Scientific Glossary

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Bioavailability (F%) is expressed as a percentage. IV administration = 100% bioavailability (reference). Subcutaneous and intramuscular routes typically achieve 70-100% for peptides. Oral bioavailability for most peptides is very low (often <1%) due to digestive enzyme degradation, which is why most research peptides are studied via injection. Nasal routes vary (Semax, Selank show meaningful CNS absorption intranasally).