Androstadienes

C19 steroids with two double bonds. Most volatile class.

Androstanes

Saturated C19 steroids. Low volatility, detected via VNO V2R pathway.

Androstenes

C19 steroids with one double bond. More volatile, detected via multiple pathways.

Other Compounds

Fatty acids, peptides, and other non-steroidal compounds.

Estratetraenes

C18 steroids related to estrogens but non-estrogenic. Female-associated signals.

Pregnanes

C21 steroids with 2-carbon side chain. Includes pregnenolone and progesterone derivatives.