Every study used a different kind of number
If you try to compare the amount of SS-31 used across these four studies, you quickly hit a problem. They do not even use the same kind of measurement.
The two animal studies use milligrams per kilogram of body weight. The two cell studies use concentrations in the liquid around the cells. Those are not the same thing, and you cannot convert one into the other without a lot of extra information.
So let me lay out exactly what each study used, and then explain what can and cannot be said from it.
The amounts
| Study | Model | Amount | How given | How often |
|---|---|---|---|---|
| Muscle, 2011 | Mouse muscle cells | 10 nanomolar | Added to the dish | Once, 20 min before injury |
| Brain, 2020 | Living rats | 2, 5 or 10 mg/kg | Injection into the abdomen | Once, 30 min after injury |
| Liver, 2021 | Living mice | 5 mg/kg | Injection into the abdomen | Four times a week for four weeks |
| BAX, 2021 | Human cells | 0.01 to 10 micromolar | Added to the dish | Once, before the trigger |
Pattern one: 5 mg/kg in both animal studies
Both animal studies landed on 5 mg/kg. In the brain study, the team tested three doses and found 5 worked best. In the liver study, the team reused the schedule from their own earlier work on the pancreas of the same mice.
But the way it was given was completely different. In the brain study, a single dose after a sudden injury. In the liver study, sixteen doses over four weeks for a long-term disease.
So the same number turned up in two very different jobs. That suggests 5 mg/kg has become a common starting point in rodent research with SS-31. It does not mean it is the right amount for every situation, only that labs tend to build on each other's choices.
Pattern two: 10 nanomolar in both cell studies
In the cell studies, a striking match appears.
The 2011 muscle study used 10 nanomolar SS-31. The 2021 Wisconsin study tested a range starting at 0.01 micromolar, which is exactly 10 nanomolar.
And in both, that low concentration was active. In the muscle study, it roughly doubled the protective protein HSP70. In the Wisconsin study, it gave the clearest single-dose effect on the timing of BAX gathering.
Two labs, ten years apart, two different cell types, and the same low concentration showing up as effective.
Pattern three: more was not better
The brain study found 10 mg/kg did not beat 5 mg/kg. The Wisconsin study found its higher concentrations did not show stronger individual effects than its lowest one. The muscle study got a large effect from a very small amount.
That is the opposite of the "more is better" thinking that runs through a lot of supplement and peptide marketing. In these studies, SS-31 seems to have a sweet spot. Below it, not enough reaches the target. Above it, extra amounts add little.
That pattern makes sense for a compound that concentrates at a specific target, the inner membrane of mitochondria. Once that target is occupied, there is nowhere useful for more to go.
Why none of this gives you a human dose
I want to be as clear as possible on this.
Rodents are not small humans. Mice and rats process drugs much faster than people do. Researchers use established methods to estimate human-equivalent doses precisely because simple scaling by body weight gets it badly wrong.
Abdominal injection is a lab route. Injecting into the abdomen is a convenient way to give compounds to rodents. It is not how medicines are given to people.
Cell concentrations are not body doses. A concentration in a dish tells you what level a cell responds to. It does not tell you how much would need to be given to a living body to reach that level in the right tissue, for the right time.
None of these studies tested safety at different doses. They measured whether SS-31 helped. They did not set out to find the highest safe amount or study side effects.
None of the papers suggest a human dose. Not one.
What you can take from this
The useful lessons from the dose puzzle are about principles, not numbers:
- SS-31 appears to work at modest amounts in these models.
- Higher amounts did not reliably give more benefit.
- The same amount was used for very different purposes, single rescue doses and repeated treatment, and both reported benefits.
- Research labs tend to reuse each other's doses, which helps with comparison but can make a number look more established than it is.
If you ever see a dose for SS-31 quoted online with a reference to one of these papers, you now know that the paper gave that amount to a rat or a mouse or a dish of cells, and did not suggest it for people.
Next, a wider look at the gap between rats, mice and dishes on one side, and people on the other.
This series discusses four laboratory studies in animals and cultured cells. None tested SS-31 in people. Nothing here is medical advice, and SS-31 is discussed for research purposes only.
