The original Stacker 2 was an ephedra weight loss supplement that was promoted as the world’s strongest fat burner.
Manufactured by NVE Pharmaceuticals, this supplement was designed as an herbal alternative for bodybuilders using an ECA stack with Ephedrine HCL, caffeine and aspirin.
This stack was formulated to maximize energy for a workout and to help athletes achieve a lean cut physique. Stacker 2 previously contained an herbal source of ephedra but has now been reformulated to remove this ingredient.
In 2004, ephedra was banned as an ingredient in dietary supplement due to the risk of side effects linked to ephedrine alkaloids. The original Stacker 2 diet pills are no longer available to buy.
NVE Pharmaceuticals also sells another product called Stacker 3 which also promotes fat loss with the active ingredient Chitosan. What is the difference between Stacker 2 vs. Stacker 3 and which of these products is better for weight loss? Click here to buy ephedra supplements online legally without a prescription.
Stacker 2 with Ephedra
Stacker 2 with ephedra was one of the original ephedra-based fat burning supplements that became popular in the 1990’s.
This product was targeted to bodybuilders who used it as a natural pre-workout ECA stack. It was formulated to promote intense energy, control appetite and increase metabolism during a cutting cycle.
This product contained a proprietary blend of 25mg ephedrine alkaloids from ephedra, 200mg caffeine alkaloids from kola nut extract and white willow bark with salicin. This last ingredient is an herbal form of Aspirin, commonly used in dietary supplements.
Ephedra has long been reputed as one of the most effective energy and weight loss supplements, primarily because of its two main alkaloids – ephedrine and pseudoephedrine – which both act as central nervous system stimulants.
Both of these alkaloids stimulate adrenergic receptors in the body, causing heart rate and blood flow to increase, boosting oxygenation and enhancing the breakdown of fat for fuel.
Caffeine and aspirin were frequently stacked with ephedrine because they promoted a synergistic effect, resulting in a physiological stronger response and greater sympathetic activation.
The original version of Stacker 2 with ephedra quickly became well-known among bodybuilders and athletes for its reported ability to melt fat and provide massive motivation to work out.
According to the manufacturers, “The Stacker2 fat burner has helped many where others left off due to the edge you receive when from its ultimate boost of energy. The energy you receive when using Stacker2 helps get you moving and keep you moving.”
In 2004, the US FDA banned ephedrine alkaloids from appearing in dietary supplements. Stacker 2 with ephedra as one of its ingredients was discontinued by NVE Pharmaceuticals and a new version was introduced.
The new formulation contains the following fat-burning ingredients:
- Green Tea
- Kola Nut
- Yerba Mate
- White Willow
The Stacker2.com website states that these ingredients can help your body burn fat at a faster rate compared to diet and exercise. This product is scientifically engineering to boost metabolism, increase alertness, energy levels, blood flow and stamina.
Most of the ingredients in this supplement are stimulants that work in a similar was as ephedra but are not as potent.
According to NVE Pharmaceuticals, the “Stacker2 formula is designed for those who are in search of a dietary supplement in a powerful Ephedra-free formula. When taken as directed, this formula may help burn fat, cut cravings, and boost a sluggish system without the use of Ephedra.”
This supplement has a positive 4/5 star review on Amazon.com, although many reviewers say that it is not as powerful as the original product.
How does the Stacker 3 supplement compare to Stacker 2? This product is another ephedra-free supplement that is designed to target fat loss through several different mechanisms of action.
Like the ingredients in the new Stacker 2 product, this supplement also contains stimulants such as caffeine and green tea leaves.
The main different ingredient in this supplement is Chitosan, which is promoted as “a powerful way to help you get rid of ugly, unwanted body fat while receiving a powerful boost of energy.”
The ingredients in Stacker 3 are designed to suppress appetite and encourage thermogenesis. This supplement also contains:
- White willow bark
- Chromium picolinate
- Green Tea leaves (Camellia Sinensis 60% polyphenols)
- Garcinia Cambogia Fruit
Each capsule contains a total of 575mg of active ingredient and the recommended serving size is one capsule. This product has a 4.1 out of 5 rating on Amazon with many users saying it gave them more energy.
Chitosan for Weight Loss
How does Chitosan support weight loss? This ingredient is found in many dietary supplements sold today. It is a type of fiber extracted from the shells of crustaceans (crabs, shrimp, and lobsters).
According to the manufacturers, “Chitosan passes through the digestive tract, it may have the ability to bond with ingested fat and carry that fat out as waste.” This suggests it may block the absorption of some fats consumed in the diet.
Chitosan has been used medically to lower blood cholesterol levels as well as body weight. It is also used in emergency situations to control bleeding.
A number of small studies have evaluated the effects of this ingredient for weight loss and body fat reduction. One eight-week study determined that chitosan, in addition to L-ascorbic acid, could promote fat loss in overweight women. Study subjects experienced a slight decrease in body mass index, averaging 1 kg to 1.6 kg. 
Chitosan has also been researched for its potential in reducing cholesterol levels or lipid profiles, as well as oxidative stress and insulin sensitivity caused by a high-fat or high-cholesterol diet. Some improvements were noted in a study involving 40 obese male rats with positive effects on cardio-metabolic processes. 
Some online reviews criticize the Stacker 2 and Stacker 3 diet pills for being glorified caffeine pills. Without ephedra as an ingredient, many of the stimulatory effects of these supplements come from the caffeine content.
How effective is caffeine for weight loss? Most fat burning supplements today contain caffeine because it does have an ability to promote thermogenesis, increase metabolism and boost energy levels.
Caffeine is a stimulant affecting the central nervous system. It can increase the heart rate, make users feel more alert and cause your body to burn more calories when at rest or when exercise. Studies have shown that use of caffeine on its own can modestly raise metabolism and contribute to fat loss, but users quickly develop a tolerance to the effects.
Sustainable weight-loss is achieved only through decreased caloric intake, eating a nutritious and balanced diet, and increased levels and intensity of exercise. While the caffeine found in the Stacker 2 and Stacker 3 supplements may help to kick-start results, long-term success will require some lifestyle changes.
Stacker 2 and Stacker 3 Side Effects
Without the ephedra content, the new version of the Stacker 2 supplement is safer but may still contribute to negative effects.
The potential for experiencing side effects will depend on sensitivity levels to the stimulants found in these products. If a person is sensitive to the effects of caffeine, they may experience some adverse reactions.
Both Stacker 2 and Stacker 3 contain multiple stimulants, but the main active ingredient in each is 200 mg – 250 mg of caffeine. A number of fat burning products on the market today contain significantly higher doses of caffeine in anhydrous form.
Studies have shown while in moderation caffeine is not particularly harmful, ingestion of concentrated forms of caffeine can produce undesired side effects.
According to one study, some dietary supplements are marketed as containing nearly two times the levels of caffeine that is recommended daily. It is difficult to determine a safe dosage for caffeine because individual tolerance varies.
This supplement also contains Yerba Mate, Yohimbine, and other herbal substitutes for the now banned ephedrine alkaloids. Combining these stimulants with caffeine can increase the risk for:
- Heart palpitations
- Tachycardia (accelerated heart rate)
- Cardiovascular toxicity
- Extreme anxiousness
- Hand tremors
It is recommended that an individual not exceed 400 mg caffeine daily. This is approximately four cups of brewed black coffee, two energy drinks or ten cans of caffeinated soda. 
Substitutes for the Original Stacker 2
Products like Stacker 2 and Stacker 3 can be purchased today without any ephedra alkaloids. However, many people continue to search for legal alternatives that can promote the same effects as the original ephedrine diet pills and ECA stacks.
One trend in the supplement industry is to use ephedra extract with the ephedrine alkaloids removed. Under US law, you can legally sell ephedra weight loss supplements and fat burners, so long as they don’t have any ephedrine alkaloids.
Considering that the ephedrine and pseudoephedrine alkaloids were the main ingredients in ephedra products that made them effective, many consumers wonder whether these new alternatives work.
Manufacturers will typically replace the removed ephedrine alkaloids with other stimulating ingredients that have similar mechanism of action. For example, Synephrine is one ingredient that is often compared to ephedrine because it activates similar receptors in the body.
Some examples of ephedra extract and ECA stack diet pills that you can buy currently include:
- Green Stinger: Contains Citrus aurantium, providing 30% synephrine extract as well as 200 mg of caffeine from herbal sources.
- Diablos ECA Fire Caps: Contains 225 mg caffeine anhydrous, 50 mg ephedra extract (from the leaves) and a 275 mg proprietary blend of additional stimulants.
- Methylephedra ECA: Contains 250 mg caffeine anhydrous and 25 mg ephedra extract (from leaves) as well as other herbal stimulants in a 485 mg proprietary blend.
- Liquid Fire: Contains 35 mg ephedra extract, 190 mg caffeine anhydrous, and a number of other stimulants.
- Black Mamba Hyperrush: Contains 85 mg ephedra extract from the leaves and 200 mg caffeine anhydrous as well as other herbal stimulants.
- Stimamine Black: Contains 50 mg ephedra (aerial extract) and a 515 mg proprietary blend with caffeine anhydrous, green tea extract, and other herbal stimulants.
When looking for substitutes for the original Stacker 2 with ephedra, take the time to read the label of ingredients and research the active compounds. Not all of these products work the same way and many manufacturers do not disclose specific ingredient concentrations.
Use caution when starting to take any supplement for weight loss. It is recommended that consumers start at the lowest recommended dose to gauge the body’s reaction to it.
Anyone who is under the age of 18 or pregnant or breast-feeding women should not use these supplements. Consult with a doctor before taking these products if you have been diagnosed with a medical condition or are currently using other drugs or supplements.
You can buy Stacker 2 and Stacker 3 online and in some offline supplement stores. This product is available on websites like Amazon and eBay as well as from GNC, Walmart, Walgreens, CVS and Vitamin Shoppe.
If you are looking for ephedra extract supplements to use as an alternative to the original Stacker 2 energy pills with ephedrine, these products are harder to find in local stores. However, you can buy them online from specialty retailers.
- Jung EY, Jun SC, Chang UJ, Suh HJ. L-ascorbic acid to chitosan reduces body weight in overweight women.
- Bahijri SM, Alsheikh L, Ajabnoor G, Borai A. Effect of Supplementation With Chitosan on Weight, Cardiometabolic, and Other Risk Indices in Wistar Rats Fed Normal and High-Fat/High-Cholesterol Diets Ad Libitum.
- Mayo Clinic. Caffeine: How much is too much?