For those of you that had normal cycles prior to IP but have had it become irregular since IP, I'd love some insight. I'm starting week 3 on IP and have its really thrown off my cycle. Does this last the entire time you're OP or does it get better with time? Ever since I've been on BC my cycles have been extremely predictable. I have lots of weight to lose and plan to be on IP for while...hoping this irregularity is just temporary.

It threw mine out of whack for a few months, but it's settled down now, and is back to regular, like clock work. Good luck. If it stays out of whack, you might want to check in with your doc.

I know what you mean!!! I'm close to being on this for 2 full months and this current cycle is the first time I've ever been later without an explanation (last time a LO popped out 9 months down the road ) This time it was officially late 16 days. Threw me way off since I was able to plan my vacation times without worry lol, now I think I need to be worried as TOM might come around during vacay.

I am on BC and IP still threw me out of cycle, kind of badly almost like before I went on BC. I have terrible issues anyway because I have PCOS which is why I am on the pill. Made an appointment with my PCM next week to discuss that and I have lost aver 20% of my body weight anyway with what I lost before I started IP and the 39 I have lost on it.
Hoping he will tell me I can also stay on 1000mg of Metformin like I am while on the plan instead of moving back up to 2000mg per day.

I have had the opposite happen! I was super irregular (basically once every 2 months) and since I've been on IP, TOM came early! Like 8 days early.

A very low calorie diet, particularly when low carb, will change how your body makes hormones. This includes thyroid hormones and sex hormones (estrogen/progesterone). You also tend to store a lot of estrogen in your abdominal fat and fat cells can produce their own hormones. A drastic diet like IP therefore is likely to cause a hormone imbalance that may take a while to reset.

IP claims that if you loose fat fast, you will increase estrogen levels due to the release of fat-stored estrogen. I don't know whether that has a scientific base or not. But if your TOM does not get regular within a few months, you may want to check with a doctor. Do not trust the "medically supervised IP diet and their trained coaches" unless they have a MD degree. Monitor your symptoms carefully for changes.

Thank you for the advice. Yes I absolutely check in with my primary doc regularly (every 3 mos for thyroid) and just had bloodwork done last week...everything looked good, even getting off some of my diabetes meds after only 2 weeks. Luckily my doc is very familiar with IP and has even been on it himself.