At Optimum Health we never pass up an opportunity to learn from our customers. So when some of them started reporting that Alpha-Lipoic Acid (ALA) had helped them regain their sense of smell after being ill, we put word out to our stores. They too said they had people report the same thing. So, I provided someone who had been ill for a long time with a bottle, and about a week later they reported they could actually smell Christmas dinner.
Next, the literature where there are studies which demonstrate how viral infections can attack the central nervous system, increase inflammation, reduce oxygen, and attack/affect sense of taste and smell.  (Not that those who have experienced it need any confirmation.) ALA's ability to help neurological problems like diabetic neuropathy have been well documented.  However, ALA has also been shown to be protective of the central nervous system, including smell and taste after viral illness. 
If you are interested in trying it, remember that even though 600mg per day is a common supplemental dose, it is a good idea to divide this dose and space it through the day, (eg. 200mg 3X per day), instead of taking it all at once. This is simply due to how quickly ALA is metabolized by the body. Plasma levels peak within an hour or less, and then drop off quickly.  So, for a more pronounced effect, spread the dose out. If you can't be bothered to take it more than once, sustained blood levels can also be achieved with some controlled release formulas.
Alpha Lipoic Acid is absorbed better on an empty stomach, eg. 40% vs. 20%, but you still absorb some if you take it with food. So if it bothers peoples' stomachs with a burning sensation, as it sometimes does, I just recommend taking it with meals.
Lastly, a personal experience... if I am ever feeling sleepy through the day, especially the afternoon nods after lunch, I will take a 200mg capsule and find that it wakes me up and increases my alertness within about 10 minutes! This is not surprising given its role in the energy-producing mitochondria. But, for this same reason be careful about taking it too close to bedtime, as it can interfere with your sleep.
Hope you find this helpful,
- https://pubmed.ncbi.nlm.nih.gov/12439184/ https://www.brainfacts.org/diseases-and-disorders/covid-19/2021/how-covid19-attacks-the-brain-and-nervous-system-110521
Very helpful indeed. It gave me insight into something else as well.
Thanks for the article on Alpha Lipoic Acid. Another good reason to take them. It is good for a number of things according to my reading. Helps liver detox and removes heavy metals + Cirrhois. Plus for your eyes = imortant to glutathione (in liver) production to protect lens / retina degeneration & glaucoma. In liver dissolves toxins. Perhaps does it in eyes as well??