Have You Discovered Black Garlic?

If you love garlic but haven’t yet tried the aged, black version, you’re in for a treat. As well as offering health benefits, its lovely, soft, savoury-sweet flavour with undertones of molasses and balsamic are socially acceptable for long-term users. It can be added to any savoury dish in place of raw white garlic, but add it towards the end of cooking for maximum effect. Once any garlic is heated for more than 3 minutes, its medicinal benefits are rapidly reduced and, after 10 minutes of heating, its ability to reduce platelet clotting is completely suppressed.

How Is It Made?

Black garlic is produced by naturally fermenting fresh garlic bulbs under controlled conditions of high temperature and humidity for at least 21 days. This converts unstable, volatile, smelly sulphurous compounds into stable, odourless substances. Five new amino acids are also generated, along with dark pigments (melanoidins) which turn the cloves black.

Aged black garlic has significantly greater antioxidant activity than non-fermented garlic, offering at least four times more antioxidant activity per gram (and the antioxidant capacity of raw garlic is already high). It therefore has the potential to offer greater therapeutic benefits.

Boosting Immunity

Black garlic extracts increase the activity of circulating white blood cells in samples analysed in the laboratory. By increasing the proliferation and activity of these immune cells such as macrophages and natural killer cells, black garlic extracts may improve immune targeting of abnormal body cells. Cell studies also suggest that aged black garlic extracts can inhibit the growth of stomach cancer, colon cancer and leukaemia cells by triggering their natural self-destruct mechanism (apoptosis). These findings must be treated with caution but may suggest a useful preventative role if confirmed in human trials

Improves Cholesterol Balance

Black garlic
Black garlic improves cholesterol balance by increasing liver production of the ‘good’ HDL-cholesterol which protects against hardening and furring up of the arteries. A 12-week study compared the effects of black garlic extracts (6g per day divided into two doses taken before the morning and evening meal) against placebo in 60 volunteers with a mildly raised cholesterol. No significant differences were seen in LDL-cholesterol, total cholesterol or triglycerides but ‘good’ HDL-cholesterol levels increased by an average of 7.45% to significantly lower the projected ten-year risk of heart attack or stroke. There is also increasing evidence that black garlic helps to reduce the accumulation of fat in liver cells, but this has not yet been confirmed in humans.


Black garlic may have additional beneficial biological effects similar to those of raw garlic, but research is in its early days and effects on blood clotting, blood pressure and arterial elasticity have not yet been confirmed. Even so, the growing evidence base may explain why many Eastern cultures revere black garlic as an anti-ageing supplement used, like ginseng and red reishi mushroom, to increase longevity.

A typical dose is 200mg concentrated extract, equivalent to 2g whole garlic. I now take black garlic supplements rather than garlic tablets and have started experimenting with its use in the kitchen. I guess I smell sweeter as a result!

Do you take garlic supplements, or have you already switched to black garlic?

Image credits: Isle of Wight Garlic Farm

About DrSarahBrewer

Dr Sarah Brewer MSc (Nutr Med), MA (Cantab), MB, BChir, RNutr, MBANT qualified from Cambridge University with degrees in Natural Sciences, Medicine and Surgery. After working in general practice, she gained a Master's degree in Nutritional Medicine from the University of Surrey. Sarah is a licensed Medical Doctor, a Registered Nutritionist, a Registered Nutritional Therapist and the award winning author of over 60 popular self-help books. Sarah's other websites are www.MyLowerBloodPressure.com and www.ExpertHealthReviews.com.

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6 thoughts on “Have You Discovered Black Garlic?

  • Lynn

    Hi, if cooking with garlic (at normal cooking temperatures) for more than 3 minutes reduces its benefits, how come fermenting at high temperature and humidity for 21 days doesn’t reduce its benefits? I would be interested to know what is the difference? Many thanks

    • DrSarahBrewer Post author

      Hi Lynn, Excellent question. Once garlic is oven-heated at 200 degrees C, or boiled for more than 3 minutes, its medicinal benefits are reduced. After 10 minutes heating at these temperatures, its ability to reduce platelet clotting is completely suppressed. But when making black garlic, the fermentation occurs under controlled conditions of 70°C and 90% relative humidity. At this temperature chemical reactions can occur that form the black pigments and a new range of antioxidants.

  • Marta

    Hi Sarah,

    every day is a good day to learn something new… It’s the first time I came across black garlic, and had no idea it has so many health benefits. I used to throw it away…. Shame on me.

    Anyway, thanks a lot for this article! It’s an awesome piece of advice.


    • admin

      If garlic in your kitchen turns black then feel free to throw it away as it is contaminated by mould or bacteria. The black garlic with health benefits is produced under strictly controlled conditions of heat and humidity which produces the black melanoidin pigments.

  • KariLee

    I have never even heard of black garlic, but I must say I am thoroughly intrigued!

    I had also not given any thought to the fact that garlic will lose it’s beneficial health properties after heating for more than 10 minutes. That makes sense yet most foods that are cooked with garlic are simmered for a long time, supposedly to blend the flavors.

    I have shared this article with Facebook and Twitter.

    I am sure there are many more like me that have been in the dark about black garlic.

    Thank you for another great article!