Supplement reviews

Every verdict is graded by evidence level and traced back to peer-reviewed trials and meta-analyses. Filter by category or evidence strength below.

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All categories
Vitamins
Minerals
Herbs
Protein
Omega-3
Probiotics
Performance
Nootropics
All evidence levels
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moderate
mixed
limited
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16 results

Performance

Creatine monohydrate

Strong evidence

One of the most studied sports supplements. Reliably increases short-burst power output and lean mass when combined with resistance training.

Verdict: Works for strength and power athletes.

1,000 studies reviewed
May cause modest short-term weight gain from water retention
Protein

Whey protein

Strong evidence

A convenient, high-quality protein source. Supports muscle protein synthesis and recovery, especially after resistance training.

Verdict: Works as a protein source, not a magic muscle builder.

540 studies reviewed
Lactose intolerance in some people
Minerals

Zinc

Strong evidence

Effective at reducing the duration of common cold symptoms when started early and supports immune function in deficient individuals.

Verdict: Works for acute colds and deficiency.

290 studies reviewed
Nasal zinc can cause permanent smell loss
Performance

Caffeine

Strong evidence

Well-established ergogenic aid that improves alertness, endurance, and power output. Dose-response is individual and habituation occurs.

Verdict: Works for performance and alertness.

760 studies reviewed
Can disrupt sleep and cause anxiety
Minerals

Iron

Strong evidence

Essential for treating iron-deficiency anemia and improving fatigue in deficient individuals. No benefit for people with normal levels.

Verdict: Critical if deficient; harmful if not.

330 studies reviewed
Do not take without testing ferritin/iron
Vitamins

Vitamin D

Moderate evidence

Essential for bone health and immune function. Supplementation helps people who are deficient, but routine mega-dosing shows mixed benefits for healthy adults.

Verdict: Worth taking if deficient; test levels first.

850 studies reviewed
Fat-soluble toxicity risk at very high doses
Omega-3

Omega-3 fish oil

Moderate evidence

Reduces triglycerides and may lower cardiovascular risk in high-risk groups. Benefits for cognition and mood are promising but less certain.

Verdict: Heart and triglyceride benefits are well-supported.

620 studies reviewed
High doses can increase bleeding risk
Minerals

Magnesium

Moderate evidence

Improves sleep quality and reduces muscle cramps in people who are deficient. Many diets are low in magnesium.

Verdict: Helpful for deficiency; limited extra benefit for replete people.

410 studies reviewed
High doses can cause diarrhea
Herbs

Ashwagandha

Moderate evidence

A traditional adaptogen with randomized trials showing reduced stress, lower cortisol, and modest improvements in sleep and strength.

Verdict: Promising for stress and recovery; choose KSM-66 or Sensoril.

120 studies reviewed
May interact with thyroid and sedative medications
Probiotics

Probiotics

Mixed evidence

Helpful for specific conditions like antibiotic-associated diarrhea and some IBS subtypes. General health benefits are highly strain-specific.

Verdict: Strain-specific effects; not a one-size-fits-all health booster.

380 studies reviewed
Benefits depend on specific strain and dose
Protein

Collagen peptides

Mixed evidence

Some studies show improved skin elasticity and reduced joint discomfort, but evidence is industry-funded and effects are modest.

Verdict: Possible skin and joint benefits; evidence is mixed.

95 studies reviewed
Often derived from animal sources
Herbs

Rhodiola rosea

Mixed evidence

Some evidence for reducing fatigue and improving stress resilience, but study quality is mixed and effects are modest.

Verdict: May help fatigue and stress; evidence is inconsistent.

70 studies reviewed
May interact with antidepressants
Vitamins

Multivitamin

Limited evidence

For most well-nourished adults, multivitamins do not reduce mortality or prevent chronic disease. May help fill gaps in restricted diets.

Verdict: Insurance policy, not a longevity pill.

310 studies reviewed
Can lead to excessive intake of some fat-soluble vitamins
Protein

BCAAs

Limited evidence

Leucine, isoleucine, and valine alone are less effective than complete protein. No added benefit if protein intake is adequate.

Verdict: Not needed if you already eat enough protein.

180 studies reviewed
May interfere with B-vitamin metabolism at high doses
Nootropics

Pre-formulated nootropic stacks

Limited evidence

Proprietary blends often hide doses and combine weakly studied ingredients. Marketing typically exceeds evidence.

Verdict: Mostly hype; individual ingredients matter more.

45 studies reviewed
Unknown ingredient interactions
Herbs

Ginkgo biloba

No evidence

Despite popularity, large trials have not shown consistent memory or cognitive enhancement in healthy adults or dementia patients.

Verdict: No convincing evidence for cognitive enhancement.

220 studies reviewed
Blood-thinning interaction risk