A clean formulation, likely appealing to anyone not out for a super-high-stim pre-workout. But with just 20 serves per jar, this one isn’t cheap.
Tag Archives: Pre-workout
Pre-workouts are one of the most widely used supplements on the planet. Said to give you that extra ‘boost’ of energy in the gym, they have embedded themselves deep into gym culture, becoming a workout staple.
However, due to their increased popularity, the supplement industry has become saturated with thousands of different pre-workout supplements -- some of which are much better than others.
Moreover, many include ingredients that have no research to support their use, or are simply ineffective -- all of which means that you need to be selective.
What should I avoid in a pre-workout supplement?
If so many pre-workouts are sub par, then how can you find a good one?
Well, when it comes to choosing a pre-workout supplement, there are a few things that you need to look out for.
1. No Proprietary Blends
A proprietary blend is a combination of several different ingredients that sit within a supplement.
Unfortunately, the term ‘proprietary blend’ is often misunderstood by people looking for supplements. Because it sounds like a legitimate term, it creates the illusion that the supplement must be of a higher quality -- however, nothing could be further from the truth.
A proprietary blend is a loophole that supplement companies use to avoid listing how much of each individual ingredient is in their pre-workout. This makes it much easier to hide smaller doses of effective (and often more costly) ingredients, while bulking it up with ‘filler’ ingredients.
Obviously this means the supplement is cheaper to make, but it also makes it much less effective -- even if it does happen to include some good ingredients.
2. Too Many Ingredients
Now, if you look at the label of a pre-workout and it has more than 6 or 7 active ingredients, I would suggest you put it back.
One thing to remember when it comes to pre-workouts is that they generally have small serving sizes (5-10 grams would be the norm). This means that the more ingredients they have, the less of each ingredient you get.
This again makes it easier to provide you with less of the effective ingredients (which again, are often more expensive) to save cost -- making the supplement less effective in the process.
3. Outlandish Claims
Finally, a good pre-workout supplement should do two things:
- Improve exercise performance
- Increase mental performance
As a result, if you see a pre-workout advertising the ability to “shred fat” or “boost muscle growth” then you should turn and run -- because they have obviously spent more money on marketing than they have on creating their product.
What Should I Look for In a Pre-workout Supplement?
So, what does a good pre-workout look like?
Well, going off the above suggestions, you want to make sure that your pre-workout makes no outlandish claims, lists the dosages of all its ingredients individually, and has less than seven active ingredients.
And once it has ticked those boxes, you want to make sure that the ingredients it contains are actually effective.
Which begs the question: what are the most effective pre-workout ingredients?
Straight out the box we have one of the most widely researched (if not the most widely researched) ingredients on the entire planet -- being caffeine.
Look, let's face it. There is a pretty good reason as to why 99% of the population start their day with a warm cup of coffee. It is because caffeine has the ability to improve mental alertness, attention, and reaction time .
More importantly, caffeine has also been shown to have an extremely potent effect on exercise performance , where it can improve:
- Muscular strength
- Muscular endurance
- Cardiorespiratory endurance
- Anaerobic power
This means that it makes the perfect pre-workout ingredient as it improves the mental and physical aspects of performance.
While the recommended dosage of caffeine does differ based on bodyweight, an effective dose should sit somewhere between 200 and 400 milligrams.
Agmatine is one of many neurotransmitters found in your brain.
With this in mind, there is evidence to suggest that supplementing with Agmatine can reduce sensations of pain and improve mood [3, 4]. These effects could conceivably improve workout performance by increasing the number of repetitions you achieve per set.
Anecdotally, there are also a number of people within the fitness space who also believe that Agmatine can increase blood flow to the muscle tissue, increasing the ‘pump’ you get in the gym. This could also increase nutrient flow to the muscle tissue, enhancing growth and recovery.
However, it is important to note that this is simply anecdotal, and thus far there is no evidence demonstrating this effect in humans.
Dosage recommendations generally sit within 200-1000mg per serving.
Citrulline is a “non-essential” amino acid found in a variety of fruits and vegetables. The reason it is considered to be non-essential is because it can be naturally made in your body, and therefore does not have to be obtained through your diet.
However, increasing your natural levels of citrulline though supplementation has been shown to have some positive effects.
Firstly, supplementing with citrulline has been shown to increase weight training performance . This means an increase in the number of reps you can perform per set, or the amount of weight you can put on the bar. Over time this can lead to improvements in muscular strength and muscle growth.
Secondly, it has also been shown to reduce intra-workout fatigue, which might increase the quality of your workouts .
And finally, citrulline has also been shown to improve recovery after exercise . While this may not sound all that impressive, improved recovery means that you can get the most out of your next training session -- which could cause lasting improvements in strength and size.
The optimal dosage of citrulline malate (a specific type of citrulline) appears to be around 6000mg.
Like Citrulline, beta-alanine is also a non-essential amino acid.
However, unlike many other amino acids, your body does not use it to create other proteins. Instead, it is used to produce a compound called carnosine -- which has been shown to limit the accumulation of lactate in your muscle tissue.
As a result, it has been shown to improve muscular and aerobic endurance, and limit fatigue during training .
Interestingly, and most likely due to improvements in acute training performance, the long term supplementation of Beta-alanine has demonstrated improvement in both muscle growth and fat loss -- suggesting it could have pretty positive effects on body composition .
Anywhere between 2 and 5 grams of Beta-alanine has shown to be effective.
L-Tyrosine is another amino acid that can be obtained from the food you eat. Uniquely, this particular amino acid is used to create the key compounds dopamine and adrenaline -- which is why it is so common in pre-workout supplements across the globe.
As such, supplementing with L-tyrosine has been shown to improve reaction time  and attention, while also promoting sensations of wellbeing .
Interestingly, one study has also found that taking L-tyrosine before exercise may actually improve performance . While this may not directly improve strength and hypertrophy gains, it could potentially improve workout quality.
Evidence would suggest that dosages between 500 and 2000mg are most effective here.
Over the last decade the supplement industry has become saturated with subpar pre-workouts. But that doesn't mean that good ones don't exist.
It just means that you need to pay close attention to the ones you buy.
Try and avoid those that contain proprietary blends, or those that have a large number of ingredients. Moreover, any that are making outlandish claims should be avoided like the plague.
And if you can find one that has a few of the scientifically supported ingredients listed above, then you can be pretty confident in its effectiveness.
- McLellan, T. M., Caldwell, J. A., & Lieberman, H. R. (2016). A review of caffeine’s effects on cognitive, physical and occupational performance. Neuroscience & Biobehavioral Reviews, 71, 294-312.
- Grgic, J., Grgic, I., Pickering, C., Schoenfeld, B. J., Bishop, D. J., & Pedisic, Z. (2020). Wake up and smell the coffee: caffeine supplementation and exercise performance—an umbrella review of 21 published meta-analyses. British Journal of Sports Medicine, 54(11), 681-688.
- Keynan, O., Mirovsky, Y., Dekel, S., Gilad, V. H., & Gilad, G. M. (2010). Safety and efficacy of dietary agmatine sulfate in lumbar disc-associated radiculopathy. An open-label, dose-escalating study followed by a randomized, double-blind, placebo-controlled trial. Pain Medicine, 11(3), 356-368.
- Shopsin, B. (2013). The clinical antidepressant effect of exogenous agmatine is not reversed by parachlorophenylalanine: a pilot study. Acta Neuropsychiatrica, 25(2), 113-118.
- Gonzalez, A. M., & Trexler, E. T. (2020). Effects of Citrulline Supplementation on Exercise Performance in Humans: A Review of the Current Literature. The Journal of Strength & Conditioning Research, 34(5), 1480-1495.
- Pérez-Guisado, J., & Jakeman, P. M. (2010). Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. The Journal of Strength & Conditioning Research, 24(5), 1215-1222.
- Hobson, R. M., Saunders, B., Ball, G., Harris, R. C., & Sale, C. (2012). Effects of ?-alanine supplementation on exercise performance: a meta-analysis. Amino acids, 43(1), 25-37.
- Kern, B. D., & Robinson, T. L. (2011). Effects of ?-alanine supplementation on performance and body composition in collegiate wrestlers and football players. The Journal of Strength & Conditioning Research, 25(7), 1804-1815.
- O'Brien, C., Mahoney, C., Tharion, W. J., Sils, I. V., & Castellani, J. W. (2007). Dietary tyrosine benefits cognitive and psychomotor performance during body cooling. Physiology & behavior, 90(2-3), 301-307.
- Banderet, L. E., & Lieberman, H. R. (1989). Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans. Brain research bulletin, 22(4), 759-762.
- Tumilty, L., Davison, G., Beckmann, M., & Thatcher, R. (2011). Oral tyrosine supplementation improves exercise capacity in the heat. European journal of applied physiology, 111(12), 2941-2950.
If you're serious about getting the most out of your workout, you will quickly discover that the use of a well-timed pre-workout supplement can go a very far away. However, realizing this is just half of the battle. The other half, more importantly, has to be selection of the best ingredients that can help you reach your goals.
In this article we are going to reveal what the five best pre-workout ingredients to look for are, and how the massive pumps they deliver on contribute to muscle gains and strength increase.
Creatine is one of the most heavily researched supplements in history, and for good reason – it absolutely works. Regardless of what your specific sport discipline is, there is a very good chance that creatine supplementation can help take you to the next level.
Creatine possesses muscle volumizing properties, which refers to its ability to increase a cell’s water content[i]. This is very important for muscle pumps as dehydration adversely affects vascular flow and dilation.
Studies have indicated that regular creatine supplementation can yield a 5 to 10% increase in strength gains, not to mention the fact that it is extremely safe and plays a very important part in energy production.
It's no secret that the more energy that is available to muscle cells for your work out, the higher your performance output will be and subsequently linear progression.
All the bells and whistles aside, creatine should probably your first stop when looking for a good pre-workout supplement. It is very affordable, and with a dose of 10 g daily, noticeable changes can be observed after a week or two.
Beta alanine is quickly becoming a favourite when it comes to high-intensity performance and endurance training, thanks to the fact that it is able to combat muscle fatigue quite effectively.
Interestingly, beta alanine itself doesn't do much for performance in the short term. Rather, it helps to raise levels of intracellular carnosine, which is a semi-essential amino acid that plays a key role in helping to buffer accumulation of positively charged hydrogen ions.
Over time, what you will notice is improved resistance to fatigue and extended exercise duration, especially when it comes to exercise of an intermediate length lasting more than one minute.
Citrulline is a very popular and effective amino acid that is naturally produced by the body in small amounts.
However, you will be hard-pressed to notice any difference if you rely on naturally produced citrulline. Instead, consumption of citrulline based supplements are known to help increase blood flow and circulation throughout the body[ii].
Upon consumption, citrulline must first be converted into L-arginine, which subsequently helps to raise blood levels of nitric oxide.
While L-citrulline is fine in terms of its vasodilator capacity, citrulline maleate is arguably much more effective by virtue of its resistance to metabolism, and the fact that it also supports energy levels.
Doses of between 3 to 6 g of citrulline are generally effective and safe, and are associated with fewer gastric side effects that are notorious to arginine supplements.
Given that you are not sensitive to the effects of stimulants, caffeine is one of the most affordable and effective pre-workout boosters that you can take advantage of right now.
There is a reason why coffee is the most popular beverage in the world, especially when it comes to elevating alertness and reducing fatigue. Caffeine, taken as is or in a pre-workout form, is highly beneficial to several aspects of your work out.
For instance, it helps to increase power output, increases the rate of fat addition, and even has a mild effect on increasing your resting metabolic rate. Not to mention that it can help increase your drive and motivation to get your workout done.
Plus, there is the lesser known effect of caffeine being a mild vasodilator[iii], which can support muscle pumps too.
Just try to take your caffeine earlier in the day as it is known to interfere with sleep if you should take it too close to bedtime.
Probably the most exciting development in pre-workout supplement science as of recent is the inclusion of powdered glycerol in some formulations. Glycerol is essential a sugar alcohol, one used naturally as a flavouring and preservative in many foods and found naturally in many plants.
Glycerol works in a unique manner, but one that can best be compared to creatine’s mechanism on enhancing muscle pumps; by promoting hyper hydration. This can have the effect of improving performance[iv].
Having strong osmotic properties it is capable of retaining water in the blood and muscle cells, leading to a profound engorging of the vascular system. This is very noticeable when working out. It is also beneficial in fighting dehydration[v], which is known to have a negative impact on performance.
Pre-workout supplements are a dime a dozen, but the fact of the matter is that many supplements will not give you what you expect unless you know what you’re looking for. You should aim for products that contain some of the ingredients we mentioned above, or even make your own if you’re feeling adventurous!
[i] Häussinger D, Roth E, Lang F, Gerok W. Cellular hydration state: an important determinant of protein catabolism in health and disease. Lancet. 1993;341(8856):1330-1332. doi:10.1016/0140-6736(93)90828-5
[ii] Bailey SJ, Blackwell JR, Lord T, Vanhatalo A, Winyard PG, Jones AM. l-Citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans. J Appl Physiol (1985). 2015;119(4):385-395. doi:10.1152/japplphysiol.00192.2014
[iii] Umemura T, Ueda K, Nishioka K, et al. Effects of acute administration of caffeine on vascular function. Am J Cardiol. 2006;98(11):1538-1541. doi:10.1016/j.amjcard.2006.06.058
[iv] Hitchins S, Martin DT, Burke L, et al. Glycerol hyperhydration improves cycle time trial performance in hot humid conditions. Eur J Appl Physiol Occup Physiol. 1999;80(5):494-501. doi:10.1007/s004210050623
[v] Wagner DR. Hyperhydrating with glycerol: implications for athletic performance. J Am Diet Assoc. 1999;99(2):207-212. doi:10.1016/s0002-8223(99)00049-8
Blackstone Labs is a recognized supplement brand, in Australia and throughout the world. When it comes to the pre-workout supplement by the name of Dust V2, it is no different, even though many people think of Blackstone Labs products as being for hard-core athletes only.
The truth is, even though there is a certain amount of enigma surrounding the Blackstone Labs brand, there is a very distinct possibility that your workouts stand to benefit handsomely from their products. So should you spend your time (and money) on Blackstone Labs Dust V2? Let's check out what it brings to the table.
Regardless of your taste preference, Dust V2 has something that will suit your palate. One of the most surprising discoveries we made about the taste is the fact that it is not overpowering. This is a good thing overall, as it means that they have included less artificial sweeteners in the product, even though you can clearly detect that there is some amount contained in it.
Dust V2 uses maltodextrin and erythritol as their sweeteners, which would explain the less intense sweetness possessed by the product, and the faint bitter aftertaste.
In terms of flavour varieties, Red Ice, Black Lemonade and Watermelon are likely to appeal to the majority of users, even though Pineapple, Blue Sky, Cotton Candy and Sour Gummy Bear aren't that bad either.
Overall, not the best tasting pre-workout on the market, but undoubtedly refreshing for people that are tired of intense and overpowering additives in their pre-workout.
One of the factors that contributes to making a pre-workout powder successful is how well it mixes in water. In the case of Dust V2, the manufacturer has taken care to ensure that it does this exceptionally.
Even though many consumers never consider the overall mixability of a supplement before purchasing, they should. Dust V2 leaves no residue in a shaker bottle after mixing, given that you indeed use the recommended 8 to 10 ounces of water per serve.
It also mixes well with a spoon if you are unable to mix it in a shaker bottle.
Pro Tip: if you dislike having to chug down more water than is necessary, do not use cold water when mixing your pre-workout powder. Mixability goes up if you add room temperature water instead.
As pre-workout supplements are becoming more advanced, arginine is not commonly employed anymore, instead opting for citrulline. Dust V2 follows this trend as well. More on that in a bit.
To start off, even though you can see the name of the ingredients found in Dust V2, it is disappointing that the specific ingredient amounts are masked in a proprietary blend known as the Blackstone Labs Dust V2 Blend. There is a total of 8.3g of ingredients, although we do not know the exact amount of any.
That aside, its ingredient profile looks solid. For instance, starting off with beta-alanine is a solid base, as this ingredient can help you to workout longer by buffering the effects of lactic acid accumulation . Muscles achieve failure- the inability to contract, as lactic acid levels raise and their pH changes to an acidic one.
The presence of betaine may help to increase the body's natural creatine production , proving useful if you do not supplement with exogenous forms of creatine.
The presence of two citrulline forms; the tartrate and malate may help to further boost absorption and ease digestive discomfort some individuals experience, although citrulline already possesses a much lower likelihood of causing these effects when compared to arginine. Citrulline also more readily supports nitric oxide production and helping you achieve muscle pumps.
While these ingredients are great, arguably what makes Dust V2 magnificent is its blend of stimulatory and nootropic ingredients. These include caffeine anhydrous and di-caffeine malate, which is a sort of buffered caffeine which delays its rapid onset and clearance. Caffeine is well established to improve exercise performance, energy levels and metabolism .
Agmatine and norvaline, combined with hordenine and N-methyl Tyramine help to exert a calming effect on typical caffeine response, in addition to Agmatine and norvaline possessing dual actions helping to support nitric oxide levels as well. Norvaline inhibits arginase-the enzyme that breaks down arginine  and reduces the amount of nitric oxide that may be synthesized. Acreoline (as Arcofuel), also supports resistance to mental fatigue and can result in improved physical performance during your workouts.
Taurine may also help to take the edge off  of caffeine even more, so users do not experience a significant crash of any sort, and may help to prevent muscle cramping from fluid loss during your workout.
Velvet Bean Extract is a very interesting ingredient, to say the least. There are times when regardless of the amount of stimulants you consume, you lack the drive to get up and get things done. This could be related to your brain dopamine levels- this neurotransmitter being necessary for your drive and ability to achieve things. Velvet Bean Extract (also known as Mucuna Pruriens) is a rich source of L-Dopa, a precursor to the synthesis of dopamine . This explains why Dust V2 is able to take your workouts to new heights, in conjunction with its other nootropic and stimulant compounds.
Lastly, is MaxxEnsureXT, also known as stearoyl vanniylamide, a compound related to capsaicin, which may help to enhance thermogenesis and metabolic rate.
Based on its ingredient profile, if you have a difficult time maintaining focus and energy levels throughout your workout you will notice a significant difference. The presence of beta-alanine and betaine also up performance levels and your resistance to fatigue helping you beat the goals you set for yourself.
Finally, citrulline does what it set out to do – increase muscle pumps and nitric oxide production, and when supported with norvaline and agmatine, you won't be disappointed.
The only ingredient whose presence seems a bit off in the mix would be stearoyl vanniylamide, which would increase your metabolism but probably not contributes to overall efficacy of the supplement.
Value For Money
Dust V2 is fairly priced, with each serve costing you approximately$1.60 (less if you're a Club Z Member), as there are other pre-workouts which are significantly more expensive but don't deliver half as much as Dust V2 might.
For this reason, it ranks among the best when it comes to value for money.
Based on the fact that it mixes well, tastes fair, and includes ingredients which are likely to deliver what you've come to expect from a good pre-workout product, Dust V2 gets our recommendation.
The only thing we would like to see changed is full disclosure of ingredient dosages, but Blackstone Labs has built an impressive reputation for a reason – they consistently make great products. If you are new to using pre-workout boosters, or are looking to take things to the next level, Dust V2 is very likely to help get you there.
- Hobson RM, Saunders B, Ball G, Harris RC, Sale C.Effects of ?-alanine supplementation on exercise performance: a meta-analysis.Amino Acids. 2012 Jul;43(1):25-37. doi: 10.1007/s00726-011-1200-z. Epub 2012 Jan 24.
- Du Vigneaud V, Simmonds S, et al. A further investigation of the role of betaine in transmethylation reactions in vivo. J Biol Chem. 1946 Oct;165(2):639-48
3.Costill DL, Dalsky GP, Fink WJ. Effects of caffeine ingestion on metabolism and exercise performance. Medicine and Science in Sports [1978, 10(3):155-158]
- NN Huynh, EE Harris, JFP Chin-Dusting, and KL Andrews. The vascular effects of different arginase inhibitors in rat isolated aorta and mesenteric arteries. Br J Pharmacol. 2009 Jan; 156(1): 84–93.doi: 10.1111/j.1476-5381.2008.00036.x
- Chen SW1, Kong WX, Zhang YJ, Li YL, Mi XJ, Mu XS. Possible anxiolytic effects of taurine in the mouse elevated plus-maze. Life Sci. 2004 Aug 6;75(12):1503-11. DOI: 10.1016/j.lfs.2004.03.010
- Lampariello LR, Cortelazzo A, Guerranti R, Sticozzi C, Valacchi G. The Magic Velvet Bean of Mucuna pruriens. J Tradit Complement Med. 2012;2(4):331-9.
TC Nutrition Batch 27 is a super concentrated pre-workout supplement that promises pump, power, and performance. Is this just another run-of-the-mill pre-workout or can Batch 27 deliver?
Most pre-workout supplements focus on caffeine for a quick jolt, but Batch 27 contains a well-rounded formula to fuel the brain and the body.
Let's talk about performance: Batch 27 contains beta alanine and betaine anhydrous, two ingredients that have been shown to increase strength levels during your workout. With one gram of creatine HCl, you'll be providing your lean tissue with instantly-available adenosine triphosphate (ATP), the preferred fuel source of muscle. (1, 2)
Batch 27 also offers you a collection of nitric oxide-boosting ingredients. Higher levels of nitric oxide during your workout can improve performance and overall results. Batch 27 delivers eight grams of citrulline malate, one of the best ingredients to increase nitric oxide production for that blood-pooling pump. You'll also get tyrosine, agmatine sulfate, theanine, and carnitine. (3)
With your muscles taken care of, what about your mental energy levels? Batch 27 goes above and beyond most other supplements, offering you two types of caffeine along with two nootropics or brain-boosting compounds for elite-level focus.
Theobromine complements caffeine anhydrous and caffeine citrate, helping to increase energy levels while alleviating the anxiousness typically felt with caffeine-based products. Huperzine A is the king of nootropics and it's been shown to skyrocket focus, cognitive performance, and memory formation. (4)
Black pepper extract ties it all together. Studies show that black pepper extract can increase bioavailability of a supplement by up to 2,000%. (5)
Overall, this is one of the most complete and advanced pre-workout formulas I've seen. It addresses energy on all levels – mind and muscle – and not just a fast boost and crash. This is a very impressive pre-workout formula.
FORMULA RATING: 5/5
TC Nutrition Batch 27 offers three unique flavours: Fuzzy Peach, Rocket Pop, and Sour Batch. For the purpose of this review, I tested Fuzzy Peach. While it doesn't taste exactly like a peach, I was pleasantly surprised with the flavour.
I've seen other reviews where people comment that the taste is a bit like cough syrup, but I think it's important to remember that supplements are meant to support your fitness performance and goals; a great taste is just a luxury.
TASTE RATING: 5/5
TC Nutrition Batch 27 is surprisingly easy to mix given that it doesn't contain lecithin, which is usually added to help with mixability. I used a shaker bottle with a mixing ball, and it took a few extra shakes but it mixed well.
MIXABILITY RATING: 5/5
Value for Money
Amazing quality doesn't come cheap and Batch 27 is not on the cheaper side of supplements. The average price you'll find for 20 servings is around fifty dollars. Despite the price tag, I still think it's a worthwhile buy considering all of the ingredients you're getting per serving.
VALUE RATING: 4/5
This is a complete and well-rounded pre-workout supplement, something you don't often find in the overcrowded market.
It has a collection of scientifically-proven ingredients to power both the mind and the body for an optimal workout experience. Flavour is great and it's easy to mix, but my only pain point is the price. Even with the higher price tag, you're paying for an elite-quality supplement.
OVERALL RATING: TC Nutrition Batch 27 gets 5/5!
- Maté-Muñoz JL, Lougedo JH, Garnacho-Castaño MV, et al. Effects of ?-alanine supplementation during a 5-week strength training program: a randomized, controlled study. J Int Soc Sports Nutr. 2018;15:19. Published 2018 Apr 25. doi:10.1186/s12970-018-0224-0
- Kreider RB. Effects of creatine supplementation on performance and training adaptations. Mol Cell Biochem. 2003 Feb;244(1-2):89-94.
- Morrissey JJ, Klahr S. Agmatine activation of nitric oxide synthase in endothelial cells. Proc Assoc Am Physicians. 1997 Jan;109(1):51-7.
- Wang R, Yan H, Tang XC. Progress in studies of huperzine A, a natural cholinesterase inhibitor from Chinese herbal medicine. Acta Pharmacol Sin. 2006 Jan;27(1):1-26.
- Prasad S, Tyagi AK, Aggarwal BB. Recent developments in delivery, bioavailability, absorption and metabolism of curcumin: the golden pigment from golden spice. Cancer Res Treat. 2014;46(1):2-18.