The Supplement Guide
built on evidence, not hype.

Each supplement is rated from Insufficient to Very Strong Evidence based on the quality and consistency of human research — systematic reviews, meta-analyses, and randomized controlled trials — not marketing claims or anecdotal reports.

Not necessarily. Strong evidence for a supplement usually applies to a specific population or use case, such as correcting a documented deficiency. Check the "Is It Worth Taking?" section on each page for context.

No. This guide is educational information based on published research. Always consult a qualified healthcare provider before starting a new supplement, especially if pregnant, breastfeeding, managing a health condition, or taking medication.

You can add up to four supplements to the comparison tool at a time to see their evidence, dosage, timing, risks, and interactions side by side.

We rate every supplement on the actual evidence, not on popularity. A few widely marketed products (like Garcinia Cambogia or Evening Primrose Oil) have been tested in rigorous trials and shown no meaningful benefit over placebo for their main claimed uses — we report that honestly rather than inflating ratings to match marketing.

Many people do, but combinations aren't automatically safe just because each ingredient is safe individually. Check the "Drug Interactions" section on each supplement's page, and be aware that some combinations (e.g., multiple sedating supplements, or several products that all affect blood sugar or blood thinning) can have additive effects. When in doubt, review your full supplement list with a pharmacist or physician.

Evidence-based dosing is tied to the active compound and standardized extract concentration (e.g., % withanolides, % ginsenosides) used in clinical trials, not to any particular commercial brand. When shopping, check the supplement facts panel for the standardized extract and dose that matches what's listed on our dosage section, rather than relying on brand marketing claims.

We review the underlying evidence periodically as new systematic reviews and major trials are published. Supplement science moves slower than headlines suggest — most ratings here are unlikely to flip dramatically year to year, but genuinely new, high-quality evidence (positive or negative) gets reflected when it changes the overall picture.

For most core nutrients, a varied diet meeting your calorie needs covers requirements without supplementation. Supplements are most clearly justified when they correct a documented gap (e.g., vitamin D in low sun-exposure climates, B12 for vegans, iron for confirmed deficiency) or serve a specific performance/therapeutic purpose with real supporting evidence — not as a blanket "just in case" addition.

No. Several supplements on this list (St. John's Wort, Ginkgo, Kava-family herbs) have serious, well-documented drug interactions or safety signals despite being plant-derived and sold over the counter. "Natural" describes origin, not safety — potency and interaction risk should be judged the same way for any substance you put in your body.

A formal Tolerable Upper Intake Level exists when there's enough toxicity data to define a safe ceiling — this is common for vitamins and minerals with long research histories (vitamin D, iron, selenium). Many herbal extracts and newer compounds lack a formal UL simply because long-term, high-dose human safety data hasn't been collected yet — that absence reflects a data gap, not proof of unlimited safety.

Stop taking it and contact a healthcare provider, especially if symptoms are significant (rash, difficulty breathing, chest pain, severe GI distress). In the US, you can also report supplement-related adverse events to the FDA's MedWatch program, which helps track safety signals across products that aren't as tightly regulated as prescription medications.