A precise word, used loosely
What a pheromone actually is.
In animal science a pheromone is exact: a species-wide chemical signal that evolved to carry one specific message — a moth drawing a mate from a mile off, an ant laying a trail. The bar for the word is high, set by careful bioassays. By that bar, not one human pheromone has ever been identified. Decades of confident claims have not survived scrutiny.
The organ that doesn’t work
A ruin where the receiver should be.
Many animals detect pheromones with a dedicated structure, the vomeronasal organ. In adult humans it is vestigial — and the gene that makes its signalling possible, TRPC2, is a genetic ruin, broken by mutations we share with the apes. The hardware other species use to read pheromones is, in us, switched off.
The sprays
The love-potion molecules failed the test.
The two molecules sold as human "sex pheromones" — androstadienone and estratetraenol — were put to a direct test: did they change how attractive or how masculine or feminine a face appeared? They did nothing. The result was a clean null. The pheromone perfume is a story the bottle tells, not a finding the science supports.
And yet — the signal is real
We do speak in scent. Just not in pheromones.
None of this means body odor is silent. Sweat gathered while someone is afraid can pass that fear to a person who merely smells it; disgust travels the same way. Mothers know their newborns by scent. These are chemosignals — cues the body emits and others read. The honest correction is not that human chemical communication is a myth. It is that the right word is cue, not pheromone.
How sure are we?
Every claim, tagged for how settled it is.
- No molecule has ever been validated as a human pheromone to the bioassay standard used for moths, mice or rabbits — decades of "human pheromone" claims rest on weak evidence (Wyatt, 2015).
- The human vomeronasal organ — the dedicated pheromone organ in many animals — is vestigial in adults, and its key signalling gene, TRPC2, is a genetic ruin (a pseudogene) in humans and apes (Zhang & Webb, 2003; Meredith, 2001).
- The flagship "sex pheromone" molecules sold in sprays — androstadienone and estratetraenol — fail to replicate: a direct test found no effect on attractiveness or perception (Hare et al., 2017).
- Yet real human chemosignals exist: sweat produced under fear or disgust induces the matching response in people who only smell it (de Groot et al., 2012). Body odor genuinely carries social and emotional information.
- Menstrual synchrony driven by axillary "pheromones" (McClintock, 1998) is contested and largely refuted on statistical grounds (Strassmann, 1999).
- The idea that we "smell out" genetically compatible mates (MHC/HLA) is weak and inconsistent at scale; the largest analysis found no robust human preference (Winternitz et al., 2017).
Common questions
Frequently asked.
- Do humans have pheromones?
- No human pheromone has ever been chemically identified and validated to the standard used for other animals (Wyatt, 2015). The vomeronasal organ that detects pheromones in many species is vestigial in adult humans, and its key gene (TRPC2) is non-functional (Zhang & Webb, 2003). However, humans do communicate through chemosignals — odor cues that carry real information about emotion, identity and kinship (de Groot et al., 2012). The accurate word is "cue," not "pheromone."
- Do pheromone perfumes and sprays work?
- There is no good evidence that they do. The molecules they advertise — usually androstadienone or estratetraenol — failed a direct replication test, showing no effect on attractiveness or gender perception (Hare et al., 2017). "Pheromone" sprays are marketing, not validated science.
- What is the difference between a pheromone and a chemosignal?
- A pheromone is a species-wide chemical signal that evolved to carry a specific message to other members of the species. A chemosignal or cue is information a receiver extracts from body odor that the sender did not necessarily evolve to broadcast. Humans have strong evidence for cues and no validated evidence for true pheromones — that distinction is the heart of the matter.
Selected sources
- Wyatt (2015), Proc. R. Soc. B 282:20142994; (2020), Phil. Trans. R. Soc. B 375:20190262 — the search for human pheromones.
- Zhang & Webb (2003), PNAS 100:8337 — TRPC2 pseudogenization; Meredith (2001), Chemical Senses — the vestigial human VNO.
- Hare et al. (2017), Royal Society Open Science 4:160831 — null replication of androstadienone / estratetraenol.
- de Groot et al. (2012), Psychological Science 23:1417 — emotional chemosignals in human sweat.
- Winternitz et al. (2017), Molecular Ecology 26:668 — MHC and human mate choice (largely null); Strassmann (1999), Human Reproduction 14:579 — refutation of menstrual synchrony.
The honest version is the interesting one.
Strip away the love-potion myth and what remains is real: body odor as a genuine, readable signal of who and how we are. That signal — not the marketing — is what SHEMIM studies.