In the past he had said a good ratio of vitamin A to E was 5:1. When I go too low on vitamin A I break out. I'm always surprised and it takes me a while to realize, once again, my vitamin A is too low. I recall Ray's saying that increased metabolism increases the need for A. And that's why some get a breakout.Yes, I agree he has talked about too much vitamin A interfering with thyroid functiion, but I think it is specific to the person. The last time I had my thyroid checked TSH was about 1.0, so not really hypothyroid (I know, could be lower but not that bad), yet still my temps were low. I lived in Palm Springs for several years and swam all of the time and was very tan, so I had plenty of Vitamin D. Then I stopped taking multivitamins with Vitamin A due to the excipients, and I don't like liver so I don't think I've been getting enough vitamin A. Maybe too much vitamin D vs vitamin A. Doesn't sunlight also increase the need for vitamin A? Then after COVID I started taking Vitamin D as I don't get that much sun especially in winter.but more now in summer. I can't find an exact quote from Peat, but he does feel that vitamin A is important or he wouldn't recommend liver. I think sufficient vitamin a is the key, and I'm pretty sure I was deficient. If you google some of the other literature out there, it does talk about vitamin a deficiency causing hypothyroidism.. All I can say is that once I started supplementing with Vitamin A my temps went up, I no longer have cold hands and feet, the hair under my underarms and on my legs and arms has started to grow back (I thought it was menopause) and I seem to need less progesterone. So I think it's a fine line and I think deficiency is the key. Maybe my thyroid is fine but it just wasn't working without the vitamin A. Too much would not be good, but for me this has been a positive thing. I think you have to experiment and adjust to your individual situation. Thanks for pointing that out because people shouldn't be mass dosing with vitamin A to get their thyroid up, it depends on the situation. I do remember distinctly though that in the beginning of COVID days someone asked him a question about increasing immunity and just off the top of his head he mentioned sufficient Vitamin A. Then later after thinking it through I guess he started mentioning Vitamin D more often. It's all a fine line and I'm just sharing my experience -- not to be taken as medical advice -- but 20k Ui is not a huge dose and if people don't see improvement then easy enough to discontinue. Peat himself has said that of course people should experiment and adjust to what works for them. It seemed to be the missing link for me, but I get your point.
I used to go to the site of those Peaty guys in Simi Valley who run a gym. They organized questions to and answers from Peat. The info on this might be there.