Stepping over $20 bills to pick up pennies
Is Pre-Workout Worth It?
I’ve tested over 20 different pre-workouts and dived deeper into this subject than almost anyone else. On top of that, I’ve been taking pre-workouts religiously for years.
In short, I know more about this shit than 99% of people out there. So, is pre-workout worth it?
The cold, hard truth is that pre-workouts are probably not worth it for most people. It’s far more important to dial-in your training and recovery, prioritize your nutrition, and manage your lifestyle.
With all the risks and general shadiness surrounding the pre-workout industry, plus the financial cost, you’re likely better off drinking coffee.
But because I know from personal experience that you, too, might be attached to your pre-workout and the 0.1% edge you might get from it, let’s examine the benefits and downsides of it all.
Then it’s up to you to decide which way to go.
Table of Contents
There Are No Solutions, Only Trade-Offs
Before we get into the risk/reward of pre-workouts, I want to present to you a theory courtesy of famous economist Thomas Sowell.
The idea is simple: Everything is a trade-off.
When you buy, consume, or do anything, you’re trading something else in return. Some of the most common trade-offs are time, status, or, in the case of pre-workouts, money (and health, but I’ll get to that a bit later).
Of all the pre-workouts I’ve tested, the average cost is $45 per 30 servings. High-quality, third-party tested products are typically even more expensive. But for the sake of simplicity, let’s stick with that $45 for now.
If you’re training four days a week, you’re spending $45 or more on pre-workouts every seven or so weeks. Over the course of a year, that adds up to somewhere north of $315.
Is that $315 you spend on pre-workouts each year worth the potential 0.1% difference in your training?
I’ll argue that if your training goal is to get totally jacked, there are way better opportunities to make $315 improve your results.
Do you have a shit workout program that isn’t focused on progressive overload? Then you should buy one from someone like Jeff Nippard instead of buying pre-workout.
Is your diet garbage, and you aren’t counting calories and macros each day? Then pay for a damn app that tracks your calories, such as Carbon or MacroFactor instead.
If you struggle to get a good sleep each night, spend that $315 on a new pillow.
Again, pre-workout is NOT essential. It will not build muscle or burn fat. It might give you a 0.1% edge in your training, but that only matters if your diet, sleep, and training are solid.
And even then, is that 0.1% edge worth $315?
What Are the Potential Rewards of Taking a Pre-Workout?
The evidence supporting most pre-workout ingredients is piss poor.
In fact, a recent study examined the effects of multi-ingredient pre-workouts compared to straight-up caffeine on resistance training performance.
Researchers found that consuming a typical pre-workout product containing a cocktail of beta-alanine, citrulline malate, arginine alpha-ketoglutarate, L-taurine, L-tyrosine, and caffeine was actually worse for performance than taking just caffeine on its own.[1]
Still, plenty of people love pre-workouts, so there must be some benefits to them.
Better Energy and Focus
Insane energy and focus are the biggest marketing catchwords that pre-workout companies deploy to attract buyers.
They love telling you how their bottled unicorn shit will hype you up, prevent fatigue, and make you lift heavier. Just to prove a point:
Image caption: A scoop of this will reverse thermodynamics🙄
But there’s nothing magical about them. This energy mainly just comes from caffeine, albeit an often high f*cking dose. But in the end, it’s the same type of caffeine you get in coffee and energy drinks.
Does caffeine help? Absolutely. Do you need a pre-workout to get caffeine? Absolutely not.
Better Muscle Pump
The next talking point for the pre-workout marketing teams is better muscle pump. This is typically done via nitric oxide boosters like L-citrulline.
Enhanced blood flow from nitric oxide boosters gives your muscles a fuller, more vascular look in training. This improved blood flow might help you squeeze out an extra rep or two.
But does it? The evidence simply isn’t conclusive (more on this below).
Better Performance
You know that tingly sensation you get from pre-workout? That’s beta-alanine. But the way beta-alanine actually improves your performance likely isn’t what you thought.
This tingling is not a sign of the pre-workout taking effect. It’s actually not an indicator of anything, really. Because it doesn’t do anything.
Instead, it is a harmless sign of an acute high dose of beta-alanine.
Now, some lifters associate this tingling with the potency of the pre-workout, which can then help them go harder in training, but that’s the only benefit.
It’s a placebo.
You feel the tingles so you think the shit is kicking your ass into gear and you, in turn, turn it on.
The sad reality? You’re just tingly, my guy.
Unlikely: Improved Endurance
There’s one more pre-workout benefit you’ll see touted by supplement companies, but it’s almost entirely pure marketing.
They claim beta-alanine (discussed above) increases muscular endurance by buffering lactic acid buildup. In theory, this could enable you to crank out a few more reps or push harder during your sets.
But unless you’ve hit the saturation point of beta-alanine after taking it for weeks and weeks, you won’t experience any of this. I’ll explain more about this in the beta-alanine section below.
What Are the Potential Risks of Taking a Pre-Workout?
The potential risks of taking pre-workout are probably going to make you feel uneasy, if not borderline paranoid, about your supplements.
Unlabeled and Potentially Unsafe and Banned Ingredients
Perhaps the most troubling downside of pre-workouts is the possibility of them containing ingredients not listed on the label, some of which could be dangerous to your health.
When I was 17, many of us on the wrestling and football teams learned about a new Muscle Fortress supplement called “Methyl V,” which contained something called “prohormone.”
None of us kids knew what a prohormone was. All we knew was if we took it we would gain massive muscle and strength. And as high school athletes, that’s all we wanted.
I went from 154 to 175 pounds in about seven weeks. All muscle. It was insane. I remember the weight coach for my football team even suggested that I look at bodybuilding if I decided not to play ball in college because I had amazing genetics.
Little did he know I was juiced up.
None of us did. But once the coach found out what we were taking, he told us to stop, saying we were f*cking with our hormones.
Lo and behold, the prohormone in Methyl V had trenbolone and other anabolic steroids in it. Multiple guys had horrible back acne from it, and tempers were high across everyone. It also gave me gynecomastia, and I still have it to this day. It’s embarrassing.
But wait, it gets worse. Muscle Fortress was creating fake accounts on sites like bodybuilding.com and telling people how amazing the product was. I even found a post where the owner of the company straight up says that Methyl V has anabolic steroids in it.
These kinds of unethical practices and lack of transparency show that many supplement companies will do anything to cut costs and maximize profits, even if it puts their customers, a large part of whom are teenage boys, at risk.
To give you an idea of how this risk is more than just overblown fearmongering, a 2017 study showed that 9.1% of 110 supplements advertised for weight loss, fat-burning, energy, or performance contained illegal stimulants.[2]
That’s f*cked up.
Having illegal stimulants in your pre-workout can lead to failed drug tests, whether at a competition or at work.
But even worse, these substances can be detrimental to your health, no matter how healthy and fit you are.
Plus, having amphetamine-like substances in your pre-workout is a sure way to get you hooked on it. I mean, there’s a reason why some folks feel the burning need to get their pre-workout hit.
Lack of Regulation and Manufacturing Issues
The supplement industry is full of cowboys. And there’s no sheriff.
What I mean by that is there’s no accountability for baseless claims. A supplement that claims to contain fairy feathers that will make you fly? Not completely outside the realm of possibility.
Either by cherry-picking studies, funding research, or simply lying through their teeth, manufacturers and brands alike will tell you exactly what you want to hear, regardless of the truth.
Only after complaints and controversies will the authorities catch on and put a stop to it. These nefarious entities then go into hiding only to come back with a new name for the same useless supplement.
And the whole circus repeats itself.
It’s also common for trace amounts of dangerous or banned ingredients to accidentally make their way into the wrong supplement.
This happens when manufacturers fail to follow proper manufacturing practices.[3] This failure results in unlabeled and potentially harmful ingredients being inadvertently included in an otherwise harmless product.
Adverse Side Effects From Even the Legal Ingredients
Even if a pre-workout is third-party tested and contains only the ingredients on the label, some of the substances in the mix can still make you feel like dogshit, or worse.
Some of the more harmless though annoying side effects can include jitters, heart palpitations, water retention, and headaches. Caffeine can also cause a significant energy crash.
If you’ve ever drank too many cups of coffee in a day, you know exactly what I mean. Now imagine exceeding your daily amount of caffeine in one hit and then having to deal with the tiredness, the inability to concentrate, and the irritability that follows.
But it doesn’t stop there.
Excessive caffeine can cause anxiety, insomnia, digestive issues, and poor performance.[4] There’s also a possibility that high caffeine intake (>3 cups per day) may increase the risk of kidney disease and hypertension in slow caffeine metabolizers.[5]
It’s not only caffeine that has unappealing side effects. Beta-alanine is well known to cause tingling sensations, which some people find super disturbing.
On top of that, some ingredients can interact with medications or worsen pre-existing health conditions, especially cardiovascular disease.
False Sense of Efficacy
With maybe the exception of late-night ThighMaster and ab cruncher infomercials, the marketing hype around pre-workouts — and supplements in general — is unparalleled to any other industry.
Just to give you an idea, the supplement industry’s annual revenue is predicted to reach $239.4 billion in 2028.[6]
Indeed, not all supplements are bad or useless. But pre-workouts are notorious for claims that falsely suggest they’re not only effective but necessary for optimal performance.
They also prey on people’s desire for magic solutions to replace hard work.
This leads people to prioritize supplements over the stuff that really matters for getting results: proper training, nutrition, and recovery.
How Can You Tell the Good Pre-Workouts From the Bad?
There are a few things you can do to mitigate your risk of stepping into a shitty pre-workout landmine.
Look for Third-Party Tested Products.
Always check to see if a pre-workout is third-party tested. Supplement companies can hire an independent, third-party organization to analyze product batches, verifying their quality and safety.
Whether a brand is third-party tested is relatively easy to check because most companies plaster it on their websites.
Here is an example of Gorilla Mind’s test results for L-citrulline:
Source: Gorilla Mind
If you don’t see a third party on the website or product label, it’s safe to assume the company hasn’t done this.
I used to think the lack of third-party testing didn’t automatically suggest anything about the quality of the product. But…
Without third-party testing, you’re trusting the company’s word that they’re not bullshitting you. And as you’ve seen, pre-workout brands are notorious for their bullshitting skills.
Also, third-party testing isn’t cheap. We’re talking north of $10,000 per ingredient per product. Companies won’t do this if they don’t want to be 100% sure their products are clean. If they don’t care about the purity (and they know their customers don’t know any better), why would they test the product?
Here are some of the well-known third-party seals of approval[7]:
Credit: Neilson M. Mathews, MD
Look for GMP Certification.
Whereas third-party testing is product-specific, GMP is facility and process-orientated.
GMP (Good Manufacturing Practice) certification means the manufacturing facilities comply with the rigorous quality standards of regulatory authorities. It covers the entire manufacturing process, including sourcing of raw materials, production processes, packaging, and labeling.
Third-party testing and GMP certifications on their own don’t mean the pre-workout is worth taking.
They simply give you the peace of mind that you can trust what the label says and that the manufacturers aren’t running your pre-workout through a process line that bottled meth the day before (or if they do, at least it gets cleaned in between).
You will still have to comb through each ingredient to ensure the doses and the ingredients themselves are effective.
Look for Licensed Ingredients.
At first sight, this might sound like I am suggesting proprietary ingredients. But it’s actually the opposite.
Licensed ingredients come from B2B (business-to-business) companies that license their products for B2C (business-to-consumer) companies to use in their pre-workout. Reputable B2B supplement companies prioritize the potency and purity of their products, putting them through strict internal and external testing to maintain their brand integrity.
In other words, unlike B2C companies, licensed B2B businesses depend on the trust they have in the market. One side step and their reputations and revenues go down the toilet.
Some of the B2B companies known for their high-quality ingredients:
- Creapure® (Creatine monohydrate)
- PurCaf® (Caffeine)
- CarnoSyn® (Beta-alanine)
Now, there is a shit-ton of licensed B2B ingredients. Although the manufacturing and testing process is rigorous, it doesn’t mean they can turn a useless ingredient with poor scientific evidence into a great one.
You can third-party test taurine or lion’s mane mushroom as much as you want, but it doesn’t make the ingredient any more effective. No matter how pure it might be.
Trust the Supplement Tier System.
The Supplement Tier is a system created by the fine folk at Stronger by Science to categorize supplements based on scientific evidence.
Credit: Stronger by Science
All new supplements start at tier three, meaning there’s insufficient evidence of potential benefits. As more evidence emerges, the supplement will move up or down the tier, depending on whether new evidence shows a positive or negative correlation.
Tier 1 is the holy grail of supplements and is reserved for supplements with strong evidence of their effect. Currently, there is only one athletic supplement with Tier 1 status: creatine.
Yes, that’s right. No pre-workout blend enjoys Tier 1 status.
The sad truth is that most supplements will eventually live in Tier 4 (evidence shows the supplement has no effect) or Tier 5 (supplement harms health and performance). That just goes to show how little value there is in most of the supplements available in the market.
For example, yohimbe (from the Pausinystalia yohimbe tree and the Rauwolfia serpentina plant) is often hyped as a fat-loss and performance supplement. There’s zero evidence that it improves strength or physical performance or increases muscle. On top of that, it may cause nausea, abdominal pain, dizziness, nervousness, and anxiety.[8]
All of which aren’t great for your training.
Let’s look at the common ingredients in pre-workouts to see where they land on the tier system.
What Are the Most Common Pre-Workout Ingredients?
As you go down this list, you’ll notice that the science barely warrants using most pre-workout ingredients.
Caffeine
Caffeine is a Tier 2 supplement. Which, when I first found out, challenged everything I thought I knew about pre-workouts. But it’s hard to argue with facts.
While caffeine has a good amount of evidence supporting its benefits for performance, the effects are generally modest, especially for strength and power, and can vary significantly between individuals.
Still, when judging pre-workout ingredients with acute effects on training, caffeine is the only one with strong enough evidence to warrant its use.[9]
L-Citrulline/Citrulline Malate
L-citrulline is a Tier 3 supplement. While there is some promising evidence for its benefits, the research is not as robust or consistent as the evidence for higher-tier supplements.
Although the minimum effective dose of 4,000 mg of L-citrulline is well known, the optimal dosage for resistance training is unclear, and studies have shown inconsistent results. There is also limited evidence for long-term benefits.
That said, L-citrulline isn’t absolute garbage because it shows some potential benefits.[10] It might enhance muscle pump and delay fatigue for a rep or two.
But, again, there is no conclusive evidence to suggest it directly impacts muscle strength or endurance. Yet.
As more research becomes available, it’s possible that L-citrulline could climb the pyramid. But if you want to spend your money on supplements with strong evidence behind them, L-citrulline isn’t going to cut it.
Citrulline malate, which you’ll often see on product labels, is a mix of L-citrulline and malic acid.
Malic acid is naturally found in various fruits and vegetables. It’s also produced in our bodies during the Krebs cycle, which is crucial for energy production.
In pre-workouts, malic acid is used to enhance the absorption and efficacy of L-citrulline, although the evidence on this is mixed.
In most pre-workouts, the ratio between the two is listed as L-citrulline first and then malic acid, as in 1:1, 2:1, 3:1, and so on. If a pre-workout has 8,000 mg of citrulline malate in 2:1, it means there’s roughly 5,200 mg of L-citrulline, and the rest is malic acid:
8,000 mg/3 parts = 2,600 mg
2 parts of L-citrulline x 2,600 mg = 5,200 mg
1 parts of malic acid x 2,600 mg = 2,600 mg
Beta-Alanine
Beta-alanine is a Tier 3 supplement. It’s shown potential benefits for high-intensity exercise performance by improving endurance and reducing fatigue.[11]
But the effects are often modest and inconsistent across studies, and it requires an annoyingly lengthy loading phase (the saturation point is 176 GRAMS) compared to other pre-workout ingredients.
Beta-alanine’s benefits for strength and hypertrophy are less clear, which is one of the big reasons why it doesn’t qualify as a Tier 2 supplement.
L-Tyrosine
L-tyrosine is a Tier 4 supplement. It’s an amino acid that serves as a precursor for the production of several important neurotransmitters, including dopamine, adrenaline, and noradrenaline.
However, the research on L-tyrosine’s effectiveness as a supplement is mixed, and the evidence for resistance-training benefits is limited.[12] Furthermore, optimal dosing is unclear.
Betaine Anhydrous
Betaine anhydrous is a Tier 4 supplement. It’s a compound found in some foods and is often touted for its potential strength and power benefits.
However, research on its effectiveness is inconsistent. The optimal dosage is unclear, and some folks may experience digestive side effects.[13]
You’ll be happy to learn that the benefits of betaine anhydrous are the same as creatine. And as you learned earlier, creatine is a Tier 1 supplement. So, ditch betaine and stick with your creatine.
L-Arginine
L-arginine is a Tier 4 supplement. It is an amino acid commonly found in pre-workout supplements and is believed to improve blood flow and exercise performance.
However, research shows limited effects on blood flow and inconsistent performance benefits, with most studies finding no significant improvements.[14] The long-term effects are unclear, and L-citrulline, a more effective alternative, has way more science behind it.
Choline
Choline is a Tier 4 supplement. It’s a nutrient involved in various physiological functions and is sometimes included in pre-workout supplements for potential cognitive and performance benefits.
But the research on its effectiveness is mixed, and the evidence for resistance training is negligible. The optimal form and dosage for performance are unclear, and most people get enough choline by eating a balanced diet.[15]
Theobromine
Theobromine is a Tier 4 supplement. It’s a compound similar to caffeine found in cacao plants, and it’s included in pre-workouts for its potential stimulant effects. So far, though, evidence supporting this claim is insufficient.[16]
Theobromine may have mild stimulant properties and potential cardiovascular benefits, but the effects are generally subtle and inconsistent.
Other Ingredients
These products have no scientific legs to stand on:
- Taurine
- Most herbal extracts
- Pink Himalayan salt (no special performance benefits compared to normal table salt)
- Vitamins and minerals
- Pretty much everything else I didn’t cover earlier
All this nonsense is in your pre-workout for one reason: to get you to buy the product.
Should You Take Pre-Workout?
Ultimately, whether or not to take a pre-workout supplement is up to you. You’re (hopefully) an adult who can make intelligent decisions. If anything, you’re already ahead of the game by actually giving a shit and questioning the need for pre-workouts.
I know this article might clash with popular opinion about pre-workouts. Your reaction to this new information probably reflects exactly how I felt when I first learned about all this: confused, angry, frustrated, and even betrayed.
The truth is that instead of chasing the next great pre-workout, you’re better off investing your money and effort in your training, nutrition, and sleep. That will yield far greater returns than any pre-workout could provide.
However, if you do choose to take a pre-workout, only settle for one with third-party testing. Once you’ve found one you like, research the ingredients and their sources. Manage your expectations about the modest potential benefits.
Don’t believe the hype, regardless of how many influencers and celebrities try to convince you otherwise. If the supplement’s claims are too good to be true, it’s because the claims are based on bullshit research or straight-up lies.
On that note, after testing 20+ pre-workouts, here are my top two recommendations for high-quality pre-workouts:
The Two Pre-Workouts I Recommend for My Friends and Family
Transparent Labs BULK
As you can guess from its name, BULK comes with third-party testing and complete transparency about its ingredients. For $1.66 per serving ($1.49 if you subscribe) BULK gives you 5,300 mg of L-citrulline, 200 mg of caffeine, and 4,000 mg of beta-alanine
You can read my full Transparent Labs BULK review here.
Outwork Nutrition Pre-Workout
At $1.99 per serving, you’ll get 5,000 mg of L-citrulline, 300 mg of caffeine and 3,200 mg of beta-alanine for the tingles. Plus, thanks to third-party testing, you can be 100% sure you get what you pay for — and nothing else.
Just a word of caution, I did have a crash each time I took this.
You can read my full Outwork Nutrition Pre-Workout review here.
Decided Against Pre-Workouts, but Want the Caffeine?
Coffee
That’s right, be a renegade. Go old school. Two cups of brewed coffee (roughly 200 mg of caffeine) before training will likely do the trick. But you can always adjust up or down depending on your caffeine sensitivity.
And if you don’t like coffee? Now’s a good time to start liking it. Just kidding:
Nutricost Caffeine Pills
Nutricost caffeine pills are third-party tested and made in a GMP-compliant, FDA-registered facility. One pill is 100 mg of caffeine, so you can dose it to your liking. It’s also ridiculously cheap compared to pre-workout: A pack of 500 pills is $16.95 on Amazon. That’s less than $0.07 per 200 mg dose.
Frequently Asked Questions
Is pre-workout necessary?
No, a pre-workout is not necessary. Proper diet, training, and sleep are necessary for building muscle or losing fat.
Does pre-workout actually make you stronger?
No, pre-workout will not make you stronger. You might be able to squeeze out an extra rep or two with the right product, but you’re likely to get that by eating a healthy diet, sleeping like a beast, and drinking coffee before your training.
Is it OK to take pre-workout regularly?
You’ll likely be okay taking pre-workout regularly as long as you make sure it’s third-party tested for purity and potency and don’t overdo the caffeine.
References
1. Kruszewski, M., Merchelski, M., Kruszewski, A., Tabęcki, R., Aksenov, M. O., & Pągowski, Ł. (2022). Effects of multi-ingredient pre-workout supplement and caffeine on bench press performance: A single-blind cross-over study. Nutrients, 14(9), 1750. https://doi.org/10.3390/nu14091750
2. Yun J, Kwon K, Choi J, Jo CH. (2017). Monitoring of the amphetamine-like substances in dietary supplements by LC-PDA and LC-MS/MS. Food Science and Biotechnology, 26(5):1185–1190. https://doi.org/10.1007%2Fs10068-017-0176-1
3. Walpurgis K., Thomas A., Geyer H., Mareck U., Thevis M. (2020). Dietary supplement and food contaminations and their implications for doping controls. Foods, 9(8):1012. https://doi.org/10.3390/foods9081012
4. James, J. (1998). Acute and chronic effects of caffeine on performance, mood, headache, and sleep. Neuropsychobiology, 38, 32–41. https://doi.org/10.1159/000026514
5. Mahdavi S., Palatini P., El-Sohemy A. (2023). CYP1A2 genetic variation, coffee intake, and kidney dysfunction. JAMA Network Open, 6(1):e2247868. https://doi.org/10.1001/jamanetworkopen.2022.47868
6. Markets and Markets. (2023). Dietary supplements by market type (botanicals, vitamins, minerals, amino acids, enzymes, probiotics), function, mode of application, target consumer, distribution channel (pharmacy, supermarket/hypermarket, online), and region – global forecast to 2028. https://www.marketsandmarkets.com/Market-Reports/dietary-supplements-market-973.html
7. Mathews N. M. (2018). Prohibited contaminants in dietary supplements. Sports Health, 10(1), 19–30. https://doi.org/10.1177/1941738117727736
8. Examine. Yohimbine. https://examine.com/supplements/yohimbine/
9. Guest, N. S., VanDusseldorp, T. A., Nelson, M. T. et al. (2021). International society of sports nutrition position stand: Caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 18,1. https://doi.org/10.1186/s12970-020-00383-4
10. Gonzalez, A. M., & Trexler, E. T. (2020). Effects of citrulline supplementation on exercise performance in humans: a review of the current literature. Journal of Strength and Conditioning Research, 34(5), 1480–1495. https://doi.org/10.1519/JSC.0000000000003426
11. Trexler, E. T., Smith-Ryan, A. E., Stout, J. R., Hoffman, J. R., Wilborn, C. D., Sale, C., Kreider, R. B., Jäger, R., Earnest, C. P., Bannock, L., Campbell, B., Kalman, D., Ziegenfuss, T. N., & Antonio, J. (2015). International society of sports nutrition position stand: Beta-alanine. Journal of the International Society of Sports Nutrition, 12, 30. https://doi.org/10.1186/s12970-015-0090-y
12. Examine. L-tyrosine. https://examine.com/supplements/l-tyrosine/
13. Ismaeel, A. (2017). Effects of betaine supplementation on muscle strength and power: A systematic review. Journal of Strength and Conditioning Research, 31(8), 2338–2346. https://doi.org/10.1519/JSC.0000000000001959
14. Rogers, J. M., Gills, J., & Gray, M. (2020). Acute effects of Nitrosigine® and citrulline malate on vasodilation in young adults. Journal of the International Society of Sports Nutrition, 17(1), 12. https://doi.org/10.1186/s12970-020-00343-y
15. Warber, J. P., Patton, J. F., Tharion, W. J., Zeisel, S. H., Mello, R. P., Kemnitz, C. P., & Lieberman, H. R. (2000). The effects of choline supplementation on physical performance. International Journal of Sport Nutrition and Exercise Metabolism, 10(2), 170–181. https://doi.org/10.1123/ijsnem.10.2.170
16. Baggott, M. J., Childs, E., Hart, A. B. et al. (2013). Psychopharmacology of theobromine in healthy volunteers. Psychopharmacology, 228, 109–118. https://doi.org/10.1007/s00213-013-3021-0