An ECY stack is defined as a combination of ephedrine, caffeine, and yohimbine.
Ephedrine is well-known as one of the strongest fat burners uses by bodybuilders and dieters to kick-start a weight loss program. Derived from the ephedra sinica plant, this natural alkaloid boost metabolism and suppresses the appetite.
Yohimbine is an alkaloid from the bark of the Pausinystalia yohimbe tree that grows in Africa. This extract was traditionally used to increase libido and sexual performance.
Yohimbine HCL also exhibits fat-burning properties and is used to enhance energy and athletic performance. However, it may be unsafe and there is limited research available to support its use for weight loss.
Caffeine is highly synergistic with ephedrine and can increase weight loss results. The ECY stack is commonly used as an alternative to an ECA stack, which uses Aspirin or White Willow bark instead of yohimbine.
Is an ECY stack safe and how do the potential weight loss results compare to taking an EC or ECA stack instead? This article will review the evidence for combining ephedra and yohimbe as well as the potential side effects and recommended dosages. Click here to buy ephedra supplements online legally without a prescription.
An ECY stack combines three powerful stimulants that are designed to boost metabolism and enhance fat burning results.
Use of ephedrine on its own has been shown to promote modest increases in calorie expenditures. This thermogenic agent can cause your body to convert more calories in the form of fat and glucose into body heath.
In research studies, taking ephedrine HCL or ephedra sinica extract can promote an average of 1-2 pounds of additional weight loss per month. This result is quite modest.
Using ephedrine in combination with other stimulants like caffeine is purported to increase efficacy. Yohimbine is another stimulant that affects metabolism via a different pathway than ephedrine.
Bodybuilders initially began experimenting with this stack believing that use of yohimbine would potentiate some of the effects of an EC stack for fat loss. However, reviews on this combination are mixed and many people warn of the high risk of cardiac side effects.
Yohimbine is one of the active alkaloids derived from Yohimbe bark. This is a component found in a number of bodybuilding as well as libido-enhancing supplements.
Historically, components of Yohimbe bark have been used in the development and composition of a numerous prescription drugs around the world. Yohimbe is primarily used by individuals as an aphrodisiac and to treat sexual issues such as erectile dysfunction.
It is also a popular ingredient for weight loss because it can antagonize alpha-2 receptors and inhibit the storage of fat in certain parts of the body. It is believed to increase metabolism and to improve glucose utilization in the body.
Yohimbine is also used in the place of Aspirin in an ECA stack because it has an anticoagulant effect. It may inhibit platelet aggregation through its effects on noradrenaline (norepinephrine).
However, there is very little research available into its weight loss effects. Aa number of studies have shown that even after three weeks of use, the supplement does not improve athletic or exercise performance or increase muscle mass. 
Results in other small studies regarding the use of Yohimbine for weight loss are mixed. There have not been any specific studies on the use of an ECY combination for fat loss.
While these ingredients are often mixed together in fat burner formulas and diet pills, the last of available research and the potential for side effects should be weighed against any purported benefits.
Effects of Ephedra, Caffeine and Yohimbe
Most of us are familiar with caffeine found in coffee, colas, and energy drinks. Caffeine is commonly consumed for that boost of cognitive focus or physical energy, but this ingredient can also support weight loss in a few different ways at once.
Caffeine acts as a stimulant to the central nervous system. It can cause your metabolism to increase, control your appetite and boost energy and motivation to be active. Bodybuilders take it to help them work out harder at the gym and as a pre-workout stamina booster.
One of the main reasons for using caffeine with ephedrine is that these two ingredients potentiate each other. Caffeine inhibits a negative feedback loop that would otherwise make ephedrine less effective for raising metabolic rate.
Ephedrine is one of the handful of alkaloids found in the ephedra plant species. This is the primary bioactive alkaloid, meaning it promotes most of the physiological effects associated with consumption of this plant.
Before 2004, ephedrine was a common component in weight loss products manufactured around the world. Hundreds of products containing ephedrine were available – and quite popular – during the 1980s and 1990s.
This ingredient is a beta-2 receptor agonist and increases activity of norepinephrine and epinephrine in the body. It also indirectly increases activation of catecholamine receptors.
Ephedrine is known as a sympathomimetic amine, which defines its influence on the sympathetic nervous system. This system is often called the autonomic system because it controls body functions that we don’t consciously control, such as:
- Heart rate and other cardiovascular functions
- Respiratory function
- Regulation of certain brain functions
When you take ephedrine, it increases the amount of calories your body burns passively even when not exercising. Combined with caffeine, dieters using ephedrine products found some success in accelerating short-term weight loss.
However, since 2004, ephedrine alkaloids have been banned in dietary supplements, so most dietary offerings today contain ephedra extract with the ephedrine alkaloid removed.
Yohimbine is an inhibitor of alpha 2-adrenergic receptors, which can prevent a decrease in the adrenergic response to ephedrine. It inhibits a reduction in sympathetic nervous system activity that occurs when high levels of adrenaline and noradrenaline course through the body.
Research also suggests that it may promote lipolysis (the breakdown of fat) by blocking or antagonizing alpha-2 adrenoceptors on fat tissue (adipocytes).
Theoretically, this combination is purported to make the effects of the EC stack stronger. However, there are no studies evaluating the efficacy or the safety of an ECY stack and all of these ingredients pose a risk of dangerous side effects.
ECY Stack Results
Athletes and bodybuilders report using an ECY stack for their cutting cycles or to drop a few pounds prior to a competition or event. While the combination of ephedrine, caffeine, and yohimbine may promote a burst of stimulation in the body, the effect is not long-term.
It is always advised to follow a well-balanced and nutritious diet and add adequate levels and intensity of exercise to aid in weight loss and fat-burning efforts.
A number of studies have shown that combining ephedrine and caffeine can promote some weight loss. The average in clinical trials is around 1 kg-2 kg per month over someone who is not taking diet pills.
Another small study found that usage of Yohimbine HCL at high dosages can boost lipolysis or fat breakdown. However, this was only found in elderly persons with impaired lipolytic response. 
Another study examined the effects thermogenic herbal ingredients including Yohimbine HCL on 20 active and healthy individuals. The study found that use of this blend could support fat loss when combined with exercise. It was purported to work by increasing fatty acid oxidation, promotion sensations of satiety (fullness) and reducing perceived exertion while working out. 
ECY Stack Dosage Schedule
The dosages provided below reflect how this fat burning stack is currently being used and do not constitute a recommendation for how to take an ECY Stack.
Use of this stack could be dangerous to your health. Before using this combination, it is critical to consult with a doctor about the potential risks and practices for mitigating said risks.
Safe and effective dosages can differ widely between users depending on tolerance to stimulants, experience with these compounds and desired results.
Safety issues should always be considered first and foremost regardless of age and experience with performance enhancers. Use this stack responsibly or do not take it at all.
Dosage recommendations for creating your own ECY stack vary. A number of bodybuilding forum or discussion threads provide information on how others have created their ECY stack. For example, one suggests:
- 32 mg ephedrine HCL (hydrochloride)
- 300 mg caffeine
- 4 mg Yohimbine HCL (hydrochloride)
Users will typically start with a low dose of 4-8 mg ephedrine to gauge tolerance. This dose is then gradually increased upwards to the full amount.
Because ephedrine is no longer legally sold in the US as a dietary supplement, it is commonly purchased in the form of an asthma medication. Some common brand names include Bronkaid, Vasopro, Primatene, Kaizen, Synergenex and 4EverFit.
These products are intended to be used as asthma bronchodilators and nasal decongestants. They often contain other ingredients that are not suitable for weight loss, such as 200 mg of guaifenesin.
The number of times an ECY stack is repeated throughout the day is based on personal preferences, tolerance, and goals, and can range from one to three times daily.
Not everyone will use yohimbine in their stacks. Many sources recommend starting with an EC or ECA stack instead because of the perceived risks of combining ephedra with yohimbe extract:
- 25 mg ephedrine HCL
- 200 mg caffeine (equates to roughly 4 cups of regular coffee)
Yohimbine is still a legal supplement ingredient in the United States. It can be purchased in the form of yohimbe bark extract with different concentrations of active alkaloids.
Always use the amount of yohimbine provided to determine the dosage to take. Do not exceed a maximum dose of the lessor of 18mg per day or 1 mg per every 10 pounds of body weight.
In research studies, this product has been used in a standardize dose of 5-6 mg per day. Higher doses will increase the risk of side effects, particularly when combined with other substances.
While other bodybuilding forums or websites might recommend higher dosage ratios for an ECY stack, it is not recommended to start with high dosages due to the risk of unanticipated side effects. Do not use these products in a stack until you are familiar with their effects independently.
Is an ECY Stack Dangerous?
All of the ingredients in the Ephedra Caffeine Yohimbe stack have the potential to cause unsafe reactions, particularly if used in high doses, taken for long periods or consumed by individuals with pre-existing medical conditions.
Use of this stack can cause side effects including:
- High blood pressure (hypertension)
- Health palpitations
- Nausea, vomiting, diarrhea
- Restlessness or jitters
- Insomnia and difficulty sleeping
- Dizziness, vertigo
- Iritability, hostility, changes in mood
- Increased urinary frequency
- Muscle aches
More serious side effects can occur including renal failure, myocardial infarction, heart arrhythmias, fluid retention, tremors, adrenal fatigue, psychosis, chest discomfort and even death.
Exposure to high doses of an ECY stack can be life-threatening. Do not take more in the hopes of increasing effects. Use of higher dosages will not improve results and could cause permanent debilitating side effects.
Some sources suggest that yohimbine may be safer than ephedrine. According to one study, “The natural alpha-2 antagonist yohimbine promotes sympathetic activity by central as well as peripheral mechanisms, and yet in moderate doses dose not usually raise heart rate, increase blood pressure, or induce anxiety (in contrast to sympathomimetic drugs such as ephedrine).”
However, yohimbine and yohimbe bark extract still have the potential to increase strain on the heart if used excessively or consumed for extended durations. Do not mix these ingredients with other medications, diet pills or herbal stimulants.
These products should be avoided by pregnant and nursing women. Ephedra, caffeine and yohimbe should also be avoided by individuals diagnosed with (or who have an elevated risk of) high blood pressure, heart disease, or any mental health conditions requiring prescription drug treatment.
Before using an ECY stack, it is important to conduct thorough research about the risks. Do not take this stack without first consulting with a doctor to determine whether it is appropriate for you.
- Ostojic SM. Yohimbine: the effects on body composition and exercise performance in soccer players. Res Sports Med. 2006 Oct-Dec;14(4):289-99.
- McCarty MR. Pre-exercise administration of yohimbine may enhance the efficacy of exercise training as a fat loss strategy by boosting lipolysis. Med Hypotheses. 2002 Jun;58(6):491-5.
- Alkhatib A, Seijo M, Larumbe E, Naclerio F. Acute effectiveness of a “fat-loss” product on substrate utilization, perception of hunger, mood state and rate of perceived exertion at rest and during exercise. J Int Soc Sports Nutr. 2015 Nov 25;12:44. doi: 10.1186/s12970-015-0105-8. eCollection 2015.