Green coffee beans extract is made from unroasted, green, raw coffee beans.
It contains chlorogenic acids that are responsible for the pharmacological properties.
It is gaining popularity in recent years as a weight-loss supplement. 
Health Benefits of Green Coffee Bean Extract
The key benefits of green coffee bean extract include reducing body weight by decreasing body fat accumulation. It may lower blood sugar levels, decrease blood pressure, and modulate serum lipid markers. There is little evidence about its possible role in improving cognitive functions and reducing periodontal pathogens.
Green coffee bean extract decreased body fat accumulation
Studies reported that green coffee bean extract decreased the accumulation of body fat.
Coffee contains caffeine, chlorogenic acids and other bioactive compounds that regulate lipogenesis and lipid uptake.
A systematic review of randomized controlled studies showed that coffee bean extracts moderately reduced body weight.
In patients with metabolic syndrome, 400 mg of green coffee (twice a day) bean extract showed BMI reduction following eight weeks.
Mouse fed with a high-fat diet and green coffee bean extract showed decreased adipocyte metabolism and lower fat mass.
0.5% and 1% coffee bean extract reduced visceral fat content and hepatic triglyceride levels.
What it means: Green coffee bean extract reduced body fat accumulation by activating fat metabolism and inhibiting fat absorption. More randomized controlled trials are required to evaluate the effectiveness of green coffee bean extract as a weight-loss supplement.
1. Green coffee bean extract may modulate the lipid markers
Green coffee bean extract may modulate serum lipid markers, including total cholesterol and LDL cholesterol levels.
A systematic review showed that green coffee extract reduced serum LDL cholesterol and total cholesterol levels.
It also produced a non-significant decrease in triglyceride levels.
Consumption of green and roasted coffee (35:65) blend also modulated serum lipid markers.
Green coffee bean extract reduced total serum cholesterol, LDL cholesterol, and triglyceride levels in high fat diet-induced obese rats.
Chlorogenic acid consumption altered plasma lipid profile in high cholesterol-fed rats.
What it means: Green coffee extract may modulate serum lipid markers. It may modestly reduce triglyceride levels and LDL cholesterol levels. Additional research studies are required to assess the hypolipemic effects of green coffee bean extract.
2. Green coffee bean extract may reduce blood pressure
Studies reported that the ingestion of green coffee bean extract might lower blood pressure in mild hypertensive patients. 
In a randomized controlled study involving mild hypertension patients, supplementation of green coffee bean extract (46mg, 93 mg, or 185 mg) decreased systolic and diastolic blood pressure significantly.
It did not report any adverse effects. 
In a pilot study, green coffee consumption reduced systolic blood pressure and arterial elasticity in healthy subjects.
A mouse study showed that ingestion of green coffee bean extract reduced blood pressure in spontaneously hypertensive rats.
What it means: Green coffee extract consumption may reduce both diastolic and systolic blood pressure in patients with mild hypertension. Further research will clarify the role of green coffee bean extract on reducing cardiovascular risk factors.
3. Green coffee bean extract may modulate blood glucose levels
Few studies showed that green coffee bean extract might reduce fasting blood glucose levels and insulin resistance.
A systematic review of randomized controlled studies showed that green coffee bean extract reduced fasting blood glucose levels.
It did not alter insulin levels.
In patients with metabolic syndrome, 400 mg of green coffee bean extract consumption reduced fasting blood glucose, and improved insulin resistance. 
What it means: Research studies showed that green coffee bean extract might modulate blood glucose parameters. It may reduce fasting blood glucose levels and insulin resistance. More extensive studies with longer follow up duration are needed to confirm the blood sugar level modulating properties of green coffee bean extract.
4. Green coffee bean extract may improve cognitive function
Preliminary research showed that chlorogenic acid from green coffee bean extract might improve cognitive function.
A randomized controlled trial with mild cognitive impairment individuals showed that the ingestion of chlorogenic acid improved attention and executive function.
In a study, participants who consumed chlorogenic acid extracted from the green coffee bean for 16 weeks improved motor speed, psychomotor speed, and executive functions compared to placebo.
What it means: Green coffee bean extract may improve cognitive functions, including executive function, attention, motor speed, and psychomotor speed. These preliminary studies are needed to be confirmed with extensive, randomized studies.
5. Green coffee bean extract may show antibacterial properties
Green coffee bean extract may show antibacterial properties against periodontal pathogens.
In a randomized controlled clinical trial, 45 subjects who rinsed the mouth with mouth wash containing 2% green coffee bean extract showed a reduced count of Streptococcus mutans colonies after 14 days.
What it means: Preliminary studies suggested that mouth wash containing green coffee bean extract may reduce periodontal bacteria. Further research studies will evaluate if green coffee bean extract can be used in mouthwash to kill periodontal pathogens.
Possible Side effects of Green Coffee Bean Extract
Green coffee bean extract is possibly safe when taken orally in recommended amounts.
Large amounts of green coffee bean extract can cause insomnia, restlessness, anxiety, headache, agitation, and irregular heartbeats.
Avoid taking green coffee bean extract if pregnant and breastfeeding as there is no reliable information about its safety during these times.
Individuals with high levels of homocysteine, anxiety disorders, bleeding conditions, diabetes, diarrhea, glaucoma, high blood pressure, IBS, and thinning bones should avoid taking green coffee bean extract.
Possible Drug Interactions of green coffee bean extract
Green coffee bean might interact with stimulants, and blood thinners Consult a healthcare professional before taking green coffee bean extract if taking other medications. 
Dosage of Green Coffee Bean Extract
The optimal recommended dose of green coffee bean extract is not known. Clinical studies used chlorogenic acid in the range of 120-300 mg.
According to examine.com, the recommended intake of the green coffee extract containing 
- 10% of chlorogenic acid is 1200-3000mg
- 20% of chlorogenic acid is 600-1500mg
- 50% of chlorogenic acid is 240-600mg
Both green coffee bean extract and roasted regular coffee have potent bioactive compounds.
Green coffee beans are raw, unroasted coffee beans. It is rich in chlorogenic acid that has anti-inflammatory, antioxidant, and hypolipidemic properties. Regular coffee contains little amount of chlorogenic acids as it gets lost during the roasting process. Roasting also alters antioxidant properties.  
Yes, Green coffee beans contain caffeine, a stimulant apart from chlorogenic acid. It has 5-o-caffeoylquinic acid twice higher than roasted coffee. Caffeine reduces oxidative stress by inhibiting lipid peroxidation and reactive oxygen species.  Future studies will determine the antioxidant properties of green coffee bean extract and its application in managing pathological diseases.
A research study showed that 25.8 % of workers in modern coffee manufacturing plant showed sensitization to green coffee beans. They complained of work-related respiratory problems including, allergies of the nose, eye, and bronchial system.   Future research studies will determine if green coffee bean extracts cause allergies.
Green coffee bean extract is popularized in recent years as a weight-loss supplement. But, as of now, limited research studies are supporting the benefits of green coffee bean extract. It may have a modest role in modulating blood pressure, lowering blood sugar levels, and reducing fat accumulation.
Future studies will determine the therapeutic benefits of green coffee bean extract.