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 goes by EST in the literature. It is an 18-carbon steroid built on the estrane backbone. That is the same core skeleton behind estradiol and the other estrogens your body makes.

The IUPAC name, estra-1,3,5(10),16-tetraen-3-ol, tells you most of what matters. There is an aromatic A-ring with a hydroxyl at position three. There is also an extra double bond at the 16,17 spot of the D-ring. The molecule carries no measurable estrogenic activity of its own.

The body produces it as a downstream metabolite of estrogen biosynthesis. It has been found at low levels in the urine of pregnant women. Smaller amounts turn up in non-pregnant adult women too.

How it smells, and why perfumers like that

On the nose, EST is faintly musky. For most people it sits below the conscious detection threshold. That is a feature, not a flaw. A chemosignal does not need to announce itself to be registered. Unlike androstenone , it has no obvious urinous or animalic edge.

There is also no well-mapped genetic split in how people perceive it. So from a perfumer's standpoint, it is easy to drop into a formula. It does not change the headline scent of the bottle.

The female-to-male signal hypothesis

EST entered the pheromone conversation as the proposed mirror image of androstadienone . The framing is symmetric. AND is a male steroid that modulates mood, cortisol or attention in women. So EST should be a female steroid that does something similar in men.

That symmetry is rhetorically tidy, which made me wary at first. Real biology rarely lines up that cleanly. But a plausible signal does not have to be a perfectly symmetric one to be real.

The pairing comes out of the same research family. Wyart and Sobel's lab at Berkeley generated the foundational AND results in the mid-2000s. They worked with smaller-N psychophysiological designs. That same lab helped popularize EST as the symmetric female candidate.

From there, downstream studies picked up the molecule. They looked for sex-specific effects on perception, mood and gender attribution. The effects they found were small, and human chemosignal work is chronically under-funded, so the picture is still coming into focus rather than closed.

Key research

Wyart 2007 — the template, not a direct test

The Wyart 2007 paper in the Journal of Neuroscience anchors the broader EST-AND family. It is not a direct test of EST. It showed that smelling AND moved cortisol levels in women. It also produced distinct fMRI activation in attention-related regions, with no matching effect in men.

Its contribution to the EST story is mostly structural. It set the template: short exposure, hormonal readout, sex-specific response. Later EST work tried to mirror that template in the opposite direction.

Zhou 2014 — the headline positive

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

Hare et al. 2017 — the careful null

Hare et al. 2017 in Royal Society Open Science is the canonical counterweight. The team ran a tighter replication aimed at both AND and EST. They tested 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 the result to argue that the EST-AND literature is overstated. A null is worth taking seriously. It also does not prove the molecule inert, because a single tightly-scoped task can miss a real effect that shows up in different conditions.

Honest summary: one suggestive positive from Zhou, one careful null from Hare, and a parent family (Wyart) whose direct claims are about AND, not EST. That is a thinner stack than AND has. It is a young, under-tested question, not a settled negative.

Where it shows up in products

EST shows up occasionally in women's pheromone perfumes pitched at attracting men. It is usually layered alongside copulins , and sometimes a small amount of AND.

The marketing logic mirrors the research framing. EST is the female molecule men's noses are thought to register. So putting it back into a perfume is meant to amplify what the wearer's skin would emit anyway.

In practice it is far less common than copulins on ingredient lists. Copulins carry a more robust set of behavioral studies. They also have a much longer history 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. There is no standard reference dose for a commercial women's perfume. As with AND, we cannot tell you whether your bottle delivers anywhere near the levels used in the lab work.

The honest verdict

Estratetraenol sits in the same promising-but-under-tested bucket as androstadienone. It has a thinner stack of papers and noticeably less commercial use. The one high-profile positive is genuinely interesting. The most careful replication is negative. Neither closes the case.

Its commercial footprint is small, too. So the practical question is largely unanswerable from the label: does my $40 perfume contain enough EST to matter? You cannot tell.

If you are shopping a women's pheromone perfume, EST is a reasonable thing to see on the list. On its own it is not the deciding factor, because it is a minor player next to copulins. Scent quality and copulin content carry more of the load, and the confidence a good perfume gives you stacks on top of the chemistry rather than replacing it. For the broader honest take on what the category does and does not deliver, see do pheromone perfumes work . For the current picks on the female side, see best pheromone perfumes for women .