Oral tretinoin has long been shown to get teratogenic in rats, mice, hamsters, and subhuman primates. It had been teratogenic and fetotoxic in Wistar rats when specified orally or topically in doses better than 1 mg/kg/day (8 periods the most human systemic dose altered for total entire body floor space). https://www.beastbeauty.co.uk/advantages-of-using-tretinoin/