The schedule
Here is exactly how SS-31 was given in this study.
- Dose: 5 mg per kg of body weight
- Route: injection into the abdomen (intraperitoneal)
- Frequency: four times a week
- Duration: four weeks
- Who got it: male diabetic TH mice at about 24 weeks of age
The two comparison groups, healthy control mice and untreated diabetic mice, got injections of plain saline on the same schedule. That way, every mouse was handled and injected the same number of times. The only difference was what was in the syringe.
The SS-31 was bought from a commercial supplier, Biogenix in California, and the paper notes it was originally developed by Szeto and Schiller, the scientists behind the SS peptide family.
Why this schedule?
The paper says the schedule follows the same group's earlier study on the pancreas of TH mice. That study used SS-31 for four weeks and found improvements in pancreatic mitochondria.
Reusing a schedule that already worked in the same mouse model is good practice. It means the liver and pancreas results can be compared directly, since they come from the same treatment.
The same number in a very different setting
Here is something interesting. The dose of 5 mg/kg is exactly the dose the Hainan team settled on in the brain bleed study we cover in our other series.
But look at how differently it was used:
| Brain bleed study | Diabetic liver study | |
|---|---|---|
| Animal | Male rats | Male mice |
| Problem | Sudden injury | Long-term disease |
| Dose | 5 mg/kg | 5 mg/kg |
| How often | Once | Four times a week |
| For how long | Single dose | Four weeks |
| When measured | 24 hours later | After four weeks |
Same number, completely different job. In the brain study, SS-31 was a one-off rescue given 30 minutes after an acute injury. In the liver study, it was repeated treatment for an ongoing disease that had already been building for months.
Both reported benefits. That tells you something about SS-31 as a research tool: it has been used both as a fast protector during acute stress and as a repeated treatment for chronic stress, and it seems to do something useful in both settings, at least in rodents.
Why "5 mg/kg" keeps turning up
When different labs land on the same dose, it is usually not coincidence. It often means they are building on the same earlier research. The brain study says its dose range was chosen based on a previous report. The liver study used its own lab's earlier schedule.
Over time, a dose like 5 mg/kg becomes a kind of standard starting point in rodent work. That is helpful for comparing studies. It does not mean it is the "right" dose for every situation. In the brain study, a lower dose did not work as well and a higher dose did not work better, but that was one model.
What this does not tell you about people
I want to be very clear on this part, because dose numbers from animal studies get passed around online with no context.
Mice are not small people. A mouse processes drugs much faster than a human. Researchers use established conversion methods to estimate human-equivalent doses, and simply multiplying a mouse dose by your body weight gives you the wrong answer.
Injection into the abdomen is a lab route. It is a common, convenient way to give drugs to rodents. It is not how medicines are given to people.
The paper suggests no human dose. It is a study of mouse mitochondria, not a dosing guide.
So the useful takeaway from this part is not the number. It is the pattern: repeated treatment, over several weeks, in an animal with long-standing disease, was enough to shift mitochondrial markers back toward normal.
Why the duration matters
Four weeks is long enough to see more than a quick antioxidant effect. Building new mitochondria (Part 5) and shifting the balance of splitting and merging (Part 4) are not overnight processes. They involve cells changing which genes they read and which proteins they make.
That is why the duration of a study like this matters. If you only treated for a day, you might see less hydrogen peroxide, but you would be unlikely to see the deeper changes in mitochondrial biogenesis.
It also raises a question the paper does not answer: what happens when the treatment stops? Do the improvements last, or does the liver slide back as the high blood sugar continues? That would be worth knowing, and it is a question for future research.
Next, the final part of this series, where I look at the one measurement that is surprisingly missing from this paper.
This series discusses a peer-reviewed laboratory study in mice. The results have not been shown in people. Nothing here is medical advice, and SS-31 is discussed for research purposes only.
