Evidence system
How we grade the evidence
Two independent labels appear on every analysis and profile: an evidence level that describes how strong the human research is for a specific claim, and a regulatory status that describes what the FDA has actually decided. One never implies the other.
Evidence levels
The grade applies to a specific claim, population and outcome — never to a molecule in general. A peptide can be established for one indication and preclinical for another. When we can’t verify a claim from a primary source we grade it unsupported rather than guessing.
- Established evidence
- Supported by regulatory approval or multiple strong human trials for the specific indication.
- Typically: FDA approval for the indication, or ≥2 adequately powered randomized trials with consistent results.
- Promising evidence
- Meaningful human evidence exists, but conclusions remain limited.
- Typically: at least one randomized controlled trial or a consistent body of controlled human studies, with meaningful limitations in size, duration or generalisability.
- Preliminary evidence
- Small, uncontrolled, or early-stage human evidence.
- Typically: small pilot studies, uncontrolled or open-label trials, or case series in humans.
- Preclinical evidence
- Cell or animal research only. No adequate human evidence.
- Typically: rodent, other animal or in-vitro studies. Human relevance unknown.
- Unsupported evidence
- Claims exceed the available evidence.
- Typically: marketing claims with no human data, or claims that contradict the available data.
- Conflicting evidence
- Credible studies reach different conclusions.
- Typically: well-designed studies with opposite or inconsistent findings that cannot yet be reconciled.
Regulatory status
Regulatory status is a fact about a decision by the U.S. Food and Drug Administration, not a judgement about evidence. We source it from FDA labels, approval databases and safety communications, and we mark it as requires verification when we cannot confirm it from those sources.
- FDA-approved for this use
- The FDA has approved this peptide for the indication discussed.
- FDA-approved for a different use
- The FDA has approved this peptide for another indication; the use discussed is off-label.
- Investigational
- Under study in registered clinical trials; not approved for marketing.
- Not FDA-approved
- No FDA approval for any indication.
- Withdrawn or discontinued
- Previously available or in development, later withdrawn or discontinued.
- Status requires verification
- The regulatory status could not be verified from primary sources at review time.
Where each peptide sits today
The matrix plots each profiled peptide by overall evidence level (rows) and U.S. regulatory status (columns) for its most-discussed use. Notice how often the two axes disagree.
| Evidence ↓ / Regulatory → | FDA-approved for this use | Not FDA-approved |
|---|---|---|
| Established | ||
| Promising | ||
| Preliminary | ||
| Preclinical |
Analyses by evidence level
Established evidence
- FDA-Approved vs Proven Effective: Why They Are Not the Same
- Counterfeit and Fake GLP-1 Products: How to Spot Them
- Compounded Semaglutide: What the FDA Actually Says
- How Long Does Semaglutide Take to Work? The Benefit Timeline
- Peptides for Weight Loss: What Works, by How Much, and for How Long
- GLP-1 Benefits Beyond Weight Loss: Heart, Kidney, Liver, and Sleep
- GLP-1 Peptides: Established Uses Versus Emerging Research
- Peptide Purity, Contamination, and the Limits of a Certificate of Analysis
- Tesamorelin: Approved Use, Off-Label Interest, and Clinical Evidence
- PT-141: Mechanism, Approved Use, Benefits, and Limitations
- FDA-Approved, Off-Label, Investigational, and Unapproved Peptides
- How to Read Peptide Research Without Falling for Marketing
- What Are Peptides? A Research-Based Introduction
Promising evidence
Preliminary evidence
Preclinical evidence
- Peptides for Hair Growth: What Has Actually Been Tested
- Peptides for Energy and Sleep: Claims Versus Trials
- Peptides for Muscle Growth: What the Evidence Supports
- Peptides for Recovery: Which Benefits Are Actually Documented
- BPC-157: Human Evidence, Animal Research, and Open Questions
- TB-500 and Thymosin Beta-4: What the Research Actually Studies