MOTS-c --- Research Product Overview

**Disclaimer:** This article is provided for educational and research purposes only. [MOTS-c](/catalog/mots-c) research material sold by Viking Labs is intended for laboratory research use only. It is not approved by the FDA for human therapeutic use, and nothing in this article constitutes medical advice or a recommendation for self-administration.

Overview

MOTS-c (Mitochondrial Open reading frame of the 12S rRNA-c) is a 16-amino acid mitochondrial-derived peptide (MDP) encoded within the small open reading frame of the mitochondrial 12S ribosomal RNA gene. It was identified and characterized by Lee, Cohen, and colleagues at the University of Southern California in 2015. Together with humanin and the SHLP family, MOTS-c is one of the most extensively studied mitochondrial-derived peptides --- a class of bioactive peptides encoded in the mitochondrial genome that act as endocrine and autocrine regulators of cellular metabolism.

MOTS-c is of broad research interest because it provides a molecular link between the mitochondrial and nuclear genomes: a peptide synthesized from a mitochondrial ORF that, under metabolic stress, translocates to the nucleus and modulates nuclear gene expression in support of metabolic homeostasis. Researchers studying broader metabolic-axis pharmacology often pair MOTS-c with GLP-1 receptor agonists or growth hormone axis reference compounds.

Sequence and Structural Notes

MOTS-c sequence: H-Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg-OH

Molecular weight: approximately 2174 Da. The peptide contains two methionine residues (positions 1 and 6), three arginine residues, and a tryptophan at position 3, giving it characteristic UV absorbance at 280 nm useful for identity confirmation. The N-terminal methionine is the site of translation initiation from the mitochondrial 12S rRNA ORF.

Mechanism of Action

MOTS-c does not engage a classical cell-surface receptor as far as has been characterized. Instead, the peptide enters cells and modulates intracellular metabolic signaling, with two principal mechanisms reported:

1. [AMPK](/research/glossary#ampk-amp-activated-protein-kinase) activation and metabolic regulation: Lee et al. (2015) demonstrated that MOTS-c activates AMP-activated protein kinase (AMPK), the master regulator of cellular energy homeostasis, in skeletal muscle and other tissues. AMPK activation leads to increased glucose uptake (independent of insulin signaling), increased fatty acid oxidation, and inhibition of anabolic pathways. The peptide's effects on glucose homeostasis in mice include improved insulin sensitivity and protection against diet-induced obesity.

1. Stress-responsive nuclear translocation: Kim et al. (2018) demonstrated that under metabolic stress (glucose restriction, exercise), MOTS-c translocates to the nucleus, where it binds to chromatin and modulates the expression of stress-response genes, including those involved in antioxidant defense and metabolic adaptation. This mechanism makes MOTS-c a unique example of "mitonuclear communication" --- a peptide encoded in mitochondrial DNA that acts directly on the nuclear genome.

These mechanisms together position MOTS-c as a research tool for studying mitochondrial-nuclear crosstalk, metabolic stress responses, and AMPK-dependent metabolic regulation. For an adjacent pathway perspective, see our mTOR pathway peptides reference.

Comparator Peptides --- MOTS-c vs. Humanin vs. SHLP Family

MOTS-c is one of approximately eight characterized mitochondrial-derived peptides; the comparator MDPs each occupy distinct mechanistic niches.

MOTS-c vs. humanin. Humanin is a 24-amino acid MDP encoded within the mitochondrial 16S rRNA gene. Unlike MOTS-c, humanin acts predominantly through extracellular receptors (FPR2, CNTFR/WSX-1/gp130 trimer) and exhibits cytoprotective and anti-apoptotic activity, particularly in neurons and pancreatic beta cells. The two peptides are mechanistically complementary: MOTS-c drives AMPK-mediated metabolic regulation, while humanin drives anti-apoptotic and cytoprotective signaling. Some research workflows pair the two to study the broader MDP-system response to metabolic stress.

MOTS-c vs. SHLP family. Small Humanin-Like Peptides (SHLP1-6) are six MDPs identified in 2016 by the Cohen group; they are encoded in the mitochondrial 16S rRNA region adjacent to humanin. SHLP2 and SHLP3 have been characterized as having insulin-sensitizing and beta-cell-protective effects partially overlapping with humanin; SHLP6 has pro-apoptotic activity in some contexts. The SHLPs are less extensively characterized than humanin or MOTS-c but represent the broader landscape of MDP biology.

MOTS-c vs. metformin. Although not a peptide, metformin is the canonical AMPK-activating reference compound and a frequent comparator in MOTS-c metabolic studies. Metformin activates AMPK indirectly via inhibition of mitochondrial complex I, while MOTS-c appears to activate AMPK more directly through a still-incompletely-characterized mechanism. The two compounds produce overlapping but not identical metabolic phenotypes in DIO mouse models.

Deeper Preclinical Breakdown

Lee et al. (2015) --- foundational characterization (Cell Metab). Methodology: identification of the 51-nucleotide MOTS-c ORF within the mitochondrial 12S rRNA region by ribosome profiling and proteomics; in vitro AMPK activation assays in C2C12 myotubes treated with synthetic MOTS-c at 1-100 nM; in vivo characterization in C57BL/6 mice dosed at 0.5-15 mg/kg/day intraperitoneally for up to 12 weeks on standard chow and high-fat diet. Key results: MOTS-c activated AMPK with EC50 approximately 5 nM in C2C12 myotubes; in DIO mice, MOTS-c at 5 mg/kg/day prevented diet-induced obesity, improved insulin sensitivity (HOMA-IR reduced ~50%), and increased glucose uptake into skeletal muscle independent of insulin. Limitation: the receptor (or receptor-like target) for MOTS-c was not identified in this paper and remains debated.

Reynolds et al. (2021) --- exercise capacity in aged mice (Nat Commun, PMID 33500416). Methodology: 22-month-old C57BL/6 mice received MOTS-c 5 mg/kg/day intraperitoneally for 8 weeks; outcome measures included treadmill running capacity, grip strength, and skeletal muscle gene expression. Key result: MOTS-c-treated aged mice ran approximately 70% farther than vehicle controls and showed gene-expression signatures consistent with restored exercise responsiveness; circulating MOTS-c levels declined with age in both mice and humans, supporting MOTS-c as an "aging-decline" peptide. Limitation: behavioral readouts only; the molecular mechanism connecting MOTS-c administration to exercise capacity was not fully resolved in this paper.

Kim et al. (2018) --- nuclear translocation under stress (Cell Metab). Methodology: subcellular fractionation of HEK293 and primary myocytes after glucose deprivation or AICAR treatment; ChIP-seq of MOTS-c binding to chromatin under stress conditions. Key result: MOTS-c translocated from cytoplasm to nucleus within 4 hours of glucose deprivation and bound to antioxidant response element (ARE) regions to drive expression of NRF2-target genes. Limitation: ChIP-seq was performed in HEK293 cells; tissue-specific binding patterns in vivo remain incompletely characterized.

Preclinical Research Summary

Lee et al. (2015) provided the foundational characterization of MOTS-c, demonstrating effects on glucose homeostasis, insulin sensitivity, and obesity in diet-induced obese mice. Subsequent work has examined MOTS-c in models of:

• Aging and exercise capacity (Reynolds et al., 2021): MOTS-c treatment in aged mice improved physical performance and skeletal muscle function
• Osteoporosis: Hu and Chen (2018) reported effects on bone metabolism in ovariectomized mouse models
• Cardiac ischemia-reperfusion injury: protective effects via AMPK
• Type 2 diabetes models (db/db, diet-induced): improvements in glucose tolerance and insulin sensitivity
• Hepatic steatosis: reduction of triglyceride accumulation in NAFLD models

The aging-related work is particularly notable: circulating MOTS-c levels decline with age in humans and mice, and exogenous administration in aged animals appears to partially restore exercise capacity and metabolic flexibility, supporting MOTS-c as a research tool in mitonuclear-aging studies. Researchers working at the intersection of MDPs and senescence often pair MOTS-c with Epitalon, FOXO4-DRI, or NAD+ reference compounds.

Common Research Applications

• AMPK signaling assays in cell culture (skeletal muscle, hepatocytes, adipocytes)
• Glucose uptake studies (insulin-dependent and insulin-independent pathways)
• Diet-induced obesity and type 2 diabetes models in rodents
• Skeletal muscle exercise-capacity studies
• Mitochondrial biogenesis and function assays
• Mitonuclear communication research (nuclear translocation, chromatin binding)
• Aging and longevity research
• Hepatic steatosis (NAFLD/NASH) models

Formulation Considerations

Lyophilized MOTS-c is supplied as a white-to-off-white amorphous cake from acetate-buffered solution at pH 6.0-7.0. The peptide is moderately water-soluble; reconstitution at 1-5 mg/mL in sterile bacteriostatic water proceeds with gentle inversion. Sterile saline or PBS pH 6.5-7.5 is acceptable; very alkaline buffers (pH greater than 8.5) can accelerate Met oxidation.

Stability and oxidation. MOTS-c contains two methionine residues at positions 1 and 6, both susceptible to oxidation to the methionine sulfoxide form. Solution stability at 2-8 degrees C is greater than 95% main-peak purity for 14-30 days under aseptic conditions; oxygen-saturated buffers shorten this window. The Trp at position 3 is also photo-labile; amber vials and refrigerated storage mitigate this risk.

Common [COA](/research/glossary#coa) impurities. Met-oxidized variants (typically 0.5-2%, reported as "M(O)" species on the COA), des-Met N-terminal truncation (less than 0.5%), and acetate counterion content are the most commonly reported. Some COAs report the ratio of native to Met-oxidized peptide explicitly. For broader formulation principles, see our peptide reconstitution guide and peptide solubility guide.

Aliquoting recommendations. For long-term storage, single-use aliquots stored at -80 degrees C are preferable to repeated freeze-thaw cycles of a single working stock; oxidation accumulates with each thaw cycle.

Research-Context Dosing Ranges

In published preclinical literature, MOTS-c doses in mice have ranged from approximately 0.5 to 15 mg/kg/day administered intraperitoneally (Lee et al., 2015; Reynolds et al., 2021), with chronic dosing periods of 4-12 weeks. In rats, comparable mg/kg ranges have been reported. In vitro, MOTS-c is commonly studied at 1-100 nM concentrations in cell-culture AMPK and glucose-uptake assays. These ranges are provided strictly as references to the rodent and cell-culture preclinical literature and are not recommendations for human use; MOTS-c research material sold by Viking Labs is for laboratory research only.

Handling, Reconstitution, and Storage

Lyophilized MOTS-c is stable at -20 degrees C protected from light for 24+ months. Reconstitute with sterile bacteriostatic water; the peptide is reasonably soluble in aqueous buffers near neutral pH. Once reconstituted, store at 2-8 degrees C and use within approximately 14-30 days based on buffer and aseptic technique. The two methionine residues make MOTS-c modestly susceptible to oxidation; protect reconstituted solutions from oxidative conditions and avoid prolonged exposure to room temperature. For long-term storage, single-use aliquots stored at -80 degrees C are preferable to repeated freeze-thaw cycles of a single working stock. See our peptide storage and stability reference.

HPLC Purity and Lab Specifications

• HPLC purity: greater than or equal to 98.0% (RP-HPLC, 214 nm)
• Identity: ESI-MS or MALDI-TOF; theoretical [M+H]+ approximately 2175 Da
• Methionine oxidation status reported on COA (an oxidized M-Met variant is the most common minor impurity)
• Counterion (typically acetate or TFA) reported on COA
• Endotoxin: less than 5 EU/mg
• Water content: typically less than 5% by Karl Fischer titration

For COA interpretation, see How to read a peptide COA.

Cross-References --- Related Viking Labs Research

• Ipamorelin / CJC-1295 blend overview
• NAD+ product overview
• Epitalon product overview
• FOXO4-DRI product overview
• Peptide drug delivery 2026
• Understanding peptide purity

*Provided for laboratory research purposes only. Not for human or veterinary use.*