Nasal absorption of progesterone in women - PubMed
Absorption profiles were obtained from women following the administration of ointment containing 20, 30 and 40 mg of progesterone to the nasal mucosa. There were no significant differences in area-under-curves between groups receiving the drug in one nostril but when 40 mg doses were divided...
pubmed.ncbi.nlm.nih.gov
Why do people bother applying progesterone lotion on skin if maximal absorption is 10%. Studies show application through nose is number one followed by labia and vaginal application