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I'm on vacation and got sunburnt, so someone said I should go get Aloa Vera since that apparently helps. There seems to be a plethora of made-for-adsense-sites that claim the same.

Is there solid ground for that belief?
Sklivvz
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Kit Sunde
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    Many things "stimulate the immune system." Pin pricks, knife cuts, chain saws, animal attacks, gunshot wounds... I've never heard of those curing sunburns, though. But maybe it's worth some experimentation. – Flimzy Jul 01 '12 at 14:41

1 Answers1

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No, Aloe Vera doesn't help prevent or heal sunburn.

I have to admit to being surprised by this. I was expecting to see a (small) effect.

This experiment involved 20 volunteers in a randomized double-blind trial, where they applied aloe vera cream (or placebo) either before, after or before and after exposure (twice daily for 3 weeks).

The results showed that the aloe vera cream has no sunburn or suntan protection and no efficacy in sunburn treatment when compared to placebo. The aloe vera cream has no bleaching effect too.

This was a review of the scientific literature that came to the same conclusion:

Topical application of A. vera is not an effective prevention for radiation-induced injuries and has no sunburn or suntan protection.

General Burns

However, there is evidence that general (e.g heat-based) burns and wounds can be helped by aloe vera.

The same paper, Feily and Namazi, also states:

It can be effective for genital herpes, psoriasis, human papiloma virus, seborrhoeic dermatitis, aphthous stomatitis, xerosis, lichen planus, frostbite, burn, wound healing and inflammation.

This also concluded that aloe vera helped with burns:

the summary weighted mean difference in healing time of the aloe vera group was 8.79 days shorter than those in the control group

The idea that aloe vera helps with regular burns but not sunburn still surprises me.

Bonus:

This essay, sometimes straying into superlatives and past what the scientific evidence supports, discusses some of the history of the research, and makes an interesting distinction between fresh aloe vera and the gels found in cosmetics.

Oddthinking
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    I don't think that the claim is that it provides protection, but that it helps to *heal* it after it happens, so I'm not sure that the second reference is any help. In any case, I have never used it because it was making it better but because it made it *feel* better in the immediate term. – dmckee --- ex-moderator kitten Jul 01 '12 at 13:04
  • You may, however, want to include something on the effects of *A. vera* on burn wound or inflammation, such as [this](http://www.ncbi.nlm.nih.gov/pubmed/17499928). Even in your second reference the authors speak about efficacy for *burn, wound healing and inflammation*. I agree with @dmckee on the fact that these products are not generally sold as protective, but rather *after-the-fact* remedies. – nico Jul 01 '12 at 13:05
  • @dmckee: Feeling better in the immediate term might just be the emollient - that was included in the placebo in the first reference above. – Oddthinking Jul 01 '12 at 14:40
  • @nico/dmckee: You are both right; I didn't read the words carefully enough. I have expanded the text, but it leads to this odd conclusion that aloe vera is more successful on first degree burns than sunburn which surprises me. I'd like more evidence here to make this definitive. – Oddthinking Jul 01 '12 at 14:43
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    So, is a UV-burn different from a heat-burn? If so, how (aside from the cause, of course)? – nico Jul 01 '12 at 14:50
  • @nico: That's the bit I am confused by. The different experiments get different results, so it appears they are qualitatively different. That surprises me. But they are different experiments, so that's not good evidence - they haven't controlled for confounding variables. – Oddthinking Jul 01 '12 at 14:58
  • The first reference speaks of a placebo creme, so *something* is being rubbed onto the skin, and it presumably has similar physical characteristics. Perhaps it is those physical (i.e. not chemical or biological) characteristics that are responsible for the perceived benefit. – dmckee --- ex-moderator kitten Jul 01 '12 at 17:29
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    @dmckee perhaps it is keeping your sunburned **moisturized** (with aloe or non aloe lotion) is what makes it feel better. – Sam I Am Jul 02 '12 at 02:27
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    @nico: Yes! They are totally different physiologically, despite the name! A heat-burn is basically the same thing you do to meat when you cook it, except its happening to your flesh instead. A sunburn is radiation poisoning from exposure to UV radiation. The chemical changes in your skin from a heat-burn are not the same as the changes that occur from a radiation burn. Though I should point out that microwave radiation can induce thermal oscillations in water (which is how a microwave oven works), which then can cause heat-burns. The sun is a negligible source of microwave radiation, though (a –  Jul 08 '12 at 03:27
  • @Farrok: can you please expand? At the cellular level UV and heat will surely denature proteins. The former will also produce cross-links, damage DNA, produce radical damage to surface proteins and so on. However, the point at hand is that aloe may have an antiinflammatory effect. So, if both agents produce an inflammation, albeit differently, an UV-burn may not be that different from a heat-burn **in terms of the actions of aloe vera**. – nico Jul 09 '12 at 06:33
  • @nico As far as I know, the primary, non-repairable damage (i.e. that causes skin cells to die) from sunburn is indeed UV damage to the DNA. – Konrad Rudolph Jul 25 '12 at 09:59