The Research Hierarchy
Peptide research progresses through distinct stages, each providing different types of evidence. Understanding these stages is essential for interpreting what research findings actually mean.
Preclinical Research
Preclinical research occurs before human testing and includes:
In Vitro Studies
Research conducted in test tubes or cell cultures. These studies:
- Investigate molecular mechanisms in controlled environments
- Cannot capture whole-organism effects
- May not reflect what happens in living systems
- Are useful for understanding basic biology
Animal Studies
Research conducted in animal models. These studies:
- Provide whole-organism data
- May not translate directly to humans
- Use species with different biology (often rodents)
- Can explore safety margins not ethical in humans
Clinical Research
Clinical research involves human subjects and follows a phased approach:
Phase 1
First-in-human studies focusing on safety:
- Small numbers of healthy volunteers (typically 20-100)
- Primary goal: safety and tolerability
- Secondary: pharmacokinetics (how the body processes the compound)
- Not designed to show efficacy
Phase 2
Early efficacy studies in target population:
- Larger groups (100-300 participants)
- Studies in people with relevant conditions
- Explores dosing and initial efficacy signals
- Still relatively small for detecting rare effects
Phase 3
Pivotal trials for regulatory approval:
- Large, multi-center studies (hundreds to thousands)
- Randomized, controlled, often double-blind
- Designed to definitively demonstrate efficacy and safety
- Required for drug approval in most jurisdictions
Phase 4
Post-market surveillance:
- Ongoing monitoring after approval
- Detects rare adverse effects not seen in trials
- Studies long-term outcomes
- May lead to label changes or withdrawals
The Translation Problem
Why don't preclinical findings always translate to humans?
- Species differences — Mice and humans have different biology
- Dosing differences — What works in rodents may not scale
- Endpoint differences — Measured outcomes may not be equivalent
- Complexity — Human conditions involve factors not modeled in animals
- Publication bias — Failed translations often aren't published
Estimates suggest only about 10% of compounds that show promise in preclinical research eventually receive approval for human use.
Interpreting Research Stages
When evaluating peptide claims, consider:
- What stage of research supports the claim?
- Has any human research been conducted?
- How well do the research subjects match the claim being made?
- Is the evidence being over-extrapolated?
Be especially skeptical when preclinical findings are presented as proof of human effects.