The Good, The Bad, and The Ugly:
The Truths and Myths About Commonly Used Fitness Supplements
Fitness Supplements: The Good
These are supplements that have been shown to have a net positive effect on training, whether in regards to stamina, recovery, or ability to build muscle. Supplements included here should be a staple if you are trying to push your exercise performance to the limit.
1. Creatine
Creatine in all of its purchasable forms in general is believed to work by replacing creatine phosphate in the muscle. Creatine phosphate itself is used to regenerate adenosine triphosphate (or ATP in short), which is the molecule that is consumed in skeletal muscle contraction-relaxation cycles during high intensity exercise. Thus, the theory is that by saturating your muscles with creatine phosphate, you will have a greater reserve of ATP, and therefore a greater ability to perform more contraction-relaxation cycles before muscle failure. In short, you should be able to squeeze a few more reps out. It is this simple science that has given creatine the reputation of a must-have fitness supplement; indeed, this is perhaps the most widely used fitness supplement worldwide.
Yet, with such widespread use comes a great deal of mysticism: “creatine is a steroid”, “creatine will damage your kidneys”, “it only gives you ‘water weight’”, etc. To put it bluntly, this is all wrong. Creatine is perhaps the most effective, safe, and cost effective fitness supplement money can buy. Don’t believe us? Here’s the data.
First, let’s dispel the myth that creatine will damage your kidneys. Do you have functional kidneys? No current kidney disease? In general, are you a young, healthy, active person? You’re safe [1][2]. What about average Joes? Still safe [1]. Lose a kidney after a rough week in Mexico? Guess what? You’re probably still safe [3]. So next time your mom or doctor thinks your kidneys are going to get damaged from creatine, send them this article. Even type II diabetics, who are at increased risk of kidney disease throughout their life, can safely take creatine as a supplement without any significant changes to indices of renal function [4].
Now that we’ve established that creatine is by and large safe, let’s look at the data proving it works. Creatine, overall, has been shown to boost performance significantly, primarily in anaerobic exercise when supplemented at approximately 3 grams per day or more. Studies have demonstrated that with creatine supplementation, athletes can see increased regional muscle thickness, increased strength in both 1 rep-max and repetitions-to-failure resistance training, and reduce fatigue in repeated bouts of sprinting [5,6,7]. Creatine is one of the few supplements in the fitness industry that has been researched this vigorously, with numerous studies touting its beneficial effects on muscle strength [8]. Almost no other supplement in the fitness industry can claim to have this much concrete data backing up its use.
Unsurprisingly, creatine has minimal to no performance boosting effect in aerobic exercise, however, some data suggests that creatine may prevent muscle protein degradation after extended endurance activity [9,10]. To put this in layman’s terms, creatine seems to increase strength in anaerobic exercise (weight lifting, sprints, etc.) decrease fatigue, and may also reduce muscle tissue breakdown after endurance exercise.
Creatine has also been studied beyond the fitness realm, with interesting results. In patients with muscular dystrophies and inflammatory myopathies - essentially diseases that lead to increased muscle tissue breakdown - creatine has been found to improve functional outcomes and decrease the rate of muscle tissue degradation [11]. It also seems to improve recovery times after musculotendinous injury, and increase the rate of recovery after muscle atrophy [12,13]. This means for the athlete suffering from muscle strain or tendinous injury, creatine might be able to decrease the time spent in rehabilitation, which means more time being on the field.
So what about the claims of water weight? For those of you with any knowledge of basic chemistry, this will be easy. At baseline, your muscles are not saturated with creatine phosphate unless you eat more than 5 lbs of red meat per day; thus, to saturate your muscle cells, you will need to supplement your diet with creatine. If you were to simply increase the amount of creatine phosphate in a muscle cell, the osmolarity of the muscle cell will increase—that is, the number of particles dissolved in water in that cell. Usually, the body doesn’t like changes in osmolarity, so the muscle cells will attempt to equilibrate. This equilibration can only be done by drawing water into cells or pumping creatine out of cells. What sounds easier? You’re right if you guessed drawing water in—in fact, this happens spontaneously as water is free to cross most cell membranes in the body. Like it or not, you will most likely see an increase in weight during creatine supplementation.
Verdict: One of the most effective supplements available for the price. Cheap, easy, and safe to use, it should be a staple for any weightlifter. Supplement with 5 grams per day—loading doses are not required—and expect a small boost in 1 RM and reps-to-failure.
2. Caffeine
Caffeine is the most widely used psychoactive substance in the world, with billions of anecdotes of its usefulness accompanying the thousands of studies proving that it works. It is among the safest and most widely studied drugs in the world; evidence suggests it’s been consumed since 3000 BC in the form of tea, and has found widespread global consumption in the form of coffee since the 16th century. We don’t need to tell you caffeine works—that’s been known for centuries. What we will tell you is how it works, and if it can be used to give you a lift in the gym.
Among the number of likely mechanisms in which caffeine works, it blocks adenosine—a molecule partly responsible for inducing the feeling of fatigue in the body—from binding to its receptors and will also stimulate the central nervous system. Caffeine has been shown time and time again to boost attentiveness, alertness, time-to-fatigue, and reduce perceptions of pain in tasks requiring mental and physical exertion [14,15]. How does this translate to performance in the gym?
In general, caffeine appears to dampen perceptions of fatigue, pain, and improve endurance in aerobic and selected anaerobic exercises when dosed at 100 to 200mg prior to workouts. Caffeine confers a significant endurance boost in aerobic activities—specifically running—but doesn’t seem to have the same effect across all anaerobic activities [16,17]. Specifically, caffeine has no acute impact on strength like we saw with creatine, meaning your 1 rep max is unlikely to improve immediately after chugging that pot of coffee (or pre-workout) [18,19]. It does, however, improve number of reps until failure, and subjects report decreased fatigue after reps-to-failure with caffeine ingestion compared to placebo [17,19]. So for those of you using a high-rep bodybuilding split, caffeine should provide a major boost. Dropsets, anyone?
Verdict: Caffeine is a safe, effective, widely used performance enhancer that might get you to squeeze a few more reps out and decrease your mile time. So get up, chug that coffee (anywhere from 100-200mg will do), and do your sets!
3. Whey (and other) proteins
For the beginners reading this article, protein—specifically whey—is probably the most widely worshipped supplement by fitness bros worldwide. From the college classroom to the campus rec, the office watercooler to the hospital OR, any reasonably muscular man is likely to encounter the question, ‘So, which protein do you use, bro?’ This is typically followed up with by, ‘Oh, cool, whey? So how much do you take a day?’ Naturally, most people respond with 1 gram of protein per pound of body weight. Why? No one really knows. This is just the number every jacked fitness geek knows as the optimal protein amount—and no one ever really questions it. So, do we truly need 1g protein per pound of body weight? Do we need to supplement at all? Let’s find out.
The theory behind using protein supplements, specifically after a workout, is to supply muscles with the building blocks for growth. The active units of muscle fibers contain a number of polypeptide (note: a polypeptide = a protein) rich subunits, particularly the two named actin and myosin. During a workout, muscle fibers are subject to microtrauma, and micro-tears develop in the muscle that is being actively worked out. Using a protein supplement after a workout should, in theory, provide a rich source of amino acids from which muscles can be repaired. Does the data support the claim? Unfortunately, not really.
Most studies do not support any benefit from acute protein supplementation either before or after a workout [20,21]. There doesn’t even seem to be any benefit in muscle soreness when a protein supplement is consumed following a workout, as long as the diets are equivalent otherwise [21]. So why do we all keep using protein powder? Are we just peeing nitrogenous compounds out, all for naught?
While the data for acute protein supplementation is poor, there is a growing body of evidence that supports that high protein diets in general will positively affect body composition and recovery from workouts [22]. Furthermore, high-protein diets appear to preserve lean body mass during times of caloric restriction when compared to their regular diet counterparts [23,24]. Now, what does this information mean? It is essentially useless to chug a protein shake before, after, or during your workout, as long as your daily diet is protein rich. That’s right. All you need to do is have a high protein diet. Luckily, protein powders are an easy and cheap method to increase the protein content in your diet. So stop worrying, you’re not wasting your money on your protein shakes, but you are wasting your time worrying about when you take it.
So now that you’re armed with the knowledge that all you need to consume is a ‘high protein diet’ while you’re weightlifting, the last piece of the puzzle is quantity. The studies in question utilize diets that contain 25-40% of all calories from protein [22]. The typical recommended daily allowance (aka the RDA, which you see on all food labels) of protein comes to about 15%. 15%! The average consumer, if using RDAs for guidelines for macronutrient intake (proteins, carbs, fat), is getting about half the protein they should be if they want to optimize body composition. Luckily, most readers aren’t the average consumer; however, you can stop using the 1g/pound myth. Instead, just think of all your total caloric intake, and aim to get >25% of daily calories from protein. So for the person requiring 2000 calories, this means 500 calories should be protein, which is 125g of protein. No that you don’t have to worry about the ‘anabolic window,’ you can stop bringing your smelly shaker cups to the gym.
Of course, there will be those individuals who claim that high protein diets are damaging to the body—particularly the kidneys. Not to worry, systematic reviews have shown that high-protein diets are harmless, and will not cause bodily harm in individuals with healthy kidney function, nor cause harm to the kidneys themselves [24,25].
Verdict: Don’t worry about protein shake timing. Instead, use protein powders to help you achieve a daily goal of getting 25% or more of your daily calories from protein alone.
Fitness Supplements: The Bad
These are supplements that have been shown to have mixed data or have absolutely no data backing their claims on training, recovery, or boosting performance. Supplements included here will likely not harm you, but are unlikely to help, either.
1. BCAA’s
You’ve heard the deal here. Pre-workout BCAAs. Intra-workout BCAAs. Post-workout BCAAs. BCAAs before bed, after waking up, before your important job meeting, during your wedding, in the middle of the night. Remember, you always have to take your muscle-boosting, anti-catabolic BCAAs or your muscles will literally shrivel while you workout. Or at least, that’s the claim, right?
BCAAs as a fitness supplement have exploded in popularity in the past few years, with companies stating that during a workout, your body requires supplementation with additional amino acids, for either fatigue-reducing or anabolic effects. Essentially, companies claim that while you workout, BCAAs will be available for uptake into muscles from the bloodstream so that your muscles can be built… while they are being torn. Nevermind the fact that most of the actual muscle growth occurs after you’re finished working out, what do our studies have to say about BCAAs?
Unlike supplements mentioned in ‘The Good’ section, BCAAs give mixed data when it comes to boosting performance. One double-blind study showed no performance enhancing whatsoever [26]. Another study showed enhancement in physical performance during exercise after athlete’s muscle glycogen stores had been depleted, while another study looking at marathon runners only found performance boosting in the slowest group of marathon runners [27,28]. So BCAAs range from completely useless, to having potential benefits in less trained/untrained athletes, to having a possible net positive effect only when you’re exhausted. Unlike creatine, caffeine, etc., BCAAs do not have a relatively large, unanimous body of data supporting their performance-boosting claims. Furthermore, if you’re like us (the writers), you’re eating chicken for breakfast, lunch, and/or dinner, and slamming down at least a protein shake a day. Do you know what can be found abundantly in these protein sources? That’s right. BCAAs.
Our verdict: More likely to affect your wallet than your training. Pass.
2. Testosterone Boosters
This category of supplements probably hosts some of the most outrageous claims possible among supplements reviewed here. ‘Test’ boosters have often been used by men suffering from low libido, men who think they have an abnormal fat distribution, those not seeing enough gains in the gym, and by those who just want to get a little more pep in their step. To many people, test boosters would be the holy grail: life-improvement in a bottle. Test booster seem like a perfect choice for those unwilling to delve into the shady world of anabolics: get all the good effects of testosterone, without any of the bad health effects! Think this sounds too good to be true?
It is.
Most testosterone boosters contain proprietary herbal blends, typically including tribulus, tongkat ali (longjack), zinc/magnesium/aspartate, possibly fenugreek, and all sorts of other exotic herbs. Since there are too many potential ingredients to investigate, we’ll take a look at two of the most widely used herbs, tribulus and tongkat ali. To make a long story short, if you’re going to use either of these herbs to increase your testosterone, you’re gonna have a bad time. Most studies on normal, healthy individuals find no changes in androgenic hormones whatsoever when either of these herbs are used [29,30,31,32]. The only time Tongkat Ali has ever been shown to have an effect is in men who are already hypogonadic—that is, men who have low testosterone to start with [33]. Tongkat Ali might have some effects on lowering cortisol and boosting testosterone in stressed individuals, but more studies would be needed to make that a definitive statement [34]. Tribulus similarly improved subjective parameters (fatigue) in men who had low sperm counts [35]. And what about fenugreek? According to one study, it has no effect on testosterone, and is useless unless you have been considering lowering your DHT levels [36].
Verdict: If test boosters actually worked, millions of men would be buying the stuff in pounds. Anything that claims to alter your natural hormonal state, or has the word ‘booster’ is garbage and a waste of money.
3. Ammonia, AKA Smelling Salts
Known by a variety of names throughout history (think; “salt of hartshorn”, sal ammoniac and “baker’s ammonia”, to name a few), “smelling salts”, in the context of sports supplements, refer to ammonium carbonate ((NH4)2CO3H2O) [37]. The use of smelling salts is extremely prevalent among powerlifters to get “amped up” before attempting a heavy PR, as well as some high-intensity sports such as American football.
How does it work? The crystalline salts of ammonium carbonate (sometimes dissolved in liquid) give off ammonia gas (NH3), which – when inhaled – irritate the mucosal membranes and nerve endings of the nose, nasal cavity and lungs. Upon irritation of these cells, a sudden inhalation reflex is stimulated. This initial reflex is followed by an increased rate of breathing and a coinciding increase in heart rate, thus promoting alertness [37,38].
Ok, great. But does all of this alertness translate to improvements in power performance? Scientifically no. Several studies have investigated the use of smelling salts in pre-designed resistance training routines, and all basically found that no, the inhalation of ammonia before beginning a lifting set did not significantly improve the athletes’ performances neither in maximum amount of weight lifted, nor the number of repetitions performed [39,40].
Nevertheless, for anyone who has spoken with someone who uses or has used ammonia salts, you can be sure to have heard remarks of praise. In fact, in one international survey 126 of the 256 participating powerlifters reported using ammonia inhalants and 78% of those lifters claimed that the use of the smelling salts significantly improved their performance. Many of these athletes claim to use ammonia predominantly at the end of their lifting meets when they “need a boost” [38]. Breathing techniques have regularly used to promote wakefulness, as well as improve performance in athletes that experience anxiety prior to competition. Due to the intense inhalation reflex caused by smelling ammonia, it is possible that indirect improvements in performance may take place on an individual basis.
In terms of safety, correct use of ammonia salts (without pre-existing health concerns) does not appear to have any long-term negative effects on your health [37,38,39].
Conclusion: The science does not show any link between using ammonia inhalants and force or power production. However, considering the general safety and inexpensive nature of smelling salts (regularly found online for $7-10 per several month’s supply), if you attempt PRs and tend to self-doubt yourself prior to competition, it doesn’t hurt to try smelling salts. If you try using this supplement and feel as though it improved your performance, then continue using it as you may. If you don’t notice a difference in performance then, well, you’ve only wasted a few bucks.
Fitness Supplements: The Ugly
These are ‘supplements’ in the loosest sense; these are most often compounds that likely lie in a legal grey area if not completely illegal. These are supplements that without a shadow of doubt work, but, they’re illegal for a reason—the performance enhancement comes at a cost to your health. We recommend against taking anything listed here because of detrimental health effects; however, their use is widespread in the fitness industry. Think twice before you think you want to make it in the fitness industry.
1. Anabolic Steroids
Androgenic anabolic steroids (AAS) are a highly sensitive subject in the fitness industry. Nearly every fitness personality, whether just an Instagram ‘pro’ or actual professional bodybuilder, will deny using illegal performance enhancers—for good reason. Sponsorships, appeal to the public, and marketing of products all keep any truth about the prevalence of steroid use in the fitness industry as murky as possible. Some studies have been done around the world, which might shed light on the true prevalence in the fitness industry. Studies done in Iran suggested that among amateur/hobby and professional bodybuilders, anabolic steroid use ranged from around 18 to beyond 30% [41,42]. Another study looking at only competitive bodybuilders in Missouri showed that 54% of study participants had used or were currently using anabolic steroids [43]. Former professional bodybuilders Sergio Oliva and even Arnold Schwarzenegger have admitted to using anabolic steroids, and state that these are nearly ubiquitous in the world of professional bodybuilding. With such widespread use, yet with little open-air discussion, let’s learn a little bit about why individuals decide to use these substances.
Androgenic anabolic steroids work by binding to intracellular receptors, aptly named the androgen receptor, and then upregulate genes responsible for protein production, and also act to block the effects of cortisol. Cortisol is a corticosteroid produced naturally in the human body, which is catabolic in nature, and released in many situations, including times of stress. AAS seem to increase muscle cell production, increase the rate of muscle cell recovery after workouts, and decrease catabolic processes in the body. At first glance, AAS seem like the perfect fitness performance-booster; furthermore, studies have shown that taking high-doses of AAS will even increase lean body mass without working out. In fact, users of AAS who didn’t work out gained more muscle mass than those who weren’t taking AAS but were on a resistive exercise regimen [44]. Knowing this, you might be asking, who wouldn’t want to take AAS if they let you grow without working out?
As with most things in life, there are no free lunches. High-dose AAS use is linked to a number of side-effects. Increased blood pressure, dangerous increases in the size of the left ventricle of the heart (known as hypertrophic cardiomyopathy), reductions in HDL (good cholesterol) and rises in LDL (bad cholesterol), and increased red blood cell production can lead to atherosclerosis, heart attacks, strokes, and, unfortunately, death [45]. Oral steroid use can damage the liver, possibly contributing to cirrhosis, hepatitis, and multiple forms of liver cancer [45,46]. Furthermore, AAS abuse can promote premature balding in men who are predisposed to the condition, cause acne, lead to the formation of breast tissue (gynecomastia) in men, and cause changes in voice [45,46]. There is also a risk that AAS abuse can lead to increased aggression and lead to exaggerated emotional responses [45,46]. The host of possible side effects are far too numerous to continue listing; however, the concept is simple. Increased production of muscle cell tissue comes at a price—to nearly every other organ system in the body.
To put it simply, the side effects are far too numerous for gains that can often be attained without using AAS in the first place.
Verdict: AAS use is prevalent in the fitness industry, with obvious appeal. The harm these substances do to the human body simply isn’t worth the strength and cosmetic gain that come with it.
2. DMAA
For a period starting in ~2010 from sometime in late 2013, this was one of the most adored ingredients in pre-workouts worldwide. This supplement came to popularity thanks to its use in the now-discontinued “Original” Jack3d. For those of you who have ever tried this beloved preworkout, you have undoubtedly held every PWO you’ve tried to this gold standard… and probably have been horribly disappointed.
There is no doubt DMAA works. There are plenty of anecdotal reports stating DMAA feels similar to amphetamines. Its structural similarity to amphetamines might yield some clues to its mechanism of action:
No wonder we all thought Jack3d was basically legal crack.
After Jack3d/DMAA was linked to deaths from its use in ~2010 and beyond, it came under intense scrutiny [47]. It has rarely been seen in a PWO since 2014. For anyone who has been disappointed, the data show that perhaps it’s for the better, but it’s still not well studied.
One of the main reasons we recommend against its use, especially in amateur or professional athletes, is the fact it can cause false-positives on drug screens for amphetamines [48]. It’s not worth the risk to an athletic career to take DMAA for performance enhancement. With regards to safety, case studies have linked DMAA to deaths when it has been consumed to fuel audacious Friday and Saturday nights, but overall, safety data is scarce [47]. The lack of significant research regarding DMAA’s safety just adds another reason to steer clear from this supplement. Furthermore, DMAA can definitely increase blood pressure in the short-term when used either alone or when in combination with other stimulants [49]. This alone isn’t bad, but for those of us with borderline hypertension (or worse) from years of neglecting to do cardio (aka the ‘cardio-kills-gains’ mantra), it could be dangerous.
Bottom-line: Difficult to get, and best to avoid especially if you have blood pressure issues. Also, never use strong stimulants as party drugs!
3. Nicotine
Present in all tobacco products (cigarettes, snus, chew, etc.), as well as dermal patches, e-cigs and gum, nicotine is seemingly everywhere. Despite the high general awareness of nicotine’s debut in today’s society, very few people in the general public understand how this compound works or the fact that it has multiple performance-enhancing effects. Unfortunately, as with the other supplements covered in this section, potentially dangerous health effects do exist. So here it is: Everything you need to know about nicotine as it relates to your general fitness…
Nicotine, chemically named 3-(1-methyl-2-pyrrolidinyl)pyridine, is considered a psychostimulant of the central nervous system (CNS), meaning it acts at the level of the brain and spinal cord. At low concentrations, nicotine binds to nicotinic acetylcholine receptors (nACRs) and activates the sympathoadrenal system (among others, although this is the most important for our purposes). This activation triggers the release of norepinephrine and epinephrine, AKA adrenaline [50,51]. Cue “fight or flight” response, and physiological changes to improve performance. These improvements have been documented during endurance exercise and time to exhaustion, but not during anaerobic high-intensity exercise such as the Wingate Test [52,53].
Specifically, increases are seen in heart rate, systolic blood pressure, stroke volume (the amount of blood pumped by the heart per beat), and blood flow to the heart muscle itself [50,54,55]. All of this leads to more blood (and the nutrients and oxygen within it) being supplied to working muscles. Another indirect benefit of nicotine on athletic performance comes from the fact that fat tissue contains nicotine-receptors as well as highly sensitive epinephrine and norepinephrine receptors. Both of these receptors, when activated, cause an increase in the rate of lipolysis, or the scientific term for the process of breaking down fat for energy. Thus, the potential of less fat and a better strength-to-weight ration could also improve overall athletic performance [56].
So right now you may be sold on adding nicotine to your supplement list – but not so fast! Nicotine has earned its spot in our “ugly” category of supplements, meaning its potentially dangerous side effects are no joke to be taken lightly. By increasing blood pressure and vascular resistance, nicotine inherently may increase one’s risk for atherosclerosis (arterial plaque formation), pathological angiogenesis (abnormal vascular growth), and increased blood clotting tendencies [50,57,58]. Furthermore, nicotine has been shown to accelerate the growth of various cancers, particularly that of the pancreas [59]. To make matters worse, nicotine enhances the effect of dopamine in certain regions of the brain, making it highly addictive [50].
Take-Away: Nicotine can be a beneficial supplement by increasing certain performance adaptations, including fat metabolism, circulating adrenaline and time-to-exhaustion. However, the risk of long-term abnormal cardiovascular repercussions is a grave one to subject your body to. This is exacerbated by the fact that heavy resistance training on its own, void of cardio, can be detrimental to your cardiovascular system as well. Thus, if deciding to use nicotine to your advantage, go forward exercising extreme caution, and taking particular care not to skip cardio in the meantime.
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