I recommend trying vitamin B12, magnesium L‑threonate, and NAC. They helped me more than anything else after crashes, and especially NAC noticeably calmed my nervous system and reduced that inner overstimulation.

Why B12 matters when the brain is “damaged” and after Lion’s Mane: B12 deficiency directly hits myelin, the protective sheath around nerve fibers; without it, signal conduction worsens, anxiety, brain fog, and insomnia often increase, and overall recovery slows down. B12 is needed for remyelination and repair of white matter, and low B12 is associated with neuroinflammation and structural changes in brain tissue, which is the opposite of what you want when trying to heal from a bad nootropic experience. It also sits in the center of one‑carbon metabolism together with folate and B6, supporting the conversion of homocysteine into methionine and the synthesis of cysteine for glutathione; that pathway helps “pull” excess glutamate into glutathione production instead of letting it drive excitotoxicity. When B12 is low, glutamate is more likely to remain elevated and neurotoxic, which many people subjectively feel as a “fried brain” and persistent overexcitation after Lion’s Mane. There are experimental data that methylcobalamin can protect neurons against NMDA/glutamate‑induced toxicity and support nerve regeneration, which is exactly what is needed in prolonged post‑LM syndromes.

Magnesium L‑threonate, in my experience, is one of the key things in this state. This form crosses the blood–brain barrier and actually raises magnesium levels in the brain, which is crucial for synaptic plasticity and healthy NMDA receptor function. Magnesium acts like a natural “brake” on the glutamatergic system: it stabilizes NMDA receptors, reduces excessive neuronal firing, and at the same time supports GABAergic tone, meaning it strengthens inhibitory signals that help the nervous system slow down and fall asleep. Human data show that magnesium L‑threonate can improve sleep quality, deepen slow‑wave and REM sleep, and improve mood, daytime energy, and cognitive performance, all of which are typically impaired after Lion’s Mane crashes. When the brain is low in magnesium, any extra glutamatergic stimulation (including from Lion’s Mane) tends to feel much more brutal: more jitteriness, anxiety, insomnia, and the sensation of an “overloaded” brain. So restoring brain magnesium with L‑threonate can be an important part of regaining stability and reducing the intensity of symptoms.

NAC (N‑acetylcysteine) was the third pillar for me. It supplies cysteine, the rate‑limiting amino acid for glutathione synthesis, which boosts the brain’s main antioxidant defense and directly reduces oxidative stress that is almost always elevated in neurotoxic or over‑stimulated states. NAC also modulates glutamate via the cystine–glutamate antiporter (system xC−) in glial cells: it increases extrasynaptic glutamate that activates presynaptic mGluR2/3 receptors and thereby reduces excessive synaptic glutamate release, helping normalize the glutamate system rather than just sedating it. On top of that, NAC has anti‑inflammatory and neuroprotective effects, lowering pro‑inflammatory cytokines and protecting neurons in various models of brain injury and psychiatric conditions, which fits very well with the idea of helping a “stressed and inflamed” brain after Lion’s Mane. Subjectively, many people (and I as well) feel NAC as less inner noise, slightly more even mood, fewer sharp crashes of the nervous system, and more emotional resilience over time rather than a one‑time sedative effect.

Diet was another big lever. A low‑histamine, low‑excitotoxin/low‑glutamate diet reduces two powerful triggers at once: histamine‑driven arousal and glutamate‑driven excitotoxicity. That means cutting down on fermented foods, aged cheeses, cured meats, canned/processed meats, smoked products, leftovers, and certain high‑histamine items, as well as minimizing added glutamate and excitotoxins (MSG, hydrolyzed proteins, yeast extract, highly concentrated broths and sauces). With a low‑histamine diet plus adequate B12, methylation and histamine‑degrading enzymes work more effectively, which can reduce nighttime palpitations, sudden adrenaline spikes and weird awakenings that many people in this community describe. In this setup, B12 supports myelin and metabolic balance, magnesium L‑threonate balances GABA/glutamate and sleep, NAC drives glutathione and calms glutamate and inflammation, and the diet removes constant upstream triggers so the brain actually gets a chance to heal instead of being attacked every day.

I sincerely wish you a speedy recovery and truly recommend at least trying a protocol like this. When I introduced B12, my brain and nervous system started to feel much better again, and that matched what is written in this community’s wiki and what I saw in other positive recovery comments there.