NutriStack
Every popular claim, with its receipts.
20 of the most-searched supplement claims, each one opened up: the strongest PubMed-cited studies, contrary evidence, the evidence tier, and a concrete recommendation.
By evidence tier
Distribution across the library.
Tier distribution
- Moderate evidence
- 10 claims
- Strong evidence
- 6 claims
- Emerging evidence
- 4 claims
Ashwagandha
Ashwagandha claims.
3 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Moderate evidence | Ashwagandha reduces serum cortisol | Biochemically real, clinically modest. |
| Moderate evidence | Ashwagandha reduces stress and anxiety symptoms | Consistently positive across small trials. |
| Emerging evidence | Ashwagandha improves sleep quality | Probably real, often secondary to the stress effect. |
Berberine
Berberine claims.
1 claim reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Strong evidence | Berberine lowers blood glucose in type 2 diabetes | Effective and underrated, but interaction-prone. |
Creatine
Creatine claims.
3 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Strong evidence | Creatine increases lean body mass and strength | Strongest evidence base of any performance supplement. |
| Moderate evidence | Creatine improves cognition, especially memory | A real cognitive signal that gets stronger with age or sleep deprivation. |
| Strong evidence | Creatine is safe for long-term use | The kidney concern is a myth; the marker artifact is not. |
Fish Oil
Fish Oil claims.
2 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Moderate evidence | Omega-3 fatty acids reduce cardiovascular risk | High-dose EPA is real medicine; over-the-counter 1g capsules in healthy adults are not. |
| Moderate evidence | Omega-3 fatty acids reduce depressive symptoms | Best as an EPA-dominant adjunct. |
L-Theanine
L-Theanine claims.
1 claim reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Moderate evidence | L-Theanine produces calm, focused alertness | Best in combination with caffeine. |
Magnesium
Magnesium claims.
3 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Moderate evidence | Magnesium improves sleep quality | A clinically credible signal, especially when daily intake from food is low. |
| Emerging evidence | Magnesium reduces anxiety and perceived stress | Worth trying, not worth overstating. |
| Strong evidence | Magnesium lowers blood pressure in hypertensive adults | A real, modest, reproducible effect. |
Vitamin D3
Vitamin D3 claims.
3 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Strong evidence | Vitamin D3 supports immune function and reduces respiratory infection risk | One of the most defensible vitamin D claims. |
| Emerging evidence | Vitamin D3 supplementation improves mood and depressive symptoms | Conditional. Replete people are unlikely to feel a difference. |
| Moderate evidence | Vitamin D3 protects bone health | Necessary, not sufficient. |
Vitamin K2
Vitamin K2 claims.
2 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Moderate evidence | Vitamin K2 supports bone density and reduces fracture risk | Most defensible in postmenopausal women. |
| Emerging evidence | Vitamin K2 may reduce arterial calcification | Mechanistically compelling, clinically unproven. |
Zinc
Zinc claims.
2 claims reviewed
| Evidence | Claim | One-liner |
|---|---|---|
| Strong evidence | Zinc lozenges shorten the duration of the common cold | Form, dose, and timing all matter. |
| Moderate evidence | Zinc supports immune function | Necessary nutrient, not a generic immune booster. |
Methodology
How these claims are picked and tiered.
Each claim maps to a supplement profile and an evidence tier. For each one the strongest meta-analyses, RCTs, and reviews are linked by PMID, contrary evidence is named, and the recommendation follows from what the studies actually report.