SS-31

Most Common Uses

Treatment of Mitochondrial Diseases

SS-31 is widely studied for its potential to treat mitochondrial diseases, such as Leigh syndrome and Barth syndrome. These conditions arise from impaired mitochondrial function, leading to energy deficits in cells. SS-31 helps stabilize mitochondrial membranes, improve energy production, and reduce oxidative stress, offering potential benefits for patients with these rare genetic disorders.

Cardiovascular Health

SS-31 shows promise in supporting heart function, especially in conditions like heart failure and ischemic heart disease. Research indicates that SS-31 can protect heart tissue from damage during reduced blood flow, enhance energy production in cardiac cells, and reduce inflammation, making it a candidate for improving outcomes in heart-related conditions.

Neuroprotection

SS-31 is being explored for its role in protecting nerve cells in neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases. By reducing oxidative damage and supporting mitochondrial function in neurons, SS-31 may help slow the progression of these conditions and preserve cognitive and motor functions.

Kidney Protection

SS-31 also shows potential in protecting kidney function, particularly in acute kidney injury and chronic kidney disease. Its ability to reduce oxidative stress and stabilize mitochondrial function in renal cells may help prevent damage from toxins, ischemia, or other stressors, supporting kidney health in at-risk patients.

Skeletal Muscle Function

SS-31 is investigated for its effects on improving skeletal muscle performance, especially in age-related muscle decline and muscular dystrophies. By enhancing mitochondrial efficiency, SS-31 may improve muscle strength and endurance, offering potential benefits for elderly individuals or those with muscle-wasting conditions.

Mechanism of Action

SS-31 is a synthetic tetrapeptide designed to target and support mitochondrial function. Its unique structure allows it to interact with mitochondria in a highly specific way, addressing cellular stress and energy deficits. The mechanism of action of SS-31 centers on its ability to stabilize mitochondrial membranes, enhance energy production, and reduce oxidative damage, making it a promising therapeutic for various conditions.

SS-31 selectively binds to cardiolipin, a phospholipid found in the inner mitochondrial membrane. Cardiolipin plays an essential role in maintaining the structure and function of mitochondria, particularly in supporting the activity of enzymes involved in ATP production. It stabilizes cardiolipin, preventing its peroxidation under conditions of oxidative stress. This interaction helps preserve the integrity of the mitochondrial membrane, ensuring efficient electron transport and ATP synthesis.

The peptide also reduces the production of reactive oxygen species (ROS) within mitochondria.   Excessive ROS can damage cellular components, including proteins, lipids, and DNA, leading to impaired mitochondrial function. SS-31 mitigates this damage by neutralizing ROS and enhancing the activity of antioxidant defenses, creating a more balanced cellular environment.

Additionally, SS-31 improves mitochondrial dynamics, including processes like fusion and fission, which maintain mitochondrial health and adaptability. By supporting these processes, SS-31 helps cells respond to metabolic demands and stressors, promoting resilience in tissues with high energy needs, such as the heart, brain, and skeletal muscles.

Through these actions, SS-31 enhances cellular energy production, protects against oxidative damage, and supports mitochondrial stability, offering potential benefits for diseases characterized by mitochondrial dysfunction.

Structure and Pharmacology

SS-31 chemical structure consists of four amino acids with the sequence D-Arg-Dmt-Lys-Phe-NH2, where Dmt represents 2′,6′-dimethyltyrosine. The molecular formula of SS-31 is C32H49N9O5, and it has a molecular weight of 639.8 g/mol. The inclusion of D-amino acids, such as D-arginine, enhances the peptide’s stability against enzymatic degradation, allowing it to maintain activity in biological systems. The amidated C-terminus further contributes to its resistance to breakdown. SS-31’s cationic and lipophilic properties enable it to penetrate cell membranes and accumulate selectively in the inner mitochondrial membrane, where it exerts its therapeutic effects.

Pharmacologically, SS-31 exhibits a unique profile due to its ability to concentrate in mitochondria, the cellular powerhouses responsible for energy production. After administration, SS-31 rapidly distributes to tissues with high mitochondrial density, such as the heart, brain, kidneys, and skeletal muscles. Studies in preclinical models, including rats, dogs, and monkeys, indicate that SS-31 has a plasma half-life of approximately 2 hours, with clearance primarily through renal and hepatic pathways. Its small size and stable structure allow for efficient absorption when administered via subcutaneous or intravenous routes, as demonstrated in clinical trials.

SS-31 interacts specifically with cardiolipin, a phospholipid in the inner mitochondrial membrane, stabilizing its structure and preventing oxidative damage. This interaction enhances the efficiency of the electron transport chain, boosting ATP production and reducing the generation of reactive oxygen species (ROS). The peptide’s antioxidant properties further protect cellular components from ROS-mediated damage, supporting mitochondrial and cellular health.

Dosages

SS-31 is administered in clinical settings primarily through subcutaneous or intravenous routes, with dosages tailored to the condition being treated and the phase of clinical investigation. The following information reflects dosing regimens observed in clinical trials and preclinical studies, though specific protocols may vary based on patient needs and ongoing research.

In clinical trials for mitochondrial diseases, such as Barth syndrome and primary mitochondrial myopathy, SS-31 is commonly administered via subcutaneous injection at doses ranging from 10 mg to 40 mg daily. These trials often involve a regimen of daily injections over weeks or months to assess improvements in mitochondrial function and symptom relief. For example, studies in Barth syndrome have used 40 mg daily subcutaneous doses to evaluate effects on cardiac and skeletal muscle function.

For cardiovascular conditions, such as heart failure or ischemic heart disease, intravenous administration of SS-31 has been explored. Doses in these studies typically range from 0.005 mg/kg to 0.25 mg/kg, often given as a single infusion or repeated doses over a short period. These regimens aim to protect cardiac tissue and enhance energy production during stress, such as during reperfusion after a heart attack.

In trials targeting acute kidney injury, SS-31 has been administered intravenously at doses around 0.05 mg/kg to 0.25 mg/kg, often as a single dose or short-term infusion. These doses focus on reducing oxidative stress and preserving renal function in high-risk settings, such as post-surgical recovery.

Most commonly in a research setting, SS-31 is used in the 2mg dose once per day.

Warnings and Cautions

Although generally well-tolerated in trials, SS-31 may cause mild to moderate side effects, most commonly injection site reactions such as redness or swelling. These usually resolve on their own, but persistent symptoms should be reported. People with known allergies to peptides or SS-31 components should avoid it. Rare allergic reactions like rash or difficulty breathing require immediate attention. Those with allergy histories should approach this peptide with caution. Its safety in pregnancy or breastfeeding is unknown, so use in these populations is discouraged unless clearly justified. Women of childbearing age should use contraception during treatment.

Since SS-31 is cleared through the kidneys and liver, patients with impairment may need monitoring and possible dose adjustments. Providers should assess organ function before and during treatment. Patients should disclose all medications and supplements to avoid risks, especially with drugs affecting mitochondrial function.
Long-term safety data are limited. Trial participants should be monitored for side effects, and any unusual symptoms, like fatigue or nausea, should be promptly reported.

Research & Clinical Trials

Ameliorates Kidney Disease

The study concludes that SS-31 is a promising new compound that targets and protects the energy centers of cells, called mitochondria, and may help treat different types of kidney disease. It helps keep mitochondria healthy, boosts energy production, reduces harmful stress in cells, and prevents damage by cleaning up unstable molecules called free radicals. Tests in lab dishes and animals, as well as some early human trials, suggest that SS-31 is generally safe and causes only mild side effects like redness or itching at the injection site, dizziness, or headaches. No serious health problems were reported.

Studies also show that the peptide is quickly absorbed by the body, builds up in the kidneys where it is needed most, and leaves the body through urine, making it a good fit for kidney-related treatments. However, scientists don’t yet fully understand how exactly SS-31 works to protect the kidneys, and more research with larger groups of people is needed to prove how well it works and to explore its full potential in treating kidney diseases. [1]

SS-31 Reverses Age-Related Redox Stress and Boosts Exercise in Aged Mice

The study found that long-term treatment with SS-31 can reverse age-related problems in energy production and cell balance, leading to better muscle function and physical performance in older mice. After 8 weeks of treatment, the older mice showed big improvements in how much energy their muscles could produce and how efficiently their cells made that energy. These changes happened without needing more mitochondria, meaning SS-31 helped the existing ones work better. The treatment also restored chemical balance in the muscle cells, helping to fix issues caused by harmful molecules that build up with age. Lab tests showed a healthier chemical state in the muscles and fewer damaging changes to proteins.

These improvements helped the mice build more muscle, resist fatigue longer, and perform better on a treadmill compared to untreated older mice. SS-31 didn’t have any major effects on younger, healthy mice, which suggests it works by fixing age-related problems rather than boosting already healthy cells. Overall, the study shows that stress and damage in aging mitochondria are key reasons for muscle weakness and low endurance, and that SS-31 could be a promising treatment to help older adults stay stronger and more active, especially since it’s already being tested in human clinical trials. [2]

Mitochondrial Protein Interaction Landscape of SS-31

The study found that SS-31 directly attaches to certain proteins inside the mitochondria that are responsible for making energy and managing cell metabolism. Researchers used a special lab method to “catch” and identify these connections, and they discovered that SS-31 binds to 12 specific mitochondrial proteins. These proteins are all connected to a fatty substance called cardiolipin, which plays a crucial role in keeping the inner structure of mitochondria stable and helping them function properly.

These proteins mainly help with producing energy (ATP) and with a key part of metabolism called 2-oxoglutarate processing, both of which are vital for healthy cells. This means SS-31 doesn’t just stick to cardiolipin, as previously believed, but also to the proteins that work with cardiolipin, showing that SS-31 may help mitochondria in more than one way. This added understanding helps explain how SS-31 can improve energy production and reduce harmful oxidative stress, especially in older or damaged cells.

The study also confirmed that SS-31 improves mitochondrial function only in aged or unhealthy mitochondria, not in young, healthy ones. Overall, this research gives us the first clear evidence that SS-31 interacts with key mitochondrial proteins, offering new clues about how it helps restore energy and cell health, and supporting its potential use in treating diseases related to aging and mitochondrial problems. [3]