Guide claim index: every checked claim, its verdict and its source
One row per claim, grouped by the guide it comes from. Each row gives a plain yes, no or partly verdict and links to the health authority document or published trial the verdict rests on. For the longer write-up behind each verdict, read the supplement fact check.
Calcium dosage guide
Calcium is best absorbed in single doses of 500 mg or less.
Verdict: Yes — splitting the dose absorbs more
Source: NIH Office of Dietary Supplements — Calcium fact sheet · Read the calcium dosage guide · Full fact check
Calcium plus vitamin D supplements reliably prevent hip fractures.
Verdict: No — the largest trial found no significant reduction
Source: Jackson RD, et al. N Engl J Med. 2006 · Read the calcium dosage guide · Full fact check
Calcium can stop levothyroxine and some antibiotics from working properly.
Verdict: Yes — separate them in time
Source: NIH Office of Dietary Supplements — Calcium fact sheet · Read the calcium dosage guide · Full fact check
Creatine dosage guide
Creatine damages the kidneys in healthy people.
Verdict: No — not shown in healthy adults
Source: NIH Office of Dietary Supplements — Dietary supplements for exercise and athletic performance · Read the creatine dosage guide · Full fact check
Folate and folic acid guide
Folic acid before conception reduces the risk of neural tube defects.
Verdict: Yes — one of the strongest findings in nutrition
Source: MRC Vitamin Study Research Group. Lancet. 1991 · Read the folate and folic acid guide · Full fact check
High-dose folic acid can hide a vitamin B12 deficiency.
Verdict: Yes — this is why the 1,000 mcg limit exists
Source: NIH Office of Dietary Supplements — Folate fact sheet · Read the folate and folic acid guide · Full fact check
Anyone with an MTHFR gene variant needs methylfolate instead of folic acid.
Verdict: No — not established
Source: NIH Office of Dietary Supplements — Folate fact sheet · Read the folate and folic acid guide · Full fact check
Ginkgo biloba dosage guide
Ginkgo biloba prevents dementia.
Verdict: No — two large long trials found no benefit
Source: DeKosky ST, et al. JAMA. 2008 · Read the ginkgo biloba dosage guide · Full fact check
Ginkgo should usually be stopped before surgery.
Verdict: Yes — because of bleeding concern
Source: National Center for Complementary and Integrative Health — Ginkgo · Read the ginkgo biloba dosage guide · Full fact check
Raw ginkgo seeds are safe to eat.
Verdict: No — they are toxic
Source: National Center for Complementary and Integrative Health — Ginkgo · Read the ginkgo biloba dosage guide · Full fact check
Lion's mane dosage guide
Lion's mane improves memory in healthy adults.
Verdict: No — that population has not been shown to benefit
Source: Mori K, et al. Phytotherapy Research. 2009 · Read the lion's mane dosage guide · Full fact check
Lion's mane regenerates nerves in people.
Verdict: No — laboratory and animal findings only
Source: National Center for Complementary and Integrative Health — Mushrooms · Read the lion's mane dosage guide · Full fact check
Rhodiola rosea guide
Rhodiola rosea is a proven treatment for fatigue.
Verdict: No — evidence is limited and inconclusive
Source: National Center for Complementary and Integrative Health — Rhodiola · Read the rhodiola rosea guide · Full fact check
The rhodiola night-duty trial used a low daily amount of a standardized extract.
Verdict: Yes — a repeated low-dose SHR-5 regimen
Source: Darbinyan V, et al. Phytomedicine. 2000 · Read the rhodiola rosea guide · Full fact check
Selenium dosage guide
Selenium supplements prevent prostate cancer.
Verdict: No — the large trial was negative
Source: Lippman SM, et al. SELECT. JAMA. 2009 · Read the selenium dosage guide · Full fact check
A single brazil nut can supply more selenium than an adult needs in a day.
Verdict: Yes — often well above the 55 mcg requirement
Source: NIH Office of Dietary Supplements — Selenium fact sheet · Read the selenium dosage guide · Full fact check
Vitamin C dosage guide
Taking 1,000 mg of vitamin C in one dose delivers roughly ten times as much as 100 mg.
Verdict: No — absorption saturates
Source: Levine M, et al. Vitamin C pharmacokinetics in healthy volunteers. PNAS. 1996 · Read the vitamin c dosage guide · Full fact check
Vitamin C prevents colds in the general population.
Verdict: No — not in the general population
Source: Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane. 2013 · Read the vitamin c dosage guide · Full fact check
Vitamin D daily dose guide
Vitamin D needs a blood test to decide the right amount.
Verdict: Partly — the RDA applies to everyone, blood level guides correction
Source: NIH Office of Dietary Supplements — Vitamin D fact sheet · Read the vitamin d daily dose guide · Full fact check
Vitamin K2 dosage guide
A three-year trial tested 180 mcg a day of MK-7 in postmenopausal women.
Verdict: Yes — that is the published protocol
Source: Knapen MHJ, et al. Osteoporosis International. 2013 · Read the vitamin k2 dosage guide · Full fact check
Vitamin K2 is proven to keep calcium out of arteries and prevent heart events.
Verdict: No — mechanism is plausible, outcomes are not shown
Source: NIH Office of Dietary Supplements — Vitamin K fact sheet · Read the vitamin k2 dosage guide · Full fact check
People on warfarin must keep vitamin K intake consistent.
Verdict: Yes — this is standard clinical advice
Source: NIH Office of Dietary Supplements — Vitamin K fact sheet · Read the vitamin k2 dosage guide · Full fact check
Zinc dosage guide
Adults should not exceed 40 mg of zinc a day from food and supplements.
Verdict: Yes — that is the published upper limit
Source: NIH Office of Dietary Supplements — Zinc fact sheet · Read the zinc dosage guide · Full fact check
Zinc definitively shortens the common cold.
Verdict: Partly — dose, timing and format dependent, and contested
Source: Hemilä H. Zinc lozenges and the common cold: a meta-analysis. JRSM Open. 2017 · Read the zinc dosage guide · Full fact check
How a claim gets its verdict
A claim is marked supported only when a named health authority document or a published trial states it directly. Where a claim rests on laboratory or animal work, or on trials too small or too short to answer the question, it is marked not supported or partly supported — even when the supplement itself is popular and well tolerated. Amounts quoted in the guides are figures reported in those sources, not recommendations from us.
Guides without a checked claim yet
These 56 guides cite their sources on the page, but none of their headline claims has been through the fact check yet. They are listed here so the coverage of this index is visible rather than implied.
- 5-HTP Dosage: Amounts Used in Studies
- Alpha-GPC Dosage: Choline Amounts and What the Evidence Shows
- Alpha-Lipoic Acid Dosage: What Neuropathy Trials Used
- Ashwagandha Dosage: How Much to Take for Stress & Sleep
- Bacopa Monnieri Dosage: Memory Trial Amounts and Timelines
- Berberine Dosage: How Much to Take and When
- Beta-Alanine Dosage: Amounts, Timing and the Tingling
- Biotin Dosage: Adequate Intake, Hair Claims and Lab Interference
- Boron Dosage: Typical Intake, the 20 mg Upper Limit and Evidence
- BPC-157 Dosage: What Protocols Report and What Research Exists
- BPH Natural Support: Supplements & Lifestyle
- Caffeine Dosage: How Much Per Day Is Safe?
- CBD Dosage for Anxiety: What the Research Actually Used
- Citrulline Dosage: L-Citrulline vs Citrulline Malate
- Collagen Dosage: How Many Grams Per Day?
- CoQ10 Dosage: Ubiquinone, Ubiquinol and the Statin Question
- DHEA Dosage: Amounts Used in Studies
- ED Supplements: What Actually Has Evidence
- Electrolytes: How Much Sodium, Potassium and Magnesium?
- GHK-Cu Dosage: Topical Concentrations, Evidence and the Injection Question
- GLP-1, Dopamine & Relationships: What We Know
- Glycine Dosage: The 3 g Sleep Studies and What Else It Does
- Hexarelin: Evidence, Reported Protocols & Risks
- Inositol Dosage for PCOS: What Trials Used
- Iron Supplement Dosage: How Much Iron Per Day?
- L-Carnitine Dosage: What Studies Used
- L-Glutamine Dosage: Study Amounts for Gut, Muscle and Recovery
- L-Theanine Dosage: Amounts Used in Stress and Focus Trials
- Low Testosterone Symptoms: Signs, Tests & Causes
- Magnesium Citrate Dosage: How Much Per Day?
- Magnesium Glycinate Dosage: How Much to Take & When
- Magnesium L-Threonate Dosage & Evidence
- Melatonin Dosage: How Much Should You Actually Take?
- Milk Thistle Dosage & Evidence for Liver Health
- MOTS-c Dosage: What the Research Shows and What It Does Not
- NAC Dosage: N-Acetylcysteine Amounts Used in Research
- NMN Dosage: What Human Trials Have Actually Used
- Omega-3 Dosage: How Much EPA and DHA Per Day
- Panax Ginseng Dosage: Trial Amounts, Ginsenosides and Safety
- Potassium Dosage: Daily Intake, the 99 mg Cap and Kidney Risk
- Probiotics Dosage: How Many CFU Do You Actually Need?
- Quercetin Dosage: Study Amounts, Absorption and Safety
- Resveratrol Dosage: Trial Amounts and the Red Wine Myth
- Saw Palmetto Dosage: What Prostate Trials Actually Used
- Semaglutide Dosage: The Approved Escalation Schedules Explained
- St John's Wort Dosage and Its Serious Drug Interactions
- Taurine Dosage: How Much Do Studies Actually Use?
- TB-500 Dosage: Reported Protocols and the Thymosin Beta-4 Evidence
- Tesamorelin Dosage: The Approved Regimen and What Trials Measured
- Tirzepatide Dosage: The Weekly Escalation Schedule Explained
- Tongkat Ali Dosage: Extract Ratios, Evidence and Safety
- Turmeric and Curcumin Dosage: What the Trials Used
- Valerian Root Dosage for Sleep: What Trials Used
- Vitamin B12 Dosage: How Much B12 Per Day?
- Vitamin B6 Dosage: How Much Is Too Much?
- Vitamin E Dosage: How Much Per Day Is Safe?
This page is reference material, not medical advice. Supplements interact with prescription medicines and with each other. Talk to a doctor or pharmacist before starting anything, especially if you are pregnant, breastfeeding, managing a health condition or taking prescription medicine.
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Frequently asked questions
What is the guide claim index?
It lists every factual claim our supplement dosing guides make, grouped by guide, with a yes, no or partly verdict and the trial, review or health authority the verdict rests on.
What does each verdict mean?
Yes means published human evidence supports the claim, partly means the evidence is mixed or limited to specific groups, and no means the evidence does not support it. Every verdict links to the source so you can read it yourself.
How often are the claims rechecked?
Claims are rechecked whenever the guide behind them is updated, and the source citation shown next to each verdict records the study or authority used at that review.
Is this medical advice?
No. The claim index is educational reference material. Supplements interact with prescription medicines, so speak to a doctor or pharmacist before starting anything.