This morning I dropped a note to my physician about immune system activation symptoms from getting my 2nd covid shot. One item cited was suspected activation of coagulation resulting in brain fog. I mention that it disappears for half of the day with 300 mg of Piracetam. I expect an email back asking what is Piracetam?
From Wikipedia, you can get general background. It is NOT to be confused with paracetamol (acetaminophen). It’s sits in a murky space in the US, so while legal, without prescription, it can be hard to find.
It improves brain function for many conditions
-  After treatment, the quality of life scores was significantly higher than the control group, and the difference was statistically significant (P<0.05). For patients with vascular dementia after cerebral infarction, piracetam combined with nimodipine can improve the cognitive function, improve the quality of life, and have a significant clinical effect.
-  Although Piracetam is officially recognized as a nootropic, its enhancing effects in the healthy individual’s brain are moderate [104,54]. The racetam molecules are being used across a range of brain disorders, including Alzheimer’s disease, narcolepsy, ADHD, Parkinson’s disease and brain aging [105,106].
-  Piracetam shifted the balance of mitochondrial fission or fusion toward fusion, which is more favorable for ATP production, which would indirectly benefit synaptic function because of the energy requirements of synapses. 43 A review indicated favorable effects on neurotransmission and neuroplasticity. 44 Another report showed that the increased neurite length after piracetam treatment was accompanied by increased expression of the synaptic marker GAP43, thus improving neural plasticity. 45
In days long ago when I often fly between Seattle and India for work, I used a heparin-piracetam cocktail to reduce risk of DVT. As a side effect, I never experienced jet-lag.
-  ” The heparin-piracetam complex had a more pronounced anticoagulant and fibrinolytic activities than the individual components.”
-  “The particular efficacy of 8 g piracetam daily in 3 divided doses at 8-hourly intervals can be attributed to its unique dual mode of action; inhibition of platelet function by inhibition of thromboxane A2 synthetase or antagonism of thromboxane A2 and increased formation of prostaglandin I2, together with a rheological effect involving reduction in blood and plasma viscosity through an increase in cell membrane deformability and a reduction of 30-40% in the plasma concentrations of fibrinogen and von Willebrand’s factor”
This last study is why it is my go to when brain fog occurs. I have a mutation that results in higher levels of fibrinogen.
Doing a search on PubMed for “covid coagulopathy“, we find over 1100 citations. For long haul covid to include persistent coagulation is very probable. It may be due to microbiome alterations or other mechanisms.
Trying piracetam for brain fog is something to discuss with your MD. You may need to educate him about the contents of this article. The  study was on humans and thus showed safety and also dosage (8 grams/day in 3 dosages).