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If a razor cuts only the hair, then how does hair thicken and become more rough with a razor shave and not after one using a trimmer? If both are used for hair removal, why is there a difference in hair growth?

I have been using a trimmer for 1 year, but the growth of hair remained unchanged. When I started shaving with a razor, the hair growth thickened.

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closed as off-topic by rg255, WYSIWYG, AliceD, ddiez, Cornelius Nov 30 '14 at 18:12

  • This question does not appear to be about biology within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ lifehacker.com/5873922/…, and under skin and hair in this page en.wikipedia.org/wiki/List_of_common_misconceptions $\endgroup$ – Satwik Pasani Nov 29 '14 at 13:26
  • $\begingroup$ This is a myth and your evidence is purely anecdotal - voting to close as not on topic. Might suit skeptics.se $\endgroup$ – rg255 Nov 29 '14 at 20:22
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    $\begingroup$ This question appears to be off-topic because it belongs on skeptics $\endgroup$ – rg255 Nov 29 '14 at 20:23
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    $\begingroup$ May I ask how this belongs in Skeptics? It is a question seemingly based in biology that has a biological answer... $\endgroup$ – Samuel Barnett Nov 30 '14 at 20:06
  • $\begingroup$ @SamuelBarnett Because the question is based on a flawed premise. It's a myth, a wives tale, that hair does this. Before it is possible to answer a question of why something happens we should first have reason to believe it happens. We know that it doesn't so there is no question of why it does happen. $\endgroup$ – rg255 Nov 30 '14 at 20:28
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Hair does not grow back thicker when it is cut. This is somewhat of an optical illusion because when you shave with a razor it leaves the top of the hair flat rather than pointed so it appears thicker. For instance see this picture:

Hair being cut

As you can see the hair is tapered at the top and when cut loses this taper to leave a large cross-sectional area. I would say that for your question with with the trimmer that it is probably cutting the hair further up the taper where the hair is 'thinner' to begin with. A razor cuts closer to the base and thus gives a thicker appearance.

Evidence: http://www.scientificamerican.com/article/fact-or-fiction-if-you-shave-or-wax-your-hair-will-come-back-thicker/

http://www.sciencedirect.com/science/article/pii/S0190962299701817

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    $\begingroup$ could you provide a source for A) a hair being tapered as in the diagram, and B) cutting it flat makes it appear thicker then when tapered. $\endgroup$ – rg255 Nov 30 '14 at 16:43
  • $\begingroup$ could you summarise the important findings of the paper - its behind a paywall $\endgroup$ – rg255 Nov 30 '14 at 20:33
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    $\begingroup$ @GriffinEvo I am sorry my institution automatically passes me through paywalls so I didn't realise. I will sum it up in the morning as it is getting quite late here. $\endgroup$ – Samuel Barnett Dec 1 '14 at 0:15