Key Takeaways of Hardgainer Workout
- A 2025 study found that everyone’s muscles respond to resistance training — some faster than others, but no one is truly “immune” to gains. For hardgainer workout enthusiasts, this is reassuring news that with the right approach, muscle growth is achievable.
- Those who gain muscle more quickly also tend to lose it faster when they stop training, showing that results depend on effort, nutrition, and consistency — not genetics alone.
- True “nonresponders” are extremely rare. If you’re not building muscle, you’re likely not eating enough or training effectively.
What Is a Hardgainer Workout?
The concept of “hardgainers” refers to individuals who struggle to increase muscle mass despite rigorous training and proper nutrition. For decades, lifters have used this term to describe people who “just can’t put on size,” no matter what they do.
The old advice for so-called hardgainers usually included training less, resting more, and eating “cleaner.” But new science is starting to debunk this myth.
According to a 2025 study from the University of Jyväskylä in Finland, published in the European Journal of Sport Science and titled “Repeated Resistance Training Reveals the Reproducibility of Muscle Strength and Size Responses Within Individuals,” everyone can grow muscle when training and nutrition are properly controlled.1
This isn’t just another gym theory — it’s real, measurable science. The study shows that while individuals differ in how much they gain, those differences are consistent and repeatable. In other words, your body isn’t randomly “resistant” to growth; it just responds at its own pace based on how well you train, eat, and recover.
Review of the Literature: What We Thought We Knew
For years, research has shown wide variation in how people respond to strength training. Some lifters add muscle quickly, while others seem to grind with little visible progress. In past studies, muscle strength gains ranged anywhere from 0% to 250% among participants doing the exact same training program.2
This led many to believe that “nonresponders” exist — people who simply can’t grow muscle. But when scientists looked closer, they discovered that much of that variation came from differences in training effort, nutrition, recovery, and even measurement error, not from a biological inability to grow.3
Research indicates that genetic, hormonal, and cellular mechanisms significantly contribute to the variability in muscle hypertrophy responses among individuals engaging in resistance training. However, those mechanisms don’t make growth impossible — they just influence how fast it happens.
Study Overview: What the Researchers Did
In this 2025 Finnish study, scientists recruited 55 untrained men and women aged 18 to 40.
- 20 participants joined a resistance training group.
- 27 participants were in a control group that didn’t train at all.
The training group lifted weights twice a week for 10 weeks, doing full-body workouts that included:
- Leg press
- Knee extension
- Bench press
- Barbell curls
- Seated row
They performed 8–10 reps per set, with the last set of the week taken to muscular failure — meaning they couldn’t do another rep with good form. Weights were adjusted weekly to ensure progression.
After these 10 weeks, participants took a 10-week break (detraining) and then repeated the same program for another 10 weeks.
Muscle size was measured using ultrasound scans of the thighs and biceps, and strength was tested with one-repetition maximum (1RM) tests for leg press and barbell curls.
Results: Everyone Made Gains
The results were clear — everyone in the training group made significant gains compared to the control group.
After the first 10 weeks:
- Thigh muscle size increased by about 16%.
- Biceps muscle size grew by 17.5%.
- Leg press strength increased by roughly 22%.
- Biceps curl strength rose by around 25%.
To put that in perspective, a beginner might add 50–70 pounds (23–32 kg) to their leg press and 10–15 pounds (4.5–7 kg) to their barbell curl in just 10 weeks.
Even more interesting: when participants repeated the exact same training after their break, they made nearly identical gains again. Their results were reproducible, with strong correlations between the two cycles (ranging from 0.67 to 0.76).
So, the same people who grew a lot the first time did so again — and those who grew less still improved consistently.
The Death of the “Nonresponder” Idea
This study drives a stake through the heart of the hardgainer myth. Everyone’s body responds to resistance training — period.
The differences between people aren’t due to an inability to grow but to individual traits like effort, nutrition, and recovery.
One critical factor influencing muscle gain is the ratio of fast-twitch (Type II) to slow-twitch (Type I) muscle fibers. Fast-twitch fibers are more conducive to hypertrophy and strength gains, while slow-twitch fibers are more endurance-oriented. Studies indicate that the initial size of muscle fibers and their type distribution can predict hypertrophic responses to resistance training, as some individuals have been documented to have a high proportion of slow-twitch fibers, thereby reducing their potential for muscle hypertrophy regardless of their exercise regimen. 2,4
This explains why some people build muscle faster than others — but it doesn’t mean anyone is incapable of building muscle.
The researchers also found something fascinating: people who made the biggest gains during training lost more muscle during detraining. So, those who adapt quickly also lose adaptations faster when they stop. In simple terms: consistency matters more than genetics.
Practical Applications for Hardgainer Workouts
Here’s what this research means for anyone who feels “stuck”:
1. Stop Blaming Genetics
1. Stop Blaming GeneticsYour DNA might influence how fast you build muscle, but it doesn’t decide whether you can. Everyone in the study gained strength and muscle when they trained properly.
2. You’re Probably Not Eating Enough
Muscle growth requires calories — more than you burn. An energy surplus is key to fueling growth. Additionally, nutritional adequacy and timing should not be underestimated. An energy surplus is generally beneficial for maximizing muscle hypertrophy [(Folland et al., 2000)], but genetic factors can influence how individuals respond to dietary changes.
If you’re not gaining weight after several weeks, you’re likely not eating enough. Track your food and aim for a 300–500 calorie surplus daily with 0.8–1 gram of protein per pound (1.8–2.2 grams per kg) of body weight.
3. Train Hard — Really Hard
In this study, participants trained close to failure every session. If your workouts feel easy, your muscles won’t have a reason to grow.
4. Stay Consistent
Participants who took a 10-week break lost much of what they gained. The solution? Don’t stop. You don’t need to train every day, but you do need to train regularly.
Effort Beats Genetics Every Time
In summary, the phenomenon of hardgainers — a term denoting individuals who find it difficult to gain muscle mass — stems from a mix of genetic, hormonal, and structural factors. But as the Finnish study makes clear, even those with less favorable genetics still make measurable progress when they train consistently and eat enough.
Your body’s capacity for growth is far greater than most people realize. The “hardgainer” label isn’t a curse — it’s often just an excuse.
So, if you’ve been telling yourself you can’t gain muscle, it’s time to look at your effort, nutrition, and consistency. When those are in place, everyone — including you — can grow stronger, bigger, and better.
References
1 Räntilä, A. et al. Repeated Resistance Training Reveals the Reproducibility of Muscle Strength and Size Responses Within Individuals. European Journal of Sport Science 25, e70095 (2025). https://doi.org/https://doi.org/10.1002/ejsc.70095
2 Haun, C. T. et al. Pre-training Skeletal Muscle Fiber Size and Predominant Fiber Type Best Predict Hypertrophic Responses to 6 Weeks of Resistance Training in Previously Trained Young Men. Front Physiol 10, 297 (2019). https://doi.org/10.3389/fphys.2019.00297
3 Ahtiainen, J. P. et al. Heterogeneity in resistance training-induced muscle strength and mass responses in men and women of different ages. Age (Dordr) 38, 10 (2016). https://doi.org/10.1007/s11357-015-9870-1
4 Roberts, M. D. et al. Physiological Differences Between Low Versus High Skeletal Muscle Hypertrophic Responders to Resistance Exercise Training: Current Perspectives and Future Research Directions. Front Physiol 9, 834 (2018). https://doi.org/10.3389/fphys.2018.00834
Frequently Asked Questions (FAQ)
What is a Hardgainer workout?
A Hardgainer workout is a training approach specifically designed for people who naturally struggle to gain muscle — often skinny guys with fast metabolisms. It emphasizes progressive overload (gradually lifting heavier or doing more reps), compound exercises (like squats, deadlifts, presses), and workouts intense enough to stimulate growth, while allowing enough recovery and pairing training with sufficient nutrition.
How can a skinny guy gain muscle effectively?
If you’re skinny and wondering how to gain muscle for skinny guys, the key steps are: follow a consistent resistance-training plan (preferably a Hardgainer workout), eat in a calorie surplus (more calories than you burn), and get enough protein and nutrition. Consistency over time matters more than fancy routines. With that approach, even “hardgainers” can build meaningful muscle.
Do hardgainers really exist, or is it just a myth?
The term “hardgainer” is often used to describe people who find building muscle difficult. While some people might gain slower, many of the difficulties come from insufficient calories, poor nutrition, inconsistent training, or lack of progressive overload. With the right Hardgainer workout and eating plan, most “hardgainers” can make consistent progress — so the myth of being completely unable to gain muscle is largely outdated.
How many times per week should a hardgainer train to build muscle?
For those following a Hardgainer workout and trying to learn how to gain muscle for skinny guys, training about 2–4 times per week is common. The goal is to stimulate muscles enough through compound movements and progressive overload — not overtrain them — and allow proper recovery and nutrition.
Do skinny guys need to eat more calories to support muscle growth?
Yes. One of the biggest mistakes skinny guys or “hardgainers” make is not eating enough. To gain muscle, you typically need a calorie surplus — eating more calories than you burn — and enough protein to support muscle repair and growth. Without sufficient calories and protein, even the best Hardgainer workout won’t produce optimal results.
What kind of exercises are best in a Hardgainer workout?
Exercises that work multiple muscle groups at once — known as compound exercises — are most effective. Think: squats, deadlifts, bench presses, rows, pull-ups, or chin-ups. These compound movements stimulate more muscle fibers, allow you to lift heavier, and generally give better returns for those asking how to gain muscle for skinny guys.
Why do some people hit plateaus even on a Hardgainer workout?
Even with a good workout plan, plateaus happen when you stop progressing — maybe you’re not increasing weight or reps (lack of overload), you’re not eating enough, or you’re not giving your body enough rest. For skinny guys in particular, failing to eat at least maintenance + some extra calories or skipping nutrition can stall gains.
How long until a skinny guy sees muscle growth with proper training and nutrition?
It varies by individual — often depending on genetics, consistency, nutrition, and workout quality — but many skinny guys following a good Hardgainer workout and eating plan begin to see visible muscle gains within 8–12 weeks. Progress might be slower for some “hardgainers,” but with consistency and patience, growth is almost inevitable.
