Nutrition Myths


  • There is lack of sufficient evidence showing that green coffee extract (or chlorogenic acid) is unsafe, toxic or unhealthy, even after long term intake or if taken in high dosages.
  • Although there is no official upper limit, 200mg per day seems to be the amount used in the studies that haven’t recorded serious side effects.
  • Pregnant women, children or people on medication should avoid it, due to possible untested side effects or contraindications.

Is taking green coffee bean extract safe?

Green coffee bean extract is a popular weight loss and blood pressure lowering supplement.

Please note that while it has been shown to be effective in reducing blood pressure, there is no sufficient evidence on its effects on weight loss.

Green coffee bean extract side effects and safety

The following explanation is based on studies on the green coffee extract effects sponsored by the supplement companies. Please bear in mind that the results presented may be biased.

There are no specific studies focusing on the daily dosages or safety levels of this product or chlorogenic acid itself. For this reason and the lack of sufficient reports on negative effects, the maximum dosage or recommended daily dosage has not yet been established.

It seems that the supplement companies set the available recommendations based on the chlorogenic acid amounts derived from the usual daily coffee intake.

Some studies conducted so far have identified cases of allergic reaction in green coffee factory workers due to the dust of the processed green coffee beans or contaminants from other products rather than the green coffee extract itself.

Other studies using the actual extract have recorded a small percentage of participants experiencing green coffee bean extract side effects from the commonly suggested (on the product labels) dosages.

Overall, there are very few reports on the negative side effects of the chlorogenic acid or green coffee extract and it is not entirely clear if these ill effects are due to other factors, chlorogenic acid or combinations.

It is important to note that green coffee extract is a reasonably new product, which in a short time became a new craze on the market and, as in most similar cases, its benefits may be way above the realm.

Yes, it may have a good set of benefits but we need to consider that it can cause some unwanted side effects in some people. The bottom line is that there is not enough evidence to support either conclusion.

Studies on green coffee extract and chlorogenic acid (main active ingredient of the supplement):

  1. Studies showing allergic reactions in workers in coffee factory (not directly linked to the supplement itself, but worth investigating further):

    Some studies showed that allergens associated with green bean coffee are mainly found in the dust generated from processing coffee and primarily affects coffee factory workers.

    These allergens are destroyed, nevertheless, by roasting the coffee beans. The other allergen found in green coffee beans comes from castor beans, through castor bean contaminated sacks which may be shared between the two products.

    It was also found that green coffee extract inhalation may cause an allergic reaction (bronchoconstriction) in some people. (1)

    A recent study from June 2012 discovered a new coffee allergen called (Cof a 1) that affected 3 out of 17 people working in the coffee processing factory. This allergen has not been linked to chlorogenic acid. However, it was extracted from green coffee extract. (2)

    These studies found some evidence of the potential side effects from green coffee beans. However, it is unlikely that it is related to the supplement itself.

  2. Study on chlorogenic acid safety shows that it is safe in its purer form:

    This study looked at the chlorogenic acid itself and discovered that high purity (92%) chlorogenic acid has not shown allergenic properties. (3)

  3. Study showing some side effects:

    One small study (using 200mg of chlorogenic acid per day derived from 400mg of green coffee extract) (4) found some side effects such as headache and urinary tract infections in 2 out of 17 participants, placing some doubt on the safety of the extract. (5)

  4. Study showing no side effects (please note the smaller dose):

    140 mg of chlorogenic acid from green coffee extract per day didn’t show side effects in participants with mild hypertension. (6)

NOTE: Absorption of minerals iron and zinc is reduced considerably when chlorogenic acid is taken within about an hour of the meal. It is best to take the supplement over one hour before or two hours after the meal for the maximum absorption of the minerals. (read more..)

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