From eye creams to body creams: the role of caffeine in skincare is growing. Dr Haran Sivapalin asks why and does it work? 

Your latte or espresso shot may help you perk up every morning, but can it also perk up your skin and hair? Caffeine is increasingly being used as an ingredient in cosmetic products where it’s purported to do everything from boosting hair growth to reducing cellulite. So, in addition to drinking a cup of Joe, is it time we smother our skin in caffeine too?

Effects of caffeine

Caffeine is found in over 60 different species of plant where it primarily serves as a natural pesticide to repel insects. Due to its stimulant effect on the central nervous system (i.e. the brain and spinal cord), caffeine from coffee, tea and cacao plants has been used since as far back as the Stone Age to boost concentration and combat fatigue. It can have various other effects too, including increasing heart rate, raising blood pressure and stimulating acid production by the stomach. That’s all very well, but what about it’s applied to the skin?

Caffeine and the skin barrier

First things first, for caffeine to have any potential effect on complex skin processes, it needs to be able to penetrate the skin barrier. By using X-rays to track the movement of substances across the skin (a process called “quantitative skin autoradiography”), researchers have indeed shown that caffeine can get into the epidermis and dermis. But, does it do anything when it’s there?

Skin Tightening

Puffy eyes and eyebags are a common problem, so these days many eye creams and gels contain caffeine. The reason behind that is that it gives a temporary tightening effect. As caffeine is a vasoconstrictor it tightens up the blood vessels supplying the area. The result is a reduction in dark circles and puffiness – in effect, it lifts and brightens the eye area. But it wont last long and the product will have to be reapplied.

It’s this tightening effect that’s made it a popular ingredient is body creams to combat cellulite.

Caffeine to combat cellulite

Cellulite, or, to the use the formal term, ‘gynoid lipodystrophy,’ is where there are fat deposits under the skin, usually on the thighs and buttocks giving them a dimpled or lumpy appearance. A some people find this unsightly there are various treatments on offer for cellulite, from liposuction to chemically-treated tights to – yes – body contouring creams containing caffeine.

Caffeine has been shown to activate an enzyme in fat cells (adipocytes) called Hormone-Sensitive-Lipase (HSL). HSL is a key enzyme involved in breaking down stored fat – a process called ‘lipolysis.’ By accentuating this process, caffeine has the potential to help people shed fat. Furthermore, it can also slow down the reverse process, namely the accumulation of fat.

Does caffeine then, applied topically, help melt away cellulite?

A study of pig’s skin found that caffeine combined with ultrasound therapy over 15 days could reduce the thickness of fat deposits under the skin. Notably, however, caffeine alone did not have any fat-reducing effect: hardly a compelling recommendation for caffeine-containing anti-cellulite creams. Another study on mice found that caffeine reduced the diameter of fat cells by 17% compared to controls.

What about humans? One study saw 99 women apply a 7% caffeine solution twice daily to their legs. At the end of the month, the women had their thighs and hips remeasured.  80% of the women experienced a significant reduction in thigh circumference while 68% had significantly thinner hips.  There’s definitely a flicker of potential then, but much more research is needed to establish whether caffeine can get rid of cellulite. Until then, diet and exercise to burn fat and tone the body are probably more effective solutions.

Hair-growth

You may have noticed caffeine as an ingredient in various hair-growth shampoos and formulas. This practice likely stemmed from a research finding in 2007, when a team from Germany found that applying caffeine to samples of hair follicles stimulated them to grow.

Furthermore, when hair follicle growth was inhibited by exposure to testosterone (a process echoing that responsible for male pattern baldness), caffeine was able to counteract this.

As ever, these studies were “in vitro” – they took place in laboratory dishes, not in living humans. Currently there’s not enough evidence from human clinical trials to suggest that caffeine is a good treatment for hair loss.

Sun protection

A barista may ask you whether you want cream in your coffee, but what about adding coffee to your sun cream? Caffeine is a well-known antioxidant molecule, which suggests it might prevent harm from free radicals that are produced when the skin is damaged by UV rays.

Studies on mice do show that caffeine can both reduce damage to the skin from UV radiation and also help the body’s natural defences in getting rid of damaged and mutated skin cells. Alas, there’s a lack of studies with human subjects. Regardless of whether or not a suncream contains caffeine, when it comes to sun protection, it’s best to stick to one with a high sun protection factor (SPF).

Take home message

Caffeine is a wide-acting substance that has the potential to increase the breakdown of fat, improve circulation to the skin and dampen down free-radical damage from UV radiation. As yet, however, there is not enough evidence to suggest that caffeine in creams, lotions and other topically-applied cosmetics readily does any of these things. That said, caffeine applied to the skin is unlikely to cause any harm – so, unlike caffeine in beverages, you ought not to ‘lose any sleep over it.’