If price is an issue, I recommend good old whey protein. If not, simply go with the best flavor/taste available. I don't think you will see a huge difference between whey and iso.
But whay doing calves with back? Do them with your legs! It's ok to do them twice a week, but it's not a good idea to have calves soreness during leg day.
My girl friend is taking sintroid, which is also used in case of hypo thyrodisim. She once took a double dose ( she forgot she already took his dose). About an hour later, she experience heart...
If you are a novice lifter, the shaking is normal, your body will adapt. Concentrate yourself on good form, and within a few weeks, the shaking will be gone.
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