When people first hear about mitochondrial peptides like SS31, MOTS-c, and Humanin, they often want to know which one is “best.” The truth is that each works on different levers inside the cell, and the right choice depends on what system is most stressed. Instead of guessing, we can use both objective markers and subjective markers to guide decisions. The key is to think of mitochondria as adaptable power plants. Each peptide teaches the plant a different skill SS31 strengthens the wiring, MOTS-c teaches it to use different fuels, and Humanin helps it resist damage signals. By paying attention to how our bodies respond, we can run small experiments and see what creates real improvements. The first place to start is redox stress. This is the balance between energy production and the “sparks” of free radicals that leak out. When sparks overwhelm the clean-up systems, we get fatigue, brain fog, and recovery issues. Labs like glutathione ratios or 8-OHdG give objective clues, but we can also use simple subjective markers. If someone feels like their workouts leave them drained for days, if their energy crashes mid-afternoon, or if their mood dips after training, redox stress may be the limiting factor. In that case, SS31 is often the best starting tool. SS31 binds to cardiolipin in the inner mitochondrial membrane, stabilizes the electron transport chain, and reduces the leakage of reactive oxygen species. In plain terms, it stops the wires from sparking and helps energy flow smoothly. Subjectively, people notice less soreness, steadier energy, and a calmer nervous system. HRV often improves, and the same training feels easier. If those markers shift in the right direction, SS31 is likely doing its job. The second area to evaluate is metabolic flexibility, which is the ability to switch between carbs and fats as needed. Poor flexibility shows up as high fasting insulin, high triglycerides, or simply the feeling that you “hit the wall” quickly without carbs. On a bike or during zone two cardio, if your heart rate climbs quickly and you feel like you cannot settle into a pace, that points to a problem in fuel choice. MOTS-c is the peptide that best addresses this. It activates AMPK, which signals the cell to clean up inefficient processes and shift toward fat oxidation. In practice, this means glucose uptake improves, fatty acid breakdown becomes more efficient, and new mitochondria are built. Subjective markers here include easier endurance work, steadier blood sugar, less hunger between meals, and a more even mood. On the performance side, lactate production during submaximal efforts goes down and zone two feels more sustainable. When those changes show up, MOTS-c is proving useful.

I have a client diagnosed with osteopenia who would like to address the problem. The client is woman middle-aged. In addition to dietary changes, sufficient protein intake, weight-bearing exercise, and supplementation with Vitamin D3 + K2 + calcium, are there also any peptides that could be useful?

Monthly Q&A is Wed, Sept 24th at 12pm EST! Peptides, mitochondria, training, recovery, redox, nutrition nothing off limits. Can’t make it? It’s recorded. Send your questions ahead & I’ll tackle as many as possible. Don’t miss this one! Anthony Castore is inviting you to a scheduled Zoom meeting. Topic: Anthony Castore's Zoom Meeting Time: Sep 24, 2025 12:00 PM Eastern Time (US and Canada) Join Zoom Meeting https://us06web.zoom.us/j/3374982270?pwd=df4BMZNo1LubZaVOX40y7ApApJMNh1.1&omn=86062393294 Meeting ID: 337 498 2270 Passcode: 12345 --- One tap mobile +13052241968,,3374982270#,,,,*12345# US +13017158592,,3374982270#,,,,*12345# US (Washington DC) Join instructions https://us06web.zoom.us/meetings/86062393294/invitations?signature=ifWS2d8Nthqfmi1D1qiFFAu-MxuZwFKHQvHy7dxGD68

Thank you

What are your thoughts on the potential role of peptide therapy in (stage I) breast cancer patients after standard treatment?