Ingredient explainer

Estratetraenol

Also known as: EST; estra-1,3,5(10),16-tetraen-3-ol

Evidence: Mixed

An estrogen-derived steroid found in female urine — proposed as the female counterpart to androstadienone in human chemosignal research, with similarly contested evidence for behavioral effects on men.

What it is, structurally

Estratetraenol (EST in the literature shorthand) is an 18-carbon steroid built on the estrane backbone — the same core skeleton that underlies estradiol and the other endogenous estrogens. The full IUPAC name, estra-1,3,5(10),16-tetraen-3-ol, tells you most of what you need: an aromatic A-ring with a hydroxyl at position three, plus an extra double bond at the 16,17 position of the D-ring. It carries no measurable estrogenic activity of its own. The body produces it as a downstream metabolite of estrogen biosynthesis, and it has been identified at low levels in the urine of pregnant women and, in smaller amounts, in non-pregnant adult women.

On the nose, EST is faintly musky and largely below the conscious detection threshold for most people. Unlike androstenone , it does not carry an obvious urinous or animalic edge, and there is no well-mapped genetic split in how people perceive it. From a perfumer's standpoint, that makes it easy to drop into a formulation without altering the headline scent profile of the bottle.

The female-to-male signal hypothesis

EST entered the human-pheromone conversation as the proposed mirror image of androstadienone . The framing is symmetric: if AND is a male-produced steroid that modulates mood, cortisol or attention in women, then EST should be a female-produced steroid that does something analogous in men. That symmetry is rhetorically tidy, and it is also exactly the kind of clean hypothesis that the actual data has refused to deliver on.

The pairing comes out of the same research family. Wyart and Sobel's lab at Berkeley, working with smaller-N psychophysiological designs in the mid-2000s, generated the foundational AND results and helped popularize EST as the symmetric female candidate. From there the molecule got picked up by downstream studies looking for sex-specific effects on perception, mood and gender attribution — most of which produced effects too small or too noisy to settle the question one way or the other.

Key research

The Wyart 2007 paper (Journal of Neuroscience) is the anchor for the broader EST-AND research family rather than a direct test of EST. It showed that smelling AND moved cortisol levels in women and produced distinct fMRI activation patterns in attention-related regions, with no corresponding effect in men. The paper's contribution to the EST story is mostly structural: it established the template — short exposure, hormonal readout, sex-specific response — that subsequent EST work tried to mirror in the opposite direction.

A 2014 paper from Zhou and colleagues in Current Biology pushed the EST-as-male-signal story furthest, reporting that smelling EST biased heterosexual men toward perceiving ambiguous walking figures as more feminine, while AND produced the opposite shift in heterosexual women. That paper drew the brightest headlines and remains the EST result most often cited in marketing copy.

Hare et al. 2017 (Royal Society Open Science) is the canonical counterweight. The team ran a tighter replication aimed squarely at both AND and EST, testing whether either compound shifted gender perception, attractiveness ratings or unfaithfulness judgements of opposite-sex faces. They could not reproduce the effects. For EST specifically, this is the most careful attempt to date, and it came up empty. Tristram Wyatt has used this result as part of his broader argument that the EST-AND literature is overstated.

Honest summary: one suggestive positive finding from Zhou, one careful null from Hare, and a parent research family (Wyart) whose direct claims are about AND rather than EST. That is genuinely less to lean on than AND has, and AND is not exactly overflowing with replications either.

Where it shows up in products

EST shows up occasionally in women's pheromone perfumes pitched at attracting men, usually layered alongside copulins and sometimes a small amount of AND. The marketing logic mirrors the research framing: if EST is the female-produced molecule men's noses are supposed to register, putting it back into a perfume is supposed to amplify what the wearer's own skin would emit anyway.

In practice it is far less common on ingredient lists than copulins, which carry both a more robust set of behavioral studies and a much longer history of inclusion in women's formulations. Brands like the ones covered in the Athena Pheromones review lean on copulin chemistry as the primary female signal; EST is more of a secondary inclusion when it appears at all. Unisex products like Pure Instinct generally skip it entirely in favor of a fragrance-first approach.

Concentrations are essentially never disclosed, and there is no standard reference dose for a commercial women's perfume. As with AND, we cannot tell you whether your bottle is delivering anywhere near the levels used in the lab work.

The honest verdict

Estratetraenol sits in the same skeptical-but-not-dismissed bucket as androstadienone, with a thinner stack of papers and noticeably less commercial use. The one high-profile positive finding is interesting; the most careful replication is negative; and the molecule's commercial footprint is small enough that the practical question — does my $40 perfume contain enough EST to matter — is largely unanswerable from the label.

If you are shopping a women's pheromone perfume, EST is a reasonable thing to see on the ingredient list, but not a reason to pick one bottle over another on its own. Scent quality, copulin content and how confident the perfume actually makes you feel are still doing more of the real work. For the broader honest take on what the category does and does not deliver, see do pheromone perfumes work , and for the current picks for the female side of the category, best pheromone perfumes for women .