Please help! I was recently diagnosed with Mitochondrial Disease (also have hashimoto, coeliac and Reynaud's), and told that I should take creatine supplements. Since doing so I have felt that my thyroid has gone more hypo (still within range-supposedly) and am wondering if it may be the creatine... any ideas? I really don't want to put on wieght, given how difficult it is to get/keep off.
Thank you!!

It is not a good idea to take creatine with Synthroid.  If you are borderline hypothyroid you need to find out why. Is there any iodine in your diet?  Iodine is food for the Thyroid.  It doesn't work well without it.  The usual foods high in iodine are fish and iodized salt. Salt in crackers and chips, etc. do not contain iodine, so don't count them. The salt at home that you add to your food shold be purchased in an iodized variety.  A normal daily dose of iodine from iodized salt is one teaspoon per day. If your diet is low in iodine, you should check with your MD about adding kelp (iodine) to your diet.  Don't go out and start taking iodine without checking with you MD.  You are taking Synthroid and adding kelp may really screw up the thyroid imbalance.

If you want to exercise and bulk up, use common sense, stay away from herbal additives.  They take your money and rarely deliver.  Creatine over the counter is absorbed in the stomach and passes thru the stool/urine with little or no absorbtion.  That is a good thing because a rise in blood serum creatine can cause kidney damage.  If you want to research herbal additives, there is a book called "physicians herbal desk reference" that can be purchase via a bookstore or can be read in the library.  

To gain weight, eat pizza.  If you want to build muscle, weight- lift slowly to get muscle to increase in size.  If you run, do your knees a favor and run on grass or a professional track at schools or gyms.  Cement and tarmac will ruin the knee in people over 40y.  Good luck