Neurosteroids are basically steroids that can either travel into the brain or get produced in the brain itself, where they affect the organ’s various functions. Neurosteroids are also called neuroactive steroids sometimes.
In terms of their action, these compounds can be divided into inhibitory and excitatory. Inhibitory neurosteroids prevent the transmission of signals across neurons, while excitatory ones increase the chances that a particular form transmission will occur. Roughly speaking, inhibitory steroids are the "brakes" and the excitatory ones are the "gas pedal" of the brain.
There are also several special kinds of neurosteroids, namely proneurosteroids and pheromones. Proneurosteroids are neurosteroids that get converted into other neurosteroids, while pheromones specifically target the hypothalamus.
Examples of neurosteroids include epipregnanolone (excitatory), tetrahydrodeoxycorticosterone (inhibitory), cholestane cholesterol (inhibitory), and androstadienol (pheromone).
Note that some neurosteroids fall under two classes. For example, pregnenolone, a progesterone precursor, can be considered both an inhibitory neurosteroid and a proneurosteroid.
The GABAA (gamma-aminobutyric acid A) receptor is the "lock" for the brain’s main inhibitory neurotransmitter, gamma-aminobutyric acid (GABA). In other words, its activation prevents neurons from firing off. Why would you want that? Well, depending on the situation, having your neurons send signals might not be beneficial.
For example, if you’re having a hard time falling asleep due to overthinking, your neurons are probably in an excited state. Depression, anxiety, and pain all occur (at the biochemical level) due to this heightened excitability.
Now, with enough inhibitory neurosteroids, the GABAA receptor becomes more capable of shutting off this barrage of neural signals. This results in a feeling of calmness and makes it easier for you to focus, relax, and sleep.
Neurosteroids are so potent in activating the GABAA receptor that they’re considered to be powerful substitutes to benzodiazepines—drugs used specifically for epilepsy treatment.
Benzodiazepines don’t always work because certain types of GABAA receptor aren’t sensitive to them. Interestingly, even in these cases, neurosteroids still function quite well.
As we’ve mentioned, pregnenolone doesn’t fall under just one single class of neurosteroids. In a way, this is indicative of how useful in can be—whether as is or when converted by the body into other organic compounds.
It’s important to note, however, that while pregnenolone is available in supplement form and is typically recommended to be taken daily, there’s no established dosing guidelines for it.
Also, given the neurosteroid’s role as a precursor for several steroid hormones, there’s the possibility of it interfering with hormonal balance – especially when taken by those with existing hormone issues.
This doesn’t mean that pregnenolone is dangerous and doesn’t provide real benefits. After all, it’s even been found to help to decrease prostate cancer risk by influencing testosterone levels.
It’s important to emphasize that pregnenolone still hasn’t undergone as much scientific analysis as one would like. It’s probably for this reason that manufacturers are required by law to put lengthy warnings on their supplements' labels.