Green Coffee Bean Extract and Chlorogenic Acid (CGA)

As I was perusing my girlfriend's gloriously well stocked vitamin supplement drawer for something good, I came across a bottle of Green Coffee Bean Extract (Life Extension brand).

"What does this do?" I asked her.

"It's supposed to boost your metabolism," she replied. "I haven't used it in a while."

"Does it have caffeine?" I asked, thinking perhaps that was the energy boosting constituent.

"No, I don't think so," she replied. That was enough compulsion for me to begin researching green coffee bean extract (GCBE) for this blog.

I am always on the lookout for non-stimulant based energy boosting supplements, since my life demands a lot of energy for writing and music, as well as surviving the day job that underwrites my writing and music. My supplement of choice for unlimited energy supply with no side effects is the herbal supplement Rhodiola rosea, a non-stimulant adaptogen, but I'm open minded.

Here's what I uncovered...

Green coffee beans are a rich source of chlorogenic acid (CGA), an antioxidant believed to have beneficial metabolic effects in humans, particularly with regard to improving sugar handling and lowering blood pressure (SOURCE). CGA appears to be readily bioavailable in humans (SOURCE) and it is most popularly used as a weight loss supplement (SOURCE). CGA may slow absorption of sugar from the digestive tract into the blood, lowering blood sugar and subsequent insulin spikes (SOURCE). If you are a proponent of the Paleo Diet, this might correlate with weight loss. However, the evidence is not super strong for a weight loss effect from GCBE. Nor is it likely an energy booster.

In a small but well controlled study of 30 overweight people, CGA fortified instant coffee incorporated into the diet over 12 weeks caused significant weight loss in CGA consuming individuals, as compared with subjects consuming un-enriched instant coffee (SOURCE). In another arm of the same study, CGA slightly reduced glucose absorption in 12 healthy volunteers (SOURCE).

Green coffee bean extract might be a valuable addition to a low carbohydrate diet. In rodent (but not human) studies, CGA was shown to lower body weight (SOURCE) and reduce fat absorbed from the diet and stored in the liver (SOURCE).

A 2011 review of clinical trials on GCBE reported that their may be a small weight loss effect, but that the studies were often flawed (SOURCE).

When coffee beans are roasted, chlorogenic acid in the beans is decreased, which is why green coffee beans are used to make CGA rich supplements, rather than roasted coffee beans. I suppose if roasted coffee beans were a good source, coffee drinkers would go insane with glee.

Green coffee beans do contain caffeine, but some commercially available green coffee bean extracts advertise as being derived from decaffeinated green coffee beans, which contain far less caffeine than regular coffee beans (but still some). A popular internationally recognized brand of GCBE is called Svetol, originally from France, and it comes from decaffeinated green coffee beans (SOURCE).

As I often tell my readers, the supplement industry is poorly regulated, so it is impossible to know how much caffeine a GCBE product has, regardless of labeling. But assuming a quality manufacturer like Life Extension has compliant labeling, whatever energy boosting effects this supplement has (probably none) are probably not derived from caffeine, although related alkaloids cannot be ruled out.

Green coffee bean extract appears to be safe (SOURCE). Conversely, direct CGA consumption by humans appears to increase homocysteine levels, a marker of cardiovascular disease, in the blood. However, there is no strong evidence that the elevated homocysteine levels due to CGA increase cardiovascular risk (SOURCE). Obviously, if you are sensitive or allergic to coffee, use your head and avoid taking a GCBE supplement.

With those caveats, I will once again quote my mom on her view of generally recognized as safe nutritional supplements: "Can't hurt, might help."

A good green coffee bean extract should list either green coffee extract or Svetol® on the label and contain at least 45% chlorogenic acid (SOURCE).

Lastly, don't believe anything about GCBE's weight loss effects that come from Dr. Oz. His study has been debunked. It was flawed and the evidence was super weak (SOURCE).


1. What’s the Deal with Green Coffee Bean Extract?
2. Dr. Oz Tries To Do Science: The Green Coffee Bean Experiment
3. Does Green Coffee Bean Extract Work? A Detailed Review

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