Caffeine has been a cosmetic ingredient for a long time, and you’ll find a jar of it on the shelves of most cosmetic development laboratories. There are three things it gets used for. There are the so called body sculpting products. The idea behind these is that you apply them to parts of your body that have more fat than you’d like. The caffeine stimulates fat burning, so you can get rid of the fat in the areas you don’t like it. Keep it up and you can change the shape of your body to something you like the look of. It is also used to improve the tone of the skin. It is supposed to stimulate energy production in the upper layers of the skin. This again uses the breakdown of fat, but in this case to release energy to improve the look of the skin. And finally it is used in shampoos to stimulate hair growth.
Of the three the body sculpting is the one that at first sight seems the most plausible. Breaking down fat selectively would certainly be an appealing thing to do. We all know that caffeine has effects on the body. Speaking personally, if I drink caffeine in the evening I have difficulty getting off to sleep later. I have avoided caffeine in the evening ever since I noticed this. I start the day with a caffeine rich drink. Because, well I do. I have to have it, right? Glad we got that cleared up.
So if it can keep you awake why shouldn’t it stimulate fat burning?
But another property of caffeine makes me dubious. It is a very small, water soluble molecule that spreads around the body very quickly. It is hard to imagine that it hangs around in one place long enough to have the effect claimed for it. Add to that the fact that I have never seen a published paper that demonstrates any cases where body sculpting has actually worked. I have kept an open mind for quite a few years now, but surely if it actually works somebody somewhere would have reported it.
The idea of energising the skin has the same objections, with the added one that it isn’t at all obvious that even if you could energise the skin that would actually have any noticeable beneficial effect. Your skin is a very complicated bit of biology, but nothing I have learnt about suggests that the rate at which burns energy makes any difference to how it looks.
The suggestion that caffeine can stimulate hair growth seems to be based on nothing more than wishful thinking. Again, the fact that caffeine has biological effects is a good start. As is the fact that it can penetrate the skin. There is also evidence that it might have some kind of effect on hormone expression – which opens up the possibility that it might have some kind of effect on hair growth, which is controlled by hormones. But against that there is the same objection as to the others above – that it spreads itself quickly through the body. And there is also no evidence that people with a high level of exposure to caffeine have more hair. If this were the case anyone who doesn’t drink caffeine but is losing their hair could demonstrate improved hair growth just by buying a jar of coffee. I am pretty sure that this would have been noticed by now if there were such an effect. On top of that nobody has published a clinical trial showing that using a caffeine shampoo has any beneficial effect at all.
The only slight sliver of evidence is that there are testimonials to particular products online where consumers report beneficial effects from their use. I don’t regard this as strong evidence at all. Even if they aren’t planted there by the sellers – which must happen – it is easy to convince yourself that something is working if you really want it to and if you have just paid for it.
So all in all, the case for using caffeine in cosmetics at all isn’t a great one. On top of that, I happened to get talking to a sports scientist recently. Caffeine does have effects on sporting performance. You can run further and faster if you have taken some caffeine. The effect is not huge, but it is big enough to be measured. It had always been thought that this was due to the way caffeine stimulates fat burning and so makes more energy available for activity. I am not a sportsman, but I have always found that the energy boost from caffeine enables me to carry out the onerous task of getting dressed in the morning more easily. But it turns out that the latest research has indicated that in fact it works by making the brain more active and less likely to give up working sooner. The extra energy is not stimulated directly by the caffeine but is the result of the psychological effect.
This is quite an interesting turn – I usually give references when I make these kinds of statements but I am afraid I don’t know the literature in this area. But if this becomes accepted as the general mechanism by which caffeine acts as a pick me up then that undermines the already weak case for using the stuff in cosmetic products. Directly affecting fat cells and hair follicles is already fairly far fetched. If caffeine turns out to work by altering your mood rather than your metabolism, then its chances of doing anything across the skin become even lower.
I think it might be time to just admit we got it wrong with caffeine and move on.
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