Workout plan for skinny guys: build muscle and gain weight when it's hard

Choosing your starting weightEmerging evidence

Warm up, then pick a weight you think you could lift about 10 to 12 times at most. Do the bottom of the rep range (for 8 to 12, do 8) and ask: how many more could I have done with good form? Two or three more: that is your weight. Five or more: go up one step next set. None or one: go down one step.

For bodyweight moves, choose the version (the easier or harder option on each move's page) where you reach the bottom of the rep range with 2 or 3 reps to spare.

In the first two weeks, stop each set with 3 or 4 reps to spare. Most people misjudge how many reps they have left by about one, and you are still learning the movements.

Sources 1, 2, 3

Progressing week to week: double progressionEmerging evidence

Each exercise has a rep range, such as 8 to 12. Keep the weight the same and add reps, set by set and session by session, while still stopping 1 to 3 reps short of failure.

When every set reaches the top of the range, add the smallest weight step you have (roughly 2 to 10%, smaller jumps for the upper body and small muscles) and go back to the bottom of the range. Adding reps and adding weight both work; this rule uses both.

With body weight, add reps, then slow the lowering, then move to the harder option. If a lift stalls for 2 or 3 sessions, hold the weight, check your sleep and food, and consider a lighter week.

Sources 4, 3, 1

How hard each set should feelStrong evidence

You do not need to train to failure. Stopping 2 or 3 reps short, often written as 2 to 3 reps in reserve (RIR), gives similar results for most people.

Big lifts stay at 2 to 3 reps in reserve, including the heavier sets of weeks 9 to 11; on the optional fourth day, the last set of raises, curls and extensions can go to 0 to 2.

Sources 1, 5

Rest between setsEmerging evidence

Heavy compound lifts in sets of 5 to 8 (squat, deadlift, bench press, overhead press, chin-up): 2 to 3 minutes. Other compound lifts in sets of 8 to 12: about 90 seconds to 2 minutes. Isolation moves such as raises, curls, extensions and calf raises: 60 to 90 seconds.

For muscle growth, resting more than about a minute gives a small advantage, with no clear extra gain past about 90 seconds. For strength the evidence on rest is mixed: 1 to 2 minutes is enough for beginners, and trained lifters may do better with longer rests on heavy lifts.

Short on time? Pair two moves that do not compete, such as a press with a row or a leg move with a core move, and rest after the pair. Supersets like this cut session time by about a third to a half while keeping the sets.

Sources 6, 7, 1, 8, 9

Lighter weeks (deloads)Mixed evidence

Not compulsory, especially for beginners. Take one in week 8, if you need it, or sooner if your performance drops for two sessions in a row and you feel run down or achy: same days, same exercises, about half the sets, and weights that feel easy (4 or more reps in reserve). Then restart at your previous weights.

Deloads are common practice: in a survey of competitive strength and physique athletes they lasted about a week, roughly every 5 to 6 weeks. Direct evidence is thin: three small trials. In trained adults, a full week off mid-programme did not change muscle growth but slightly reduced strength gains. In one small trial in 19 untrained men, with no control group, two lighter weeks neither held back nor added to gains; the second came just before testing, so it also worked as a taper. After very high-volume training, a lighter week and a week off gave similar results in 30 trained men. So a lighter week looks better than a week off if strength matters.

Sources 10, 11, 12, 13, 14

Warm-up and cool-downEmerging evidence

Warm up with 3 to 5 minutes of easy movement, the moves listed at the start of each session, then 1 or 2 lighter sets of the first lift. A short warm-up specific to the exercise is enough.

The cool-down is optional. Its stretches are there for comfort and flexibility; they do not add strength or muscle.

Source 8

Missed days, soreness and when to stop

Missed a session? Do the next one in the order rather than doubling up. Muscle soreness for a day or two after a new exercise is common and fades as you repeat it.

Stop and get medical help for chest pain or pressure, unusual breathlessness, dizziness or fainting. If a joint pain is sharp, gets worse during a set or lingers into the next day, swap to the move's easier option, and see a clinician if it persists.

WHO notes that people without contraindications generally do not need medical clearance before light or moderate activity. If you have a heart, lung or metabolic condition, are pregnant, or have osteoporosis with fractures, ask your clinician first.

Source 15

Health firstStrong evidence

If you've lost weight suddenly or without changing your diet or exercise, or you use control of food to cope with feelings, see a GP before you start: the NHS says losing weight without trying can be a sign of stress or a serious illness. Being underweight can mean missing out on vitamins and minerals, which can lead to a weak immune system and fractures. A body mass index (BMI) under 18.5 is below the healthy-weight range that NICE (the National Institute for Health and Care Excellence) uses. Our how to gain weight guide covers the food side in detail.

Sources 16, 17, 18

Why gaining is hard for some peopleEmerging evidence

People really do differ. When 12 pairs of identical twins ate 1,000 extra calories a day for 84 days, they gained anything from 4.3 to 13.3 kg, and each pair gained alike. In 16 adults overfed for 8 weeks, those whose everyday movement, such as fidgeting, standing and walking about, rose the most stored the least fat, and healthy thinness runs partly in families. But every twin pair gained weight: slower doesn't mean never.

Sources 19, 20, 21

People respond to training very differentlyStrong evidence

On the same training, some people gain a lot of muscle and others very little. After 12 weeks of arm training in 585 adults, biceps size changed by anything from 2% smaller to 59% bigger. In a pooled analysis of 287 untrained adults aged 19 to 78, about 3 in 10 gained little or no measurable muscle size, whatever their age or sex, and in a trial of 66 untrained adults, about a quarter showed no growth in their muscle fibres on average after 16 weeks. Genes explain part of the difference: in a study of male twins, genes linked to the training response explained about a fifth of the differences in strength after 10 weeks.

Strength is a different story: in the same pooled analysis, only 7% were low responders for strength, so most people got stronger even when their muscles grew little.

Sources 22, 23, 24, 25

A slow start: more sets and more timeEmerging evidence

If progress is slow, more sets and more time are the most promising next steps, though the evidence is thin. In one trial, 34 untrained young adults trained one leg with 1 set and the other with 3 sets of each exercise for 12 weeks: the 3-set legs grew more on average (5.2% against 3.7%), and 13 of the 34 people clearly grew more with 3 sets. That's a single within-person trial, and it hasn't been tested in people who call themselves hardgainers. Across studies, more weekly sets build more muscle, with smaller returns the more you add, which is why this plan adds sets from week 5.

In older adults the picture is more hopeful still: in pooled data from people over 65 who trained for 12 or 24 weeks, everyone improved on at least one measure, and more people responded the longer they trained. That finding is about adults over 65, and may not hold for younger people.

Sources 26, 27, 28, 29

How much more to eatStrong evidence

The NHS suggests adults who need to gain weight add around 300 to 500 extra calories a day, gradually: smaller meals more often with healthy snacks between them, extra cheese, nuts and seeds, high-calorie drinks such as milkshakes between meals rather than before them, and protein from beans, pulses, fish, eggs and lean meat. It says not to rely on chocolate, cakes and sugary drinks. Weigh yourself on a few mornings a week and watch the weekly average; if it hasn't risen after 2 or 3 weeks, add a snack or a milky drink a day (our suggestion).

Source 16

Lifting decides where the extra goesEmerging evidence

Training steers extra food into muscle. In 73 men lifting four days a week for 8 weeks, a high-calorie supplement added about 3 kg, nearly all of it fat-free mass; in 25 adults overeating for 8 weeks without training, between half and more than 90% of the extra energy their bodies stored went to fat.

Bigger surpluses don't build more muscle: in 17 trained lifters, gaining faster added more fat, and in 39 elite athletes a bigger surplus raised weight and fat but not lean mass. The ideal surplus hasn't been worked out. As a check, gaining about 0.25 to 0.5% of your body weight a week is the pace bodybuilding guidance suggests, though it hasn't been tested in people who are underweight.

Sources 30, 31, 32, 33, 34, 35

Protein, from foodStrong evidence

About 1.6 g of protein per kg of body weight a day is where extra protein stopped adding muscle across 49 trials. That's about 100 g a day for a 60 kg man, spread over three to five meals and snacks: eggs, milk, yoghurt, fish, meat, beans, pulses and tofu. Sports nutrition guidance favours whole foods; a shake is just a convenience.

Sources 36, 37, 16

PatienceStrong evidence

Across 111 studies of men lasting from 2 weeks to a year, muscle rose by about 1.5 kg on average, with a huge range between people. Strength comes sooner: it rose within 2 to 6 weeks in a 12-week trial, and in the records of 14,690 adults training once a week it kept rising for the first year before levelling off.

Sources 38, 39, 40

SleepEmerging evidence

The NHS says adults need 7 to 9 hours' sleep. In small trials, one night without sleep cut muscle protein building by 18% in 13 adults, and five nights of 4 hours in bed lowered it in a trial of 24 young men, unless they also did interval exercise; losing sleep also cut exercise performance by about 7.6% across 69 publications.

Sources 41, 42, 43, 44

Supplements: what the guidelines sayStrong evidence

You don't need supplements to gain weight or muscle: the NHS's advice is food, and sports nutrition guidance favours whole-food protein, so a shake is a convenience, not a requirement. Weight-gainer drinks add calories, which food can do too: in the trial of 73 men, a carbohydrate drink added as much fat-free mass as a high-protein one, and the authors concluded that once protein needs are met, calories matter most. The International Olympic Committee's consensus statement, written for elite athletes, says only a few supplements, creatine among them, have good evidence of helping performance, that some products contain banned substances, and that a full look at your diet and expert advice should come first.

Sources 16, 37, 45, 30

Anabolic steroidsStrong evidence

The NHS warns that anabolic steroids taken to build muscle can cause serious side effects, from infertility, shrunken testicles and severe acne to heart attacks, strokes and liver or kidney problems, as well as aggression and mood swings, and that they're addictive. It notes that people with body dysmorphic disorder may take them because they don't see themselves as big or strong enough. If you think you're addicted, see a GP.

Source 46

Your body, your healthStrong evidence

Wanting to fill out is common. But if worrying about your size or shape takes up a lot of your day, you check mirrors constantly or avoid them, or eating and training feel driven, talk to someone. The NHS says to see a GP if you think you might have body dysmorphic disorder, or to refer yourself to an NHS talking therapies service, and that you have nothing to feel ashamed or embarrassed about. It lists exercising too much and worrying a lot about your weight and body shape among the signs of an eating disorder.

Beat lists a drive for masculinity, with "less of a focus on thinness and a greater tendency to experience muscle dysmorphia", among signs that may be more common in men with eating disorders, while noting that not all men with an eating disorder feel driven to become more muscular. Beat's helplines are open 3pm to 8pm on weekdays: England 0808 801 0677, Scotland 0808 801 0432, Wales 0808 801 0433 and Northern Ireland 0808 801 0434. In the US, ANAD's free helpline is 1-888-375-7767, Monday to Friday, 9am to 9pm Central time. In immediate danger, call 999 or Samaritans on 116 123 in the UK, or call or text 988 in the US.

Sources 47, 48, 49, 50, 51, 52

No gymEmerging evidence

Bodyweight training builds muscle when the sets are hard: in 18 young men, push-ups matched to a light bench press built as much chest muscle and strength over 8 weeks, and in 23 men, 4 weeks of harder push-up variations raised bench press strength as much as bench pressing did. Use the dumbbell track here, or our calisthenics plan.

Sources 53, 54, 55

How much training this isStrong evidence

Counting direct sets in the build phase, this plan gives about 7 to 8 hard sets a week for the chest, 9 for the back, 4 to 5 for overhead pressing, 12 for the quads and 12 for the glutes and hamstrings in weeks 3 and 4, and from week 5 about 9 for the chest, 10 to 11 for the back, 15 for the quads and 13 to 14 for the glutes and hamstrings, averaged over two weeks; the optional fourth day adds 3 sets of overhead pressing, 6 for the side and back of the shoulders and 5 each for the biceps and triceps.

More weekly sets build more muscle, with diminishing returns that arrive sooner for strength than for size. The 2026 ACSM position stand saw extra growth from about 10 or more sets per muscle a week, and a review of time-efficient training suggests about 4 hard sets a week as a reasonable floor for busy people.

That reaches 10 or more sets for the back and legs from week 5, with the chest just under. The fourth day adds direct work for the shoulders and arms, which also work in every press and row.

Sources 1, 27, 28, 8

Cardio does not cost you muscleStrong evidence

Doing cardio as well as strength training does not reduce muscle growth or maximal strength. It can blunt explosive strength, such as jumping, mainly when both are done in the same session; keep them at least 3 hours apart if that matters to you.

Source 56

Check firstStrong evidence

Answer the 7 questions of the PAR-Q+ (the Physical Activity Readiness Questionnaire for Everyone) before you start. They cover a heart condition or high blood pressure, chest pain, dizziness or fainting, another long-term condition, medicines for one, a bone or joint problem that more activity could make worse, and being told to exercise only under medical supervision. A yes leads to follow-up questions that may send you to your GP or a qualified exercise professional first. With a cold or fever, wait until you're better; if you're pregnant, talk to your midwife or doctor first.

The NHS suggests speaking to a GP first if you haven't exercised for some time, or have a medical condition or concerns. The World Health Organization (WHO) notes that most people without such problems don't need a medical check before light or moderate activity, and the American College of Sports Medicine's (ACSM's) screening looks at how active you are now, any symptoms or known heart, metabolic or kidney disease, and how hard you plan to train.

Hard, all-out effort briefly raises the risk of a heart attack or sudden death from a heart problem in people at risk, mostly those who rarely exercise, and warning signs often come first. If you're over 45 and not used to it, the PAR-Q+ asks you to check with a qualified exercise professional before very hard efforts. Whatever your age, breathe out on the effort rather than holding your breath, which raises blood pressure, as the British Heart Foundation advises.

With ME/CFS (myalgic encephalomyelitis or chronic fatigue syndrome), NICE (the National Institute for Health and Care Excellence) advises against programmes with fixed increases in activity, which is what this plan is.

Sources 57, 58, 15, 59, 60, 61, 62

Stop and get helpStrong evidence

Call 999 in the UK or 911 in the US for chest pain that comes on suddenly and doesn't go away, feels tight or like squeezing or pressure, or spreads to your arms, neck, jaw, stomach or back; chest pain with sweating, feeling sick, light-headedness or breathlessness; severe difficulty breathing; or signs of a stroke, such as one side of the face drooping, weakness in one arm or slurred speech, even if they pass. Don't drive yourself to hospital.

Call 999 or go to A&E for palpitations that don't go away, or that come with chest pain, breathlessness or feeling faint. Call 999 if someone has fainted and isn't breathing, or can't be woken within a minute, and see a GP after any faint. Contact NHS 111 (in the US, your doctor or an urgent care centre) if you're suddenly more short of breath than usual, or have chest pain with feeling sick or a heartbeat that races, skips or flutters.

Dark, red or cola-coloured urine, much less urine than usual, or very painful, weak or swollen muscles after unusually hard training can be rhabdomyolysis, a breakdown of muscle that can harm the kidneys: get medical help the same day.

Severe difficulty breathing means gasping, choking or not being able to get your words out: call 999 for that, or if your lips or skin are turning very pale, blue or grey, or you suddenly feel confused. Call 999, too, if someone faints while exercising.

Sources 63, 64, 65, 66, 67, 68, 69, 70

How to adapt it

Our suggestions, with the evidence where there is some:

• Two days: workouts A and B, with a day between. It's slower, but it still works.
• Four days: the optional Saturday from week 5; or, after 12 weeks, the muscle-building plan.
• Small appetite: the NHS's tips, such as smaller meals more often, drinks between meals rather than before them, and snacks such as yoghurt, cheese and nuts. A lasting loss of appetite with weight loss needs a GP.
• Vegetarian or vegan: beans, pulses, tofu, soya milk and soya yoghurt; our protein calculator shows how much of each gives 25 g.
• Sore joints: the leg press instead of the trap bar deadlift for a few weeks, and neutral-grip presses for sore shoulders.
• Under 18: our plan for teenagers, and a GP or school nurse if you're worried about your weight.
• Missed a week: repeat it. Two weeks or more off: go back a phase.

Sources 16, 17