Plz help in stopping side effect of L-methyl folate

Hi,

TLDR: Had symptoms like anxiety and insomnia for 2 years. After taking L-methyl folate 1mg/day for few weeks, symptoms disappeared but two side effects started - 1) dizziness when body and head moves/turns many times in a day due to day to day activities and 2) inability to think deeply. Stopped it and started niacin 30 mg/day for 3 weeks. Deep thinking came back but dizziness has continued. What should I do? BP and b12 are normal. No other disease.

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Details:

About me - I am MTFHR A1298C variant. COMT is normal. Due to some personal tragedies, I have been experiencing anxiety and insomnia for 2 years. I have taken b complex supplements in past. My b12 and BP are normal. I don’t have any other health problems and dont take any medicine, except supplements like melatonin/magnesium/ashwagandha for insomnia. Age.- middle age, Male gender.

To solve these chronic symptoms of anxiety and insomnia, I took L-methyl folate for few weeks: 

• First 2-3 weeks - L-methyl folate 1 mg/day. -> Anxiety and insomnia both solved!! - AMAZING
• Next 2-3 weeks - Two side effects started - 1) dizziness when body and head moves/turns many times in a day due to day to day activities and 2) inability to think deeply. No other side effect. So reduced dose to 100 mcg/day. Symptoms continued. Dizziness stops temporarily upon resting.
• Next 3 weeks - Stopped L-methyl folate completely. Started NIACIN 30 mg/day. Deep thinking came back. But dizziness reduced only by 30%.

What should I do to solve the Orthostatic dizziness? There is no functional medicine expert in my country to consult. Plz help.

Chatgpt/Gemini suggested to try following:

1. Hydroxycobalamin or NAC or curcumin (first option preferred) to absorb Nitric Oxide (which might be the culprit of this symptom)

2. Potassium supplement was an initial recommendation but chatgpt ruled it out as there is no other symptom of potassium deficiency like muscle pain, anxiety, jitteriness etc.

Q1 - What should I do. Without any new supplement, will this side effect go away on its own? If yes, in how many weeks. It’s quite difficult living daily life with this side effect.
Q2 - If at all I have to take some supplement to solve this side effect, what sld I choose?

Q3 - As Niacin is not showing any further benefit, I am planning to stop it. Is that ok?

Plz help.