Dear JWM...
Supplementing is not an exact science, and the jury is still out on the effects of certain herbal combinations and long term use.
Thermo-stack type drugs combine caffeine, ephedrine and aspirin (in herbal form, it's guarana, Ma Huang and white willow bark); there is some proof that this blend accelerates metabolic processes, but if you are caffeine and/or ephedra sensitive, they can be dangerous. The metabolism accelerates because caffeine and ephedra are stimulants, which causes the heart rate to elevate. Whenever the heart works harder (be it due to vigorous exercise or drugs) all the cellular processes increase. This is why drugs like Xanadrine and Metabolife can work. However, their effect is short-lived and the side effects can be extremely dangerous. I have used the EAS form of a thermal "stack", called Beta-Lean. It is time-released, and the company recommends using it for 12 weeks and then going off for a week or two. I haven't had any side effects, fortunately, but my daughter tried it for a couple of days and had scary palpitations. She has since discovered an extreme sensitivity to caffeine, and cannot even drink caffeinated beverages. You have to weigh all your options. Does drinking coffee make you jittery? Then you probably shouldn't take a thermal accelerator. If you do decide to give it a try, be very cautious. DO NOT start with the total recommended dosing. Start with one capsule (caplet) per day and watch for your body's response. And always use a well-known brand.
Another supplement gaining extreme popularity is Creatine. It is in powdered form and needs to be mixed in room-temperature apple or grape juice. Since Creatine relies on insulin to transport it into muscle cells, the sweetened juice stimulates the pancreas to release insulin, thereby assuring the transport of creatine into the muscle cells. When you exercise, (if you remember, from biology classes) the muscles utilize ATP for energy. ATP (Adenosine Tri-Phosphate) converts to ADP (Adenosine DI-Phos). The greater the amount of ATP in the muscle during exercise, the longer you can endure and usually the heavier you can lift. Once the ATP converts to ADP, however, the muscle cell must find an additional phosphate to convert back to ATP so that it can keep contracting. Creatine floods muscle cells with that additional phosphate, making more available during exercise than when you exercise without the supplement. Clear as mud, eh? Bottom line is, you CAN get additional phosphate from your diet, but hardly the amount you get from supplementing with Creatine. Despite a little bad press a few years ago, more and more research is showing that Creatine is relatively harmless. I use it and find that my endurance is greater and my ability to pump out a few extra reps is far better than when I exercised without it. There is a loading phase, where you take 20 grams per day for five days, to get the blood levels up quickly. Thereafter, you take 5 grams daily, often within the hour after exercise, when the muscle cells are most receptive. The EAS website has a lot of medically-oriented research articles re: Creatine on their website;
www.eas.com . I use the MetRx brand of micronized Creatine, because the granular particles are smaller and mix more easily into liquid. Also, I have mixed it into a weak solution of Tang (the sugery kind). New research has shown that Creatine is better absorbed when taken with room-temperature liquid, rather than cold or hot.
As far as other "supplements", when you go to the eas website, you might want to take a look at something called CLA...conjugated Linoleic Acid, which is a supplement that has been proven to spare lean muscle and force the body to utilize fat for its energy source. I don't use this because it is rather cost prohibitive, but there's some interesting info out there on its use.
Above all, the best supplement you can take is a multi-vitamin (I use chewable, cuz my stomach is a wuss with regular horse pill type vitamins). Also, a calcium supplement, iron (I take it separately because dosing with iron every day gives me too much and I get constipated...so I take it every other day)and green tea extract. Green Tea and its extracts are proving to be a more powerful anti-oxidant than Vit C and E combined. It is also showing evidence of prevention of gastro-intestinal cancers. As hearty exercisers, we ALL need to be using a good anti-oxidant to prevent those free-radicals we produce after exercise from doing post-exercise damage. It is a rather complex process that I won't go into here, but suffice it to say, free radicals are not a good thing.
That's the basics. I am an RN, which shouldn't necessarily qualify me out-right, however, I've exercised for years and have read everything I can get my hands on regarding supplementation. The EAS website is now offering their newest edition of "Sport Supplement Guide" (I think its the fourth edition) absolutely free. It is a very comprehensive guide, well written and thorough. It will tell you all you ever wanted (and didn't want) to know about sport supplements. I just ordered mine, because, like everything in the medical community, things are constantly changing, and I like to stay updated.
Good luck! Hope this little diatribe helps...
Lynn