Caffeine

This is one of my recommended supplements. During high intensity exercise caffeine can improve performance and stamina. The average male requires ~200-400 mg of caffeine to improve performance, you want about 5mg/kg body weight for an efficacious dose. This can be a lot of caffeine.

Something to consider: will it affect your sleep quality, how does it impact your stress levels, and really and truly, how much does it improve your performance?

Andrea’s Advice: use sparingly, experiment with smaller doses to start, and titrate up.  Always test before a big event – don’t just decide on race day you’re going to take 400 mg of caffeine – otherwise the only place you’ll be racing is to the bathroom.  My philosophy is similar to Mike’s – use it on an as-needed basis.

Creatine

This is also one of my recommended supplements. Creatine is a naturally occurring compound in the body that helps with energy metabolism. Research shows that it can help improve sports performance and improve your capacity to train. It is also associated with protein muscle synthesis. It’s quite safe, especially in doses recommended for sport.

Andrea’s Advice: out of all the supplements, alongside caffeine, I feel the evidence is the strongest for this one. It is also least likely to have negative effects on the body.

Nitrates & Nitric Oxide

Despite some studies looking hopeful in this area, well designed, placebo controlled, crossover trials (read: good quality studies) have been really underwhelming. Product endorsers claim that products with Nitrates and Nitric Oxide help improve exercise performance, reduces O2 cost of exercise, and reduces resting blood pressure. However, long-term studies are lacking and there is potential toxicity from large doses. People claim to take it for the ‘pump’ in weight training – however there is no evidence to support that it actually improves blood flow or vasodilation. The body is a finely tuned machine and likely compensates for oral ingestion of nitric oxide.

Things to consider: Cost, Gastrointestinal sensitivities & Issues. I used to use N.O. Xplode, a pre-workout that has nitric oxide, it should be more appropriately be called N.O.-make-your-butt-Xplode, because, yeah, because of that.

Andrea’s Advice: I tried Beet juice once – guys – it made me feel awful.  The concentrated juice, plus high intensity exercise gave me a serious stomach ache. I’d pass on this poorly proven supplement.  If you want someone to help lighten your wallet, Mike and I are taking donations to our vacation funds. I kid – but really – where is your money going when you spend on pre-workout supplements? Often times, pre-workout supplements on the market are untested, unproven, and often have very little impact on your performance.

Beta-alanine

Wonder why your pre-workout makes you tingle? It’s the beta-alanine. Beta-alanine is an amino acid that has been shown to potentially be beneficial in exercise performance for high intensity, short duration exercise; supplementation results in higher skeletal muscle carnosine, an intracellular buffer. Typically, most of the studies have found the biggest impact in the first ~4 minutes of exercise. For the average exerciser, the split second difference in high intensity exercise performance is not likely worth it – or even going to be noticeable for you. For the Olympic or professional athlete? Maybe. However, there is limited research that suggests it may offer benefits in high-intensity anaerobic performance: greater than 1 min, less than 5 min, delays onset of neuromuscular fatigue, increased time to exhaustion (no change in VO2 max or max strength).

Andrea’s Advice: Though beta-alanine is not likely to cause harm, this is one I would skip.  For the average person those minute differences are not likely to make an impact on overall health, and therefore the risks outweigh the benefits.

L-carnitine

L-carnitine is a vitamin-like compound with well-established functions in intermediary metabolism. L-carnitine is vital to normal metabolism; the liver and kidneys synthesize L-carnitine from methionine and lysine. L-carnitine is found mostly in meat and dairy products.

Claim: L-carnitine acts as a vasodilator in peripheral tissues, which may enhance regional blood flow and oxygen delivery; might improve oxygen supply to injured tissue and promote clearance of muscle damage byproducts, thus reducing DOMS. L-carnitine is involved in the transfer of LCFA (Long Chain Fatty Acid) across the mitochondrial membrane. Theory is that supplementing with L-carnitine could enhance FA (Fatty acid) oxidation in athletes.

There is no substantial evidence to support this theory; even so, supplements are widely sold.

Hydroxycitrate (HCA)

A principal constituent of the rind of the fruit of Garcinia cambogia use in Asian cuisine.  Appears as an ingredient in multiple different products such as the No-diet diet, Bio Max 3000, PhytriMax, Lite Bites, Garcinia, TrimePlus, GarciniaeMax, Diet+System, Citrilite, Citrichrome, Lipotrol, MicroSlim, Body+Busters, and Super Prolean Mega Fat Burner.

Claim: “natural fat burner” that facilitates weight loss, touted generally as being able to enhance endurance performance.

Research findings indicate that increasing plasma HCA availability with supplementation exerts no effect on skeletal muscle fat oxidation during rest or exercise. In other words, it does nothing.