You might be familiar with this situation – you have a workout planned, but you feel too tired to look forward to it. This feeling is extremely common and can significantly affect your performance and motivation. The causes can vary: from a lack of sleep to nutritional deficiencies.
In this article, you will learn how to recognize the causes of fatigue, when to reach for supplements and when not to, how to prevent tolerance to stimulants, and what the risks of their excessive use are. You will also learn how to safely combine pre-workouts with other supplements and when to avoid stimulant-based variants.
Fatigue, Tolerance, and Potential Risks
What to do when you are tired before a workout
Fatigue before a workout isn't always just a psychological problem. It is often a clear signal from your body that something is wrong. Before you reach for stimulants, it's important to understand what is actually causing this state.
Physiological causes of fatigue:
Lack of sleep – even a single night with less than 6 hours of sleep can decrease performance – from 3% in strength training up to 20% in coordination-demanding activities.
Low blood sugar – a problem during morning workouts on an empty stomach.
Dehydration – a 2% loss of body weight in fluids reduces performance by 2-10%, depending on the intensity and duration of the activity.
Overtraining – chronically elevated cortisol, disrupted hormonal balance, overall fatigue.
Chronic stress – long-term elevated cortisol leads to fatigue and impaired recovery.
Nutritional deficiencies – lack of iron (especially in women), vitamin D, B-complex vitamins, or magnesium.
Acute vs. Chronic Fatigue Before a Workout
Acute fatigue is a one-time occurrence – poor sleep, a demanding day at work, a long commute to the gym... In this case, a single-use stimulant supplement or a simple strategy to boost energy will help.
Chronic fatigue is a long-term problem lasting weeks to months. Stimulants in this case only mask the problem. It is necessary to address the root cause: adjust recovery, change the training plan, or visit a doctor to resolve nutritional deficiencies or potential health issues.
Natural methods to get energized before a workout:
Proper diet and timing: It is optimal to eat 1.5-3 hours before a workout – a medium-sized portion with a combination of complex carbohydrates and protein. Training on an empty stomach or right after a large meal can cause a lack of energy.
Hydration: Drink 400-600 ml of water 2 hours before your workout and another 200-300 ml 15 minutes before starting.
More information about diet and hydration before a workout can be found in the article "What to Eat and Take Before a Workout: Diet vs. Supplements".
Power nap: A 10-20 minute nap demonstrably improves alertness and performance. Important: no longer than 20 minutes, otherwise you will fall into a deep sleep and the effect upon waking will be the opposite.
Music and mental preparation: Studies show that listening to music with a tempo of 120-140 BPM (beats per minute) before and during a workout increases performance by 5-15%.
💡 Do you have a playlist at the right tempo? These are energetic songs like Timber (Pitbull ft. Ke$ha, 130 BPM), Applause (Lady Gaga, 140 BPM), You Make Me (Avicii, 125 BPM), or Can't Hold Us (Macklemore, 147 BPM). You can find plenty of ready-made playlists on streaming platforms – just search for "workout 120-140 BPM". |
Warm-up and central nervous system activation: 5-10 minutes of dynamic stretching, jumps, or light cardio is a great way to get pumped up before a workout.
Cold shower or washing your face with cold water: This activates the sympathetic nervous system and instantly increases alertness.
When to reach for supplements:
If you chronically lack sleep, live in stress, and eat chaotically, no booster will fix it. Conversely, if you have slept well, eaten properly, and are hydrated, but still need a little "boost," pre-workouts make sense. Read on in this article for tips on how to get energized before a workout.
For a comprehensive overview of pre-workouts and their timing, we recommend the article Pre-workout supplements: usage, timing, and safe combinations.
The Risks of Excessive Stimulant Use
Many fitness enthusiasts fall into a vicious cycle: they take stimulants to increase energy, these disrupt their sleep, they wake up tired, so they take even more stimulants. The result? Tolerance, dependence, and health problems.
How tolerance to caffeine and stimulants develops: In the context of supplements, we distinguish between two concepts: tolerability and tolerance.
Tolerability means that the body handles a drug or its ingredient well without side effects.
Tolerance (drug tolerance) is something else – it is a physiological adaptation where the same dose gradually stops working with its original strength, and a higher dose is needed to achieve the same effect.
With caffeine and other stimulants, tolerance develops relatively quickly. The mechanism is as follows: caffeine blocks adenosine receptors in the brain. Adenosine is a substance that signals fatigue and the need for rest. When caffeine blocks these receptors, you feel awake and energetic.
But our brain isn't stupid. After 1-2 weeks of regular caffeine use, the body starts producing more adenosine receptors (up-regulation). The result? The same dose of caffeine stops working as strongly because there are more receptors that need to be blocked.
Caffeine tolerance develops surprisingly quickly. The first signs of adaptation can appear after just 1-4 days of regular use. After 7-14 days of taking the same dose daily, the subjective feeling of energy is significantly reduced compared to the first few days. That is exactly why experts recommend cycling.
Symptoms of tolerance: the need to increase the dose for the same effect, a weaker subjective feeling of energy, and withdrawal symptoms upon omission (fatigue, headaches, irritability within 12-24 hours after the last dose).
Cycling Stimulants:
The only way to restore sensitivity to stimulants is taking a break.
Recommended protocol: 2-4 weeks of use, then 1-2 weeks of a complete break. During the break, you can expect lethargy and headaches for the first 2-3 days, then it will improve.
When taking pre-workouts, an alternative is alternating between stimulant and stim-free products. One week you take a stimulant pre-workout, the next week a stim-free version (for example, the instant nighttime pre-workout Warrior Crea Pump).
Health Risks of Excessive Stimulant Use:
Accelerated heart rate is a common side effect of high doses of stimulants.
Elevated blood pressure – caffeine and other stimulants cause the narrowing of blood vessels, which increases pressure. In healthy individuals, this is temporary, but for people with hypertension, it can be a dangerous condition.
Anxiety, nervousness, and panic attacks are common in cases of overdose. Caffeine increases levels of adrenaline – the hormone responsible for the "fight or flight" response. The result: trembling hands, feelings of anxiety, and an accelerated heart rate.
Insomnia and disruption of the sleep cycle – the half-life of caffeine is 5-6 hours. This means that if you drink 300 mg of caffeine at 4:00 PM, at 10:00 PM you still have 150 mg in your body. This significantly disrupts sleep quality, reduces growth hormone production, and impairs recovery.
Digestive issues – high doses of caffeine stimulate the production of stomach acid, which can cause heartburn, nausea, or diarrhea.
In extreme cases, cardiac arrhythmias and cardiovascular events may occur. If you experience palpitations, chest pressure, dizziness, or difficulty breathing after taking stimulants, immediately stop taking them and seek medical help.
💡 How do people use pre-workouts? According to a survey, 72% of pre-workout users have been using them for more than a year, and 89% cite increased energy and focus as the primary reason. Worryingly, 14% of respondents admitted to taking two or more servings at once – which is potentially dangerous and goes against manufacturers' recommendations. |
How to Prevent Overdose
Overdosing on caffeine and other stimulants is a real risk, especially when combining multiple sources. The problem is that many gym-goers do not realize how many stimulants they are actually consuming.
Practical guidelines:
Read the labels. Check the exact caffeine content in your pre-workout. Some products contain 150 mg, while others have up to 400 mg per serving. Besides caffeine, they may also contain other stimulants (DMHA, DMAA, synephrine, yohimbine) that potentiate each other.
Starting with lower doses is the golden rule. Even if the label states a recommended dose, start with half and see how you react. If you experience tremors, anxiety, or a racing heart, the dose is too high.
Monitor your total daily caffeine intake. We detail caffeine amounts and accumulation in the next section of this article.
DMHA, DMAA – Exercise Extra Caution
DMHA (2-aminoisoheptane) and DMAA (1,3-dimethylamylamine) are stronger stimulants than caffeine. Human research on them is practically non-existent. We covered them in more detail in the article Supplements before training: BCAAs, arginine, magnesium, caffeine, and others.
🚫 NEVER try:
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Combining Pre-workout with Other Supplements
Many gym-goers combine their pre-workout with other supplements to maximize results. But which combinations are safe? And which should you rather avoid?
Pre-workout and Creatine
Creatine and pre-workouts are a safe and synergistic combination. There are no negative interactions between these supplements. The synergistic effect lies in the fact that stimulants (caffeine, DMHA) provide energy and mental focus, while creatine increases strength and performance. Older research from 2000 suggested that caffeine might reduce the effectiveness of creatine, but newer studies have debunked this concern.
Practical recommendation: Take 5 g of creatine daily – either together with your pre-workout or separately at another time of the day.
Pre-workout and BCAAs
BCAAs (branched-chain amino acids) and pre-workouts are also a safe combination. The question, however, is: when does this combination make sense? Read our previous article Supplements before training: BCAAs, arginine, magnesium, caffeine, and others, where we also looked at when to take BCAAs and in which cases they are rather an unnecessary, albeit harmless, supplement.
Caffeine, Coffee, and Stimulants
This is exactly where overdosing happens most frequently. Many people do not realize how much caffeine they actually consume when combining different sources.
Created using Claude AI (Anthropic)
Example of dangerous accumulation during the day
7:00 AM – Morning coffee (100 mg) → Total: 100 mg ✓
10:00 AM – Second coffee (100 mg) → Total: 200 mg ✓
2:00 PM – Energy drink (80 mg) → Total: 280 mg ✓
5:00 PM – Pre-workout (300 mg) → Total: 580 mg ⚠️ LIMIT EXCEEDED!
The safe daily maximum is 400 mg for healthy adults. However, caffeine tolerance is individual, so listen to your body's signals.
💡 The CYP1A2 gene determines how quickly the body metabolizes caffeine. Approximately 50% of the population are "fast metabolizers" – caffeine affects them for a shorter time. The other half are "slow metabolizers" – caffeine works longer and more intensely, including negative effects on sleep. If you can't fall asleep in the evening after coffee, you likely belong to the second group. |
Practical recommendation: If you plan to take a pre-workout with 300 mg of caffeine, limit other sources of caffeine that day (if you can tolerate it, have a maximum of 1-2 cups of coffee).
💡 L-theanine + caffeine: perfect synergy. If caffeine causes you nervousness and hand tremors, look for pre-workouts containing L-theanine. This amino acid from tea leaves mitigates the negative effects of caffeine without reducing energy. The combination of caffeine + L-theanine (so-called "smart caffeine") demonstrably improves focus and performance more than caffeine alone. |
A detailed analysis of caffeine and its effects can be found in the article "Supplements before training: BCAAs, arginine, magnesium, caffeine, and others".
Pre-workout and Fat Burners
Combining a pre-workout with a fat burner is common, but potentially risky. Both types of products often contain high doses of stimulants – caffeine, synephrine, or yohimbine. When combining them, there is a risk of stimulant overdose.
Safe approach: Combine a stimulant pre-workout with a stim-free fat burner (or vice versa). Never take two highly stimulating products simultaneously.
Pre-workout and Alcohol
Never combine stimulant pre-workouts and alcohol. Caffeine masks the feeling of drunkenness but does not improve coordination – creating a so-called "wide-awake drunk" effect. Both substances are diuretics, which leads to extreme dehydration. Alcohol also reduces protein synthesis and impairs recovery.
Stim-free pre-workouts are less risky from this perspective, as they do not contain caffeine or other stimulants. Nevertheless, drinking alcohol before a workout impairs coordination, increases the risk of injury, and negatively affects both performance and recovery.
If you plan to consume alcohol, wait at least 4 hours after your workout. On that day, it is better to reach for a stim-free variant or skip the pre-workout entirely.
Pre-workout and Protein
A safe combination. Some athletes take whey protein (20-25 g) together with their pre-workout 30-45 minutes before training. However, research shows that protein timing is not as important as total daily intake – you can take it before or after training according to your preference.
How to Choose the Right Pre-workout
Choosing a pre-workout isn't just about which one has the best reviews. You must consider your training time, your goals, and your experience level.
By training time:
Morning/forenoon training (until 12:00 PM) → a stimulant pre-workout is fine if you tolerate it well. In the morning, the body is naturally most sensitive to stimulants, and you have the whole day for the caffeine to clear from your system.
Afternoon training (1:00 PM - 4:00 PM) → a stimulant pre-workout with a milder dose of caffeine (150-250 mg). Avoid extremely strong products.
Evening training (after 5:00 PM, ideally even earlier) → strictly stim-free versions.
By goal:
Energy and focus → a stimulant pre-workout with caffeine, DMHA, Alpha-GPC. The priority is mental sharpness and reducing fatigue.
Pump and blood flow → citrulline malate, arginine, agmatine sulfate. These substances increase nitric oxide (NO) production, which dilates blood vessels and improves blood flow.
Strength and performance → creatine, beta-alanine. Creatine regenerates ATP (energy for muscles), beta-alanine neutralizes acidic byproducts in muscles.
All together → a comprehensive pre-workout combining stimulants, vasodilators, and performance-enhancing substances.
By experience:
Beginner → try stim-free variants first, and then those with 150-200 mg of caffeine. Start with lower doses and products without DMAA/DMHA. Monitor your body's reaction.
Warrior Crea Pump – a stim-free pre-workout ideal for evening training or for those who want to avoid stimulants. It contains creatine, citrulline, and other pump-supporting substances without disrupting sleep.
Advanced → with good tolerance, you can take standard doses (200-300 mg of caffeine). Try to follow cycling – more in the "Cycling Stimulants" section above.
Experienced → you can experiment with higher doses and stronger stimulants (DMHA) depending on tolerance and preferences. Always adhere to cycling to prevent tolerance.
Kamikadze Extreme Pre-Workout – for experienced users looking for intense stimulation and maximum pump. It contains a combination of citrulline malate, caffeine, and cognitive enhancers. Suitable for morning and forenoon workouts.
Who pre-workout is not suitable for
Pre-workout supplements are not for everyone. In some cases, they can be dangerous or contraindicated.
Do not use if you have: heart disease, uncontrolled hypertension, a history of heart attack or stroke, or if you are under 18 years of age. For women, pregnancy and breastfeeding are absolute contraindications.
Consult with a doctor if you have: anxiety disorders, thyroid problems, are taking antidepressants or blood pressure medication, or have a high sensitivity to caffeine and stimulants.
Recommendation: If you have any doubts, consult your usage with a physician. Caution is appropriate and can help prevent health complications.
Notice: This article is for educational purposes only and does not replace professional medical consultation. Before taking any supplements, consult with your doctor, especially if you are taking medication or have health problems. The effects of supplements are individual, and results may vary.
With this article, we conclude our series on pre-workout supplements.
For a comprehensive overview, we recommend reading all three articles:
Pre-workout supplements: usage, timing, and safe combinations – A basic introduction to the world of pre-workouts, types of products, optimal timing, and initial safety principles.
What to eat and take before a workout: diet vs. supplements – A comprehensive look at pre-workout nutrition, when food is sufficient, and when supplementation makes sense.
Supplements before training: BCAAs, arginine, magnesium, caffeine, and others – A detailed breakdown of individual ingredients, their effects, dosages, and scientific evidence.
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