There is a shorter half live in albuterol than clenbuterol but this may not be a clear disadvantage:
"Albuterol, like its closely related chemical cousin clenbuterol, is an asthma medication that has been adopted by athletes and bodybuilders as an ergogenic aid. Like clenbuterol, albuterol binds to the so called beta 2 adrenergic receptors found on cells throughout the body. The beta 2 receptors on fat cells activate an enzyme called hormone sensitive lipase. This breaks up stored fat into free fatty acids that are able to then leave the fat cell and serve as a fuel source in other tissues. In athletes the primary target of these fatty acids is working muscle. This is the familiar process we know as lipolysis. Albuterol, like clen, is a potent lipolytic agent. But simply freeing up fat is not enough. Unless the body can burn the extra FFA they will simply be reincorporated into fat. Albuterol has the ability to elevate a person's metabolic rate so these FFA can be utilized for fuel. Numerous animal studies have shown that clenbuterol increases both muscle size and strength; data supporting these effects in humans are sparse. Albuterol on the the other hand has been shown to significantly increase both strength and endurance in humans (1,2). As an added benfit, albuterol lowers LDL and total cholesterol, while at the same time elevating HDL, the "good cholesterol": "Significant alterations (P < or = .02) were observed in total cholesterol ([TC] -9.1% +/- 2.5%), low-density lipoprotein cholesterol ([LDL-C] - 15.0% +/- 2.9%), and high-density lipoprotein cholesterol ([HDL-C] +10.4% +/- 3.2%) concentrations, as well as the TC/HDL-C (-17.4% +/- 2.6%) and LDL-C/HDL-C (-22.9% +/- 2.4%) ratios." (3) 4 mg of albuterol taken approximately 1 to 2 hours before a workout allows for peak plasma levels to be reached during the training session. Additionally the much shorter half life of albuterol compared to clenbuterol allows one to benefit from its ergogenic effects during a training session but not suffer the sleeplessness that many clenbuterol users experience. Moreover, the short half life leads to much less beta 2 receptor downregulation than with clenbuterol, allowing one to use the drug daily for longer periods of time. On the other hand, if one is primarily interested in fat loss rather than performance enhancement, one could take 3 or 4 multiple doses of albuterol throughout the day, always of course cutting back if clenbuterol-like side effects are felt. 1 Bottle Of CEM Laboratories Liquid USP Albuterol Sulfate is 30 ML at 4 MG/ML. (1) Med Sci Sports Exerc. 2000 Jul;32(7):1300-6. Effect of salbutamol on muscle strength and endurance performance in nonasthmatic men. van Baak MA, Mayer LH, Kempinski RE, Hartgens F. (2) Aviat Space Environ Med. 2004 Jun;75(6):505-11 Albuterol helps resistance exercise attenuate unloading-induced knee extensor losses. Caruso JF, Hamill JL, Yamauchi M, Mercado DR, Cook TD, Keller CP, Montgomery AG, Elias J. (3) Metabolism. 1996 Jun;45(6):712-7 Effects of oral albuterol on serum lipids and carbohydrate metabolism in healthy men.
Maki KC, Skorodin MS, Jessen JH, Laghi F."
More info...
By Nandi
I've noticed that with albuterol the increase in heart rate is there, but since the half life is short, you don't notice the effect nearly as much as with clen. This is probably because I use it prior to a workout when my heart rate is up anyway. With clen, I notice it when I'm trying to get to sleep, for example.
The stimulation of the heart is a result of the fact that neither clenbuterol nor albuterol are completely selective for beta-2 receptors. They still act on beta-1 receptors to some degree, and these are the receptors that are primarily responsible for the cardiac effects. Ephedrine is nonselective, and that's probably why many people say they get better fat burning effects with an EC or ECA stack than with clen: the increase in heart rate is contributing to the calorigenic effect more than is the case with clen or albuterol. But it also has more side effects.
As far as the enantiomers go, albuterol contains an equal mixture of the R/S enantiomers, Xopenex consists of the R enantiomer. From the discussion above you can see that both enantiomers contribute to the calorigenic effect. The S form present in albuterol contributes to beta-1 activity, which increases heart contractility contributing to a portion of the calorigenic effect. Beta-1 receptors also contribute to lipolysis in fat cells.
In humans both beta-1 and beta-2 receptors contribute to thermogenesis, with there being conflicting data about the contribution from beta-3 receptors. See (1) for example. So some degree of beta 1 stimulation is desirable.
Both the R and S enantiomers of albuterol contribute to thermogensis by activating both the beta-1 and beta-2 (and probably beta-3 as well) receptors. Xopenex would likely be a much less effective thermogenic than albuterol because of its lack of beta-1 stimulation.
(1) Am J Physiol. 1993 Jan;264(1 Pt 1):E11-7.
Role of alpha- and beta-adrenoceptors in sympathetically mediated thermogenesis.
Blaak EE, van Baak MA, Kempen KP, Saris WH
