My 16-month theanine self-experiment

It is strange to discuss L-theanine with vitamin D as one has nothing much to do with the other. It could've been better to compare L-theanine with a placebo (cellulose) which is how research conventionally works.

L-theanine at 200-300 mg before bed is extremely useful for canceling excessive caffeine while trying to sleep at night. Add piperine to the mix for possible further cancelation of caffeine. [PMID 35684048]

> It is strange to discuss L-theanine with vitamin D as one has nothing much to do with the other.

That's the idea, vitamin D was used as a placebo. They bought vitamin D supplements rather than cellulose because the supplier sold both L-theanine and vitamin D and the pills looked (nearly) identical.

Vitamin D3 is not a placebo at all. It 100% promotes energy quite quickly even though it takes much longer for the body to convert it to the active form. Also, its mental effect is distinctly different from that of L-theanine, like day and night. For these reasons, it's not a great candidate for comparison with L-theanine.

Unless it's the active D vitamin, it takes weeks to convert it into reserves.

Taking vitamin D once, right before bed will do nothing. Our bodies don't use it that way.

Cholecalciferol = weeks

calcidiol = hours

Personal anecdote, Vitamin D is a horrible placebo.

I have been trying to increase my Vitamin D levels for 15 years now but I just can't tolerate this supplement.

  Lower dosage: ~1000 IE -> side effects come after around 3-4 days of daily intake.
  Higher dosage: ~5000 IE -> side effects after a few hours.

I tried following most advice over here in the past but it did not work: https://vitamindwiki.com/Vitamin+D+Cofactors+in+a+nutshell

I'll just live with my low blood Vitamin D levels.

What side effects? It promotes energy in just a few hours, so take it early in the day. Your link is not loading. Ensure you have sufficient calcium and magnesium as cofactors.

The conversion period strongly depends on the input dose and on available cofactors. Numerous people have reported that 5000 IU of vitamin D3 can produce energy benefits in just a few hours if one has been skipping taking it. If one is low on cofactors, or takes a low dose of D3, then I imagine it taking days or even longer as you noted.

> After ingestion, cholecalciferol is first converted to calcidiol in the liver, which can take several hours. Then, calcidiol is further converted to calcitriol, the active form, in the kidneys, which may take additional time.

read as if you're perfectly healthy, at minimum it's 24 hours. What you're talking about is probably placebo effect. For reserves to start building up to the point where your body has "enough" calcitriol, it takes weeks

Imagine the following variables:

* CalcitrolLevel: float

* CalcitrolReserveCapacity: float

* Is_Energetic: bool

Imagine the following equation:

* Is_Energetic = CalcitrolLevel > 90% of CalcitrolReserveCapacity

For most people, it will take days, weeks, or even months to come above 90%. But for those who have dipped just below 90%, such as to 89%, if they're optimally healthy in other ways, they will see a rapid rise in energy by high dose D3. If it's not this, then there is something else going on physiologically to explain the subjective effect.