EHX acts as an enterovirus RNA-dependent RNA polymerase (RdRp)
EHX binds to some non-structural proteins of enterovirus, and in particular, it binds to enterovirus 3D protein, which is the enterovirus RdRp protein. RdRp is a critical protein in RNA virus replication. By binding to and deactivating this RdRp protein, EHX acts as an enterovirus replication inhibitor
The mouse study
linked to above administered 250 mg/kg of EHX twice daily for 5 days by intraperitoneal injection.
In the group of coxsackievirus B-infected mice not given EHX, 57% died; whereas in the group given EHX, 37% died. So that demonstrates in vivo efficacy of EHX against coxsackievirus B.
The mouse dose of 250 mg/kg twice daily would work out as a human dose of 20.3 mg/kg (diving 250 by the mouse-to-human conversion factor of 12.3). So for a 75 kg human, that is a dose of about 1500 mg twice daily. Whether that dose is safe in humans is not known.
This food ingredient safety paper
(full text here
) says the EHX no observed adverse effects level (NOAEL) is 13.47 mg/kg daily, but I am not sure if that figure is for rats or humans.
An interesting thing about the mouse study is that they tested EHX against some enterovirus replicons
that the authors engineered. Replicons are very similar to non-cytolytic enterovirus
found in ME/CFS patients.
They found EHX inhibits the enterovirus replicons too. This is good, as it suggests EHX could be effective against the non-cytolytic enterovirus infections that researchers like Dr Chia believe cause ME/CFS.
If you look at table 1 of the study
, this shows the computer-calculated docking affinity of EHX to various viral proteins. You can see that it docks to the viral RdRp proteins of poliovirus and rhinovirus, which are both enteroviruses.
So EHX will likely have broad-spectrum antiviral effects against a wide range of enteroviruses
Table 1 also shows that EHX binds to SARS coronavirus replicase 1a protein, so EHX may work for COVID infections too
The half-life of plant-derived volatile compounds like EHX is short, but in the study, they found that EHX binds tightly to viral proteins, and it remains attached to these proteins up to 48 hours
. So its antiviral action in the body lasts much longer that its short half life would suggest. So that's good.
EHX is a volatile organic compound (VOC) found in fruits, and such VOC compounds can usually cross biological membranes and the blood–brain barrier. So EHX should have antiviral effects within the brain
In the EU, ethyl 3-hydroxyhexanoate (EHX) can be bought from Laboratorium Discounter
. 25 grams costs €65. 100 grams costs €176.
I've got some EHX on order, and will be trying this antiviral within weeks. It's one of the most interesting new enterovirus antiviral substances I have seen in a while.
EHX is a registered food additive and food fragrance (FEMA number 3545
), with a fruity taste similar to grapes. EHX is a liquid at room temperature, with a density very similar to water (0.97 g/ml).
Given that the water solubility of EHX is reasonable (17 mg/ml), we can guess that oral bioavailability is going to be good. The food ingredient safety paper mentioned above says that oral bioavailability is assumed to be 100%, and dermal bioavailability (when EHX is placed on the skin) is also assumed to be 100%.
As with all substances tried experimentally, I am going to start with lower doses, and titrate up slowly, observing any side effects that may appear.