You don’t need vitamin D supplements even for the winter.
We were designed to get through winter without supplements as this vitamin is stored.
Supplements are fat soluble, not the major form you need.

**You need water soluble D sulfate from the Sun or Milk. **
Water soluble D sulfate can convert to fat soluble when needed in a minority of its functions.

**D sulfate is made on the skin by combining sun, cholesterol and sulfur. **

**The only food source of D sulfate is milk, more utilizable in raw milk. **
​Many people will have to solve dairy intolerance first.
​Dairy intolerance has a dozen reasons and can be fixed, but not in social media comments.

**Don’t take supplements: they are more likely to make you worse. **
Even “natural” supplements are fat soluble D which only play a small role when we need water soluble D sulfate.
Sure you can find examples of people who say they felt better with fat soluble D, but better is not always best, and it is risky. Arguing the counter point just to argue does not get us anywhere.

Don’t take fish oils for D
It’s fat soluble, not what you need
Oils are highly likely to be rancid.
Again, there can be evidence both ways, but better is not best.
Fix the milk allergy and use raw milk for many benefits.

D Cofactor Problems.
Cofactors deficiencies for utilizing vitamin D are often the problem: retinol vitamin A, vitamin K, boron, etc.

Vitamin A is a cofactor and if you are vitamin A toxic that means that you are unable to utilize A.
The main cause of vitamin A toxic is exposure to artificial light dominant in the blue range, which disconnects the vitamin A retinal from melanopsin, its cofactor for utilization. Read that again, and again, and again.

Vitamin deficiencies are not solved best by taking isolated supplements.
A whole food approach solves problems faster without fully knowing what they are, rather than trying to micromanage every detail separately in ways that are impossible.
Often minerals can be taken transdermally via the sea or sea water.

D Lights
If you missed vitamin D for the summer, the only really reliable way to get it besides milk is through UVB lights but these are mostly mercury based bulbs that mercury sensitive people cannot tolerate.
There may be some small LED lights but those are can be hard to tolerate, too.
I’ve never used any of those successfully.
I don’t have a shopping guide, you’re on your own.

**But, but, but, I’m deficient. **
Maybe, But that should not compel you into a risky attempt at a solution.
There may be problems with labs tests you have to research yourself.
Even if lab tests accurately identify a deficiency, taking a supplement is more likely to make you worse.
Increasing lab values is not the same as feeling better.
People have had improved health with dropping lab values.
Doctors that push supps don’t understand nutrition.
If you are having chronic health problems you no doubt have multiple nutritional deficiencies that they can’t identify or know how to treat. Vitamin D is just a popular thing to focus on.