In the science-fiction film Lucy, the titular character takes a drug called CPH4 that increases her brain capacity.

The writer and director of the film, Luc Besson, claims in several interviews that this drug is based on a real chemical compound.

Interview from CraveOnline:

Q:Tell me about the drug that makes Lucy superhuman. Is that based on anything real or is that entirely a fiction?

A: It’s totally real. It’s not a real name. CPH4 is a name that I invented, but it’s a molecule that the pregnant woman is making it after six weeks of pregnancy in very, very tiny quantities. But it’s totally real, and it’s true that the power of this product for a baby is the power of an atomic bomb. It’s real. It’s totally real. So it’s not a drug in fact, it’s a natural molecule that pregnant women produce.

Interview from Vulture:

Q: Some people are complaining about the fact that the science behind your film — the whole idea that humans only use 10 percent of their brains — is not true. What’s your response to that?

A: It’s totally not true. Do they think that I don’t know this? I work on this thing for nine years and they think that I don’t know it’s not true? Of course I know it’s not true! But, you know, there are lots of facts in the film that are totally right. The CPH4, even if it’s not the real name — because I want to hide the real name — this molecule exists and is carried by the woman at six weeks of pregnancy. […]

So, does a similar chemical compound actually exist? What is it called? What does it do?

  • 2
    I suspect he's not referring to hCG, since that just keeps building, rather than just being a tiny amount.
    – Bobson
    Aug 11, 2014 at 18:15
  • 1
    did they ever show a structure for the molecule? If we all have is a fake name we can't say much. Embryo development is very complex and lots of compounds are made at various times to coordinate that development. Are there important molecules that start to be synthesized at about 6 weeks into the pregnancy? There are probably several of them. There is no need to keep the identity of the molecule secret either, I doubt Luc Besson discovered this molecule, it's probably in the literature anyway. Until he gives a source for his claim about "CPH4" I wouldn't trust him at all.
    – user137
    Aug 13, 2014 at 0:23
  • @user137 I don't think they showed the molecule in the film.
    – svick
    Aug 13, 2014 at 13:40
  • 5
    @georgechalhoub My guess is that if it's actually real, then he's hiding the name, because what the molecule actually does is boring and not that big of a deal.
    – svick
    Aug 13, 2014 at 15:50
  • Given that Luc Besson doesn't want to reveal the name of the molecule that he's talking about I don't think the question is answerable in it's present form. I vote to close.
    – Christian
    Aug 13, 2014 at 18:58

2 Answers 2


There's a group of molecule called Protocadherin-2 (Pcad-2) that

become visible along the nerve fiber in the brain stem at the 8th week, and spread over the entire brain at the 11th week. At the 18th week, however, expression in the nerve fascicles, which had been visible by that time, was no longer visible or had decreased. These results suggest that Pcad-2 appears relatively early in the critical stage of development of the fetal CNS [central nervous system], and is involved in the induction, fasciculation, and extension of axons.

This might explain the part where Lucy described something along the lines of cells talking to each other, forming communities that interact with each other.

Source: http://www.ncbi.nlm.nih.gov/m/pubmed/15327484/

Axon meaning: http://en.m.wikipedia.org/wiki/Axon

  • 2
    It would be nice to add a note that this molecule does not have the effect that is portrayed in the movie (except for vague statements like "it's a thing that does something on axons", which would hold for generic neurotransmitters too). The forming of the brain is complex, forming axons is certainly necessary, but there is no proof that increasing the number of axons increases even basic intelligence (let alone unlock superpowers). Your answer uses good research to help support shortsighted fantasy.
    – Spork
    Oct 30, 2014 at 14:46

CAUTION: I believe this is a publicity statement by the director, not based in fact. The drug can't be known until he specifies it.

Points to Consider

  • The sixth week is time when the brain is started forming. In other words the glob of cells started forming brain and heart like organs. Cerebral cortex is formed and synapses starts connecting.

  • If such kind of chemical actually exists, what it will be? It could be a substrate which bind any of the enzyme which helps in brain development or may be the enzyme itself (in both cases the enzyme is important)

  • Now the real problem, there are tons of enzymes which binds 100 times more substrates, which is the one?

My Guess: Why not the one with highest production and a high activity?

Estradiol or its derivative:

It is a female steroid hormone in the family of Estrogen. It not only influence the sex in the embryo it also helps in neural development and Neuroprotection. Estradiol and the Developing Brain, by MARGARET M. McCARTHY, American Physiological Society, 2008

The 2005 published paper, Low-dose estradiol alters brain activity., suggest that the low dose of this drug can actually alter the brain activity in adult.

Paper published in The Journal of Neuroscience, Estrogen, Menopause, and the Aging Brain: How Basic Neuroscience Can Inform Hormone Therapy in Women, supports the theory that it can have a effect on mental age.

PS: It's not the only possibility nor is the correct compound. But it is one of the many possibility.

Other possibilities:

  • Substrates of Fructose-1, 6-bisphosphatase can actually have effect on brain activity.
  • Substrates of FMRP (fragile X mental retardation protein)


  1. The Basics of Brain Development

  2. Fructose-1, 6-bisphosphatase in human fetal brain and liver during development

  • I would expect something more pregnancy-specific.
    – svick
    Aug 13, 2014 at 13:58
  • 1
    Welcome to Skeptics. If either of these answers actually had any effect approaching the claim, I would accept them as plausible answers, but you haven't shown that.
    – Oddthinking
    Aug 13, 2014 at 14:57
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    @DevashishDas what you need to do, I think, is to focus on the evidence that is relevant to the actual question. For example, show that there are significant chemicals that do influence foetal brains but also address why and how they could impact adult brains and, perhaps most importantly, why if they are common (like estradiol) we haven't noticed the effect before now.
    – matt_black
    Aug 13, 2014 at 15:00
  • 1
    @DevashishDas Much better. Though I would add more consideration of the magnitude of any adult effects of the potential candidates.
    – matt_black
    Aug 14, 2014 at 14:50
  • 1
    1) estradiol is not a protein but a steroid hormone. 2) estradiol is far from being the only pregnancy-related substance influencing brain development. What about cortisol, prolactin, oxytocin, placental lactogen, vasopressin, progesterone, etc. etc. etc.?
    – nico
    Aug 25, 2014 at 16:36

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