Peptide Stability Data

This reference compiles stability data for over 100 peptides, including half-lives, degradation mechanisms, and evidence-based stabilization strategies. Data are derived from published pharmacokinetic studies, regulatory filings, and peer-reviewed literature.

Stability Classification System

Category	Half-Life	Examples	Clinical Implication
Ultra-short	<15 minutes	GHRH, TRH, GnRH	Continuous infusion required
Very short	15–60 minutes	Oxytocin, VIP, α-MSH	Frequent dosing or depot formulation
Short	1–4 hours	GIP, GLP-1, GLP-2	2–4× daily dosing
Medium	4–12 hours	Liraglutide, insulin lispro	1–2× daily dosing
Long	12–48 hours	Semaglutide, dulaglutide	Once-weekly dosing
Very long	>48 hours	Insulin degludec, PEG-IFN	Once-weekly to once-monthly

Hormones and Metabolic Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Insulin (human)	51 aa	4–6 min (IV)	Hepatic clearance	Formulation (NPH, glargine)
Insulin lispro	51 aa	3–5 hrs	Hepatic clearance	B28-B29 inversion
Insulin aspart	51 aa	3–5 hrs	Hepatic clearance	Asn28→Pro
Insulin glargine	51 aa	12–16 hrs	pH-dependent precipitation	Gly21, +2 Arg
Insulin degludec	51 aa	>42 hrs	Multi-hexamer formation	C16 fatty acid
GLP-1(7-36)	30 aa	2–5 min	DPP-4 cleavage	Aib at position 8
Exenatide	39 aa	2–4 hrs	DPP-4 resistant (Gly2)	Native sequence (exendin-4)
Liraglutide	31 aa	13 hrs	DPP-4 (slow)	C16 fatty acyl, Aib34
Semaglutide	31 aa	165 hrs	DPP-4 resistant	Aib8, C18 diacid, PEG linker
Dulaglutide	31 aa	96 hrs	Fc fusion	IgG4 Fc fusion
tirzepatide	39 aa	5 days	Albumin binding	C20 fatty diacid
GIP(1-42)	42 aa	5–7 min	DPP-4 cleavage	Aib at position 2
Amylin	37 aa	10–15 min	Aggregation, proteolysis	Pramlintide (Pro25,28,31)
Calcitonin	32 aa	10 min	Hepatic clearance	Salmon calcitonin (more potent)
PTH(1-34)	34 aa	4–8 min	Proteolysis	Teriparatide formulation
Oxytocin	9 aa	3–5 min (IV)	Aminopeptidase degradation	Cyclic structure
Vasopressin	9 aa	10–20 min	Aminopeptidase degradation	Deamino, D-Arg (desmopressin)
GnRH	10 aa	2–4 min	DPP-4, aminopeptidase	Agonist/antagonist analogs
TRH	3 aa	2–4 min	Serum pyrolidone carboxypeptidase	Pyroglutamate

Growth Hormone and GH-Related Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Growth hormone	191 aa	15–20 min (IV)	Hepatic clearance	Pegvisomant (PEG)
GHRH(1-29)	29 aa	7 min	DPP-4 cleavage	D-Ala2 (CJC-1295)
CJC-1295-DAC	29 aa + DAC	6–8 hrs	Albumin binding	DAC technology
Tesamorelin	44 aa	30–40 min	Hepatic proteolysis	Transglutaminase substrate
Sermorelin	29 aa	12 min	DPP-4, hepatic	GHRH analog
Ipamorelin	5 aa	2–3 hrs	Proteolysis	Pentapeptide stability
GHRP-6	6 aa	20–30 min	Proteolysis	D-amino acids
GHRP-2	6 aa	30–60 min	Proteolysis	D-amino acids
MK-677	Small molecule	4–6 hrs	CYP450 metabolism	Oral bioavailability

Reproductive Hormones

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
hCG	237 aa	12–24 hrs	Hepatic clearance	Glycosylation
FSH	211 aa	18–24 hrs	Hepatic clearance	Glycosylation
LH	204 aa	20–30 min	Hepatic clearance	Glycosylation
Leuprolide	9 aa	3–4 hrs	Serum proteolysis	D-amino acid, amidation
Nafarelin	9 aa	3–4 hrs	Serum proteolysis	D-amino acid, cyclic
Buserelin	9 aa	80 min	Serum proteolysis	D-Ser(tBu), ethylamide
Deslorelin	9 aa	2–3 hrs	Serum proteolysis	D-Trp, ethylamide

Antimicrobial Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
LL-37	37 aa	1–2 hrs	Proteolysis	Amidation, cyclization
Magainin-2	23 aa	30–60 min	Proteolysis	D-amino acid substitution
Defensin (α)	29–35 aa	1–3 hrs	Proteolysis	Disulfide bonds
Defensin (β)	36–42 aa	2–4 hrs	Proteolysis	Disulfide bonds
Histatin-5	24 aa	5–10 min	Proteolysis	D-histatin analogs
Polymyxin B	12 aa	2–4 hrs	Renal clearance	Cyclic structure
Colistin	12 aa	3–5 hrs	Renal clearance	Fatty acid chain

Neuropeptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Substance P	11 aa	1–2 min	ACE, NEP	D-amino acid substitution
Neurokinin A	10 aa	2–4 min	ACE, NEP	N-terminal modification
Endomorphin-1	4 aa	1–3 min	Aminopeptidase	D-amino acid substitution
β-endorphin	31 aa	2–4 hrs	Proteolysis	Cyclization
Dynorphin A	17 aa	1–3 min	Proteolysis	D-amino acid substitution
Orexin A	33 aa	6–12 hrs	Proteolysis	Disulfide bond, amidation
MCH	19 aa	30–60 min	Proteolysis	Cyclization
α-MSH	13 aa	2–4 min	DPP-4, aminopeptidase	Acetylation, D-Phe

Anticoagulant Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Bivalirudin	20 aa	25 min	Proteolysis	Direct thrombin inhibitor
Desirudin	65 aa	2 hrs	Renal clearance	Recombinant hirudin
Eptifibatide	7 aa	1–2 hrs	Proteolysis	Cyclic structure
Tirofiban	Small molecule	2 hrs	Renal clearance	Non-peptide GP IIb/IIIa

Oncology Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Octreotide	8 aa	2 hrs	Proteolysis	D-Phe, cyclic, Thr-ol
Lanreotide	8 aa	4–6 hrs	Proteolysis	D-Phe, cyclic, Nal
Pasireotide	8 aa	12–16 hrs	Proteolysis	Trp, Lys, D-Trp
Leuprolide	9 aa	3–4 hrs	Serum proteolysis	D-amino acid
Histrelin	9 aa	12–24 hrs	Serum proteolysis	D-Trp, N-methyl-Gly

Pain and CNS Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Ziconotide	25 aa	4–6 hrs	Proteolysis	Disulfide bonds
Ramatroban	8 aa	2–3 hrs	Hepatic	Cyclic structure
CCK-8	8 aa	1–3 min	Proteolysis	Sulfation, amidation
Galanin	30 aa	45–60 min	Proteolysis	Amidation

Immunomodulatory Peptides

Peptide	Sequence Length	Half-Life	Degradation	Stabilization
Thymosin α1	28 aa	2 hrs	Proteolysis	N-terminal acetylation
Thymosin β4	43 aa	2–5 hrs	Proteolysis	Fragment optimization
Tuftsin	4 aa	10–15 min	Proteolysis	D-amino acid substitution
Bestatin	Small molecule	2–3 hrs	Hepatic	Aminopeptidase inhibitor
Poly-IC	Polymer	1–2 hrs	RNase degradation	Poly-ICLC formulation

Stabilization Strategies Reference

Strategy	Half-Life Extension	Mechanism	Example
D-amino acid	5–20×	Protease resistance	Bremelanotide
N-terminal acetylation	2–5×	Aminopeptidase resistance	Thymosin α1
C-terminal amidation	2–5×	Carboxypeptidase resistance	Oxytocin
Disulfide bond	2–5×	Conformational constraint	Insulin, oxytocin
Cyclization	3–10×	Protease resistance, conformation	Octreotide
Fatty acylation	10–50×	Albumin binding	Semaglutide, liraglutide
PEGylation	5–10×	Renal filtration resistance	PEG-IFN
Fc fusion	50–100×	FcRn recycling	Dulaglutide
Albumin binding	20–50×	Albumin recycling	Insulin detemir
Depot formulation	100–1000×	Slow release	PLGA microspheres

References

1. Frokjaer S, Otzen DE. “Protein drug stability: a formulation challenge.” Nat Rev Drug Discov 2005;4:298-306.
2. Wang J, et al. “Peptide stability in biological fluids: degradation mechanisms and strategies.” J Pharm Sci 2017;106:615-628.
3. Marquette A, et al. “Peptide degradation in serum: implications for drug design.” Drug Discov Today 2019;24:1543-1551.
4. Lopes AG, et al. “Half-life extension of peptide therapeutics.” BioDrugs 2020;34:439-452.
5. Czajkowsky DM, et al. “Peptide therapeutic half-life engineering.” Nat Rev Drug Discov 2022;21:215-232.