SS-31 (Elamipretide) half-life & pharmacokinetics

Reported half-life

Approximately 2-4 hours plasma half-life after subcutaneous administration. Tissue retention — particularly in mitochondria-rich tissues (cardiac muscle, skeletal muscle, retina) — substantially exceeds plasma exposure through the selective mitochondrial partitioning. Phase III trials have used both continuous intravenous infusion (short-term acute settings) and daily subcutaneous administration (chronic protocols).

The half-life and pharmacokinetic profile of SS-31 (Elamipretide) reported above is drawn from the published pre-clinical literature. Plasma half-life describes the time taken for the circulating concentration to fall by half after a single dose; tissue half-life — which may be longer for peptides retained in specific organs or matrices — is a distinct and often more relevant parameter for healing research, where the duration of exposure at the injury site matters more than the systemic exposure profile.

Routes of administration studied

• Subcutaneous injection (chronic clinical trial route)
• Intravenous infusion (acute clinical trial route)
• Topical ocular preparations (age-related macular degeneration research)

Different routes produce materially different pharmacokinetic profiles for the same peptide. Subcutaneous administration generally produces flatter, more sustained plasma profiles than intravenous bolus dosing; intraperitoneal administration (common in rodent models) is not directly translatable to human routes; oral administration faces the additional challenge of luminal and brush-border peptidase degradation, which is why most research peptides have very low oral bioavailability without protective formulation.

Drug class

Cell-permeable mitochondria-targeted tetrapeptide; cardiolipin-binding compound stabilising inner mitochondrial membrane cristae architecture.

Mechanism context

Half-life interpretation depends on the underlying mechanism. SS-31 (Elamipretide) acts as follows:

SS-31 (elamipretide, formerly Bendavia, development code MTP-131) is a small synthetic tetrapeptide (D-Arg-2',6'-dimethyl-Tyr-Lys-Phe-NH₂) developed by Hazel Szeto's laboratory at Weill Cornell Medical College as part of a systematic effort to develop small mitochondria-penetrant peptides addressing cardiolipin biology. The molecular design combines four essential features. First, the alternating aromatic-cationic amino acid architecture confers cell membrane penetration through a receptor-independent mechanism that allows the compound to enter cells without transporter dependence. Second, the D-arginine substitution at the N-terminus and the 2',6'-dimethyl-tyrosine at position 2 confer proteolytic stability against exopeptidase and endopeptidase degradation. Third, the two aromatic residues (dimethyl-tyrosine and phenylalanine) enable strong non-covalent interactions with cardiolipin's four fatty-acyl chains. Fourth, the two cationic residues (arginine and lysine) mediate selective partitioning to the inner mitochondrial membrane, which carries the physiologically largest negative electrical potential of any cellular compartment (~-180 mV inside).

See the full SS-31 (Elamipretide) research profile for the complete mechanism summary, history, study citations, and references.

Practical considerations

Short plasma half-life does not necessarily mean short duration of biological effect. Many peptides — including BPC-157, GHK-Cu, and the thymosin-derived compounds — exhibit tissue retention or mechanistic effects (gene expression, signalling cascades) that outlast plasma exposure by hours to days. The pharmacological half-life and the biological-effect half-life are distinct parameters that must both be specified in any rigorous research design. Repeated-dose protocols should account for accumulation only where tissue half-life is genuinely long; for most peptides with short plasma half-life and rapid degradation, accumulation is not a practical concern.

For dose ranges in published research, see the dosing reference page. For reconstitution guidance, see the reconstitution reference page.