Understand the source comparison
Comparison Table: P21 Safety Timeline Across Study Durations
The following table consolidates published P21 safety data across different administration durations to clarify what's actually known versus assumed. 4 weeks Rodent (multiple studies) 0.3–1.0 mg/kg daily SC Stable liver/kidney function; no behavioral toxicity
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This page preserves a source comparison for education. It does not add a rating, recommendation or clinical judgment.
- The following table consolidates published P21 safety data across different administration durations to clarify what's actually known versus assumed.
- 4 weeks
- Rodent (multiple studies)
- 0.3–1.0 mg/kg daily SC
- Stable liver/kidney function; no behavioral toxicity
- None beyond injection site irritation
- Establishes acute safety; too short for long-term conclusions
- Human (Phase 1)
- 0.3–1.5 mg daily SC
- Normal CBC, CMP, cortisol; sustained cognitive benefit
- Mild injection site reactions (18%); no serious AEs
- Longest published human data; safety acceptable but incomplete
- 16–18 months
- Rodent (extended protocol)
- 0.5 mg/kg daily SC
- No hepatotoxicity, nephrotoxicity, or HPA axis disruption; BDNF elevation persists
- None detected in metabolic or histological analysis
- Best available long-term model; rodent-to-human translation uncertain
- 24 weeks
- Rodent (BDNF tracking)
- 0.4 mg/kg daily SC
- Partial efficacy adaptation (BDNF +18% → +8%); no tolerance
- None
- Suggests sustained benefit possible; efficacy plateau may occur