How We Score Supplement Safety (2026)
What this page covers: We grade supplement brands A-D based on FDA adverse event report data (CAERS/FAERS). A = fewest reports relative to other brands. D = most reports. D scores almost always reflect high sales volume, not poor safety. This page explains the methodology, shows every brand's score, and lists the limitations you should know.
What Is FAERS / CAERS?
The FDA maintains the Center for Food Safety and Applied Nutrition Adverse Event Reporting System (CAERS) — the supplement equivalent of FAERS (which covers drugs). Anyone — consumers, healthcare providers, manufacturers — can voluntarily report adverse events they believe are associated with a dietary supplement.
We query this database via the FDA's public API (api.fda.gov/food/event.json) to count reports associated with each supplement brand and category we track. As of our latest data pull, there are 53,636 total supplement adverse event reports in the system.
How We Calculate Safety Scores (A-D)
Method: Events normalized by quartile across tracked brands. A = bottom quartile (fewest events), B = below median, C = above median, D = top quartile.
| Score | Meaning | What It Tells You |
|---|---|---|
| A | Bottom quartile (fewest reports) | Very few adverse event reports. May reflect low market share, newer brand, or genuinely fewer issues. Not proof of superior safety. |
| B | Below median | Below-average report count. Generally a positive signal, but could also reflect moderate market share. |
| C | Above median | Average-to-above-average reports. Often reflects solid market presence and wider consumer base. |
| D | Top quartile (most reports) | Highest report count. Almost always correlates with being a market leader (Nature Made, Nature's Bounty, etc.). More users = more reports. |
Critical Limitations
You must understand these limitations before interpreting safety scores:
- Reports are voluntary — not all adverse events are reported
- No causal proof — a reported event does not mean the supplement caused it
- High-selling products naturally accumulate more reports (volume bias)
- Brand name matching is fuzzy — some reports may be misattributed or missed
- Many reports list multiple products, making attribution uncertain
- Report quality varies — some lack detail or contain errors
Bottom line: FAERS reports are voluntary and unvalidated. Low report count may reflect low usage, not high safety. High reports may reflect high usage, not low safety. No causal relationship is implied.
All Brand Safety Scores
| Brand | Score | Total Reports | Serious Events | Top Reactions | Note |
|---|---|---|---|---|---|
| Carlson | B | 13 | 5 | NAUSEA, DIARRHOEA, Headache | Below-average adverse event reports |
| Doctor's Best | B | 28 | 12 | DIARRHOEA, NAUSEA, PAIN | Below-average adverse event reports |
| KAL | B | 28 | 7 | FLUSHING, ERYTHEMA, GRAND MAL CONVULSION | Below-average adverse event reports |
| MegaFood | B | 19 | 6 | Diarrhoea, Vomiting, ABDOMINAL PAIN UPPER | Below-average adverse event reports |
| NATURELO | B | 11 | 6 | Aphasia, Blood pressure increased, Dry mouth | Below-average adverse event reports |
| Optimum Nutrition | B | 23 | 10 | Anxiety, NAUSEA, ABDOMINAL PAIN | Below-average adverse event reports |
| Premier Protein | B | 11 | 6 | Urinary tract infection, Pain, Vomiting | Below-average adverse event reports |
| Vital Proteins | B | 26 | 6 | Abdominal discomfort, Diarrhoea, Headache | Below-average adverse event reports |
| Align | C | 89 | 49 | DIARRHOEA, Abdominal pain, DIZZINESS | Average adverse event reports — may reflect higher sales volume |
| Garden of Life | C | 81 | 26 | DIARRHOEA, NAUSEA, Nausea | Average adverse event reports — may reflect higher sales volume |
| Jarrow Formulas | C | 49 | 20 | Vomiting, Nausea, DIARRHOEA | Average adverse event reports — may reflect higher sales volume |
| Nordic Naturals | C | 29 | 10 | DYSPNOEA, Diarrhoea, RASH | Average adverse event reports — may reflect higher sales volume |
| NOW Foods | C | 40 | 19 | DIARRHOEA, HEADACHE, NAUSEA | Average adverse event reports — may reflect higher sales volume |
| Qunol | C | 32 | 15 | Diarrhoea, Dehydration, Dyspnoea | Average adverse event reports — may reflect higher sales volume |
| Thorne | C | 48 | 17 | Vomiting, Nausea, Abdominal pain | Average adverse event reports — may reflect higher sales volume |
| Culturelle | D | 101 | 45 | Diarrhoea, DYSPNOEA, DIARRHOEA | Higher report count — likely reflects large market share rather than safety concern |
| Florastor | D | 132 | 45 | Fungaemia, Fungal infection, Death | Higher report count — likely reflects large market share rather than safety concern |
| Life Extension | D | 106 | 60 | Dizziness, Anaphylactic reaction, Hypertension | Higher report count — likely reflects large market share rather than safety concern |
| Nature Made | D | 488 | 37 | DYSPNOEA, Dyspnoea, CHOKING | Higher report count — likely reflects large market share rather than safety concern |
| Nature's Bounty | D | 543 | 38 | DYSPNOEA, Choking, HYPERSENSITIVITY | Higher report count — likely reflects large market share rather than safety concern |
| Ritual | D | 132 | 20 | Gastrointestinal disorder, Hypersensitivity, Nausea | Higher report count — likely reflects large market share rather than safety concern |
| Seed | D | 202 | 40 | DYSPNOEA, PRURITUS, RASH | Higher report count — likely reflects large market share rather than safety concern |
| Solgar | D | 148 | 42 | DYSPNOEA, HYPERSENSITIVITY, DIZZINESS | Higher report count — likely reflects large market share rather than safety concern |
| BulkSupplements.com | A | 3 | 2 | Dry mouth, Heart rate increased, Balance disorder | Low adverse event rate relative to other supplement brands |
| Citracal (Bayer) | A | 0 | 0 | None reported | No adverse event reports found in FAERS database |
| Double Wood | A | 7 | 0 | Abdominal discomfort, Muscle spasms, Abdominal distension | Very few reports, no serious events |
| Dymatize | A | 7 | 4 | DYSPNOEA, HEADACHE, HEART RATE INCREASED | Low adverse event rate relative to other supplement brands |
| Momentous | A | 0 | 0 | None reported | No adverse event reports found in FAERS database |
| Nootropics Depot | A | 3 | 0 | Feeling abnormal, Headache, Anxiety | Very few reports, no serious events |
| Sports Research | A | 7 | 4 | Rash, Hypersensitivity, Acne | Low adverse event rate relative to other supplement brands |
| The Vitamin Shoppe | A | 4 | 1 | ASTHENIA, DIZZINESS, NAUSEA | Low adverse event rate relative to other supplement brands |
| Transparent Labs | A | 0 | 0 | None reported | No adverse event reports found in FAERS database |
| Viva Naturals | A | 2 | 1 | Diarrhoea, Migraine | Low adverse event rate relative to other supplement brands |
Adverse Events by Supplement Category
Which supplement types generate the most FDA reports? High numbers reflect both usage volume and inherent risk factors (e.g., choking on large calcium tablets).
| Category | Total Reports | Serious Events | Serious Rate | Top Reactions |
|---|---|---|---|---|
| Calcium Citrate | 4,143 | 3,229 | 77.9% | CHOKING, DYSPHAGIA, FOREIGN BODY TRAUMA |
| Multivitamin | 3,766 | 2,716 | 72.1% | CHOKING, Diarrhoea, Nausea |
| Vitamin D3 | 3,425 | 2,446 | 71.4% | CHOKING, Diarrhoea, DYSPHAGIA |
| Omega 3 | 2,068 | 1,443 | 69.8% | CHOKING, DYSPNOEA, DIARRHOEA |
| Vitamin C | 1,837 | 1,296 | 70.5% | Nausea, DYSPNOEA, CHOKING |
| Magnesium Glycinate | 1,798 | 1,260 | 70.1% | Diarrhoea, CHOKING, Nausea |
| Probiotics | 1,162 | 808 | 69.5% | Diarrhoea, Nausea, Vomiting |
| Iron Bisglycinate | 1,072 | 723 | 67.4% | Diarrhoea, BLOOD IRON DECREASED, NAUSEA |
| Zinc | 959 | 725 | 75.6% | CHOKING, Diarrhoea, Nausea |
| Biotin | 862 | 554 | 64.3% | Alopecia, ALOPECIA, DYSPNOEA |
| Vitamin B12 | 682 | 487 | 71.4% | CHOKING, DYSPNOEA, ALOPECIA |
| Collagen | 417 | 246 | 59% | Nausea, Diarrhoea, Hypersensitivity |
| Coq10 | 409 | 285 | 69.7% | Diarrhoea, Nausea, NAUSEA |
| Methylfolate | 404 | 265 | 65.6% | NAUSEA, VOMITING, DIARRHOEA |
| Creatine | 366 | 161 | 44% | BLOOD CREATINE PHOSPHOKINASE INCREASED, RHABDOMYOLYSIS, ASPARTATE AMINOTRANSFERASE INCREASED |
| Protein | 189 | 118 | 62.4% | DIARRHOEA, VOMITING, NAUSEA |
| Ashwagandha | 166 | 104 | 62.7% | Diarrhoea, Nausea, Pruritus |
| L Theanine | 50 | 38 | 76% | Anxiety, Diarrhoea, Nausea |
| Tongkat Ali | 6 | 4 | 66.7% | Urinary retention, Abdominal pain upper, CHILLS |
How to Use Safety Scores
What they're good for
- Transparency: You can see exactly how many adverse event reports exist for a brand you're considering
- Relative comparison: Within the same product category, comparing report counts between brands of similar market share is meaningful
- Signal detection: Unusually high serious event rates relative to total reports can flag categories worth investigating further
What they're NOT good for
- Absolute safety claims: An A score does not mean "safe" and a D score does not mean "dangerous"
- Comparing across categories: Calcium having more reports than tongkat ali primarily reflects calcium being consumed by 100x more people
- Replacing medical advice: Your doctor knows your specific health context — no database score replaces that
Frequently Asked Questions
What is a FAERS safety score for supplements?
Our safety scores (A-D) are based on FDA adverse event reports from the CAERS/FAERS database. Brands are ranked by quartile: A = bottom quartile (fewest reports), B = below median, C = above median, D = top quartile (most reports). These scores reflect report volume, not proven safety — high-selling brands naturally accumulate more reports.
Does a D safety score mean a supplement is dangerous?
No. A D score means the brand has more FDA adverse event reports than most brands we track, but this almost always reflects higher sales volume rather than worse safety. Nature Made and Nature's Bounty both score D because they are the two best-selling supplement brands in America — more users means more reports. FAERS data is voluntary, unvalidated, and does not prove causation.
Are supplement adverse event reports reliable?
FAERS reports are useful for signal detection but have major limitations: they are voluntary (most events go unreported), unvalidated (no confirmation the supplement caused the event), subject to volume bias (popular products get more reports), and many reports list multiple products making attribution uncertain. We include this data for transparency, not as a definitive safety ranking.
Which supplement categories have the most adverse event reports?
Calcium supplements lead with over 4,000 reports, followed by multivitamins (~3,700), vitamin D3 (~3,400), and omega-3/fish oil (~2,000). These are also among the most-consumed supplement categories, so high report counts primarily reflect market size.
Where does the FAERS supplement data come from?
We pull data from the FDA's CAERS (Center for Food Safety and Applied Nutrition Adverse Event Reporting System) via api.fda.gov/food/event.json. This is the supplement-specific counterpart to FAERS (which covers drugs). Reports come from consumers, healthcare providers, and manufacturers.
Data Source
- FDA CAERS (FAERS for Foods/Supplements) — api.fda.gov/food/event.json
- Data generated: 2026-03-17. Total supplement events in database: 53,636