ECA stack

Contents

1 ECA Stack

2 Mechanism of Effect in Weight Loss

3 Mechanisms of Effect in Energy Gain

4 Dosage

5 Addiction

6 Risks

7 Controversy and Legality

8 References

ECA Stack

The ECA stack is a popular drug combination for use as an energy booster and in weight loss. ECA is an acronym for ephedrine, caffeine, and aspirin.

Mechanism of Effect in Weight Loss

The effects of the ECA stack in weight loss are primarily due to the ephedrine component. Ephedrine acts as a beta agonist and stimulates the release of noradrenaline. The noradrenaline in the body then acts on brown adapose tissue by increasing cAMP levels, which is said to be a thermogenic effect, raising body temperature by about 2 degrees and increasing the user's metabolism by 10% in conjunction with the rest of the stack.

However, the body's negative feedback system then activates to normalize the metabolism. This is done via the production of phosphodiesterase inside the cells, and prostaglandins outside the cell, which both lower cAMP levels within the cell.

Caffeine inhibits the production of phosphodiesterase inside the cell and therefore slows the cAMP breakdown. It also, in binding with adenosine receptors in the brain, triggers the release of adrenaline which increases cAMP levels further.

Aspirin inhibits prostaglandin production outside of the cells, which, in conjunction with caffeine, greatly prolongs the thermogenic effects and increased metabolism by substaining elevated cAMP levels.

Ephedrine also has an anorectic, or appetite suppressant effect. The mechanisms behind this are not fully understood, but this aids in weight loss as well. However, these effects only last for about two weeks if the stack is not cycled as the body becomes tolerant to ephedrine to some degree. It is estimated that 60%-75% of the weight loss from using the ECA stack comes from the anorectic effect, and the remainder from thermogenesis.

The final component in weight loss of the ECA stack is that of a simple stimulant; the higher adrenaline and noradrenaline levels result in increased aerobic exercise performance and less fatigue.

Mechanisms of Effect in Energy Gain

Ephedrine acts to increase energy by its actions as a sympathomimetic amine. It increases dopamine and noradrenaline levels in the brain, and also partially serves as a dopamine reuptake inhibitor. Caffeine blocks adenosine receptors which lessens feelings of tiredness, and also increases dopamine levels, resulting in greater concentration, focus, and memory. The effects of caffeine on dopamine levels are usually short lived, but ephedrine's action as a dopamine reuptake inhibitor lengthens the duration.

Dosage

Typically the ECA stack is consumed two or three times per day in a 1:10:10 or 1:10:15 ratio of ephedrine:caffeine:aspirin. These ratios vary across studies and across users but despite variance they all seem to be effective. Usually, no more than 25mg of ephedrine or 200mg of caffeine is consumed in a single dose. It is not recommended that the stack be taken past late afternoon as this contributes to insomnia.

Addiction

While ephedrine and aspirin are not physically addictive, caffeine is, and users develop a tolerance to lowered adenosine levels, leading to withdrawl symptoms from adenosine sensitivity if caffeine use is discontinued too quickly. Psychological addiction to ephedrine and caffeine are also possible.

Risks

The primary risk of the ECA stack is in the effects of ephedrine on a pre-existing heart condition. Ephedrine has been linked to deaths in people with valve damage, cardiac hypertrophy , and other heart problems and heart disease. It is not recommended that stimulants be taken in users with a pre-existing heart condition. Additionally, there is some evidence that the long term use of amphetamines can lead to heart damage, but this has not been shown for ephedrine use.

Caffeine and ephedrine also act to raise blood pressure by appoximately 4-7mmHg on average, so users with existing hypertension must be careful that the stack does not increase their blood pressure to dangerous levels -- especially during exercise. The prescence of aspirin in the stack thins the blood and counteracts this partially, however.

Other risks include insomnia, dry mouth, irritability, stress, euphoria, headache, dizziness, nauseua, irregular heartbeat, interaction with MAO inhibitors, trembling hands, increased need for water and potassium, and psychosis resulting from the long-term use of ephedrine.

Controversy and Legality

Due to deaths linked to ephedrine many countries have taken steps to outlaw or control ephedrine. In the US, it is still legal to purchase as a bronchial decongestant with an exporant, but cannot be purchased in pure form or in a pre-existing stack.

If ephedrine cannot be obtained, pseudoephedrine, ephedrine's optical isomer, can be substituted in. Contarary to popular belief studies have shown pseudoephedrine to have a thermogenic effect; approximately three times less than L-ephedrine. Therefore, three Sudafed tablets, or 90mg pseudoephedrine should provide approximately the same thermogenic effect as 25mg ephedrine, but the overall effects of a pseudoephedrine based stack compared to an ephedrine based stack have not been studied. Unfortunately, due to the misuse of pseudoephedrine in the production of methamphetamine, many countries are banning or restricting pseudoephedrine sales as well, despite its safety record.

As of 4/14/2005, U.S. District Judge Tena Campbell struck down the FDA's ban of ephedrine in the US, which may pave the way for its reintroduction as a weight loss supplement in the US.

Many people have felt that ephedrine is not worth the risks, and have tried "ephedrine free" stack formulas. However, there is no proof that any of these formulations are actually effective, whereas a great deal of evidence exists to support the effectiveness of the ECA stack.