Delusional conspiracy theorists are commonly portrayed as wearing tin-foil hats to protect against mind-control rays from sinister organisations such as [goverments/aliens/NSA/CIA/FBI/liberals/conservatives/devil/god].

Are there any (electromagnetic or other natural world) rays that would be blocked by a tinfoil or aluminium foil hat?

To clarify, I am not asking for proof that anyone is trying to tamper with our minds, I am just wondering if a tinfoil hat would offer protection against anything at all. Is there any form of emitted radiation that would be blocked by such a hat?

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    @Tor-EinarJarnbjo doesn't a Faraday cage need to be closed? The tinfoil hats only cover the back of the skull, the face is still open (as is the neck), so how would that provide protection?
    – terdon
    Feb 20, 2014 at 14:52
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    Definitely protects the covered parts against the visible parts of the EM spectrum :) Feb 20, 2014 at 15:48
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    You appear to be asking for a rational explanation to justify the behaviour of delusional people. It seems counter-productive to me. Am I missing something?
    – Oddthinking
    Feb 20, 2014 at 21:03
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    @Oddthinking well, there are two claims here, the delusional one (someone is trying to control my brain) and the other, possibly less delusional, one (wearing a tinfoil hat might protect me). It is the latter I'm interested in, I am wondering whether it is conceivably possible that such a hat might help in any way. That seems like a perfectly verifiable claim (the comment about Faraday cages is the kind of thing I was aiming for). I don't hang out here much so if you think it's off topic, fair enough, but it seems answerable to me.
    – terdon
    Feb 20, 2014 at 22:46
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3 Answers 3


Though tin foil hats do protect you from electromagnetic radiation and from some forms of ionizing radiation, they do not protect you from all possible electromagnetic radiation:

In a not-too-serious-studyRead the conclusion first, it was found that tin foil hats actually amplify frequency bands that coincide with those allocated to the US government between 1.2 Ghz and 1.4 Ghz. Link to PDF with FCC band allocations.


For all helmets, we noticed a 30 db amplification at 2.6 Ghz and a 20 db amplification at 1.2 Ghz, regardless of the position of the antenna on the cranium. In addition, all helmets exhibited a marked 20 db attenuation at around 1.5 Ghz, with no significant attenuation beyond 10 db anywhere else.


The helmets amplify frequency bands that coincide with those allocated to the US government between 1.2 Ghz and 1.4 Ghz. According to the FCC, These bands are supposedly reserved for ''radio location'' (ie, GPS), and other communications with satellites [...] The 2.6 Ghz band coincides with mobile phone technology. Though not affiliated by government, these bands are at the hands of multinational corporations.

It requires no stretch of the imagination to conclude that the current helmet craze is likely to have been propagated by the Government, possibly with the involvement of the FCC. We hope this report will encourage the paranoid community to develop improved helmet designs to avoid falling prey to these shortcomings.

As these bands are reserved for radio location some people might interpret that as brain location...


  • 2
    No, I'm not a conspiracy theorist! :-) Read the paper before downvoting... :P
    – Fabby
    Mar 30, 2016 at 14:43
  • Not voting, but the question asks "does any", so saying "not all" is kinda awkward.
    – Weaver
    Mar 30, 2016 at 17:02
  • Well, no vote needed if I put a smile on your face today... (And that was the whole reason to post this lighter-hearted answer) @StarWeaver ;-)
    – Fabby
    Mar 30, 2016 at 17:26
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    @Fabby I'm a conspiracy theorist, I believe Julius Caesar was killed as the result of a conspiracy. I've lost contact with all my friends due to these crazy conspiratorial beliefs such as that one.
    – Fiksdal
    Sep 5, 2016 at 6:54
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    There you have it! Tinfoil hats are a government conspiracy to help them track conspiracy theorists! Jan 31, 2019 at 13:04

Another benefit is that it will block alpha radiation (helium nuclei) and most of beta radiation (electrons).

You can read more here.

Of course, this will have no significative benefit.

  • 2
    Could you expand a little? A reference would be nice for example.
    – terdon
    Feb 21, 2014 at 18:05
  • Alpha particles aren't going to get through the skull. I'm not sure either way about the beta particles though. ("0.5 cm of body tissue" is the figure I found quickly.)
    – Oddthinking
    Feb 22, 2014 at 0:01
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    @Oddthinking A trivial answer is an answer (unless the question asked for health protection).
    – jinawee
    Feb 22, 2014 at 17:07
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    I didn't deny it was an answer. I just suggested it was in some respects a poor answer, in the hope you'd improve it.
    – Oddthinking
    Feb 22, 2014 at 23:27
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    Wrong--there's no such thing as blocking your internal radiation from escaping. It's absorbing it, not acting as a mirror. Jul 16, 2015 at 23:56

To add to the existing answers in the long (signal) electromagnetic and in the visible wavelenghts:

According to this source, Al has a high reflectance in infrared wavelenghts (>90% for near infrared radiation, >95% for far infrared).

According to this paper, human skin has a reflectance around or below 10% in most of the near infrared spectrum and presumably no higher values in the far infrared. Even though I have some difficulties finding a good source, hair doesn't appear to be a perfect reflector either. In any case, the following must apply for hairless heads.

So, in combination with sufficient water comsumption, good protection against a heat stroke should be achievable. The effect is probably much better if some air vents are cut in to get rid of the internal heat.

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