Oolong vs Green Tea: Which One is Healthier?
When it comes to tea, there are a lot of options. Oolong tea and green tea are some of the most popular, with green tea being known as one of the healthiest beverages in the world . But both of these teas offer a host of health benefits, so which one is better for you?
In this blog post, we’ll take a look at the research on green tea and oolong tea to see if there’s a difference in the benefits they offer. Spoiler alert: there is!
Keep reading to learn more.
Oolong Tea Vs. Green Tea at a Glance
In a hurry? Here are the main points in short form:
Oolong Tea Advantages:
- Oolong tea helps prevent diabetes
- Oolong tea has been proven to help with weight loss
- Oolong tea helps prevent heart disease
- Oolong tea can improve your mental clarity
- Oolong tea is a natural detoxifier
- While oolong tea contains tannins, it has fewer than green tea
Oolong Tea Disadvantages:
- Oolong tea contains caffeine (this can be a pro or a con depending on your goals)
- Oolong tea contains levels of tannins which can reduce iron absorption
- Oolong tea contains oxalic acid which increases your risk of kidney stones
Green Tea Advantages:
- Green tea has been shown to boost metabolism and help with weight loss
- Green tea is a natural detoxifier and helps the body eliminate toxins
- Green tea is rich in antioxidants which can help protect cells from damage
- Green tea has been shown to lower cholesterol levels and improve heart health: it has been linked to lower rates of heart disease, cancer, and other chronic conditions
- Green tea improves brain function
- Lightly caffeinated (this can be a pro or a con depending on your goals!)
Green Tea Disadvantages:
- Can taste bitter when it is over-brewed
- Contains tannins which can reduce iron absorption
- Contains oxalic acid which increases your risk of kidney stones
- Contains caffeine (this can be a pro or a con depending on your goals)
Winner: Don’t have time to read the full article? The editor’s choice is green tea due to its higher antioxidant levels and the long-lasting energy it gives. However, both oolong tea and green tea are great options that can energize you and provide many perks. Both of these teas have different health benefits that could make either a better fit depending on your needs.
What’s the Difference Between Them?
Anything you eat or drink can affect your digestive system, and that includes tea. This is particularly true for people with Irritable Bowel Syndrome (IBS) or Small Intestinal Bacterial Overgrowth (SIBO). You’ve probably heard that herbal teas like ginger tea or peppermint tea are a great way to settle a troubled tummy. But oolong and green tea can support your digestion, too!
Research suggests that oolong tea can help to improve digestion by increasing the production of digestive enzymes in the body. This is thought to be due to the high levels of polyphenols found in oolong tea, which have been shown to stimulate the release of digestive enzymes.
Oolong tea has been shown to help reduce inflammation in the gut and promote a healthy gut flora. This 2014 study  showed that green tea was very effective in reducing diarrhea and vomiting in pelvic radiotherapy patients with abdominal and pelvic malignancy. However, due to its higher caffeine levels, drinking a lot of green tea can actually cause digestive distress, so make sure you stick to just one or two cups a day.
Verdict: When it comes to digestive health, oolong tea is the clear winner because of the digestive enzyme boost it provides, improvement of gut flora, and reduction of inflammation.
All kinds of tea have been shown to help protect against diabetes and complications from diabetes. This could be by reducing insulin resistance and decreasing inflammation, among other mechanisms. 
This study  showed that oolong tea may cause plasma glucose in patients with type 2 diabetes, stating that Oolong tea may be an effective adjunct to oral hypoglycemic agents in the treatment of type 2 diabetes.
Studies on green tea and diabetes are mixed, with some studies showing improvements but others suggesting that green tea may actually make it worse. However, green tea can help control weight which is always helpful in preventing type II diabetes. But with oolong tea having more caffeine, it’s still the better choice in this instance.
Verdict: Oolong tea!
Antioxidants are bioactive compounds that combat oxidative stress. What does oxidative stress do? Well, oxidative stress leads to numerous non-communicable diseases like cardiovascular diseases, arthritis, type 2 diabetes, different types of cancer, Alzheimer’s, diabetes, Parkinson’s disease, autoimmune diseases, and neurodegenerative disorders. Because they fight free radicals in the body and help restore optimal health, antioxidants are considered health superheroes.
The polyphenols in teas are known to be excellent antioxidants . So when it comes to the health benefits and differences between green tea and oolong tea, it in large part comes down to the types and numbers of antioxidants. While both oolong tea and green tea contain antioxidants, the amounts and types of antioxidants differ.
Green tea contains more antioxidants than any other type of tea. It has high levels of active catechins and epigallocatechin gallate, which act as powerful antioxidants that fight cancer and inflammation. When it comes to antioxidants, green tea contains more antioxidants than oolong tea. Green tea also contains more polyphenols than oolong tea, which are another type of antioxidant.
However, this study  found that oolong tea also has beneficial antioxidants.
“The [oolong tea water extract] were evaluated in the present study. The [oolong tea water extract] was found to have strong antioxidative activities in all of the model systems tested…The present results support the concept that oolong tea contains several low molecular weight antioxidants that may have health promotion activities.”
Verdict: Both green tea and black tea contains healthy antioxidants. However, green tea’s higher levels make it the clear winner here!
Green tea and oolong tea contain similar ranges of caffeine. However oolong contains slightly more, with 38 mg of caffeine per cup compared to a cup of green tea which contains about 29 mg of caffeine.
Both green tea and oolong tea contain L-Theanine, which makes them quite special!
The combination of caffeine and L-Theanine slows down caffeine absorption and stretches it throughout your day. With these teas, instead of having a caffeine high and then an energy crash, you get prolonged, smooth energy throughout your day. L-Theanine supports calm and focus, helping you be more productive. 
Of course, caffeine can cause problems in some people like anxiety, insomnia, and digestive distress. To avoid problems from caffeine consumption, we suggest drinking caffeine before noon and in moderation.
Verdict: We choose green tea because it contains slightly less caffeine than oolong tea. However, the difference is not significant enough to make a big impact on your overall health. Too much caffeine can cause problems, but if you prefer more caffeine, then opt for green tea.
When it comes to brain function, when enjoyed in moderation, caffeine’s superpowers come to the rescue. Caffeine from green tea and oolong tea can improve your memory, reaction time, mood, and overall brain function.
Verdict: While both types of tea help brain function, green tea is the winner due to its additional age-fighting powers.
Tannins and Oxalic Acid
Have you ever heard of oxalic acid and tannins? Particularly for those with digestion or nutrition struggles, they are important to be aware of. Both green tea and oolong tea contain oxalic acid and tannins, whereas most herbal teas do not.
Oxalic acid is an organic compound called an antinutrient. This antinutrient binds to minerals in your digestive system and prevents your body from absorbing them. For instance, many leafy greens are high in both calcium and oxalic acid, which prevents too-high levels of calcium from being absorbed into the body.
Many healthy foods contain oxalic acid, but your doctor may recommend avoiding these acids if you are prone to kidney stones. Tannins, like oxalic acid, interfere with our body’s ability to digest and absorb nutrients like iron in our food. They are water-soluble polyphenols common in many plant foods, and it is important to know that green tea and black tea contain higher levels of tannins than herbal teas.
Verdict: It’s a tie- both contain tannins and oxalic acid. If you are concerned about kidney stones or nutrient absorption, talk to your doctor before you include high amounts of green tea and black tea in your diet.
So, what’s the verdict? When it comes to oolong vs green tea, there is no clear winner. Both teas offer a variety of health benefits, so it really depends on your own personal preferences. If you’re looking for a tea to help improve your digestive health, oolong tea is the way to go. When your goal is to help improve your overall health, green tea is the better choice.
And ultimately each type of tea comes with different perks, so if you switch between both oolong tea and green tea, you get the best of both worlds!
Written by Stephanie Moore
Stephanie is a professional freelance writer who is a ‘SIBO survivor’ herself with broad experience writing in the health field. She is a regular writer for SIBO Survivor and calls Berlin, Germany home.