In tracking my #'s within MFP, I noticed my potassium levels have been absurdly low. I have had some muscle cramping and my sleep has been a bit off, so I am figuring my magnesium levels are not within desired limits as well. I ended up buying a magnesium citrate and oxide 'complex' version as I went to 4 stores and got fed up not being able to find mag glycinate. Figured what I got was better than nothing for now and will source the glycinate online somewhere after this bottle is done.

I also picked up a potassium supplement yesterday at a low 99mg, but read something somewhere that potassium pills may sit in the stomach and mess with the lining. I am more focusing on shoring things up short falls through diet now due to pleasing results.

I recently looked up and saw that many magnesium rich foods are also high in Potassium and/or can be integrated into the Keto / LC woe without moving mountains. Will be picking up pink Himalayan salt to round things out as well.

have your doctor do general bloodwork and they can tell you if you have any major vitamin deficiencies. I have heard a lot of people starting out lose a lot of water weight and this really throws off your electrolyte balance and can give you "keto flu" symptoms. another common symptom of low potassium or magnesium is muscle cramps, which I get sometimes.

The flu feeling and muscle cramps are helped by hydration and adding some electrolytes: Sodium, potassium, chloride, calcium, magnesium. bone broth is often recommended to help with keto flu as well.
I add magnesium citrate powder to a drink every few days. For potassium supplementation, you can get "no salt" at any grocery store = potassium chloride. I prefer the taste of 'lite salt' which is half potassium and half sodium and I use that instead of salt a few meals each week. it helps digestion of potassium supplement having it with food, or just look for foods higher in potassium.

I take a daily vitamin because I don't eat a large range of different fruits and veggies (sticking to low carbs) so I feel I may be missing some essential vitamins.

If you have a well formulated diet, supplementation needed should be minimal. One area that I found seems to be off though is the omega 6/omega 3 ratio. Ideally, this is addressed on both sides by reducing the omega 6 content of what you eat (think veg oils and anything fried in them as the biggest contributors) and increasing omega 3 in your diet (ideally fatty fish lower on the food chain like sardines, mackerel, anchovies, wild caught salmon). Although you can get omega 3's from some plant foods like flax and chia seeds, they only have ALA and not DHA or EPA which are essential. If you don't eat fish regularly, you may need to supplement with a quality omega 3.

This is one area that is not specific to low carb or keto. The reason so many people have joint problems as they get older now is the high inflammation due to these being out of balance. I found when I got these in balance the knee that had 2 surgeries on it in the 1980's including an ACL reconstruction, no longer gave me any problems. My bad ankle stopped hurting. Basically, in may late forties, I now feel better than I did in my twenties. This also showed up in my labs where my hsCRP (most widely accepted marker for inflammation) is now consistently around 0.2. The recommendation is to be below 2.0 with 1.0 or less being considered optimal.