There is some contention over the figures that calculator produces.
Bear in mind that it is a heat driven process.
Lying outside near naked for 5 hrs midwinter will do more harm than good.
In both Edmonton and Boston where records have been kept NO increase in 25(OH)D is recorded midwinter whatever the calculator says is theoretically possible.

We tried to buy some Vit D3 today, but the shops here in Australia are only allowed to sell capsules of 1000 iu. Why would that be? Is it possible to overdose and hurt your liver or something?

You can overdose....but it takes repeated ingestion of amounts over 20,000 iu over a long period of time.

tell me about canadian government ...
They are artificially limiting vitamin d dose of only 1000IU and that's it. You can't get anything else and you can't even import it . I have to basically smuggle it

Whuh? Is this very recent? I've bought bottles of D-Drops for the last couple of years and now there are even generic brands of the same thing. They're right on the shelf with other supplements, not even OTC. 1 drop = 1000 IU Vit D. It's completely flavourless, so taking more than 1 drop is no biggy. I take 5 daily all winter. Try Shoppers Drug Mart, Zehr's/Superstore, or health food stores.

So they allow 1000IU only no matter what. I have psoriasis and I need much more than that and I can't gulp 50 tablets daily or even drops . I tried to buy from an internet store but they won't ship to Canada. Fortunatelly for me, my sister lives in the states so she sends me by mail

I know of at least one person whose doctor prescribed 50,000 IU per dose for her - whether that's all in one capsule I don't know. I also take the D-Drops - available in my grocery store (Thrifty Foods - now Sobeys) with all the other vitamins & supps. I don't think that 50 drops would fill a teaspoon and, as Kristine says, they're tasteless. That would sure beat trying to swallow 50 capsules!

Oh please, doctors prescribe D2 which is a plant form . not human form so it's useless . I am taking this one but not if Canadian government knows it. http://www.amazon.com/Vitamin-D3-50...ef=pd_sim_hpc_2

It's all very weird that the governments are doing this. What happens to you if you take an overdose? Will it kill you or something?

Not immediately. It takes a LONG TIME.

Here is some good info on why many doctors are vitamin D morons...
"In 1999, Vieth indirectly asked the medical community to produce any evidence 10,000 units of vitamin D a day was toxic, saying "Throughout my preparation of this review, I was amazed at the lack of evidence supporting statements about the toxicity of moderate doses of vitamin D." He added: "If there is published evidence of toxicity in adults from an intake of 250 ug (10,000 IU) per day, and that is verified by the 25(OH)D concentration, I have yet to find it."

Like most medication, cholecalciferol is certainly toxic in excess, and, like Coumadin, is used as a rodent poison for this purpose. Animal data indicates signs of toxicity can occur with ingestion of 0.5 mg/kg (20,000 IU/kg ), while the oral LD50 (the dose it takes to kill half the animals) for cholecalciferol in dogs is about 88 mg/kg, or 3,520,000 IU/kg. This would be equivalent to a 110-pound adult taking 176,000,000 IU or 440,000 of the 400 unit cholecalciferol capsules.

Vieth reports human toxicity probably begins to occur after chronic daily consumption of approximately 40,000 IU/day (100 of the 400 IU capsules). Heavy sun exposure when combined with excessive supplement use is a theoretical risk for vitamin D toxicity, but if such a case has been reported, I am not aware of it.

Physician ignorance about vitamin D toxicity is widespread. A case report of four patients appeared in the 1997 Annals of Internal Medicine, accompanied by an editorial warning about vitamin D toxicity. However, careful examination of the patients reveals that both papers are a testimony to the fact that incompetence about vitamin D toxicity can reach the highest levels of academia"
http://www.vitamindcouncil.org/vitaminDToxicity.shtml

About 15 years ago I moved from the US midwest to the US Virgin Islands. I lived there for a year and a half and spontaneously lost 40 pounds, going from about 160 to 122. I've never been able to figure out why but have often wondered if vitamin D might be the reason.

Last year I tried supplementing vitamin D3 for a while with no effect (on my weight). Maybe I wasn't taking enough?

I seem to recall Michael Holick saying there are about 10 other known products of sun exposure besides Vitamin D. You might not have been taking enough, but it could be that "whole sunlight" works better than a supplement.

By the way, I'm sitting in a hammock in the backyard right now. Oh, the wonders of modern wireless computing!

Bummer! I bought some vitamin D3 over my lunch break, determined to take more this time. I recall taking 3000 to 6000 IU before. Can't remember exactly. I'll bump that up to 10,000 and see what - if anything - happens. (I never know how long to run these little experiments before I give up. I think it was 3 or 4 months last time.)

If it doesn't work, maybe I'll buy a hammock.

We have the whole backyard surrounded by stockade fencing, so we don't have to worry too much about modesty...

Unfortunately I have a whole backyard (and front yard) full of trees. So the sun wouldn't be able to find me anyway.