Interesting stuff, I'm a bit sceptical of vitamin D mega dosing. Also, If I remember correctly, if you're getting sufficient magnesium (the majority of people don't) your Vitamin D requirements are significantly lowered.

meh

10,000 IU for me at this time of the year. I still think it has health benefits other than just maintaining bone health.

Also, some nutritionists believe that very high doses when a patient is very ill (esp cancer) can help.

No need to superdose protein or booze either but people do it.

keep your sly digs to yourself chopsicle
not my fault your nation cannot cope with adverse weather conditions.

i have started to take it again, but at 5000iu per day (but going to dust off the SAD lamp in addition to)

i think vit d can be pretty harmful to the hormonal axis

^^ tbh I don't understand how high doses of Vit D3 can be bad for us in anyway shape or form. Exposing our bodies to summer sun for a few hours leads to MASSIVE doses of Vit D in the body. Sure, that is produced naturally by the body, but afaik Vit D3 is as close as it gets to replicating that.

Vit D ramps up thyroid hormone T4 -> T3 conversion, but it doesn't increase your ACTH and thus doesn't increase your cortisol.

So if your cortisol is already too low, then boosting Vit D will further reduce your cortisol, because thyroid hormone T3 requires plenty of cortisol to achieve the boost in metabolism (since thyroid hormone T3 and cortisol work synergistically to achieve the metabolism boost which is incorrectly attributed to thyroid hormone T3 alone).

so lots of time on the sun is now bad for you?

has it ever been good for you?
is it not purported that you only need 30 mins exposure to get adequate amounts of endogenous production?

all i am saying is (more and more as i get older and perhaps wiser):
there are always consequences up and downstream

so to joe blow who reads the daily mail and sees that vitamin d is a fcuking miracle worker and rushes out to buy some d3, is totally fcuking oblivious to:
sensitivity to it
his/her own hormonal state of being

true, but i think megadoses imo are 10,000+.

taking say 5,000 in summer & 10,000 in winter in the uk seems spot on to me and i don't view it as a megadose.

just had a quick google and 20-30mins of sun (prob full body) will produce ~10,000iu of vit d3.

julesm wrote:Vit D ramps up thyroid hormone T4 -> T3 conversion, but it doesn't increase your ACTH and thus doesn't increase your cortisol.

So if your cortisol is already too low, then boosting Vit D will further reduce your cortisol, because thyroid hormone T3 requires plenty of cortisol to achieve the boost in metabolism (since thyroid hormone T3 and cortisol work synergistically to achieve the metabolism boost which is incorrectly attributed to thyroid hormone T3 alone).

In therory at least though personally I'd rather have low-ish cortisol than a slightly ramped up metabolism - raised metabolism equals extra oxidative stress and faster cellular aging, low cortisol equals increased immunity and slower degeneration of many tissues, as well as less muscle catabolism.

Anyone got any thoughts on combining vit d3 supplementation and melatonin? Worth taking both in the winter or just one due to the overlap?

cortisol is paramount to T production though
so using a rabiola-esque quote- would sooner age faster- than have suppressed T levels

Hmmm, I need soem help understanding this as my understanding was that while test and cortisol are often co released, there is no direct relationship one for the other and that the only established correlations are a) that they are both stimulated initially by the hypothalamus and pituitary and so illness affecting either of these glands is likely to affect both hormones, and b) that high levels of circulating cortisol reduce total levels of testosterone.

Maybe you can link me something to clarify?

My understanding (please correct if wrong) has always been that cortisol (certainly elevated cortisol anyway) supresses total test production: stress = increase in CRH in hypothalamus, CRH stimulates ACTH in pituitary, and ACTH stimulates cortisol in adrenal gland... but CRH also inhibits GnRH corelease in the hypothalamus which then reduces LH in the testes and lowers overal test production.

The body then does go into a feedback loop in that the hypothalamus detects the raised cortisol and stops CRH synthesis, but only if the initial stimulatory cause of cortisol is first removed - otherwise, so long as cortisol remains above baseline (60% above baseline is the magic figure), total body testosterone levels become reduced. Prolonged high levels of C also apparently may reduce IGF-1 synthesis too.

There may well be some requirement for cortisol to produce testosterone but am not sure it can be that high - phosphatidyl serine at 300-600mg for example is shown to significantly reduce cortisol, but not effect either total or free levels of testosterone or other hormones like GH or IGF... if there is a minimum requirement for cortisol to produce test it must therefore be quite low, possibly lower even than baseline C levels.

Many people rave about insulin being the most damaging hormone to health but from the stuff I've read IMHO I'd say that cortisol is more important to keep in check and low than insulin.

sorry det i meant metabolism as opposed to production.

my overall concern in all of this is again METABOLISM!!!

as we know the body should be very finely regulated with a ylang/ylang/negative feedback kind of way
so testosterone metabolism should be regulated by cortisol- but again it is only one piece of the complex puzzle.

but as we get older our cortisol output dwindles, and in order to keep our testosterone metabolism in check-and especially if cortisol is too low, increases estrogen levels to downregulate testosterone metabolism- ie aromatose- synthesis of estrogen from testosterone. This also impacts on neurotransmitters
the body can also signal the liver to increase shbg output- which again can downregulate testosterone metabolism, granted it isnt as bad as estrogen doing the job, but it is still indicative of too low cortisol levels.

in my opinion it is best to modulate testosterone metabolism via cortisol rather than the other 2 methods.

and again in my opinion- i dont understand why we would want to use cortisol suppressive supplements, as in my mind would inhibit the overall synthesis, which would then inhibit neurotransmitters, which would then clearly require the above.
obviously if cortisol levels too high, blunt them
but my take on all of this, especially with me being 36, is that i actually want to be INCREASING my cortisol, so i dont fall asleep in the afternoons and i sure as shit do not want my t metabolism being taken care of by estrogen

nb- this is purely based on my little and relative understanding of hormone synthesis

Do you think that low cortisol is why you are wanting to fall asleep in the afternoons?

as a rough guess yes, i think it is pretty well documented that low cortisol causes tiredness, diminished mental clarity etc
but again it is a very fine line- i could go and take a cortisol boosting supp, but you can easily spill over (take too much) and the negative feedback loop kicks in again via acth signalling- thus quad salivary tests required to determine salivary cortisol levels

and what do you think is causing your low cortisol levels on the pm?

--

just saw this: http://jonnybowdenblog.com/why-you-shou ... vitamin-d/

could be anything in the cortisol cascade
it isnt so bad now, but earlier on in the year (may) was horrific for it, i was in majorca having a scoop and i nearly glassed myself because i literally fell asleep and my head hit the glass on the table that was my first drink!!

jonny who? may as well be jonny mathis to me
i think the whole point is, as with prob anything, we should ascertain our own basepoints before ramming stuff down our throats.
i have read a few albeit anecdotal things saying people feel like shit on vit d, so it kind of tallies with what i am saying.

julesm wrote:sorry det i meant metabolism as opposed to production.

my overall concern in all of this is again METABOLISM!!!

as we know the body should be very finely regulated with a ylang/ylang/negative feedback kind of way
so testosterone metabolism should be regulated by cortisol- but again it is only one piece of the complex puzzle.

but as we get older our cortisol output dwindles, and in order to keep our testosterone metabolism in check-and especially if cortisol is too low, increases estrogen levels to downregulate testosterone metabolism- ie aromatose- synthesis of estrogen from testosterone. This also impacts on neurotransmitters
the body can also signal the liver to increase shbg output- which again can downregulate testosterone metabolism, granted it isnt as bad as estrogen doing the job, but it is still indicative of too low cortisol levels.

in my opinion it is best to modulate testosterone metabolism via cortisol rather than the other 2 methods.

and again in my opinion- i dont understand why we would want to use cortisol suppressive supplements, as in my mind would inhibit the overall synthesis, which would then inhibit neurotransmitters, which would then clearly require the above.
obviously if cortisol levels too high, blunt them
but my take on all of this, especially with me being 36, is that i actually want to be INCREASING my cortisol, so i dont fall asleep in the afternoons and i sure as shit do not want my t metabolism being taken care of by estrogen

nb- this is purely based on my little and relative understanding of hormone synthesis

Totally different focus to me but very interesting - I see where you are coming from and makes sense as a premise to self experiment on. The bit I find hard to figure out though is the interaction between cortisol and test when both are elevated in your system - if cortisol is dominant it partially blocks androgen receptors and so limits the action of free test. So, in theory at least, the extra free test may well at the same time be less effctive due to the very same cortisol that helps prevent its aromatization. I guess this feedback loop is part of the body keeping its status quo, but without knowing all factors is hard to say anything definite... and i have lots of holes in knowledge here.

Anecdotally I've had a lot of benefit from cortisol blocking supps - on phosphatidyl serine I feel amazing, sleep like a stone at night but feel more energised and mood stable during the day. I really want to say i grow better too, but can't confidently claim that... have certainly grown and increased strength very quickly when taking the stuff, but am sure that other factors played in to overall progress too.

Another reason why maybe I seem to get on well with cotisol blockers is possibly my physiology... if you follow the model of depression that puts a lot of the blame on overactivity of the HPA axis, then that means that me, as someone who suffers bouts of depression, has an over active HPA axis and elevated cortisol above the norm. This stuff would effectively then function to help correct any imbalance.

my point is that you only take PS and other cortisol blockers acutely, and so you would without doubt see the effects (short term)
i could see them being really beneficial for someone like rab when getting ready for a show- ie copious amounts of long duration cardio (bd or tid), he would want to dampen down cortisol in this regard.

SOmething i might trial when i get my lazy ass out of bed and do some cardio...im hopin gin january or maybe make a start over the xmas break to break myself into it daily