Camellia sinensis Leaf Extract: Benefits, Uses, and Side Effects

Camellia sinensis leaf extract is rich in the same bioactive compounds that are responsible for tea’s aroma, flavor, astringency, taste, and medicinal value (2).

Here are some of the extract’s main compounds.

Catechins

Catechins are one of the primary active compounds found in the Camellia sinensis plant. Studies have credited them with cancer-fighting properties (1).

They’re classified as flavonoids, which are one of the most common types of polyphenols — a large family of compounds with potent antioxidant properties (3).

Antioxidant compounds neutralize harmful molecules called free radicals. They help prevent and fight diseases that can occur when free radicals build up in your body, causing a state called oxidative stress (4).

The extract contains four different types of catechins: epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC). EGCG is the most potent and predominant of these (1, 5, 6, 7).

Caffeine

Caffeine is the most studied stimulant compound in coffee and tea. A typical cup of green tea generally contains about 6% caffeine (1, 8).

It’s widely known for exerting both positive and negative health effects.

For instance, studies have shown regular caffeine intake may help prevent people from developing type 2 diabetes, metabolic syndrome, heart disease, dementia, and Alzheimer’s disease (8, 9, 10, 11).

As a stimulant, caffeine may also increase alertness, reduce fatigue, and improve exercise performance and mental functioning (12, 13).

That said, consuming too much caffeine can cause potentially dangerous health effects, such as an irregular heart rate (14).

L-theanine

L-theanine is a non-protein amino acid derived from the tea plant. It’s the most abundant amino acid in green tea, comprising about half of its amino acid content (15).

L-theanine contributes to the characteristic flavor and aroma of tea.

It’s also the compound behind tea’s relaxing effect, which may help improve concentration and learning (16, 17).

Furthermore, L-theanine has anti-inflammatory and antioxidant effects and is associated with improved immune function (15, 16, 17).

Other compounds

In addition to the three main compounds above, tea leaf extract contains B vitamins, lipids such as linoleic and alpha-linolenic acids, and trace minerals, including magnesium, calcium, iron, zinc, and selenium (3).

Summary

Camellia sinensis leaf extract is rich in catechins, caffeine, and L-theanine — the main bioactive compounds behind tea’s health benefits.

Camellia sinensis leaf extract has a long history of use in the cosmetic industry due to its positive effects on skin health and appearance.

Due to the antioxidant potential of EGCG, it may protect the skin from damage from ultraviolet radiation (UVR), which causes sunburn and may lead to premature skin aging and nonmelanoma skin cancer (18, 19, 20).

Furthermore, research shows that applying the extract topically and taking it orally reduces scaling and increases blood flow to the skin, skin elasticity, hydration, and density (18, 21).

What’s more, people often use the extract as an anti-cellulite agent due to its caffeine content (22).

It may also help reduce wound healing time and may decrease excess sebum production — one main characteristic of an oily face (18, 23).

Summary

People use Camellia sinensis leaf extract widely to improve skin health and appearance. These effects are mainly due to its antioxidant and caffeine contents.

Taking Camellia sinensis leaf extract or drinking tea may help improve heart health.

Their catechin and L-theanine contents may help lower risk factors for heart disease, including:

• Blood cholesterol and triglycerides. Studies suggest that the extract may reduce levels of total and LDL (bad) cholesterol and triglycerides by reducing their absorption (1, 15, 23, 24, 25).
• Arterial plaque. Catechins in the extract reduce LDL (bad) cholesterol oxidation, helping prevent plaque from building up and clogging your arteries (1, 23, 25, 26).
• Blood pressure. The extract may lower blood pressure by promoting blood vessel relaxation and improving blood vessel function (23, 27).

What’s more, the extract may also reduce the risk of heart attack. Its compounds may reduce the enlargement of the heart, improve blood pressure dysfunction, and restore antioxidant enzyme activity (23).

Summary

Camellia sinensis leaf extract may improve heart health by lowering blood pressure, cholesterol, triglycerides, and preventing plaque buildup in the blood vessels.

The extract’s cancer-fighting properties are mostly attributed to its catechins, particularly EGCG.

Test tube and animal studies have found that EGCG offers a cancer-protective effect by inducing apoptosis — or programmed cell death — in cancerous cells (3, 23, 28, 29, 30).

Additionally, it may help prevent tumor progression and spread by inhibiting angiogenesis. This is the growth of new blood vessels that would otherwise feed cancerous cells (23, 25, 28, 31).

Furthermore, EGCG increases the activity of antioxidant enzymes in your body, which neutralize free radicals. Excessive amounts of free radicals can damage your DNA, contributing to the development of cancer (28, 29, 31).

Research has found EGCG may help with several types of cancers, including:

• Prostate cancer. EGCG may reduce the risk of low-grade prostate cancer, prevent its recurrence, and increase quality of life in people with the disease (1, 7, 32, 33, 34).
• Breast cancer. Aside from reducing cancer risk, EGCG may reduce mortality, lower its recurrence rate, and increase the cancer-free period in people with stage one and two breast cancer (1, 23, 35).
• Other types of cancer. EGCG may also lower the risk of lung, stomach, colorectal, and liver cancer (1, 3, 23, 36).

Summary

Catechins in the extract may help reduce the risk of multiple types of cancer.

L-theanine and EGCG are key compounds when it comes to boosting your body’s immune system.

Studies show that L-theanine may potentially enhance T-cell production. T cells are a type of white blood cell that fights disease (15).

Therefore, it may play an important role in combating infections, allergic diseases, and hypersensitivity reactions (15).

Furthermore, research suggests that EGCG may restore the body’s immunological balance in multiple autoimmune diseases by decreasing the production of many inflammatory markers (37).

It may also improve your body’s resistance to infection and act as an antiviral agent by inhibiting the early stages of infection and blocking a virus’s life cycle in infected cells (38, 39, 40).

Summary

L-theanine and EGCG in Camellia sinensis leaf extract may boost your immune system and help your body fight infections and viruses.

L-theanine plays a major role in the extract’s anti-stress effect (41).

Research shows that L-theanine promotes relaxation and reduces anxiety by increasing levels of dopamine and serotonin. Brain cells produce these two signaling molecules, and they regulate motivation and happiness, among other functions (15).

L-theanine also appears to increase the brain’s production of alpha brain waves, which researchers use as a measure of relaxation. They’re associated with a calm, alert mental state (15, 42, 43).

Interestingly enough, one study found that L-theanine’s calming effect may be enhanced when it’s combined with caffeine, which is also present in the extract (44).

Summary

Camellia sinensis leaf extract offers a calming effect mostly due to its L-theanine content, which promotes relaxation and reduces anxiety.

Obesity is a major health concern worldwide.

Studies show that both the EGCG and caffeine in Camellia sinensis leaf extract may help increase weight loss (45).

EGCG may promote weight loss by inhibiting enzymes that cause the body to absorb and digest carbs and fat from the gut. This may help lower energy intake (23, 45, 46, 47).

Additionally, it may influence gut microbiota and induce weight loss by regulating fat metabolism and increasing fat breakdown (45, 46, 47, 48).

Meanwhile, caffeine may increase your metabolic rate, energy expenditure, and fat oxidation, thereby leading to weight reduction (23, 49).

Some studies suggest that this weight loss effect is enhanced when people consume EGCG and caffeine combined, as they are in this extract (50, 51, 52, 53).

However, other studies have found that neither green tea nor green tea extract caused statistically significant weight loss (54, 55).

Thus, scientists need to do more research on how consuming Camellia sinensis leaf extract affects weight loss.

Summary

Caffeine and EGCG in the extract may promote weight loss, especially when people consume them together. However, some studies have found that consuming Camellia sinensis leaf extract did not significantly affect weight loss.

Camellia sinensis leaf extract may provide additional health benefits, including:

• Anti-inflammatory effect. Animal studies suggest that compounds in the extract may inhibit the production of pro-inflammatory substances associated with inflammatory diseases like arthritis (23, 56).
• May improve bone health. Animal and human studies show that catechins may help regulate bone metabolism and reduce bone loss (23, 57).
• May improve liver health. The extract’s catechin and L-theanine content may protect against liver injury by decreasing liver enzymes that lead to inflammation and disease when they’re present in high quantities (15, 23, 58).

Summary

Camellia sinensis leaf extract may also protect against inflammatory, bone, and liver diseases.

Although Camellia sinensis leaf extract is considered safe and usually well tolerated, there are some reports of unwanted side effects.

For example, it may lead to jitteriness and headaches due to its caffeine content (7).

Studies have also found that consuming caffeine in higher amounts during pregnancy is associated with a higher risk of pregnancy loss and low birth weight (59, 60).

Additional mild side effects of Camellia sinensis leaf extract include skin reactions, such as rash or allergy, and digestive symptoms like diarrhea and nausea (61).

However, research has also linked the extract to liver toxicity, which is a more serious effect.

A comprehensive review by United States Pharmacopeia (USP) concluded that green tea extracts can cause liver toxicity, albeit very rarely (62).

The toxic effects may occur due to either high EGCG levels interacting with medications or a particular condition related to a person’s metabolism (28, 61, 62, 63, 64).

Studies have reported liver toxicity with intakes of the extract ranging from 700–2,100 mg per day, although liver damage may occur at lower doses of 140–1,000 mg per day (26, 62).

These amounts are around the same as a single dose of commercially available Camellia sinensis leaf extract, though product concentrations and suggested dosages vary. Thus, it’s possible to experience liver toxicity while taking “normal” dosages of the extract.

Note that in most cases, the side effects were linked to consumption on an empty stomach. Therefore, if you take the extract, make sure to take it with food (61, 62, 65).

Consult a healthcare provider if you’re interested in taking Camellia sinensis extract and pregnant, as well as if you have a health condition or are concerned about liver toxicity or other side effects.

Stop taking the extract immediately if you experience symptoms of liver toxicity. These include dark urine, abdominal pain, or yellowed skin or whites of the eyes, which indicate jaundice (62).

Summary

The extract is considered safe and people usually tolerate it well. However, consuming high amounts may lead to jitteriness, headaches, skin rashes, nausea, diarrhea, and even liver toxicity in rare cases.

Scientific research has demonstrated that the extract helps prevent and treat multiple ailments.

Still, people use it primarily for its weight loss potential and cosmetic applications in skin health.

While you may reap most of the benefits by sipping a cup of tea, the extract provides higher concentrations of the beneficial compounds.

You may find Camellia sinensis leaf extract online as a supplement in powder, capsule, and liquid form.

Alternatively, you may make your own extract at home.

Homemade Camellia sinensis leaf extract

Follow these steps to make a homemade, glycerin-based Camellia sinensis leaf extract.

Ingredients

• 10 grams of green tea leaves, ground
• 80 mL of glycerine
• water

Supplies

• a fine filter or food-grade oil filter
• an airtight, dark-colored storage container that holds at least 150 mL

Directions

1. Place 10 grams of ground green tea leaves in a pot on your stovetop and cover them with water. If you only have larger leaves available, make sure to grind them beforehand.
2. Bring the water to a gentle boil, cover, and boil it for at least 30 minutes and up to 2 hours.
3. Strain the extract using a strainer and food-grade oil filter or any other fine filter you have at home.
4. Filter the mix to separate the leaves. This leaves you with a concentrated extract that now has to be diluted.
5. To dilute it to 80% glycerine, add 20 mL of water and 80 mL of glycerine. This will give you an extract with a 3–5 year shelf life.
6. Stir well and pour the mixture into a storage container.

Note that the extract’s antioxidants are sensitive to light and oxygen. Thus, make sure to store the extract in an airtight and dark-colored container to prevent it from degrading (17).

Always consult your healthcare provider before purchasing or consuming Camellia sinensis leaf extract.

Summary

Camellia sinensis leaf extract is mostly known for its weight loss and skin applications. You may buy it online or make an extract at home.

Camellia sinensis leaf extract is the oil obtained from the leaves of tea plants.

It’s rich in bioactive compounds, such as catechins, L-theanine, and caffeine, and studies have linked it to multiple beneficial effects.

It may also boost your immune system, reduce stress and anxiety, and promote weight loss.

However, it may lead to unwanted side effects, such as jitteriness, nausea, skin rashes, and liver toxicity in rare cases.

If you want to give it a try, consider talking to a healthcare provider first. You can buy Camellia sinensis leaf extract online or even make it yourself.