Is There Such Thing as Truth Serum?

We’ve all seen films where the protagonists will be given a truth serum and then instantly blurt out their entire life story and give the game away to the bad guys. It happens in True Lies, The Good Shepherd, Agents and Shields and countless other shows and movies, but is it possible?

Looking at this from a scientific standpoint, is there any drug or any other means that can genuinely get you to openly answer questions with no inhibitions? And if so – why don’t we see these serums in courts and other uses? Read on and let’s get to the truth of the matter…

The most famous ‘truth serum’ that you see in films like True Lies is ‘sodium pentothal’, also known as ‘sodium thiopental’. This is a drug that has been researched by numerous institutions as a truth serum, and that is still used by some organisations for that purpose. Scarily though, this is also the drug that is most commonly used for lethal injections – so it’s important that you get the dosage right first and foremost or you aren’t getting any information out of anyone…

What makes sodium pentothal interesting and potentially useful though is the fact that it is a barbiturate, meaning that it can decrease higher cortical brain functioning – which is the part of the brain that handles planning, imagination, goal setting and other higher-order processes.

The idea then is that without your high-order brain functions to stand in the way, you might become very loose tongued when asked a question and may answer before truly considering the consequences. It can also be used to help treat phobias.

So does it work? Well to a degree yes – this drug will make the subject more cooperative and loquacious, but at the same time it isn’t 100% effective by any means. The drug’s effectiveness will depend partly on the individual, while the reliability of the answers is questionable. As a tool to be used alongside other techniques it may be legitimately useful (questionable morality issues aside), but as a stand-alone truth serum it isn’t quite what the films would have you believe.


Yes you read that right – LSD, as in ‘lysergic acid diethylamide’, was once believed to be a truth serum. By interfering with serotonin receptors, LSD can once again alter high-order brain function and also increase moods, which lead some agencies to believe that it could possibly be used as a truth serum. This lead to numerous test being carried out where subjects were unknowingly dosed with LSD, but of course the results were rather disastrous. The exact mechanisms of LSD are not fully understood, but what is known is that it causes hallucinations and generally impairs cognition to the point where the subject is far from a reliable source of information. So is LSD a truth serum? No, not at all.


Something you will hear quite often in conversation is that alcohol ‘reveals the real you’ or that it ‘makes you tell the truth’. Could alcohol then be used as a truth serum?

Well again it helps to look at how alcohol actually acts on the brain, which can help us to work out whether it could really make us more truthful. And again what you find is that alcohol suppresses our high-order brain functions that take place in the cerebral cortex. This means that our ability to plan ahead, to set goals and to moderate our behaviour to suit the situation are all diminished and that we are more likely to blurt out things that we shouldn’t as a result.

But does this make it a good truth serum? Not really. Apart from anything else, alcohol will also exaggerate emotions and damage recall which means that not everything you say is going to be truthful. It can also increase aggression, meaning that you won’t always necessarily be more agreeable and in fact may be the exact opposite. And just because you have fewer inhibitions, that doesn’t mean that you’re going to be more likely to want to speak truthfully – you could just as easily decide to lie out of spitefulness, or because you’re court up in the moment.

So the short answer to the question posited at the start of this article is no, there is no such thing as a ‘truth serum’ like the ones we see in the movies.

But what do exist, are drugs that can be used to make us more talkative and more cooperative. When used correctly by the right people, these could be used to extract information – especially if we don’t know to keep quiet. So watch your back, and be careful who you talk to when you’ve been drinking!

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