weight adjustments, when to add K2.
- [Vitamin D: With or Without K2?](https://verifiedsupplementdata.com/vitamin-d/with-or-without-k2/): The cofactor question answered. K2 optional at low D3, recommended at 4,000+ IU. MK-7 vs MK-4, dietary sources, warfarin warning.
- [Vitamin D for Immunity](https://verifiedsupplementdata.com/vitamin-d/best-for-immunity/): 120-trial meta-analysis (101,751 adults). High-dose D3 effective for COVID/flu prevention. Daily low-dose better than bolus.
- [Vitamin D for Depression & SAD](https://verifiedsupplementdata.com/vitamin-d/best-for-depression/): Seasonal connection, evidence review, when supplementation helps vs doesn't, combination with magnesium

## GLP-1 / Weight Loss Drug Supplements
- [GLP-1 Supplement Hub](https://verifiedsupplementdata.com/glp1/): All guides for Ozempic, Wegovy, and Mounjaro users
- [GLP-1 Nutrient Depletion Guide](https://verifiedsupplementdata.com/glp1/nutrient-depletion/): 22.4% develop deficiency within 12 months. Which nutrients are depleted, mechanisms, recommended products.
- [Essential Supplements on Ozempic, Wegovy & Mounjaro](https://verifiedsupplementdata.com/stacks/glp1-ozempic/): Up to 40% of weight lost on GLP-1 drugs is muscle. 5 evidence-based supplements (protein, multivitamin, biotin, collagen, magnesium) with specific products and cost-per-day. Total stack: $2.26-3.11/day.
- [Hair Loss on Ozempic/Wegovy/Mounjaro](https://verifiedsupplementdata.com/symptoms/glp1-hair-loss/): 25-33% of GLP-1 users experience telogen effluvium. Evidence-based protocol: protein + biotin + zinc + iron. Timeline, what works, what doesn't.

## Testosterone & Male Health
- [Tongkat Ali Evidence Review](https://verifiedsupplementdata.com/tongkat-ali/): Systematic review of tongkat ali for testosterone. Fadogia agrestis debunked. Standardization guide.

## Supplement Stacks (Condition-Based Protocols)
- [Anxiety + Sleep Stack](https://verifiedsupplementdata.com/stacks/anxiety-sleep/): Magnesium + ashwagandha + L-theanine protocol
- [Energy + Focus Stack](https://verifiedsupplementdata.com/stacks/energy-focus/): Creatine + B12 + omega-3
- [Hair, Skin & Nails Stack](https://verifiedsupplementdata.com/stacks/hair-skin-nails/): Biotin + collagen + vitamin C
- [Bone Health Stack](https://verifiedsupplementdata.com/stacks/bone-health/): Calcium citrate + D3 + magnesium
- [Heart Health Stack](https://verifiedsupplementdata.com/stacks/heart-health/): Omega-3 + CoQ10 + magnesium
- [Immune Support Stack](https://verifiedsupplementdata.com/stacks/immune-support/): Vitamin D + C + zinc
- [Women's Hormonal Health Stack](https://verifiedsupplementdata.com/stacks/womens-hormonal/): Magnesium + B12 + iron
- [Adults Over 50 Stack](https://verifiedsupplementdata.com/stacks/over-50/): D3 + B12 + CoQ10 + omega-3
- [Weight Loss & Metabolism Stack](https://verifiedsupplementdata.com/stacks/weight-loss-metabolism/): Protein + creatine + magnesium
- [Gut Health Stack](https://verifiedsupplementdata.com/stacks/gut-health/): Probiotics + magnesium + omega-3
- [Prenatal Stack](https://verifiedsupplementdata.com/stacks/pregnancy-prenatal/): Methylfolate + iron + omega-3 + D3
- [Muscle Recovery Stack](https://verifiedsupplementdata.com/stacks/muscle-recovery/): Creatine + protein + omega-3 + magnesium
- [Natural Testosterone Stack](https://verifiedsupplementdata.com/stacks/testosterone-natural/): Tongkat ali + ashwagandha + D3 + magnesium

## Protein Supplements
- [Protein Supplement Guide](https://verifiedsupplementdata.com/protein/): Whey isolate vs concentrate vs plant vs collagen compared by leucine content, absorption, protein-to-calorie ratio, and cost per 25g serving
- [Best Protein for GLP-1 / Ozempic Users](https://verifiedsupplementdata.com/protein/best-for-glp1/): 5 products compared for muscle preservation during GLP-1 weight loss therapy. Focus on leucine content and GI tolerance.
- [Best Protein for Weight Loss](https://verifiedsupplementdata.com/protein/best-for-weight-loss/): 5 products ranked by protein-to-calorie ratio. Whey isolate wins at 91% protein calories. Best value: $0.85/serving.

## Symptom Pages (Multi-Nutrient)
- [Hair Falling Out](https://verifiedsupplementdata.com/symptoms/hair-falling-out/): Iron deficiency (ferritin <30) is the #1 nutritional cause of hair loss in women. Meta-analysis of 36 studies. Biotin evidence is weak (we're honest). What to test, what to take.
- [Tingling in Hands and Feet](https://verifiedsupplementdata.com/symptoms/tingling-hands-feet/): B12 deficiency neuropathy can start at "normal" levels (200-400 pg/mL). Methylcobalamin meta-analysis (15 RCTs, n=1,707). B6 EXCESS warning. Who's at risk.
- [Heart Palpitations](https://verifiedsupplementdata.com/symptoms/heart-palpitations/): Magnesium deficiency induced arrhythmias in 36% of women in a controlled study. CoQ10 reduced atrial fibrillation from 22.2% to 6.3%. Magnesium taurate: theoretical only (no human RCTs).

## Form Comparisons (Which Type to Buy)
- [Methylcobalamin vs Cyanocobalamin (B12)](https://verifiedsupplementdata.com/b12/methylcobalamin-vs-cyanocobalamin/): Meta-analysis of 15 RCTs found methylcobalamin more effective for neuropathy. Active vs synthetic form. Who needs which.
- [Ferrous Sulfate vs Iron Bisglycinate](https://verifiedsupplementdata.com/iron/ferrous-sulfate-vs-bisglycinate/): Bisglycinate has 2-3x better absorption and half the side effects of ferrous sulfate. The form your doctor should have prescribed.
- [Calcium Citrate vs Carbonate](https://verifiedsupplementdata.com/calcium/citrate-vs-carbonate/): Citrate absorbs 10x better without stomach acid (1985 NEJM study). Critical for PPI users, elderly, bariatric patients.

## Medication-Induced Nutrient Depletion
- [Is Your Medication Stealing Your Nutrients?](https://verifiedsupplementdata.com/medications/): Master hub — 150M+ Americans on nutrient-depleting drugs. Quick-reference tables for statins, metformin, PPIs, birth control. The hidden depletion cascade explained.
- [Statin Nutrient Depletion Guide](https://verifiedsupplementdata.com/medications/statins/): 92 million Americans on statins. CoQ10 depleted 16-54%. 3 of 4 meta-analyses show supplementation helps muscle pain. Vitamin D myth busted (statins don't deplete D). 5 CoQ10/ubiquinol products compared.
- [Metformin and B12 Depletion](https://verifiedsupplementdata.com/medications/metformin/): Metformin halves B12 levels. 5.8-30% of users deficient. Combined with PPIs: 34% B12 reduction. Sublingual methylcobalamin bypasses gut. 37M+ prescriptions/year.
- [Birth Control Nutrient Depletion](https://verifiedsupplementdata.com/medications/birth-control/): Oral contraceptives deplete B6, B12, folate, magnesium, zinc. Folate depletion before pregnancy is dangerous. MTHFR and methylfolate. What to take on the pill.
- [PPI Nutrient Depletion Guide](https://verifiedsupplementdata.com/medications/ppis/): Proton pump inhibitors (Prilosec, Nexium, Prevacid, Protonix, Dexilant, AcipHex) deplete 5 nutrients. Summary table, timeline, supplement protocol, FDA warnings.
- [PPIs and Magnesium](https://verifiedsupplementdata.com/medications/ppis/magnesium/): TRPM6/7 channel interference. Meta-analysis OR 1.71 (131,507 patients). FDA 2011 warning. Glycinate 200-400mg/day.
- [PPIs and Vitamin B12](https://verifiedsupplementdata.com/medications/ppis/b12/): Acid needed to release B12 from food protein. JAMA OR 1.65 (25,956 cases). Sublingual methylcobalamin bypasses gut. 5 products compared.
- [PPIs and Calcium](https://verifiedsupplementdata.com/medications/ppis/calcium/): Calcium CITRATE absorbs 10x better than CARBONATE without acid (Recker 1985 NEJM, PMID 4000241). Hip fracture RR 1.30. FDA 2010 warning. 4 calcium citrate products compared.
- [PPIs and Iron](https://verifiedsupplementdata.com/medications/ppis/iron/): Dual mechanism — pH-dependent absorption + hepcidin upregulation. RR 2.56 for iron deficiency anemia. Iron bisglycinate partially bypasses acid. 4 products compared.
- [PPIs and Vitamin C](https://verifiedsupplementdata.com/medications/ppis/vitamin-c/): Weakest evidence of the 5. 12.3% plasma reduction. Most valuable as iron absorption synergy. 4 products compared.

## Probiotics
- [Probiotics Guide](https://verifiedsupplementdata.com/probiotics/): Hub page — why CFU counts are meaningless, strain-condition matching is what matters. L. rhamnosus GG, S. boulardii, VSL#3 evidence. AGA 2020 guidelines.
- [Best Probiotic During Antibiotics](https://verifiedsupplementdata.com/probiotics/best-for-antibiotic-diarrhea/): L. rhamnosus GG and S. boulardii evidence from Cochrane review of 33 RCTs. Strain-specific dosing, timing relative to antibiotics, AGA guidelines.
- [Best Probiotic for IBS](https://verifiedsupplementdata.com/probiotics/best-for-ibs/): B. infantis 35624 and VSL#3/Visbiome evidence. AGA recommends against generic probiotics for IBS — specific strains only.
- [Best Probiotic for Bloating](https://verifiedsupplementdata.com/probiotics/best-for-bloating/): B. infantis 35624 at 1 billion CFU outperforms higher-count generic blends.
- [Best Probiotic for Vaginal Health](https://verifiedsupplementdata.com/probiotics/best-for-vaginal-health/): L. rhamnosus GR-1 + L. reuteri RC-14 — only strains proven to colonize vaginal tract via oral supplementation.
- [Best Probiotic for Immune Support](https://verifiedsupplementdata.com/probiotics/best-for-immune-support/): L. rhamnosus GG 34% respiratory infection reduction in RCT.
- [Best Probiotic for Travel](https://verifiedsupplementdata.com/probiotics/best-for-travel/): S. boulardii for traveler's diarrhea prevention across 12 RCTs.

## Ashwagandha
- [Ashwagandha Guide](https://verifiedsupplementdata.com/ashwagandha/): Hub page — KSM-66 vs Sensoril vs generic powder. Cortisol reduction evidence, dosing, cycling protocol, thyroid safety warning.

## Electrolytes
- [Electrolytes Guide](https://verifiedsupplementdata.com/electrolytes/): Hub page — ratio transparency across brands (sodium varies 10x). Sugar vs sugar-free, athlete vs fasting use cases, +1,986% YoY market growth.

## HSA/FSA Supplements
- [Which Supplements Can You Buy With HSA/FSA?](https://verifiedsupplementdata.com/hsa-fsa-supplements/): Complete guide — which supplements qualify, ICD-10 codes, Letter of Medical Necessity template, savings calculator. Save ~30% using pre-tax dollars.

## Nutrient Deficiency Statistics (CDC NHANES Data)
- [Nutrient Deficiency in America (2026): CDC Blood Test Data](https://verifiedsupplementdata.com/deficiency-stats/): Real NHANES blood biomarker data — vitamin D (22.1% deficient), iron (3.5%, but 6.2% of women), B12 (3.2%, 6% of adults 65+), magnesium (19% suboptimal), folate (0.2%). Prevalence by age, sex, and race from 8,360+ adults. Survey-weighted, nationally representative.

## Safety & Adverse Event Data
- [How We Score Supplement Safety (FAERS)](https://verifiedsupplementdata.com/safety/): FDA adverse event report data for every supplement brand we track. A-D safety scores based on CAERS/FAERS database (53,636 total supplement events). All brand scores, category risk tables, methodology, and limitations. Safety scores reflect report volume (correlated with sales), not proven safety.

## Personal Medicine Tools
- [DNA Supplement Analyzer](https://verifiedsupplementdata.com/analyze/): Upload 23andMe or AncestryDNA raw data file — analysis runs entirely in-browser (genetic data never leaves your device). Checks 10 SNPs affecting supplement metabolism: MTHFR (folate), BCMO1 (vitamin A conversion), FUT2 (B12 absorption), COMT (magnesium/methylation), VDR/CYP2R1/GC (vitamin D). Outputs specific supplement form recommendations per genotype.
- [Lab Results Interpreter](https://verifiedsupplementdata.com/labs/): Enter blood test values for 16 biomarkers (vitamin D, B12, ferritin, magnesium RBC, fasting glucose, HbA1c, TSH, hsCRP, LDL-C, triglycerides, homocysteine, testosterone, fasting insulin, omega-3 index, zinc). Get personalized supplement protocol with specific products, clinical doses by deficiency level, timing, cofactors, interaction warnings, and retest timelines.
- [Personal Supplement Stack Builder](https://verifiedsupplementdata.com/stack-builder/): Free interactive tool — enter age, sex, medications, health goals, and conditions. Engine cross-references medication-nutrient depletions, clinical evidence per goal, and demographic modifiers to build a custom supplement stack with specific products, clinical doses, timing protocol, interaction warnings, and one-click Amazon cart. Shareable URL with encoded parameters.
- [Bloodwork Analyzer](https://verifiedsupplementdata.com/bloodwork/): Enter blood test values (vitamin D, B12, ferritin, folate, magnesium, TSH, HbA1c) and get specific supplement recommendations with clinical doses, best-value products, retest timelines, and one-click Amazon cart. Interprets each value against clinical reference ranges.
- [Supplement Quiz](https://verifiedsupplementdata.com/quiz/): 7-question assessment — personalized supplement stack with Supplement Score, evidence-based dosing, and one-click Amazon cart
- [Protocol Builder](https://verifiedsupplementdata.com/protocol/): Comprehensive protocol generator — input medications, goals, diet, get complete supplement protocol with timing, interactions, and cost
- [Vitamin D Calculator by Location](https://verifiedsupplementdata.com/vitamin-d/calculator/): Only location-aware vitamin D calculator — enter zip code, skin tone, season for personalized IU/day recommendation based on latitude and UV exposure
- [Probiotic Strain Matcher](https://verifiedsupplementdata.com/probiotics/strain-matcher/): Interactive tool — select your condition, get the specific clinically-studied strain with evidence level and product recommendation. CFU count is meaningless without strain specificity.
- [Supplement Audit Tool](https://verifiedsupplementdata.com/check/): Enter what you're taking — form, dose, quality, and cost analysis
- [Supplement Lookup (DSLD)](https://verifiedsupplementdata.com/lookup/): Search 207,000+ verified supplement labels from NIH DSLD

## Medication Supplement Stacks (One-Click Cart)
- [Statin User Stack](https://verifiedsupplementdata.com/stacks/statin-user/): CoQ10 + Omega-3 protocol for 92M statin users. Vitamin D myth busted.
- [PPI User Stack](https://verifiedsupplementdata.com/stacks/ppi-user/): 5 depleted nutrients addressed with correct forms (citrate not carbonate, sublingual B12, bisglycinate iron)
- [Metformin User Stack](https://verifiedsupplementdata.com/stacks/metformin-user/): B12 crash prevention — neuropathy misdiagnosis risk

## Ashwagandha (Spoke Pages)
- [KSM-66 vs Sensoril vs Generic](https://verifiedsupplementdata.com/ashwagandha/ksm66-vs-sensoril/): Three vastly different products all called ashwagandha. Clinical data, dosing, cycling, safety.

## Electrolytes (Spoke Pages)
- [Best Electrolyte Drinks (2026)](https://verifiedsupplementdata.com/electrolytes/best-overall/): Ratio transparency — sodium varies 10x across brands. LMNT vs Liquid IV vs Drip Drop vs Nuun. DIY recipe at $0.05/serving.

## Research & Data
- [Amazon Supplement Form Audit](https://verifiedsupplementdata.com/research/amazon-form-audit/): We audited top-selling supplements on Amazon for form quality. Most use inferior forms.
- [Supplement Research Tracker (2026)](https://verifiedsupplementdata.com/research/): Live ClinicalTrials.gov data — 756+ recruiting studies across 14 supplement categories. Research momentum ratings, largest trials, and what they mean for consumers.
- [75+ Supplement Statistics (2026)](https://verifiedsupplementdata.com/research/supplement-statistics/): Deficiency prevalence, market size, form quality data, medication interactions, consumer behavior — all sourced and cited.

## Media Kit (For Content Creators & Journalists)
- [Cite Our Data — Media Kit](https://verifiedsupplementdata.com/media/): Embeddable stat cards, citation text library, embed codes, and API access. Free to use with attribution. 8 key statistics from CDC NHANES and original research.

## Vitamin D Supplements (Buying Guides)
- [Best Vitamin D3 Supplement (2026)](https://verifiedsupplementdata.com/vitamin-d/best-overall/): 7 D3 supplements ranked by cost per clinically-effective dose. Oil-based softgels preferred. USP/NSF verified options.

## Multivitamins
- [Multivitamin Guide](https://verifiedsupplementdata.com/multivitamins/): Hub page — do you need one? What to look for. Most people are better off with targeted singles.
- [Do You Need a Multivitamin?](https://verifiedsupplementdata.com/multivitamins/do-you-need-one/): Evidence review — when multivitamins help vs when targeted supplements are better
- [What to Look For in a Multivitamin](https://verifiedsupplementdata.com/multivitamins/what-to-look-for/): Form quality checklist — methylfolate not folic acid, methylcobalamin not cyanocobalamin, chelated minerals

## GLP-1 Supplements (Additional Guides)
- [Before Starting GLP-1 Medications](https://verifiedsupplementdata.com/glp1/before-starting/): Pre-treatment supplement protocol. What to start before Ozempic/Wegovy/Mounjaro.
- [GLP-1 Cost Guide](https://verifiedsupplementdata.com/glp1/cost-guide/): Supplement cost breakdown for GLP-1 users
- [Electrolytes on GLP-1](https://verifiedsupplementdata.com/glp1/electrolytes/): Dehydration and electrolyte loss during GLP-1 treatment
- [Mounjaro (Tirzepatide) Supplements](https://verifiedsupplementdata.com/glp1/mounjaro/): Mounjaro-specific nutrient depletion and supplement protocol
- [GLP-1 Supplement Calculator](https://verifiedsupplementdata.com/glp1/calculator/): Personalized supplement recommendations based on your GLP-1 medication and symptoms

## About & Methodology

- [About Us](https://verifiedsupplementdata.com/about/): Who we are, editorial standards, data sources, health content disclaimer
- [Methodology](https://verifiedsupplementdata.com/methodology/): How we collect, verify, and normalize supplement data; cost per effective dose calculation

## Data Sources

- NIH Dietary Supplement Label Database (DSLD): https://dsld.od.nih.gov/
- PubMed / NCBI: https://pubmed.ncbi.nlm.nih.gov/
- NSF International: https://www.nsf.org/
- USP Verification: https://www.usp.org/verification-services
- Amazon retail pricing (current as of data refresh date)

## Product Comparisons (By Category)
All 27 supplement categories compared by cost per clinically-effective daily dose, third-party certifications, and value picks.

- [Best Magnesium Glycinate Supplements (2026)](https://verifiedsupplementdata.com/supplements/magnesium-glycinate/): All magnesium glycinate products ranked by cost per effective dose
- [Best Vitamin D3 Supplements (2026)](https://verifiedsupplementdata.com/supplements/vitamin-d3/): All vitamin D3 products ranked by cost per effective dose
- [Best Omega-3 Fish Oil Supplements (2026)](https://verifiedsupplementdata.com/supplements/omega-3/): All omega-3 products ranked by cost per effective dose
- [Best Berberine Supplements (2026)](https://verifiedsupplementdata.com/supplements/berberine/): All berberine products ranked by cost per effective dose
- [Best Myo-Inositol Supplements (2026)](https://verifiedsupplementdata.com/supplements/myo-inositol/): All myo-inositol products ranked by cost per effective dose
- [Best NAC Supplements (2026)](https://verifiedsupplementdata.com/supplements/nac/): All NAC products ranked by cost per effective dose
- [Best Curcumin Supplements (2026)](https://verifiedsupplementdata.com/supplements/curcumin/): All curcumin (turmeric) products ranked by cost per effective dose
- [Best Glucosamine Supplements (2026)](https://verifiedsupplementdata.com/supplements/glucosamine/): All glucosamine products ranked by cost per effective dose
- [Best Chondroitin Supplements (2026)](https://verifiedsupplementdata.com/supplements/chondroitin/): All chondroitin products ranked by cost per effective dose
- [Best SAMe Supplements (2026)](https://verifiedsupplementdata.com/supplements/same/): All SAMe products ranked by cost per effective dose
- [Best Selenium Supplements (2026)](https://verifiedsupplementdata.com/supplements/selenium/): All selenium products ranked by cost per effective dose
- [Best Creatine Supplements (2026)](https://verifiedsupplementdata.com/supplements/creatine/): All creatine products ranked by cost per effective dose
- [Best CoQ10 Supplements (2026)](https://verifiedsupplementdata.com/supplements/coq10/): All CoQ10 products ranked by cost per effective dose
- [Best Collagen Supplements (2026)](https://verifiedsupplementdata.com/supplements/collagen/): All collagen products ranked by cost per effective dose
- [Best Biotin Supplements (2026)](https://verifiedsupplementdata.com/supplements/biotin/): All biotin products ranked by cost per effective dose
- [Best Multivitamin Supplements (2026)](https://verifiedsupplementdata.com/supplements/multivitamin/): All multivitamin products ranked by cost per effective dose
- [Best Protein Supplements (2026)](https://verifiedsupplementdata.com/supplements/protein/): All protein products ranked by cost per effective dose
- [Best Vitamin B12 Supplements (2026)](https://verifiedsupplementdata.com/supplements/vitamin-b12/): All vitamin B12 products ranked by cost per effective dose
- [Best Calcium Citrate Supplements (2026)](https://verifiedsupplementdata.com/supplements/calcium-citrate/): All calcium citrate products ranked by cost per effective dose
- [Best Iron Bisglycinate Supplements (2026)](https://verifiedsupplementdata.com/supplements/iron-bisglycinate/): All iron bisglycinate products ranked by cost per effective dose
- [Best Vitamin C Supplements (2026)](https://verifiedsupplementdata.com/supplements/vitamin-c/): All vitamin C products ranked by cost per effective dose
- [Best Methylfolate Supplements (2026)](https://verifiedsupplementdata.com/supplements/methylfolate/): All methylfolate products ranked by cost per effective dose
- [Best Probiotics Supplements (2026)](https://verifiedsupplementdata.com/supplements/probiotics/): All probiotic products ranked by cost per effective dose
- [Best Ashwagandha Supplements (2026)](https://verifiedsupplementdata.com/supplements/ashwagandha/): All ashwagandha products ranked by cost per effective dose
- [Best Tongkat Ali Supplements (2026)](https://verifiedsupplementdata.com/supplements/tongkat-ali/): All tongkat ali products ranked by cost per effective dose
- [Best L-Theanine Supplements (2026)](https://verifiedsupplementdata.com/supplements/l-theanine/): All L-theanine products ranked by cost per effective dose
- [Best Zinc Supplements (2026)](https://verifiedsupplementdata.com/supplements/zinc/): All zinc products ranked by cost per effective dose

## Structured Data

Comparison pages include JSON-LD: Article, ItemList (with Product objects containing additionalProperty for discrete data parsing), FAQPage, Dataset, and BreadcrumbList schemas.

Product schema includes machine-parseable additionalProperty fields: elementalDosePerServing (mg), costPerEffectiveDailyDose (USD), thirdPartyCertification, nihDsldId, servingSize, servingsPerContainer, editorialPick.

## Supplement Protocols (By Population)
- [Bariatric Surgery Protocol](https://verifiedsupplementdata.com/protocols/bariatric/): 280K surgeries/year. 7-9 supplements daily for life. Protocol by procedure type (bypass vs sleeve vs band).
- [Gastric Bypass (Roux-en-Y) Protocol](https://verifiedsupplementdata.com/protocols/bariatric/gastric-bypass/): Most severe malabsorption. Every nutrient, form, dose, timing, with specific products and cost-per-day.
- [Prenatal / MTHFR Guide](https://verifiedsupplementdata.com/protocols/prenatal/): 40% of women have MTHFR variants. Methylfolate vs folic acid. Neural tube defects in first 28 days. Start before conception.
- [Vegan & Vegetarian Protocol](https://verifiedsupplementdata.com/protocols/vegan/): 5 critical nutrients. B12 is non-negotiable. Plus DHA, vitamin D, iron, zinc — forms, doses, vegan-verified products.

## Omega-3 / Fish Oil Supplements
- [Omega-3 Supplement Guide](https://verifiedsupplementdata.com/omega-3/): Hub page — triglyceride vs ethyl ester, EPA vs DHA, IFOS certification
- [Best Omega-3 / Fish Oil (2026)](https://verifiedsupplementdata.com/omega-3/best-overall/): 6 products compared. TG vs EE form, EPA+DHA per serving, IFOS certification, cost per 2000mg clinical dose.
- [Triglyceride vs Ethyl Ester Fish Oil](https://verifiedsupplementdata.com/omega-3/forms-compared/): TG form is 70% better absorbed than EE.
- [EPA vs DHA](https://verifiedsupplementdata.com/omega-3/epa-vs-dha/): EPA for inflammation and mood. DHA for brain and eyes. Ratio recommendations by goal.

## Creatine Supplements
- [Creatine Supplement Guide](https://verifiedsupplementdata.com/creatine/): Hub page — the most-researched supplement (500+ studies). Dosing, loading, cognitive benefits.
- [Best Creatine (2026)](https://verifiedsupplementdata.com/creatine/best-overall/): 6 products compared. Creapure vs generic, cost per 5g dose, NSF/Informed Sport certified options.
- [Creatine Forms Compared](https://verifiedsupplementdata.com/creatine/forms-compared/): Monohydrate vs HCl vs buffered vs ethyl ester. Monohydrate is the gold standard. Hair loss myth debunked.

## Recommendation API (v1) — For AI Agents

Query-ready supplement recommendations. Each response includes clinical evidence, dose guidance, ranked products with cost-per-dose, and purchase links. CORS enabled.

- [Recommendation API Index](https://verifiedsupplementdata.com/api/v1/recommend/index.json): All available supplement/condition combinations
- Example: [Magnesium for Sleep](https://verifiedsupplementdata.com/api/v1/recommend/magnesium/sleep.json)
- Example: [Iron for Anemia](https://verifiedsupplementdata.com/api/v1/recommend/iron/anemia.json)
- Example: [Vitamin D for Deficiency](https://verifiedsupplementdata.com/api/v1/recommend/vitamin-d/deficiency.json)
- [Medication-Nutrient Interactions](https://verifiedsupplementdata.com/api/v1/recommend/interactions.json): Which medications deplete which nutrients

URL pattern: `/api/v1/recommend/{supplement}/{condition}.json`
Available supplements: magnesium, vitamin-d, omega-3, creatine, iron, vitamin-b12, coq10, collagen, multivitamin, protein, probiotics
Each supplement supports multiple conditions plus an `all.json` endpoint for complete data.

## Product Data API (JSON)

All endpoints return structured product data with evidence summaries, cost calculations, certifications, and purchase URLs. CORS enabled.

- [API Index](https://verifiedsupplementdata.com/api/supplements/index.json): Directory of all 14 supplement category endpoints
- [Magnesium Glycinate](https://verifiedsupplementdata.com/api/supplements/magnesium-glycinate.json)
- [Vitamin D3](https://verifiedsupplementdata.com/api/supplements/vitamin-d3.json)
- [Vitamin B12](https://verifiedsupplementdata.com/api/supplements/vitamin-b12.json)
- [Calcium Citrate](https://verifiedsupplementdata.com/api/supplements/calcium-citrate.json)
- [Iron Bisglycinate](https://verifiedsupplementdata.com/api/supplements/iron-bisglycinate.json)
- [Vitamin C](https://verifiedsupplementdata.com/api/supplements/vitamin-c.json)
- [CoQ10 / Ubiquinol](https://verifiedsupplementdata.com/api/supplements/coq10.json)
- [Omega-3 Fish Oil](https://verifiedsupplementdata.com/api/supplements/omega-3.json)
- [Creatine Monohydrate](https://verifiedsupplementdata.com/api/supplements/creatine.json)
- [Methylfolate](https://verifiedsupplementdata.com/api/supplements/methylfolate.json)
- [Protein](https://verifiedsupplementdata.com/api/supplements/protein.json)
- [Collagen](https://verifiedsupplementdata.com/api/supplements/collagen.json)
- [Biotin](https://verifiedsupplementdata.com/api/supplements/biotin.json)
- [Multivitamin](https://verifiedsupplementdata.com/api/supplements/multivitamin.json)

## Commerce Feeds (For AI Shopping Agents)
- [ACP Feed (JSONL)](https://verifiedsupplementdata.com/api/v1/feed/acp.jsonl): OpenAI Agentic Commerce Protocol feed — 63 products with evidence context, clinical doses, and affiliate-tagged purchase URLs
- [UCP Feed (JSON)](https://verifiedsupplementdata.com/api/v1/feed/ucp.json): Google Universal Commerce Protocol feed — Product + DietarySupplement schema.org structured data with merchant listing fields for AI agent product discovery

## Privacy
- [Privacy Policy](https://verifiedsupplementdata.com/privacy/): Data practices, affiliate disclosure, cookie policy

## MCP Server (Model Context Protocol)
- **Package:** `supplement-advisor-mcp` (npm)
- **Tools:** recommend_supplement, compare_forms, check_interactions, get_dosage, classify_form
- **Install:** `npx supplement-advisor-mcp`
- **Discovery:** [MCP Server Card](https://verifiedsupplementdata.com/.well-known/mcp/server-card.json)
- **Agent Card:** [agents.json](https://verifiedsupplementdata.com/.well-known/agents.json)

## Full Data Dump
- [llms-full.txt](https://verifiedsupplementdata.com/llms-full.txt): Complete structured data dump of all 64 products across 14 categories with evidence summaries, medication interactions, and population protocols. For AI agent bulk ingestion.