Research on Lipo-6 Side Effects - Weighing Benefits and Risks of Nutrex Fat Burner

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The most blatant case of severe adverse reactions from Lipo-6 is that of a myocardial infarction, recorded in the scientific literature in 2009 by Dr John E. Thomas, MD. The case pertains to a 24-year-old healthy man, member of US Navy, who presented acute chest pain followed by shortness of breath, anxiousness, sweating and repeated vomiting, just a few hours after ingesting Nutrex Lipo-6.

The physically well-developed young man was not at high risk for developing heart or thromboembolic disease. Yet, cardiac angiography revealed extensive thrombi formation in his coronary artery.

Before the event, the patient exercised 5 times a week lifting weights. He would take 1 capsule of Nutrex Lipo-6 twice weekly before his workout. He had not been taking any other weight loss products (such as Hydroxycut, Stacker, etc) for 3 weeks before the side effect occurred.

Is Lipo-6 Safe?

Lipo-6 is a very popular fat burner. To better understand the potential side effects of Lipo 6 one needs to be aware of the ingredients of this dietary supplement.

Lipo-6 was named after the number of ingredients it initially contained. One of them used to be Ephedra, a very effective weight loss supplement. The inclusion of this ingredient in the Lipo-6 formula made Lipo-6 one of the best fat burners in the market.

However, over-the-counter use of Ephedra-containing supplements was banned in the US in May 2004 because Ephedra was found to be a potentially dangerous stimulant. Its addictive nature and its association with incidences of stroke, heart arrhythmia and even death lead FDA to impose stringent regulations to protect the public’s health.

Therefore, today, Lipo-6 really should be called Lipo-5 because there is no Ephedra in it. Although the ingredients that are left over are pretty descent, making Lipo-6 “fat-loss product of the year” during 2005-2008, the product is not nearly as effective as it used to be.

The product now basically consists of these 5 ingredients:

Lipo 6 Ingredients and Side Effects

1. Caffeine Anhydrous (200 mg)

Found in coffee, tea and soda/energy drinks, caffeine is the most frequently consumed pharmacologically active substance in the world.

Lipo 6 contains twice the amount of caffeine included in a 5 oz. serving of coffee and 4 times that contained in a 5 oz. serving of black tea or 12 oz. Coca-Cola. Caffeine promotes mental alertness and acts as an appetite suppressant. It is the basis of almost every stimulating pill out there.

Caffeine Side Effects
Caffeine is a neurostimulant that is considered generally harmless by the FDA. Side effects can occur depending on the ingested amount. Research suggests that healthy adults can consume up to 400 mg/day caffeine without experiencing any adverse reactions.

Tachycardia (rapid heart rate) and abnormal heart rhythm are some of the documented caffeine side effects. In addition, clinical research shows that regular caffeine consumers experience withdrawal symptoms when they cut abruptly their daily consumption.

A 2010 report evaluating the potential dangers of caffeine says that those who might be more vulnerable to caffeine are pregnant women.

“Caffeine is readily absorbed from the mucosa of the gastrointestinal tract. It crosses the human placenta rapidly reaching concentration in the fetus similar to maternal plasma levels. Caffeine has been implicated as a cause of spontaneous abortion, intrauterine growth restriction, low birth weight and pre-term delivery”

According to the report, other “at risk” populations are reproductive-aged women, and children. The suggested maximum amount of caffeine that can be consumed risk-free by reproductive-aged women is 300 mg/day.

A recent review however that evaluated all evidence todate on the reproductive health effects of caffeine consumption, concluded that

“The available studies do not provide convincing evidence that caffeine consumption increases risk of any reproductive adversity. Future studies addressing the methodological limitations of current research may alter this conclusion.”

2. Guggulsterones (20mg)

These substances are extracted from guggulu, a gum resin taken from a small tree (Commiphora mukul) commonly found in India. Guggulu has been used over thousands of years to treat various diseases such as tumors, obesity, atherosclerosis, arthritis, ulcers and intestinal worms.

Guggulsterones are the major active components of guggulu. Research suggests that these phytosteroids:

Guggulsterones Side Effects
Generally, no severe side effects have been reported from the use of guggul in clinical studies. The main adverse reactions noted are digestive discomfort, due to alteration of gut microflora, and skin rash.

One particular study examined the effect of guggul—Commiphora mukul or CM—on pain reduction in osteoarthritis patients. The investigators noted,

“There were no side effects reported during the trial. CM appears to be a relatively safe and effective supplement to reduce symptoms of OA”.

Another study that reviewed all scientific evidence on guggul accumulated up to 2005, states:

“Guggul may cause stomach discomfort or allergic rash as well as other serious side effects and interactions. It should be avoided in pregnant or breast-feeding women and in children. Safety of use beyond 4 months has not been well studied.”

A 2009 Norwegian study examined the effect of a guggul-based encapsulated preparation (daily dose contained 1080mg natural, raw guggul) or a placebo capsule, on the cholesterol levels of 43 people. The 12-week study confirmed the previously reported cholesterol-lowering effect of guggul, however, half of the participants reported some sort of mild adverse effects.

The side effects comprised mainly of gastroinstestinal discomfort and skin rash. Increased tiredness was also reported, but only from the participants who were taking thyroxin—this effect was explained on the basis that guggul affects thyroid metabolism.

The study points that:

“More research is needed to establish the safety of guggul-containing remedies”.

Hypersensitivity rash after consumption of guggul has been reported (at 10% frequency) by another study conducted in Pennsylvania, too.

Guggul-Drug Interactions
A report from the department of pharmacology of the university of Verona, Italy, mentions that those who are diagnosed with hypercholesterolemia and take statins (like Lovastatin) in order to lower their cholesterol levels, should be cautious when using guggul since it may affect the actions of the drug “by eliciting reductions in cholesterol and triglycerides”.

In short, guggul is generally well tolerated and its plant sterols appear to be relatively safe.

Guggul and Contaminants
The potential dangers from guggul-containing supplements do not emanate from guggul itself but from the large amounts of heavy metals and even arsenic—harmful substances that recent studies have associated with Indian alternative medicine (ayurvedic) herb preparations, including guggul.

Researchers advise that guggul-based supplements should be accompanied with laboratory test certificates on poisonous content. Interestingly, according to the Journal of American Medical Association:

“In England, 30% of Ayurvedic herbal medicine preperations sampled contained lead, mercury, or arsenic. Of 22 Ayurvedic herbal medicine preperations purchased in India, 64% contained lead and mercury, and 41% contained arsenic. Traditional medicines from China, Malaysia, Mexico, Africa, and the Middle East have also been shown to contain heavy metals.”

Therefore, guggul-based supplements and guggul-derived substances (like guggulsterones) per se may not impose health risks, but it is important that they are tested for heavy metals and other contaminants.

3. Synephrine HCl (20 mg)

Since the 2004 FDA ban of ephedrine, synephrine has emerged as the most potent ephedra-like alternative and has been increasingly used as a key ingredient in fat-burning products.

Synephrine is a plant-derived substance extracted from the herb “bitter orange” that has effects similar to the sympathetic neurotransmitter adrenaline. That’s why synephrine is also called sympathomimetic. Adrenaline is a human hormone that increases heart rate, dilates air passages and elicits what is known as a fight-or-flight response.

Synephrine purportedly causes lipolysis and although it is included  in over-the-counter weight-loss products, little evidence supports its use for weight loss.

The amount of synephrine contained in a liquid Lipo6 capsule is much higher than that reported for traditional extracts of the dried “bitter orange” fruit.

Synephrine Side Effects
Synephrine is the suggested culprit that caused the acute myocardial infarction to the 24-year old man mentioned at the beginning of this article.

Although the physiological action of synephrine is not much different to that of ephedra, the cardiovascular effects of synephrine have not been studied adequately. Synephrine increases blood pressure in humans and has the potential to increase cardivascular events. Many cases of adverse cardiovascular events from the use of synephrine-containing supplements have been reported.

4. Yohimbine HCl (3mg)

Yohimbine is a natural product made from the yohimbe tree that is marketed as stimulant and weight loss supplement. It is also used as a natural mild aphrodisiac although evidence for its efficacy remains anecdotal only.

Yohimbine Side Effects
A 2010 study examined 238 cases of adverse reactions reported between 2000 and 2006 that were associated with consumption of yohimbine herbal products. Gastrointestinal distress and tachycardia were the most commonly reported side effects, accounting for almost half the reported adverse reactions. Anxiety/agitation and hypertension were manifested in about 30% of the studied cases.

The study noted:

“A re-examination of whether yohimbine should be considered a "safe" dietary supplement under the Dietary Supplement Health and Education Act is warranted.”

5. Bioperine

Bioperine, a nutrient extracted from the fruit of black pepper, is a natural bioavailablility enhancer. As such, it increases the absorption of other nutrients. This is exactly why it was included in the five ingredients of Lipo-6.

Bioperine Side Effects
According to, Bioperine is side-effect-free. Its safety and efficacy for nutritional use have been documented in clinical studies.

In Conlusion

Like all herbal supplements, Lipo-6 is considered food rather than drug, and therefore is not controlled by the FDA. Although testimonies and anecdotal evidence show that it delivers what it promises, it goes without saying that, since, it has not been clinically tested for safety, it carries with it a certain risk—like most performance-enhancing dietary supplements.

Given that Nutrex Lipo-6 contains sympathomimetic and stimulant compounds with pharmacologic similarities to ephedra, the potential health hazards do exist. As Dr. John E. Thomas, says in his report:

“We believe that greater FDA involvement in the regulation of such supplements is warranted.”

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