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EvidenceBase

What does the evidence actually say?

Search any supplement + condition pair. Get the verdict in seconds, not hours. Every claim backed by cited studies.

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Summary Cards

Scannable in 3 seconds. Answer first, evidence second.

Magnesium→Migraine Prevention
Strong (B+)We have good evidence from multiple controlled studies. Results mostly agree, but there's still some uncertainty.Likely benefit ↑
“Likely reduces migraine frequency by 1–2 episodes per month in chronic sufferers”
Dose400–600 mg/day
Timeframe3+ months for full effect
Best formCitrate or oxide
Cost~$0.05/day
⚠ 1 interaction12 studies1,847 participants
Evidence breakdown
Study types
8 RCTs · 3 Obs · 1 Meta
Effect size
d = 0.42
Small-to-medium effect
Consistency
9 of 12 positive
3 null results, 0 negative
Population
Chronic migraine patients
Adults 18–65, both sexes
Dosage details
FormDoseTimingNotes
CITRATE400–600 mgWith dinnerBest absorbed; most studied
OXIDE400–500 mgWith foodCheaper; lower bioavailability
GLYCINATE300–400 mgBefore bedGentler on stomach; less studied for migraine
Safety & interactions
  • !
    Ciprofloxacin & fluoroquinolones: Magnesium reduces antibiotic absorption by up to 50%. Take 2+ hours apart.
  • i
    Common side effect: Loose stools at doses >400mg, especially with oxide form. Start low.
  • ×
    Kidney disease: Avoid without physician guidance. Impaired clearance can cause dangerous buildup.
Individual studies
Meta
Oral Mg reduced migraine frequency by 1.6 episodes/month vs placebo across 5 pooled RCTs
Chiu et al. 2016n = 8955 trials pooled
−1.6 ep/mo
95% CI [−2.1, −1.0]
PubMed →
RCT
600mg Mg citrate daily reduced migraine days from 6.2 to 3.8/month after 12 weeks
Köseoglu et al. 2008n = 4012 weeks
−2.4 days/mo
p = 0.012
PubMed →
RCT
400mg Mg oxide vs placebo showed no significant difference in migraine frequency at 8 weeks
Pfaffenrath et al. 1996n = 698 weeks
NS
p = 0.34
PubMed →
RCT
Mg supplementation reduced migraine attack frequency by 41.6% vs 15.8% for placebo
Peikert et al. 1996n = 8112 weeks
−41.6%
p < 0.05
PubMed →
Ashwagandha→Anxiety
Strong (B+)Multiple RCTs show consistent anxiolytic effects. Evidence is solid, though most trials are relatively small.Clear benefit ↑
“Consistently reduces self-reported anxiety scores by 30–45% across multiple trials”
Dose300–600 mg/day
Timeframe6–8 weeks
Best formKSM-66 root extract
Cost~$0.25/day
⚠ 2 interactions9 studies1,201 participants
Evidence breakdown
Study types
7 RCTs · 1 Meta · 1 Obs
Effect size
d = 0.58
Medium effect
Consistency
8 of 9 positive
Highly consistent
Population
Stressed adults, GAD patients
Ages 18–60
Safety & interactions
  • !
    Thyroid medication (levothyroxine): Ashwagandha may increase thyroid hormone levels. Monitor TSH if on thyroid meds.
  • !
    Sedatives & benzodiazepines: May enhance sedative effects. Use caution with sleep/anxiety medications.
  • ×
    Pregnancy: Contraindicated. Traditional use as abortifacient. Do not use during pregnancy.
CoQ10→Migraine Prevention
Moderate (B)Some controlled trials show benefit, but sample sizes are small and results aren't always consistent.Likely benefit ↑
“May reduce migraine frequency by 1–3 episodes per month, but evidence is less robust than magnesium”
Dose100–300 mg/day
Timeframe4–12 weeks
Best formUbiquinol (reduced)
Cost~$0.30/day
No known interactions5 studies346 participants
Evidence breakdown
Study types
4 RCTs · 1 Obs
Effect size
d = 0.35
Small effect
Consistency
4 of 5 positive
Population
Episodic migraine patients
Vitamin D→Depression
Limited (C)Results are inconsistent. Some studies show benefit in deficient populations, but large RCTs in general populations found no effect.Mixed ⇕
“May help if you're deficient, but supplementation in non-deficient adults shows no consistent antidepressant effect”
Dose1,000–4,000 IU/day
Timeframe8–12 weeks
Key caveatCheck blood levels first
Cost~$0.03/day
⚠ 1 interaction18 studies12,648 participants
Evidence breakdown
Study types
12 RCTs · 4 Meta · 2 Obs
Effect size
d = 0.28 (deficient only)
Near zero in non-deficient
Consistency
10 of 18 positive
Strongly split by baseline status
Population
Highly variable
Deficient vs non-deficient matters most
02

Comparison View

Side-by-side for the same condition. Which supplement has stronger evidence?

vs
Magnesium→Migraine
Strong (B+)Likely ↑
Evidence12 studies · 1,847 ppl
Dose400–600 mg/day
Effect~1–2 fewer/month
Timeframe3+ months
Cost$0.05/day
Side effectsGI (dose-dependent)
CoQ10→Migraine
Moderate (B)Likely ↑
Evidence5 studies · 346 ppl
Dose100–300 mg/day
Effect~1–3 fewer/month
Timeframe4–12 weeks
Cost$0.30/day
Side effectsRare · well tolerated
03

Interaction Checker

Enter your full stack. We flag every conflict.

Supp Magnesium 400mg ×
Supp Ashwagandha 600mg ×
Med Levothyroxine 50mcg ×
Med Ciprofloxacin 500mg ×
⛔Magnesium + Ciprofloxacin
High Severity

Magnesium chelates ciprofloxacin in the GI tract, reducing antibiotic absorption by up to 50%. This can lead to treatment failure for the infection you're treating.

Recommended action
Take magnesium at least 2 hours before OR 6 hours after ciprofloxacin. Consider pausing magnesium during the antibiotic course.
Source: FDA prescribing information · Stass et al. 2001 · Lode et al. 1998
⚠️Ashwagandha + Levothyroxine
Moderate Severity

Ashwagandha may stimulate thyroid hormone production (T3 and T4), potentially causing hyperthyroid symptoms when combined with thyroid replacement therapy. 8-week trial showed significant TSH decrease in subclinical hypothyroid patients.

Recommended action
Monitor TSH levels every 4–6 weeks after starting ashwagandha. Your levothyroxine dose may need adjustment. Consult your prescriber.
Source: Sharma et al. 2018 · Panda & Kar 1998
04

Research Feed

New evidence that affects your stack or conditions. AI-triaged, human-reviewed.

📊 Evidence update
Ashwagandha → Anxiety
B (Moderate)→B+ (Strong)

New meta-analysis by Bonilla et al. (2024, n=1,200 across 7 RCTs) confirms prior findings with tighter confidence intervals. Effect size now well-established at d = 0.58 for standardized anxiety measures. Upgraded from Moderate to Strong.

Updated Feb 3, 2026 · Review ID #4821
⚠ Safety update
Ashwagandha → Liver Safety
No prior signal→Under review

Iceland and the Netherlands flagged liver injury cases associated with ashwagandha-containing products. Case reports suggest idiosyncratic hepatotoxicity in rare cases. Risk appears very low but is being evaluated.

Updated Jan 28, 2026 · Safety alert #112
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How We Grade Evidence

Dual-axis system: how confident we are × what direction the evidence points.

GradeLabelConfidenceWhat it means
A+Very High
Multiple large RCTs agree. Settled science.
AHigh
Strong RCT evidence, consistent results.
B+Strong
Good RCT evidence, mostly consistent.
BModerate
Some RCTs or strong observational data.
CLimited
Few small studies or mixed results.
DPreliminary
Animal/cell studies or single small human trials.