Workout Plan for Skinny Guys to Build Muscle Fast (13 Pounds in 28 Days)

Workout Routines | Written by Nathan Petitpas | Updated on 6 April 2023

On the left, a ripped man or muscular man of color wearing white sorts is flexing his bicep, and on the right, a Caucasian man who is skinny and lean is flexing his bicep next to the other guys hoping he'll provide a workout plan for skinny guys to build muscle fast.

Whether it’s putting on weight or building muscle, thinner guys may not know where to start or realize there is a way out— a workout plan for skinny guys to build muscle fast.9

It may sound impossible but a skinny guy can gain as much as 3 pounds a week—gaining a massive 13 pounds of lean mass in 28 days with a lot of hard work in the gym and a mass-focused diet.

How Long Does it Take to Go From Skinny to Jacked?

This depends on someone’s definition of being jacked, but it can take about a month to put on 10-13 pounds. To achieve this, someone must ‘go hardin training or in other words, give it they’re all in the gym to ensure maximum muscle growth. Of course, this will need to be done safely to avoid injuries, especially since the body is not used to handling the stress during the initial phase.

The body adapts to these new stresses of resistance training and has a hyper response to the stimuli provided; this results in gains in strength and mass faster than will ever happen once someone becomes an experienced lifter.1 A slang term for this is ‘newbie gains.

Best Workout Routine for Skinny Guys to Build Muscle Quick (in 28 Days)

The best workout plan for skinny guys to build muscle fastthat is, gaining 13 pounds in 28 days would call for individuals to engage in compound and isolation exercises targeting specific muscles. Compound exercises such as deadlifts recruit several muscle groups simultaneously and tend to mimic natural movements.2 These are beneficial as they work out more muscles concurrently, increasing efficiency and saving time.

The ideal workout routine for skinny guys to gain muscle would be to split into two sections which translate into two days that cover the whole body. These two days can be denoted as workout A and workout B.

The workout days will be alternated and between them a rest day— a rest day between workouts A and B.

Week 1

Monday  Wednesday Friday
Workout A Workout B Workout A

Week 2

Monday  Wednesday Friday
Workout B Workout A Workout B

In this case, the rest days will be Tuesday and Thursday, making for a workout week totaling 3 days. The aim would be to progressively increase the weights after each session taking advantage of the newbie gains effect.

A skinny white male wearing black tank top performing a bicep curl using a light dumbbell.

Source: deeepblue via Canva.com7

The key to this routine is to start with low weights and progressively increase them throughout the program. For every lift, find a weight that you can do with good form first and foremost. Then for squats, in the first 2-3 sessions, 10 pounds can be added if the weight moves quickly and with good form. Afterward, lifters can move up in 5 to 2.5-pound increments if the same lies true.

The deadlift will follow the same progression protocol but can have 15-20 pounds increments for the first number of sessions. Bench and shoulder press can have an initial 10-pound jump but 5 pounds will also do if someone is unable.

Workout A

This will consist of compound exercises targeting both the upper and lower body. The key is stimulating the major muscle groups to maximize hypertrophy. Exercises that will be performed here are back squats, bench press, and deadlift workout.

Back squat—the back squat can either be a high bar or low bar and be 3 sets of 5 reps. However, low bar squats are more challenging and will build muscle at an accelerated pace. The squats will target the quads, hamstrings, adductors, glutes, calves, and hip flexors muscles.

Bench press—bench presses will be composed of 3 sets of 5 reps; the first session will be done with relatively light weights and subsequently increasing weights. The bench press will target the pectoralis major (pecs), triceps, serratus anterior, and biceps.

Deadlift—this back-intensive workout will be performed in 1 set of 5 reps. The deadlift will target the upper and lower back muscles, glutes, hamstrings, core, quads, and glutes.

Workout B

This workout will be similar to workout A but will have some key differences in sets performed and will have an overhead shoulder press in lieu of the bench press. Therefore, exercises are squats, deadlifts, and overhead shoulder presses.

Back squat—like workout A, back squats are performed in 3 sets of 5 reps; the increments will carry over from day A.

Overhead press—the overhead press will be done while standing—making it compound in nature since the core will be engaged and will consist of 3 sets of 5 reps. The overhead press will target the deltoids, triceps, upper back, and chest.

Deadlift—unlike workout A, this deadlift will have increased volume. The sets will be increased to 3 but will remain at 5 reps; the increments will spill over from workout A and vice versa.

Individuals looking to achieve even more explosive growth may incorporate a 5-day workout plan for skinny guys as opposed to the three-day routine outline.

Auxiliary Exercises

New lifters may want to work on a certain muscle more than others, and if so, those wanting to go the extra may incorporate up to 4 of the exercises below on Monday, Wednesday, and Friday or 3 sets of 8-12 reps. These days can be used to perform isolation exercises targeting specific muscle groups. Overachievers can do the following:

  • Chin-ups—this exercise is performed by pulling the body up a bar and it targets the back muscles. Chin-ups are not fully isolation exercises and do engage muscles such as the biceps, in addition to the back muscles.
  • Dumbbell rows—performed on a bench using dumbbells, this exercise is also not purely an isolation exercise as it targets the lats, biceps as well as the core.
  • Cable chest flyes—using a cable, this exercise is performed by squeezing the cables inwards and targeting the chest muscles.
  • Cable stiff-arm pull-down—this uses a cable machine by pulling down on the cable and targets the upper back, triceps, chest, and core.
  • Hamstring curls—this exercise strengthens the hamstrings and can be done with a machine.
  • Leg extensions—leg extensions target the quads and are an excellent complement to the back squat.
  • Barbell curls—these are great for targeting the biceps and complementing compound movements.
  • One-arm preacher curls—these are great for addressing bicep imbalances and are performed on an inclined bench by curling the bicep using dumbbells.
  • Lying triceps extensions—these are done on a bench and target the triceps using a dumbbell weight.
  • Cable push down—these are completed using a cable machine pushing down on the cable, and this targets the triceps.
  • Dumbbell lateral raises—hold the dumbbells to the side and raise arms up in a to make a T. These will target the medial delts primarily 
Monday (Workout A) Wednesday (Workout B) Friday (Workout A)
Back squat: 3 X 5

Bench press: 3 X 5

Deadlift: 1 X 5

Chin-ups: 3 X 5

Dumbbell Rows: 3 X 5

Cable chest flys: 3 X 5

Cable pull-down: 3 X 5

Lying triceps extensions: 3 x 5

Back squat: 3 X 5

Bench press: 3 X 5

Deadlift: 3 x 5

Hamstring curls: 3 X 5

Leg extensions: 3 X 5

Barbell curls: 3 X 5

One arm preacher curls: 3 X 5

Cable push down: 3 X 5

Dumbbell lateral raises 3 x 5

Back squat: 3 X 5

Bench press: 3 X 5

Deadlift: 1 X 5

Chin-ups: 3 X 5

Dumbbell Rows: 3 X 5

Cable chest flys: 3 X 5

Cable pull-down: 3 X 5

Lying triceps extensions: 3 x 5


A young man doing dumbbell lateral raises or side raises in a gym with a stack of weights and dumbbell rack in front of him and bunch of equipment in the background.

Source: SOK-STUDIO via Canva.com8

Home Workout Plan for Skinny Guys to Build Muscle Fast

Individuals that do not have access to the gym or gym equipment may incorporate a home workout plan for skinny guys to build muscle fast and gain 13 pounds in 28 days. Just because someone doesn’t have access to weights, doesn’t mean that they will not be able to muscle fast.

While these methods may not be as optimal as weights, they do work and provide gains as long as the muscles face resistance.

These workout plans call for using calisthenics—essentially using the body weight as the resistance. Calisthenics is a very effective form of resistance training using high repetitions, producing similar results as weights.3 Bands may be used in these workouts, adding variety and intensity to the workouts.

Exercises must also be done in high-intensity—high-intensity interval training (HIIT). HIIT involves explosive workouts with short rest periods, which exhaustively tires the muscles and saves time.4 Incorporating HIIT makes these workouts effective and provides an alternate bulking workout plan for skinny guys. Skinny guys should always warm up before embarking on the routine.

Workout A

This will involve upper and lower body parts and compound movements such as squats and pushups. Before embarking on the routine, there should always be a warm-up—walking or marching would suffice.

Squats—these should be done at an all-out effort for 30 seconds for 4 sets, and jumping squats should be incorporated to increase the intensity. They target the quads and glutes. The use of a band for banded squats will help increase intensity.

Side lunges—side lunges would help address imbalances and also be done for 30 for 4 sets seconds alternating between the two legs. In addition to the glutes, this target the hip flexors. These can also use a band to increase intensity.

Push-ups—they are great for the chest and should be done explosively for 30 seconds for 4 sets. They can be done at a 45-degree angle on a support like a chair to increase the intensity. Dead stop push-ups that use bands will increase the intensity here and to answer the question of “Is doing push ups everyday overtraining?“, the answer is it can be and this can be determined if strength decreases. 

Pull-ups—pull-ups are excellent for the pulling muscles—latissimus dorsi (lats), biceps, and forearms. They should also be explosive, done for 30 seconds for 4 sets. Isometric pull-ups can also be done where there is a pause for several seconds.

Workout B

This day will also have a combination of upper and lower body workouts but with various exercises. The routine will include jumping jacks, triceps dips, and sit-ups.

Jumping jacks—these should be for 30 seconds for 4 sets. They are excellent for quads, glutes, and hip flexors.

Triceps dips—this target the triceps and should be performed in 4 sets times at 30 seconds per set. Tricep extensions can be performed here with the use of bands

Shoulder press—these can be done with bands by holding them and mimicking an overhead press.

Alternating high knees—this explosive exercise involves bringing the knees up to the torso and can be done in 30 seconds for 4 sets.

Sit-ups—sit-ups will be done intensely for 30 seconds in sets of 4. For increased intensity, they may be done on an exercise ball

Monday (Workout A) Wednesday (Workout B) Friday (Workout A)
Squats: 4 sets for 30 secs.

Side lunges: 4 sets for 30 secs.

Push-ups: 4 sets for 30 secs.

Pull-ups: 4 sets for 30 secs.

Jumping jacks: 4 sets for 30 secs.

Tricep dips 4 sets for 30 secs.

Shoulder press: 4 sets for 30 secs.

Alternating high knees: 4 sets for 30 secs.

Sit-ups: 4 sets for 30 secs.

Squats: 4 sets for 30 secs.

Side lunges: 4 sets for 30 secs.

Push-ups: 4 sets for 30 secs.

Pull-ups: 4 sets for 30 secs.

Skinny Guys Can Maximize Gains By Focusing on the Fundamentals

The key to skinny guys maximizing gains is focusing on certain fundamentals that will allow them to bulk up efficiently. It incorporates techniques and ensures some proven basics are adhered to in the workout plans for skinny guys to get big such as tracking volume and strength, utilizing reps in reserve, i.e., hitting the muscle to failure, among others.

RIR (Reps in Reserve)

Reps in reserve (RIR) is, as the name implies, the number of reps that someone can still potentially do at the end of a set—before technical failure.5 Hitting the muscle to failure is beneficial as it is a gauge of strength and provides an excellent stimulus for hypertrophy especially taking advantage of newbie gains— but it should not be used always. Most training sessions should have 2-3 RIR to prevent overtraining.

Tracking Volume & Strength

Of all the variables in a training regimen, volume is one of the most important. Volume is essentially the amount of work or effort put into a training exercise quantified by the number of reps and sets. The inadequate volume will not produce the desired results since muscles will not receive enough stimulus to grow and too much can result in counterproductive overtraining.

By keeping track of volume and strength, a baseline for future workouts is also established. Keeping a notepad when working out and noting the volume of exercises—a product of weights, sets, and reps is best. A fitness tracker like whoop can also be used—this device measures variables such as heart rate, sleep quality, and heart rate variability, thus indicating volume.

Tracking Weight or Size

It is critical to track the weight and size during a workout routine to gauge the progress that is being made. This includes total body weight or measuring the circumference of muscle groups—chest, biceps, quads, etc.

By keeping track of these two variables, someone may alter the training routine to ensure results are being realized. This should be an objective exercise, and no emotion should be attached—the goal is to ensure a workout routine to build muscle is being implemented.

Mind Muscle Connection

The mind-muscle connection is focusing on the exercise and the specific muscles being performed— this establishes a neural link to perform the exercise with the correct form.6 Thinking attentively and consciously focusing on the exercise as it is being performed will lead to better activation of the muscles, which will translate into more muscle growth.

Simply put, this is one of the most important fundamentals that can enhance a workout routine for skinny guys to gain muscle.

Adhering to these four fundamentals will provide a platform for an effective workout plan for skinny guys to build muscle fast and easily pack on 13 pounds of lean mass in 28 days.

The Other Half to Bulking Up & Getting Big As a Skinny Guy: Diet & Recovery

The other half to bulking and getting big as a skinny guy boils down to diet and recovery. With all the hard work put in, the body will need nutrients to nourish and grow lean mass— to recover and repair the muscles that have been broken down due to strength training.

Bulking Diet for Skinny Guys

A bulking diet is critical for skinny guys to build lean mass after hard training and is key to realizing gains— it is also a recovery strategy. It is challenging for underweight individuals to put on a decent amount of weight as they often assume they have eaten more than they actually have and thus, consider themselves “hard gainers”.

Therefore, it’s imperative to track calories and remember, that you will only see newbie gains once so be sure you’re getting sufficient calories and protein.

Individuals may eat between 2800-3500 calories for 2 weeks and check to see if they are gaining or losing weight. An excellent tool that can be used to monitor and track weight would be the body weight planner. There are apps available on the market, such as Macro factor, that will aid someone tracks their calories to reach bulking goals.

Again, adequate protein intake is critical for growing muscles and ensuring a calorie surplus in the system— this aids in the journey from being ripped skinny guys to bulking up. Eating while full is something that skinny individuals will need to adjust to, to avoid leaving gains on the table.

A bulking diet would typically include the following food:

  • Eggs
  • Whole milk
  • Ground beef
  • Peanut butter
  • Oats
  • Bananas
  • Whey protein
  • Tuna
  • Chicken
  • Rice
  • Nuts
  • Vegetables

Another technique called If It Fits Your Macros (IFFYM) may also work for some individuals. This program does not focus on calories but rather on macronutrients—protein, fat, and carbs. It does not restrict what foods can be consumed.

Other recovery techniques that can be incorporated are changes in the lifestyle—these include increased sleep, foam rolling, getting sports massages, staying hydrated etc.

Supplements to Incorporate on a Workout Plan for Skinny Guys to Build Muscle Fast

In addition to the aforementioned diet, supplements and vitamins may be included for skinny guys to stack on mass. Skinny individuals often have increased metabolic rates that make it very challenging to bulk up or have allergies to foods.

These supplements are commercially available and include:

  • Mass gainers—the best ones will have low-fat levels, medium protein, and high carbs.
  • Multivitamins— these would be a great addition as they aid membrane repair and reduce oxidative stresses induced by training.
  • Fish oil—is an excellent source of omega-3 and fatty acids which muscles need to grow.
  • Creatine— this is a proven supplement that fuels the workout of lifters by elevating endurance levels, augmenting hypertrophy, and decreasing the time it takes for muscles to recover.

Of course, there are a million other supplements on the market, but these four are scientifically proven and will give skinny guys the most bang for their buck.

Go From Skinny to Ripped – Make Your Dreams a Reality

It is possible to go from skinny to ripped and make your dreams a reality! This can be done by being focused, and driven and ensuring that the above strict training regimen is followed. There can be no gains if there are no pains, as the familiar adage goes.

In addition, it is essential to fuel this hard work with quality, abundant nutrition, and altering the lifestyle to maximize gains made in the workout plan for skinny guys. This can be done in the least small amount of time—28 days.

Skinny guys would be pleased to know that there is indeed a workout plan for skinny guys to build muscle fast and, even more pleasing, that a whopping 13 pounds can be amassed in 28 days!


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2Academy, A. F. (2018, October 31). WHAT ARE COMPOUND EXERCISES? Retrieved from <>

3Medicine, N. L. (2014, October 28). Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. Retrieved 2022, from <>

4Health, H. T. (2022). HIIT (High Intensity Interval Training). Retrieved 2022, from <,periods%20of%20lower%20intensity%20movements.>

5Medicine, N. L. (2016, August 3). Application of the Repetitions in Reserve-Based Rating of Perceived Exertion Scale for Resistance Training. Retrieved from <>

6Medicine, N. L. (2016, March). Importance of mind-muscle connection during progressive resistance training. Retrieved 2022, from <>

7deeepblue. “skinny man workouts.” Canva. Accessed 7 April 2023. <>

8SOK-STUDIO. “Young Man Performing Dumbbell Lateral Raise.” Canva. Accessed 7 April 2023. <>

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About the Author

Nathan Petitpas

Nathan has been a fitness enthusiast for the past 12 years and jumps between several types of training such as bodybuilding, powerlifting, cycling, gymnastics, and backcountry hiking. Due to the varying caloric needs of numerous sports, he has cycled between all types of diets and currently eats a whole food diet. In addition, Nathan lives with several injuries such as hip impingement, spondylolisthesis, and scoliosis, so he underwent self-rehabilitation and no longer lives with debilitating pain.