Half-Life and Clearance
What half-life and clearance mean for peptides, with label values from natural hormones to semaglutide, why longer is not simply better, and why one number does not transfer.
Content last updated . This page has not been medically reviewed.
Two ideas in plain words
Half-life is the time it takes for the amount of a substance in the blood to fall by half. Clearance is how fast the body removes it, through the kidneys, the liver and breakdown by enzymes. Peptides are often cleared quickly, so the half-life of a peptide is one of the first things drug makers try to change. See enzymes and peptide breakdown for the reasons.Half-lives printed in medicine labels
All values below come from US prescribing information. They are measured for each specific product, in the people studied, by the route given.| Substance | Half-life in the label | What shapes it |
|---|---|---|
| Natural GLP-1 | 1.5 to 2 minutes [1] | Broken down by DPP-IV and neutral endopeptidases [1] |
| Liraglutide (injected) | About 13 hours [1] | Slower absorption, protein binding and stability against enzymes [1] |
| Tirzepatide (injected) | About 5 days [2] | A fatty diacid side chain lets it bind albumin [2] |
| Semaglutide (tablet label) | About one week [3] | Albumin binding lowers kidney clearance and protects from breakdown [3] |
| Natural somatostatin | 1 to 3 minutes [4] | Natural hormone, for comparison [4] |
| Octreotide (injected) | 1.7 to 1.9 hours [4] | A ring-shaped, modified copy of somatostatin [4] |
| Teriparatide (injected) | About 1 hour [5] | Cleared by liver and by other tissues [5] |
| Degarelix (depot) | About 53 days (terminal) [6] | Slow release from a depot under the skin, not slow removal [6] |
The last row shows that a long number can reflect the product design (a slow-release depot) rather than the molecule alone. [6]
Clearance changes with the person
Label data show that the same molecule can behave differently between people. Desmopressin had a half-life of 2.8 hours with normal kidney function, rising to 8.7 hours in severe kidney impairment in a small study (24 people). [7] The octreotide label notes a 46% increase in half-life in an elderly population. [4] Liraglutide's body-weight effect is also described: exposure goes down as baseline body weight goes up. [1]This is why kidney and liver conditions matter in peptide safety. Whether a particular product is a problem depends on the product; see peptides, liver and kidney conditions.
Longer is not simply better
- It stays longer, in both directions. The semaglutide label says the drug remains in circulation for about five weeks after the last tablet. [3] That is a design choice for a once-weekly medicine, and it also means any side effect fades slowly.
- Timing of exposure can change the effect. The teriparatide label says its skeletal effects depend on the pattern of exposure. Brief once-daily exposure stimulates new bone formation, while continuous excess of the natural hormone may harm the skeleton. [5]
- Blood level does not equal effect. Peak and half-life describe the molecule in blood. Effects on symptoms need their own measurement. See pharmacokinetics vs clinical effectiveness.
Half-life numbers outside the labels
Unapproved research compounds seldom have label data. Two examples show how careful reading helps.- CJC-1295. In a 2006 trial in healthy adults, the estimated half-life of CJC-1295 was 5.8 to 8.1 days. [8] The abstract does not say whether that product matches other products sold under similar names. A later paper explains that CJC-1295 has an extended half-life because of a "drug affinity complex" (DAC) that chemically attaches the peptide to plasma proteins. [9] A review lists "with DAC" and "without DAC" as separate agents. [10] Treat the number as belonging to the exact material tested; see CJC-1295.
- BPC-157. A 2025 systematic review states that BPC-157 has a half-life of under 30 minutes and is cleared by the kidneys. [11] That is a summary in a review of mostly preclinical studies (35 of 36), so it is weaker than a label value. [11]
Do not use any of these numbers to plan use of a product. This page is education only.
Frequently asked questions
Is a longer half-life better?
Not by itself. It can reduce how often a medicine is needed, but the compound also lingers after stopping. The semaglutide label says it is present for about five weeks after the last tablet. [3]
Why do some peptides last only minutes?
Natural GLP-1 and somatostatin are broken down by enzymes within minutes, according to the labels of drugs modeled on them. [1][4]
Does kidney function change half-life?
For desmopressin, yes: the half-life rose from 2.8 to 8.7 hours in severe kidney impairment in one study. [7]
Can I compare half-lives between two similar-sounding products?
Not safely. A half-life belongs to one exact molecule and formulation. The CJC-1295 trial abstract gives one number without naming the version, while the literature separates versions with and without DAC. [8][10]
References
- U.S. FDA prescribing information, Victoza (liraglutide), sections 12.1 and 12.3, label effective 2023-02-06, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- U.S. FDA prescribing information, Mounjaro (tirzepatide), sections 12.1 and 12.3, label effective 2026-07-29, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- U.S. FDA prescribing information, oral semaglutide tablets (RYBELSUS and OZEMPIC tablets), sections 12.1 and 12.3, label effective 2026-01-30, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- U.S. FDA prescribing information, Sandostatin (octreotide) Injection, sections 11 and 12, label effective 2026-07-22, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- U.S. FDA prescribing information, Forteo (teriparatide), sections 12.1 and 12.3, label effective 2026-08-03, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- U.S. FDA prescribing information, Firmagon (degarelix), section 12, label effective 2024-01-30, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- U.S. FDA prescribing information, DDAVP (desmopressin acetate) Injection, section 12, label effective 2022-09-28, read as the FDA label record at openFDA drug label API. Read 2026-10-22.
- Teichman SL, et al. Prolonged stimulation of growth hormone and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. J Clin Endocrinol Metab. 2006. PubMed 16352683 (abstract). Read 2026-10-22.
- Detection of CJC-1295 in Equine Plasma by ELISA. Drug Test Anal. 2026. PubMed 42876013 (abstract). Read 2026-10-22.
- The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration. Front Endocrinol. 2026. PubMed 42395176 (abstract). Read 2026-10-22.
- Emerging Use of BPC-157 in Orthopaedic Sports Medicine: A Systematic Review. HSS J. 2025. PubMed 40756949 (abstract). Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.