The vibrant green in chlorophyll juice and chlorophyll liquids sure looks healthy. Fans of the stuff say it can detoxify you – oxygenating your blood, replenishing blood cells –and contains anti-cancer and antibacterial properties.

Chlorophyll (as you probably remember from high-school science class) is a family of green pigments in plants. It’s part of the system that allows plants to photosynthesise, or use energy from the sun. Because green leafy vegetables are healthy and contain chlorophyll, it stands to reason that chlorophyll on its own will be healthy, too.

Right? Let’s take a look.

Firstly, it’s important to note that there is no food or supplement that “detoxifies”. That’s what your kidneys and liver do. The rumours about oxygenating blood and replenishing red blood cells appears to have started because chlorophyll has a similar chemical structure to haemoglobin, the molecule that carries oxygen in our blood. But in chemistry and biology, near enough is not good enough.

When you put it straight on cancer cells or bacteria, chlorophyll might have an effect, possibly due to its antioxidant activity. But there is no evidence that chlorophyll survives the stomach acid or is absorbed. Experiments in the lab that have these results also often use chlorophyllin, a semi-synthetic chlorophyll that also contains copper to keep it stable, so it’s thought these effects are actually down to the copper. The chlorophyll in juices or supplements might also be chlorophyllin, so if you think chlorophyll is healthy because it's natural, it's probably not even that. Without the modifications, it wouldn’t be water soluble or last long in the bottle.

There is some evidence that chlorophyll can bind to some carcinogens found in cooked meats or tobacco smoke, so it might prevent them from being absorbed in the gastrointestinal tract. But more research is needed to show this actually works in the body, as opposed to in lab conditions. There is currently no evidence that the health benefits of green vegetables can be put down to chlorophyll. What there is, though, is lots of evidence pointing to other things in veggies such as fibre and micronutrients.

Chlorophyll juice and supplements are expensive. Nutritionally you are probably better off spending your money on actual fruit and veggies, or even green smoothies, which have many more benefits and taste better.

The good news is, if you love your chlorophyll juice and have the cash, it’s pretty safe (though it’s safety hasn’t been tested in pregnant and breastfeeding women). Worth bearing in mind, however, is that beyond lightening your wallet, another potential side-effect may include sun sensitivity, which is worth considering if you are taking medications that have the same side effect (such as some anti-acne meds).

Dr Emma Beckett is Broadsheet’s nutrition columnist. A molecular nutritionist with a PhD in Food Science, she is a post-doctoral fellow in the School of Medicine and Public Health and the University of Newcastle. In a world of mixed messages she can be found busting nutrition myths and empowering people to critically assess nutrition information. She tweets at @synapse101.