Verified Supplement Data Primary-sourced

Supplements A–Z (2026): Evidence-Based Comparison Guides

By Erin Rose · Updated · Methodology · About Us

Every supplement we cover, in one place. Each guide compares the real forms, gives evidence-based dosing, and ranks products by cost per clinically-effective dose — with every clinical claim linked to its primary source on PubMed. We say so plainly when the evidence is weak.

  • Ashwagandha

    KSM-66 vs Sensoril vs generic, stress, sleep.

  • Berberine

    Dosing, dihydroberberine, blood sugar, safety.

  • Biotin

    Hair and nails evidence, dosing, lab-test interference.

  • Calcium

    Citrate vs carbonate, absorption with/without stomach acid.

  • Chondroitin

    Osteoarthritis evidence and how it pairs with glucosamine.

  • Collagen

    Types, skin and joint evidence, dosing.

  • CoQ10

    Ubiquinol vs ubiquinone, absorption, statins.

  • Creatine

    Monohydrate vs HCl, dosing, what actually works.

  • Curcumin

    Bioavailability problem, enhanced forms, joint pain.

  • Electrolytes

    Sodium/potassium/magnesium ratios, sugar-free picks, keto and sweat loss.

  • Glucosamine

    Osteoarthritis evidence, sulfate vs HCl, dosing.

  • Iron

    Ferrous sulfate vs bisglycinate, low ferritin, tolerability.

  • L-Theanine

    Calm-focus evidence, dosing, and stacking with caffeine.

  • Magnesium

    Forms compared, sleep/anxiety/cramps picks, dosage, deficiency signs.

  • Melatonin

    How much to take (less is often more), timing for sleep vs jet lag, and the label-accuracy problem.

  • Methylfolate

    Vs folic acid, MTHFR, pregnancy dosing.

  • Multivitamins

    Who actually needs one, what to look for, best picks.

  • Myo-Inositol

    PCOS evidence, the 40:1 ratio, and dosing.

  • NAC

    Liver/glutathione and mental health, dosing.

  • Omega-3

    EPA vs DHA, triglyceride vs ethyl ester, best fish oil.

  • Probiotics

    Strain-specific evidence, condition matching.

  • Protein

    Whey vs plant, dosing, protein for GLP-1 users and weight loss.

  • SAMe

    Depression evidence, dosing, and stability caveats.

  • Selenium

    Thyroid (Hashimoto’s) evidence, dosing, and the narrow safe range.

  • Tongkat Ali

    Testosterone evidence, dosing, tongkat vs fadogia.

  • Vitamin B12

    Methylcobalamin vs cyanocobalamin, energy, deficiency risk.

  • Vitamin C

    Forms, the absorption ceiling, immune evidence.

  • Vitamin D

    D2 vs D3, dosing (1000–5000 IU), K2 pairing, deficiency.

  • Vitamin K2

    MK-7 vs MK-4, how much to take with vitamin D, and the calcium-routing (bone vs artery) evidence.

  • Zinc

    Forms, copper balance, immunity and colds, upper limits.

How we compare supplements

We pull product label data from the NIH Dietary Supplement Label Database, clinical evidence from PubMed systematic reviews, and third-party certifications from USP and NSF. Read our methodology and editorial standards.