Monk fruit extract is a natural sweetener that may help with calorie control, diabetes, immunity, and more. Still, the science behind it is young and warrants further investigation. Read on to learn about the benefits and side effects of this peculiar Asian fruit.
What is Monk Fruit?
Monk fruit (Siraitia grosvenori) or Luo han guo is a fruit native to south-east Asia and a member of the gourd (Cucurbitaceae) family. It is named after the Buddhist monks who first cultivated the fruit nearly 800 years ago.
It contains powerful antioxidants called mogrosides that are 250 times sweeter than table sugar (sucrose) .
For this reason, monk fruit extract has been traditionally used as a natural, non-caloric sweetener to replace sugar .
- May help with obesity and diabetes by replacing sugar
- Zero calories and rich in nutrients
- May have anticancer effects
- May protect the liver
- May combat infections and fatigue
- Can be costly
- Potential benefits lack clinical evidence
- Long-term safety is unknown
Monk fruit has:
- Zero calories [2, 3]
- Vitamin C, which decreases blood histamine levels and maintains collagen [4, 5]
- Kaempferol, a flavonoid with potent antimicrobial and antioxidant effects [6, 7]
- Triterpene glycosides, compounds that suppress reduce the growth of tumor cells [8, 9]
- Mogrosides I-V :
- Cucurbitacins, compounds that have anti-inflammatory effects by inhibiting TNF-alpha and COX-2 [13, 14]
- Polysaccharide fibers, which lower cholesterol levels [15, 16]
Mechanism of Action
Monk fruit extract contains mogrosides, antioxidants that decrease blood vessel leakiness (permeability), inhibit histamine release from mast cells, and prevent inflammatory damage.
Mogrosides are saponins, chemicals that prevent the excess leakiness of cell membranes (membrane hyperpermeability), which protects mitochondria and DNA from oxidative damage [17, 18, 19, 20, 2, 21].
Mogrosides also protect DNA by increasing the production of PARP1, p53, and MAPK9 .
They decrease inflammation by:
- Reducing NF-kB and suppressing the PI3K/Akt pathway 
- Decreasing the production of inflammatory molecules such as iNOS, COX-2, and IL-6 
Monk fruit extract may improve glucose and fat metabolism by reducing CREB and activating AMPK [23, 24].
Monk Fruit Extract Health Benefits
Animal and Cellular Research (Lacking Evidence)
No clinical evidence supports the use of monk fruit extract for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based studies; they should guide further investigational efforts but should not be interpreted as supportive of any health benefit.
1) Anticancer Effects
Different compounds from monk fruit extract showed anti-cancer effects in preclinical research:
- Mogroside IV suppressed throat and colorectal cancers in mice (dose-dependent) .
- Mogroside V inhibited tumor growth in mice with pancreatic cancer. It also inhibited the growth of new blood vessels (angiogenesis) in mice with cancer, which helps reduce tumor growth .
- Mogrosides inhibited the proliferation of cancer cells in mice .
- Cucurbitacin E inhibited the growth of human breast cancer cells in the lab .
- Triterpene glycosides significantly inhibited the effects of carcinogens (cancer-causing substances) on mouse skin tumors .
If used as a replacement for sugar, monk fruit extract may help limit the fuel (glucose) cancer needs to thrive and protect the genes that initiate cancer cell death (p53) [27, 28, 29].
Clinical trials are needed to investigate the anticancer effects of monk fruit extract. At this point, we can’t tell what role, if any, it may have in cancer prevention or treatment.
4) Obesity and Diabetes
The therapeutic effects of monk fruit on diabetic rabbits was studied by administering an extract for 4 weeks. It significantly decreased sugar, total cholesterol, and triglyceride levels in the blood, while increasing HDL cholesterol (“good” cholesterol) .
Monk fruit extract prevented the rise of blood sugar in mice when given 3 minutes before a high-sugar meal .
It also reduced blood sugar and urinary albumin levels in diabetic rats, indicating that it may improve kidney damage caused by diabetes .
Monk fruit extract decreased physical fatigue in mice in a dose-dependent manner. The treated mice had extended swimming times compared to the control group .
The extract also enhanced endurance by increasing liver and muscle glycogen, while decreasing blood lactic acid and serum urea nitrogen (SUN).
According to cellular research, monk fruit extract may stimulate mitochondrial function (by increasing PGC-1ɑ activity) .
9) Liver Protection
Mogroside helps break down cholesterol and protect the liver from oxidative damage. In diabetic mice, mogroside treatment reactivated liver antioxidant enzymes (superoxide dismutase, and glutathione peroxidase), which play a critical role in detoxification [15, 33, 34].
The fruit has been used for centuries in traditional Chinese medicine to treat a sore throat and cough.
A compound of monk fruit extract called siraitiflavandiol is antimicrobial against the growth of Streptococcus mutans, Porphyromonas gingivalis, and Candida albicans in cell culture .
In the lab, components of monk fruit prevented the growth of oral bacteria and fungal species .
11) Allergies and Histamine Release
After repeated administration, monk fruit extract prevented allergic symptoms (nasal rubbing or scratching) in mice. The mogrosides and extract inhibited the release of histamine from mast cells .
Mogrosides significantly enhanced cellular immunity in immunosuppressed mice (by promoting phagocytosis and T lymphocyte proliferation) .
Monk Fruit Side Effects and Precautions
Keep in mind that the safety profile of monk fruit extract is relatively unknown, given the lack of well-designed clinical studies. The list of side effects below is not a definite one, and you should consult your doctor about other potential side effects, based on your health condition and possible drug or supplement interactions.
A review found that extracts and individual compounds in monk fruit are non-toxic according to existing research .
Monk fruit juice concentrate is generally recognized as safe (GRAS) by the FDA as an ingredient in conventional food and infant and toddler foods .
Just like with any other food, there’s a possibility of monk fruit allergy. Monk fruit belongs to the Curcurbitaceae (gourd) family, along with pumpkin, squash, melons, and cucumbers. People allergic to gourds should pay special attention.
Monk Fruit Available Forms and Dosage
The available forms include:
- Whole fruit extract
- Mogroside extract
- Pure Monk
- Lakanto (powder and liquid)
- Monk Fruit in the Raw
- Health Garden
- Smart 138
- Dried fruit (tea)
Monk Fruit Extract vs. Stevia
Both are zero-calorie, high-intensity sweeteners .
Although monk fruit and stevia are increasingly used as sweeteners, the number of studies on their health effects is limited .
Monk Fruit Pros:
- The carbon and water footprint of cultivating stevia is significantly lower than beet or cane sugar 
- Stevia is proven safe in more than 200 studies 
The serving size of commercial monk fruit extracts ranges from 0.8-4 grams.
The opinions expressed in this section are solely from the users who may or may not have a medical background. SelfDecode does not endorse any specific product, service, or treatment. Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice because of something you have read on SelfDecode.
One user reports that the whole fruit concentrate tastes like molasses and goes very well with coffee and chocolate.
An experienced non-nutritive sweetener user reports that the whole fruit concentrate does not sweeten coffee and has a bitter aftertaste.
Another user reports a maple syrup smell and flavor, with no aftertaste.
A review on Luo Han Guo whole fruit concentrate prefers the taste compared to Stevia but also reports a faint alcohol aftertaste when used in drinks.
Overall, it comes down to preference with taste. Some users are disappointed with the flavor/aftertaste, while others report no aftertaste and prefer the flavor.