Ursolic Acid and Muscle Mass
The problem of muscle atrophy or loss of muscle mass is of concern to the aging individual as well as to those suffering from certain illnesses. Muscle atrophy usually leads to a downward spiral of physical debilitation and eventually death. Recent research suggests that a compound found in apple skins may help reverse this debilitating phenomenon. This compound is called ursolic acid and this post will provide basic information to the potential consumer on this unique compound.
What is Ursolic Acid?
Ursolic acid is a class of compounds called pentacyclic triterpenoic acids. It has a chemical structure somewhat similar to steroidal compounds like testosterone.
Ursolic acid can be found in a variety of plants and seems to be particularly concentrated in apple skins but also in prunes.
Many interesting compounds are found in the skins of fruits and vegetables. This is most likely due them providing a first line of defense against stressors like UV light, insect and fungal attack and cold.
We humans then can take advantage of these protective compounds by consuming them.
Unfortunately the skins of our fruits and vegetables are where pesticides and other contaminants are concentrated.
Interestingly, the holy basil plant, also known as Tulsi, has high concentrations of ursolic acid in its leaves and is available as an extract in supplement form.
Buy Supercritical Holy Basil from LEF
What is the Research Behind Ursolic Acid?
Dr. Christopher Adams at the University of Iowa conducted the research that has generated all the buzz around ursolic acid in the scientific community and popular media. The research was published in the journal Cell Metabolism 2011:13(6):627-38.
One must be aware that all the promising results come from experiments conducted in mice and not humans.
However, muscle atrophy in mice is associated with the same changes seen at the molecular level in humans. With this in mind, the researchers used an ingenious molecular screening process to identify ursolic acid as a potential reverser of muscle wasting and then proceeded to feed it to the mice.
The mice fed ursolic acid had both the size and strength of their muscles increased. The other benefit was that the ursolic acid group had reduced body fat and lowered glucose and cholesterol levels.
The researchers propose that ursolic acid acts by increasing the sensitivity of IGF and insulin receptors. IGF is a type of growth hormone that positively affects muscle growth.
What Type of Ursolic Acid Supplements are Out There?
The mice were given food that contained 0.25% ursolic acid. I have no idea how much they actually consumed total.
A supplement sold by Swanson Health Products that contains ursolic acid is their Holy Basil (Tulsi) Extract which contains 2.0% ursolic acid in 400 mg capules. So that would be 8 mg of ursolic acid per capsule.
Of course the hardcore weightlifting community is all over this stuff. One product that is being marketed to them is called ‘Ursobolic’.
4 Comments
MGF
The dosing for humans would have to be pretty high–unless I made an error in conversions. Mice on average eat about 5 grams of food a day. The amount given in chow was 0.27% (not 0.25%); that comes to 0.0135g/day. Converting that to mg/kg for a mouse (which on average weighs 20 grams), comes to 675 mg/kg. If you did a straight extrapolation to a 60 kg human, thats a pretty big dose. If you use a more recent conversion formula (Reagan-Shaw, et al., FASEB 2007), you get a more reasonable 54.8 mg/kg, but that is still comes out to about 3.3 grams/day. That is manageable, but you would be taking a LOT of these pills. I wonder if there is any toxicity associated with the other compounds contained in this extract, since you would have to take so much of it. Seems the better option is to find a pure source.
Rob
You bring up some interesting points. The extract mentioned in my post uses Holy Basil as the plant source. Holy Basil is related to common basil and like all herbs is a rich mixture of compounds other than ursolic acid. Interestingly, there is a compound contained in holy basil known as beta-caryophyllene, which acts similarly to some of the beneficial non-psychoactive antiinflammatory cannabinoids in cannabis that is sought out by medical users.
There is a rich mix of essential oils that give basil its characteristic smells and tastes that have the potential to be toxic in large doses but would actually have beneficial health properties at low doses like, eugenol. The poison in this case being in the dose. Some might cause alterations in consciousness, like methyl chavicol in high doses. In this case, “One man’s poison might be another man’s paradise.”
However, depending on the extraction method these not very water soluble compounds may not be included at all in the extract. Supplement makers usually provide no details as to how these extracts are prepared for proprietary reasons. However, my holy basil extract has a strong smell of the volatile oils that give the herb its smell and flavor characteristics.
One thing that should concern the consumer of concentrated extracts is that naturally occurring compounds co-occurring with the desired compound(s) being standardized for may by be toxic when concentrated. Of even greater concern is herbs that concentrate heavy metals like Astragalus known for concentrating selenium. In fact this herb is used in bioremediation of soils contaminated with high levels of selenium. So with an extract of this herb one may be ingesting heroic toxic doses of selenium. Hopefully the supplement manufacturer is checking for these things.
Then there are possible concentration of pesticides, herbicides, molds, etc. Maybe we should be just as concerned with what the other 95% of an extract contains and not just the 5% of standardized compound.
The product I mentioned contains 8 mg of ursolic acid so one would have to take 412 capsules to achieve the 3.3 g /day from the extrapolation from the rat study.
This brings up another point. It is probably dangerous to extrapolate doses used in animal studies to humans. An example of this, back in the days of scientific studies on LSD, researches calculated by extrapolation from human studies a comparable safe effective dose of LSD for an elephant based on weight. The elephant dropped over dead.
Furthermore, it is unwise to get overexcited about studies done in mice and rats, as well as on human cells and organs in a petri dish, and then go out and consume mass quantities of it because you might get a “a little huger”. Its hard to get huge when your kidneys and liver are failing.
Animal studies typically use heroic doses of things to get results due to time and money constraints. The fact that human studies of Holy Basil, mainly done in India where the herb has been used and revered for millenia, with much lower doses and having a positive effect on parameters as seen in study that generated all the buzz, is encouraging.
There are products offered of pure ursolic acid. However, these won’t be found at your friendly supplement retail store or by well known reliable manufactures. No, these are isolated to the murky world of Internet “grey market” anabolic muscle-head sites. I’m relatively sure most of these things are being manufactured overseas in shady laboratories. The question becomes: Are these 98-99% pure products being isolated through chemical processes from a natural product and if so, which one, or prepared semisynthetically from natural products or synthesized denovo? This opens up a whole other can of worms.
MGF
The dosing for humans would have to be pretty high–unless I made an error in conversions. Mice on average eat about 5 grams of food a day. The amount given in chow was 0.27% (not 0.25%); that comes to 0.0135g/day. Converting that to mg/kg for a mouse (which on average weighs 20 grams), comes to 675 mg/kg. If you did a straight extrapolation to a 60 kg human, thats a pretty big dose. If you use a more recent conversion formula (Reagan-Shaw, et al., FASEB 2007), you get a more reasonable 54.8 mg/kg, but that is still comes out to about 3.3 grams/day. That is manageable, but you would be taking a LOT of these pills. I wonder if there is any toxicity associated with the other compounds contained in this extract, since you would have to take so much of it. Seems the better option is to find a pure source.
MGF
I agree 100% with your comments. Extrapolating from rodent studies to humans is very tricky indeed. The best one can hope for is a pure source at some point coupled with human clinical trials. Still, if we believe the Reagan-Shaw study, an effective dose may be reasonable. However, that is still largely speculation in the absence of human trials.
Great site you have here! I was very happy to find one so well-grounded in solid reasoning and science.