Mitochondrial & energy peptides: research

✦ In short

Mitochondrial peptides in research: MOTS-C, SS-31, humanin, 5-Amino-1MQ and NAD+, and how they are studied in cellular energy research. RUO.

Research context (RUO): Mitochondrial & energy peptides such as MOTS-c, SS-31, humanin, 5-Amino-1MQ and NAD+ are research compounds studied around cellular energy and mitochondrial function. All products are supplied exclusively for in-vitro laboratory research and are not intended for human or animal use.

Mitochondrial peptides: the research into cellular energy

Overview of the mitochondrial peptides as studied in an RUO context.

Mitochondrial peptides are one of the most studied research categories within longevity and metabolism science. The common thread is the mitochondrion: the tiny power-plant organelle that produces adenosine triphosphate (ATP), the body's universal energy currency, in almost every cell. Researchers study a group of compounds — partly genuine mitochondrial-derived peptides (MDPs), partly small molecules and coenzymes — that in preclinical models are linked to mitochondrial function, energy metabolism and ageing. This overview covers MOTS-c, SS-31 (elamipretide), humanin, 5-Amino-1MQ and NAD+, each from the published research.

What are mitochondrial peptides?

Some of these substances belong to the mitochondria-derived peptides (MDPs): short protein fragments encoded by small open reading frames (sORFs) in the mitochondrial DNA itself, not in the nuclear genome. MOTS-c and humanin are the best-known examples. In research they are described as signalling molecules with which the mitochondrion communicates with the rest of the cell — a concept scientists call ‘mitochondrial-nuclear signalling’. Other compounds in this category, such as SS-31, 5-Amino-1MQ and NAD+, are strictly speaking not MDPs but are often studied alongside them because they act on the same mitochondrial energy metabolism. They are studied within themes such as AMPK signalling, cardiolipin stability, the electron transport chain and NAD+ metabolism.

MOTS-c: AMPK and metabolic homeostasis

MOTS-c is a highly conserved peptide of 16 amino acids, encoded by the 12S-rRNA region (MT-RNR1) of the mitochondrial genome. In the pioneering study by Lee et al. (Cell Metabolism, 2015), researchers described that MOTS-c intervenes in the folate cycle, causing the intermediate AICAR to accumulate and subsequently activating AMPK — the cell's central ‘energy sensor’. In animal models on a high-fat diet, MOTS-c was associated with improved insulin sensitivity and protection against diet-induced obesity. Later studies reported lower MOTS-c levels in people with type 2 diabetes and described recovery of mitochondrial respiration in diabetic animal models. Scientists therefore study MOTS-c as a potential target in research into metabolism, exercise and ageing.

SS-31 / elamipretide: cardiolipin and the electron transport chain

SS-31, also known as elamipretide, is a tetrapeptide (D-Arg-Dmt-Lys-Phe-NH₂) that selectively binds to cardiolipin — a phospholipid that occurs almost exclusively in the inner mitochondrial membrane. In an extensive review article (2025), researchers describe that this binding stabilises the cristae structure of the mitochondrion, reduces cardiolipin peroxidation and supports the assembly of the electron transport chain (complexes I, III and IV). In preclinical models this was associated with increased ATP production, less electron leakage and thereby less production of reactive oxygen species (ROS). SS-31 is studied in clinical research programmes in mitochondrial disorders such as Barth syndrome and primary mitochondrial myopathy, and in animal models it was linked to recovery of heart function in older animals. Delve further into the SS-31 research.

Humanin: cytoprotection and the mitochondrial stress signal

Humanin was the first mitochondrial-derived peptide discovered: a chain of 24 amino acids encoded by the MT-RNR2 gene. In a 2023 review, researchers summarised that humanin can counteract apoptosis (programmed cell death) in cell models via multiple pathways — including through direct binding to the pro-apoptotic protein Bax, through interaction with IGFBP-3, and through activation of STAT3 survival signalling via a receptor complex (CNTFR/WSX-1/gp130). In neuronal and cardiovascular models, humanin is studied as a ‘stress-resistance’ signal that protects cells against oxidative and metabolic stress. It is therefore often cited as an example of how the mitochondrion regulates broader cell physiology via peptides.

5-Amino-1MQ: NNMT inhibition and the NAD+/SAM metabolism

5-Amino-1MQ is a small-molecule inhibitor of the enzyme nicotinamide N-methyltransferase (NNMT). NNMT consumes both nicotinamide (an NAD+ precursor) and S-adenosylmethionine (SAM, the cell's main methyl donor). In a review article on NNMT in obesity and type 2 diabetes, researchers describe that elevated NNMT activity in fat tissue can affect NAD+ recycling and energy metabolism. In preclinical studies, inhibition of NNMT was associated with increased energy expenditure in adipocytes (fat cells) and with protection against diet-induced obesity in mouse models. 5-Amino-1MQ is therefore studied at the interface of fat metabolism and NAD+ biology.

NAD+: the coenzyme behind mitochondrial energy

NAD+ (nicotinamide adenine dinucleotide) is not a peptide but a coenzyme that is central to almost every account of cellular energy. In a 2025 review, researchers summarised that NAD+ acts as an electron acceptor in the electron transport chain — the NAD+/NADH ratio is decisive for optimal ATP production — and that it fuels NAD+-consuming enzymes such as the sirtuins (including the mitochondrial SIRT3) and PARPs. The literature describes that NAD+ levels decline with age, which in research is linked to ageing and metabolic disorders. Because MOTS-c (via AMPK) and 5-Amino-1MQ (via NNMT) both touch on NAD+ metabolism, these compounds are often studied together in research. Read more in the pillar research on NAD+ and glutathione.

What are mitochondrial peptides studied for?

Metabolism & insulin sensitivity: MOTS-c and 5-Amino-1MQ are studied in animal models around glucose homeostasis, fat metabolism and diet-induced obesity.
Mitochondrial function & energy: SS-31 and NAD+ are investigated for their role in ATP production, the electron transport chain and oxidative stress.
Longevity & ageing: declining NAD+ levels and mitochondrial dysfunction are recurring themes in ageing research.
Cytoprotection: humanin is studied as a stress-resistance signal in neuronal and cardiovascular cell models.
Heart & muscle: SS-31 is studied in research programmes around mitochondrial myopathy and heart function.

Mitochondrial peptides in laboratory research: handling & dissolving

Most of these compounds are supplied as freeze-dried (lyophilised) powder and must be reconstituted before in-vitro use, usually with bacteriostatic or sterile water. The right choice of solvent and concentration depends on the research protocol. More background is in the pillar on dissolving peptides: which liquid and about reconstituting peptides. Lyophilised peptides are usually stored cool and dark; after reconstitution, refrigeration is customary.

Quality & purity

Every relevant batch is independently HPLC-tested by an external laboratory; the certificate of analysis (CoA) is publicly verifiable per batch. For mitochondrial research, measurable purity is essential: impurities or breakdown products can distort in-vitro results. The fact that Peplife sometimes rejects batches shows how strict this control is — read why we rejected a batch.

Frequently asked questions about mitochondrial peptides

What exactly are mitochondrial peptides?
They are short protein fragments encoded by the mitochondrial DNA — such as MOTS-c and humanin — plus closely related compounds (SS-31, 5-Amino-1MQ, NAD+) that in research act on the mitochondrial energy metabolism. They are studied exclusively as research material.

What is the difference between MOTS-c and SS-31?
MOTS-c is a genuine mitochondrial-derived peptide that in studies acts on metabolism via AMPK. SS-31 (elamipretide) is a tetrapeptide that binds to cardiolipin in the mitochondrial membrane and in research is linked to the electron transport chain and ATP production.

How do mitochondrial peptides relate to NAD+?
NAD+ is the coenzyme that fuels the electron transport chain and sirtuins. MOTS-c influences energy signalling via AMPK, and 5-Amino-1MQ inhibits NNMT, an enzyme that consumes nicotinamide (an NAD+ precursor). In research, these pathways are therefore studied together.

Is 5-Amino-1MQ a peptide?
No. 5-Amino-1MQ is a small-molecule NNMT inhibitor, not a peptide. It is however studied alongside the mitochondrial peptides because it acts on the NAD+/SAM metabolism.

Where can I buy mitochondrial peptides for research?
At Peplife, MOTS-c, SS-31, humanin, 5-Amino-1MQ and NAD+ are available as Research Use Only material, HPLC-tested with a CoA per batch. They are intended exclusively for in-vitro laboratory research.

May I use these substances myself?
No. All the compounds mentioned are supplied exclusively for in-vitro laboratory research and are not intended for diagnostic or therapeutic use in humans or animals.

Mitochondrial & energy peptides: the research into cellular energy