Overview

Androstadienone (androsta-4,16-dien-3-one), universally known as "A1" or "dienone" in the pheromone community, is the most scientifically studied human pheromone and one of the most potent romantic molecules available. It is derived from progesterone and pregnenolone and is most commonly found in male perspiration and hair secretions. It is predominantly produced during sleep, which some researchers believe supports its role in strengthening pair bonds between partners.

The community calls it "The Love Pheromone" because of the nature of the feelings it induces: comfort, emotional bonding, longing, and romantic attachment. On the PheroTruth forum, the dedicated androstadienone thread spans 27 pages of discussion -- a testament to how central this molecule is to pheromone practice.

A1 is highly polarizing. It produces powerful romantic effects on women while frequently causing depressive side effects ("the downer") in male wearers. Managing this tradeoff is a major topic of community discussion.

Pharmacology

What It Is

Androstadienone (androsta-4,16-dien-3-one) is a C19 androstadiene steroid with two double bonds (at C-4 and C-16) and a 3-ketone. Molecular formula Cโ‚โ‚‰Hโ‚‚โ‚†O, MW 270.41. The two double bonds make it one of the most volatile pheromone steroids โ€” it readily evaporates from skin and disperses through air. Classified as a "vomeropherin" due to demonstrated VNO stimulation.

Biosynthesis

Endogenous steroid derived from progesterone and pregnenolone:

Cholesterol โ†’ Pregnenolone โ†’ Progesterone โ†’ Androstadienone

It is found predominantly in male perspiration and hair secretions. Notably, production is highest during sleep โ€” researchers believe this supports its role in strengthening pair bonds between sleeping partners. Individual skin bacteria can metabolize androstadienone into androstenone, which fundamentally changes the signal from romantic to sexual/dominant.

Detection

One of the most scientifically validated pheromone detection pathways:

  • VNO stimulation โ€” demonstrated electrovomeronasogram responses
  • Main olfactory system โ€” consciously perceptible musky scent
  • Hypothalamic activation โ€” PET studies (Savic et al., 2001) show gender-specific activation of the medial preoptic area/anterior hypothalamus in women, a region critically involved in sexual and bonding behavior
  • Produces measurable physiological changes: relaxation, slower breathing, reduced heart rate, increased skin sensitivity in women