TLDR: even just small amounts of topical estrogen (prescribed for atrophy) cause headaches, nausea, and diarrhea the day after use. Here to ask if anyone knows why this happens or if anyone has had a similar experience?

I use topical estrogen for atrophy issues (mostly dryness). I was prescribed a few grams or something daily, for 3 weeks, but my doctor as well as the pharmacist mentioned that for me it might work better to just use a pea-sized drop on my finger and apply it mostly to the outside. I find it works best that way!

They also said it wouldn't have an effect on the overall levels in my system, and that it would only have a localized effect on that particular area... however, I have been having some side effects.

Whenever I apply it, I tend to be fine until the next day. I'll get really bad headaches, like migraines (which was what made me realize it was related to the cream because I never get migraines except for after I apply this cream), a lot of nausea and diarrhea, too. I have IBS so that last bit wasn't shocking at first, until I realized it happened alongside the headaches, and at a particular severity, always after applying the E cream!

These side effects have been slightly lessened by using even less than a pea-sized drop (like I use the tiniest little smudge now) daily, but I still feel icky every single day. I thought maybe if I did a smaller amount more frequently the side effects would eventually go away, but I started applying it on Monday and have been feeling ill every day since then.

If it's important to note, I am also taking Norethrindrone, I haven't had a period (or any bleeding) for about a year but my periods used to be horrendous (heavy flow, extremely painful cramps, always with tummy upset), and I'm suspected to have Endometriosis.

I'm mostly just here to ask if anyone knows why this could be happening to me, or if anyone has had a similar experience? I couldn't really find anything online so I'm a bit lost. Keeping things healthy & functioning down there is important to me, so I'd ideally like to make this work 🥲

Thanks in advance.