History and Development of Szeto-Schiller SS Peptides: The Research Origins of SS-31
Research Notice: This article covers research on SS-31 research peptide and MOTS-C research peptide — available from Palmetto Peptides for laboratory use only.
Research Disclaimer: SS-31 is sold by Palmetto Peptides strictly as a research compound for in vitro and laboratory use only. It is not intended for human or veterinary consumption, administration, or therapeutic use.
SS-31 did not emerge from a targeted drug discovery campaign. It came out of a basic science program that started with a different problem entirely and arrived at mitochondrial biology through scientific observation over more than a decade. Researchers can source SS-31 research peptide from Palmetto Peptides for in vitro laboratory work. Related: MOTS-C research history and mitochondrial function research.
The Scientific Founders: Szeto and Schiller
Dr. Hazel H. Szeto
Dr. Szeto spent her career at Weill Cornell Medical College focused on drug delivery across biological membranes, mitochondrial pharmacology, and cell-permeable peptide development. Her background in perinatal pharmacology gave her a distinct perspective on membrane permeability that shaped the SS peptide series design.
Dr. Peter W. Schiller
Dr. Schiller is a medicinal chemist at the Institut de Recherches Cliniques de Montreal whose career focused on opioid peptide analogs and the synthesis of non-standard amino acids including 2',6'-dimethyltyrosine (Dmt). The Dmt residue originated from his opioid peptide research, where it was developed to improve potency and selectivity. The Szeto-Schiller collaboration combined membrane transport expertise with synthetic chemistry knowhow that proved unexpectedly productive.
Phase 1: Developing Cell-Permeable Antioxidant Peptides (Early 2000s)
The SS peptide program began with the goal of developing cell-permeable antioxidants that could work inside cells. The aromatic-cationic scaffold was conceived as a structural motif that could interact with anionic membrane phospholipids while aromatic rings provided scavenging chemistry. Early SS peptides were shown to penetrate cell membranes and reduce oxidative stress markers in cell-based models.
Phase 2: Discovering Mitochondrial Accumulation (Mid-2000s)
A pivotal observation: rather than distributing evenly throughout the cell, SS peptides showed preferential accumulation co-localizing with mitochondrial markers. The mechanism was understood to be electrostatic — the large negative membrane potential of the inner mitochondrial membrane (approximately -180 mV) creates a thermodynamic driving force for cationic compounds to concentrate inside mitochondria.
Phase 3: Identifying Cardiolipin as the Molecular Target
Subsequent work identified cardiolipin as the key binding partner at the inner mitochondrial membrane, reframing SS-31 from a general antioxidant to a cardiolipin-targeted research tool. This led to studies on cytochrome c interactions, electron transport chain activity, and mitochondrial bioenergetics in laboratory models.
Phase 4: Clinical Development as Elamipretide
SS-31 (as elamipretide or MTP-131) entered multiple clinical trials for conditions including Barth syndrome, heart failure with preserved ejection fraction (EMBRACE-HF trial), primary mitochondrial myopathy, and Friedreich's ataxia. As of this writing, elamipretide has not received FDA approval for any human therapeutic indication. The clinical history provides extensive secondary literature informing laboratory research design even for in vitro researchers. See also: NAD+ research, longevity peptide research, cellular health research. Order SS-31 here.
Frequently Asked Questions
Who developed the Szeto-Schiller peptides?
Dr. Hazel H. Szeto at Weill Cornell Medical College in collaboration with Dr. Peter W. Schiller at the Institut de Recherches Cliniques de Montreal, beginning in the early 2000s.
What was the original research goal?
To develop cell-permeable peptide antioxidants that could reach the inner mitochondrial membrane to address oxidative stress at the site of generation inside mitochondria.
Has SS-31 entered clinical trials?
Yes. Under the clinical name elamipretide (MTP-131), SS-31 has been evaluated in multiple human clinical trials. As of this writing, it has not received FDA approval for any indication.
See Also: SS-31 Research Peptide: Complete Guide