Peptide Half-Life Reference Chart
Half-life is one of the most practical pieces of information for designing peptide research protocols. It determines how often you need to dose, how long effects last after each administration, and when a peptide reaches steady-state concentration in the body. This chart provides quick-reference half-life data for the most commonly researched peptides.
Key Takeaways
- Short half-life peptides (minutes to hours) require daily or multiple daily dosing for consistent blood levels
- Long half-life peptides (days) allow weekly dosing and take 4-5 half-lives to reach steady-state concentration
- Some peptides like Semax have very short half-lives but prolonged biological effects through downstream mechanisms
- Steady-state is reached after approximately 4-5 half-lives of consistent dosing, which is when full effects are expected
Growth Hormone Peptides
Growth hormone secretagogues and releasing hormones generally have short half-lives, requiring daily or multiple daily administrations. This is by design, as they work by triggering pulsatile release of growth hormone, which mimics the body's natural GH secretion pattern.
- 1.Ipamorelin: approximately 2 hours. Dose 1-3 times daily, typically before bed and/or morning fasted.
- 2.CJC-1295 (no DAC): approximately 30 minutes. Usually combined with Ipamorelin, dosed 1-3 times daily.
- 3.CJC-1295 (with DAC): approximately 6-8 days. Dose once or twice weekly due to extended half-life from Drug Affinity Complex.
- 4.Tesamorelin: approximately 26 minutes after subcutaneous injection. Dosed once daily, typically in the morning.
- 5.GHRP-6: approximately 15-60 minutes. Dosed 2-3 times daily on empty stomach.
Weight Management Peptides
GLP-1 receptor agonists and other weight management peptides span a wide range of half-lives, from the convenient weekly dosing of semaglutide to daily administration of shorter-acting compounds.
- 1.Semaglutide: approximately 7 days (168 hours). Dosed once weekly, allowing steady-state in 4-5 weeks.
- 2.Tirzepatide: approximately 5 days (120 hours). Dosed once weekly.
- 3.Retatrutide: approximately 6 days. Dosed once weekly in clinical trials.
- 4.AOD-9604: approximately 30-60 minutes. Requires daily dosing on empty stomach.
- 5.Tesofensine: approximately 8-9 days. Oral administration, dosed once daily in clinical trials.
Healing and Recovery Peptides
Healing peptides generally have moderate half-lives that support once or twice daily dosing protocols. Their effects are cumulative, meaning consistent daily dosing over weeks produces the most significant results.
- 1.BPC-157: approximately 4 hours (estimated from animal data). Typically dosed twice daily for research purposes.
- 2.TB-500: approximately 2-3 hours for the active fragment. Loading phase often uses more frequent dosing, then maintenance at 1-2 times weekly.
- 3.GHK-Cu: approximately 12 minutes in plasma, but copper peptide effects are cumulative in tissues. Applied topically or injected subcutaneously.
Understanding Half-Life in Practice
Half-life affects more than just dosing frequency. It takes approximately 4-5 half-lives for a peptide to reach steady-state concentration with regular dosing. This means effects may build gradually over the first several doses. Conversely, after discontinuation, it takes 4-5 half-lives for the peptide to be essentially eliminated from the body. For semaglutide (7-day half-life), this means full washout takes approximately 5 weeks after the last dose. For ipamorelin (2-hour half-life), the peptide is effectively cleared within 10 hours.
Cognitive and Anti-Aging Peptides
Cognitive and anti-aging peptides have variable half-lives, and some have mechanisms of action that persist well beyond their circulating half-life due to downstream cellular effects.
- 1.Semax: approximately 60-90 seconds in blood, but neurological effects persist for 20-24 hours due to downstream signaling. Dosed intranasally 1-3 times daily.
- 2.Selank: approximately 1-3 minutes in blood, effects last several hours. Dosed intranasally 2-3 times daily.
- 3.Epitalon: approximately 30 minutes. Typically administered in short cycles (10-20 days) once or twice yearly, as telomerase activation persists beyond the dosing period.
Frequently Asked Questions
Why do some peptides with very short half-lives still work for hours?
Because a peptide's half-life measures how long it circulates in the blood, not how long its effects last. Many peptides trigger intracellular signaling cascades that continue long after the peptide itself is cleared. Semax, for example, is eliminated from blood within minutes but its effects on BDNF expression and neurotransmitter levels persist for 20+ hours.
Should I dose my peptide at the same time every day?
Yes, for most peptides consistent timing improves both your compliance and the reliability of your data. For short half-life peptides, consistent timing also helps maintain more stable blood levels. The optimal time depends on the specific peptide: growth hormone peptides work best fasted (morning or before bed), while some other peptides have less time-sensitive dosing.
How do I calculate when a peptide reaches steady state?
Multiply the half-life by 4-5. For example, semaglutide (7-day half-life) reaches steady state in approximately 28-35 days of weekly dosing. Ipamorelin (2-hour half-life) reaches daily steady state within hours if dosed consistently. This calculation tells you when to expect the full magnitude of effects from a given dose level.