We have a lot of experience with this! The good news is that there should be no issue traveling with your Landish collagen and other dry products.
We'll break this down into two parts: air travel and customs.
Air travel
There should be no issue flying with Landish marine collagen or any dry (powdered) Landish products, as these are not liquids and are not in any way prohibited on commercial flights.
For this purpose it does not matter whether the container is sealed or not, so long as the lid is properly screwed on to avoid a powdery mess.
If you're packing your Landish collagen or other dry Landish product in your checked luggage, there are no further considerations.
If you're carrying it through security in your carry-on, the best practice to avoid delays is to take it out of your bag and place it into a bin with your other personal items as they go through the scanner. This is helpful to security since they'll need to ensure that the contents of the container are not liquid, usually by giving the bottle a quick shake. If the jar is in your bag, this can cost you and security staff additional time as they retrieve it from your bag. In our experience security personnel are appreciative of this extra little bit of thoughtfulness as it makes their job easier. You'll look like a real pro!
Customs
For the purpose of customs, it's best if the product is in its original container with the label on. In our experience it has not made a difference whether the product is sealed or unsealed.
There is no issue traveling to the United States or European Union with collagen powder or other powdered Landish products as this category of product is allowed through, and we have yet to travel to a country where this was not the case.
However, every country has its own rules, so please check your destination's list of food items that are not permitted through customs.