The real science behind 3 weight-loss supplements
Dr. Jan Patterson. Published in Wise & Well
What if there was an affordable, natural, effective alternative to Ozempic for weight loss? Semaglutide medications (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) have been proven to enhance weight loss. Their expenses are often not covered by insurance, and the cost of around $1,000 monthly is prohibitive for many people.
These drugs are GLP-1 (glucagon-like peptides) agonists (activators). They mimic the GLP-1 hormone produced by intestinal cells and stimulate the body to produce more insulin after eating. This helps to lower blood sugar levels, which has benefits in controlling diabetes. It’s not entirely clear how the drugs cause weight loss, but they do help curb hunger and cravings, likely related to GLP-1 receptors in the brain. The drugs also slow movement of food from the stomach to the small intestine, helping to increase the sense of being full. Common side effects are nausea, vomiting, diarrhea, and/or constipation.
Due to the expense and inaccessibility of the GLP-1 agonist drugs, there has been interest in alternatives. Three commonly cited supplements are: berberine, cinnamon, and green tea. But while some studies and anecdotes support it, consistent evidence that these cause weight loss is lacking.
Berberine
Berberine is a natural compound found in plants, including goldenseal, barberry, Oregon grape, and others. It is an active compound in a Chinese herb used for diabetes, Huanglian, or Coptis chinensis and has been used as a health supplement since ancient times.
Because it supports normal blood sugar levels, it has been studied for effects on diabetes and heart disease risk factors. Berberine is not well-absorbed by the body, so higher doses are needed for benefits. Some supplements are available in a berberine metabolite form, dihydroberberine, which is more easily absorbed.
Its mechanisms of action appear to include increased expression of insulin receptors and decreased glucose production by the liver. Some animal studies suggest that berberine may inhibit the formation of fat cells and fat synthesis in the body. A 2022 review of multiple berberine studies showed that weight and body mass decreased in people who took more than one gram daily of berberine for more than eight weeks. However, individual study results were inconsistent, and many studies in this review did not use high quality research methods, suggesting outcomes may not be valid. Some studies suggest that berberine’s effect decreases over time. Better research is needed before we can conclude that berberine is proven for weight loss.
Side effects of berberine are primarily gastrointestinal and include nausea, bloating, abdominal pain, diarrhea, and/or constipation. It interacts with liver enzymes that affect the metabolism of some medicines including cyclosporine, an important medicine used in transplant patients. It should not be used in pregnancy because it can cause uterine contractions. It can also cause a buildup of bilirubin which is dangerous to an infant’s brain, so is best avoided if breastfeeding.
Cinnamon
As a supplement, cinnamon has been touted for its effect on glucose control, and some research for its effect on improving blood sugar levels and lipid metabolism in diabetes have been positive.
Cinnamon is more than you might realize: It’s the name commonly used for more than 200 plants that are in the cinnamon family. Cinnamomum zelanicum, or Ceylon cinnamon, is referred to as ‘true’ cinnamon and is native to Sri Lanka. The most used cinnamon in the US — Cinnamomum cassia, known as “false” or “bastard” cinnamon — is from Southeast Asia and is less expensive.
True cinnamon is preferred for cooking due to its more delicate and smoother flavor. The other difference between the two is that false cinnamon contains substantially higher levels of coumarin, a flavor enhancer, that can cause liver inflammation in high doses. While this effect is not thought to be significant with the typical use of cinnamon — intermittently in small amounts — it can be toxic if used in large amounts over time.
Many berberine weight loss supplements contain cinnamon for potential additive benefit, and Ceylon cinnamon is typically used to avoid this side effect.
Cinnamon’s mechanism of action may be mimicking insulin to increase glucose uptake in muscle, thus helping to control blood sugar and improve metabolism. The use of cinnamon in food has shown benefit using 2 to 3 grams daily, which would be approximately one teaspoon a day. It has also been studied in the prevention of diabetes. Results are mixed, however.
Recently, Consumers Reports found high levels of lead in some cinnamon powders, and the publication lists those causing the most risk. Even a quarter teaspoon of some of these cinnamon brands can pose a risk, so be informed about which brands are safe if you are including cinnamon in your diet regularly.
Green tea
Another compound cited for weight loss effect is green tea. Camellia sinensis, the plant used for green or black tea, has been a popular beverage for centuries.
Black tea is fermented, but green tea is not, so the powerful antioxidants, catechins or polyphenols, found in the plant are preserved. These compounds help protect cells from inflammation and damage. Because of these antioxidant effects, there is some data showing that green tea consumption may decrease heart disease risk, and limited evidence that it can decrease cancer risk.
Green tea’s purported weight loss effects were touted by ancient Chinese people. The mechanisms thought to contribute to potential weight loss include increased metabolic rate (from the antioxidant catechins and caffeine), improved utilization of fat, and decreased appetite.
The main catechin in green tea, ECTC (epigallocatechin gallate), is available as a supplement. A recent review of green tea extract (GTE), usually in the form of an ECTC supplement, can decrease weight, but the effect is small. The authors conclude that the supplement should be combined with dietary and exercise lifestyle changes for best weight loss results.
GTE in the form of the supplement ECGC can be a risk factor for liver toxicity and gastrointestinal cancers, especially in dosages more than 800 mg daily. This effect is very rarely observed with drinking green tea itself, even up to five cups daily.
Recent social media posts tout that green tea boosts GLP-1 production and mimics the GLP-1 agonist drugs. Clinical studies have been few and inconclusive, however, and experts advise that any effect on GLP-1 production would be small and short-lived.
Green tea can interact with chemotherapeutic agents. Those sensitive to caffeine should be aware of potential effects, but green tea has less caffeine than black tea or coffee. Green tea also contains L-theanine, an amino acid that can relieve stress and anxiety. Some report an “alert calm” feeling with green tea consumption.
The beverage is included in the anti-inflammatory diet and the ingestion of catechins can be beneficial for overall health. Matcha green tea is a powder made from the leaf, designed to be mixed with water in its entirety whereas regular green tea is made from a tea bag or loose leaf preparation steeped in water and the leaves discarded. So, a cup of matcha contains substantially more of the antioxidant catechins than a cup of green tea made with a tea bag.
The cautious, thoughtful approach
Berberine, cinnamon, and green tea have shown some effect on controlling blood sugar, but studies are inconsistent, and they have not shown consistently substantial weight loss results. The American Diabetes Association does not recommend the use of supplements or herbs in the management of diabetes. It’s always important to discuss any supplements with your healthcare provider. Even if your provider is not familiar with the supplement you are using, most point-of-care databases used by healthcare providers these days will have information about potential interactions of supplements with medications.
Also beware that supplements are not regulated by the FDA in the manner of medications, and many brands have been found to contain ingredients not on the list, or more or less of the ingredients that are listed. Look for the USP symbol on any supplement, which ensures it has at least been tested to ensure it contains what it claims.
While berberine may be promising, there is still not enough data to recommend it for weight loss.
Enjoy cinnamon as a tasty seasoning in beverages and food, knowing that you may also be supporting blood sugar control. I often blend a small amount of cinnamon (I use a brand of commonly available false cinnamon without high amounts of lead) in my coffee drink or dusted over fruit in the morning. Avoid large doses of false Cassia cinnamon over extended periods of time because of risk of liver injury. Check your brand of cinnamon to avoid unnecessary exposure to lead, especially for young children and pregnant women.
Green tea can be beneficial in your diet because of its antioxidant effects for prevention of heart disease risk factors and potential cancer prevention, even if it doesn’t work for you for weight loss. I must admit I don’t really like the flavor of green tea, but I often blend matcha powder into a hot beverage. Because of the risk of liver injury, the GTE supplement ECGC is usually best avoided.
So, the quest for nature’s Ozempic is still on. The cost of GLP-1 weight loss drugs will eventually come down. Eli Lilly has made low doses of tirzepatide available at a lower cost as single dose vials for those willing to forego the ready-use injectors. It is anticipated that Medicare negotiations and availability of similar agents will adjust the market over the next couple of years. In the meantime, empower your body’ with health benefits using the Mediterranean or anti-inflammatory dietary guidelines and incorporating enjoyable movement into your lifestyle. These are both proven ways to manage weight and promote overall good physical and mental health.
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