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Muscle Guide

How to Build Bigger Arms: Biceps & Triceps

Build bigger arms by training biceps and triceps smart: the best exercises, weekly volume, rep ranges and progression — plus why the triceps drive most of your arm size.

Key takeaways
  • The triceps make up about two-thirds of your upper arm — they drive more arm size than the biceps, yet most people under-train them.
  • Train arms with a mix of stretch and contraction: curls and extensions that load the muscle long and short.
  • Build size with 10–20 hard sets per week for each muscle (including indirect work) split over two sessions.
  • Growth is non-negotiably tied to progressive overload — your curls and extensions must trend heavier or higher-rep over weeks.
  • Pair direct arm work with the compound lifts in our best arm exercises guide, and fuel it with enough protein and calories.

Bigger arms are the goal that pulls a lot of people into the gym in the first place — and the goal they often go about backwards. Endless biceps curls in the mirror feel productive, but they ignore the muscle that actually makes the biggest difference to arm size. Building impressive arms is not complicated, but it does require training the right muscles, with enough volume, and progressing them over time. This guide lays out exactly how.

We will cover the anatomy that decides where size comes from, the most effective exercises for both heads of the biceps and all three heads of the triceps, how much to train, and the mistakes that keep most people's arms stuck. Whether you train with a barbell, dumbbells or both, the principles are the same.

TRICEPS ~2/3 BICEPS Train hard — biggest size driver Don't neglect the smaller third
Upper-arm size is dominated by the triceps, which make up roughly two-thirds of the upper arm. Prioritise them, then add focused biceps work — both matter for a complete look.

Arm anatomy: where size comes from

Your upper arm is mostly two muscle groups. The biceps brachii on the front has two heads and flexes the elbow and supinates the forearm. The triceps brachii on the back has three heads — long, lateral and medial — and extends the elbow. The triceps are the bigger muscle by a wide margin, making up roughly two-thirds of upper-arm mass. The practical takeaway is blunt: if you want bigger arms, you cannot skip triceps. Train them at least as hard as your biceps.

Building bigger triceps

The triceps respond best to a combination of heavy pressing and direct extension work, and to training the long head in a stretched position (arm overhead). Build your triceps work around:

  • Close-grip bench or dip: Heavy compound pressing that overloads all three heads.
  • Overhead extension: Dumbbell, cable or EZ-bar overhead — this stretches and loads the long head, which the other movements miss.
  • Pushdown or skull crusher: An arm-by-side movement that hammers the lateral head and lets you chase a strong contraction.
Train the long head overhead

The long head of the triceps crosses the shoulder, so it gets the best stretch when your arm is overhead. If you only ever do pushdowns, you leave size on the table. Include at least one overhead extension every week.

Building bigger biceps

The biceps are simpler. They flex the elbow and supinate the wrist, so curls in their many forms are your tools. Cover both heads and the brachialis underneath with:

  • Incline dumbbell curl: The arm hangs behind the body, stretching the long head — excellent for growth.
  • Standing barbell or dumbbell curl: Your heaviest curl for overall mass.
  • Hammer curl: A neutral grip that targets the brachialis and brachioradialis, adding thickness and forearm size.

Chin-ups and rows also train the biceps heavily, which is why arm work and back work overlap — see our best arm exercises guide for how the compounds fit in.

Volume, frequency and reps

Three variables drive arm growth: how much you do, how often, and how hard. Research and practice point to a useful range:

VariablePractical targetNotes
Weekly sets (each muscle)10–20 hard setsCount indirect work from presses, rows and chin-ups
Frequency2 sessions / weekSplitting volume across two days beats one
Rep rangeMostly 8–15Heavier and higher both work if taken near failure
Effort1–3 reps in reserveStop just short of, or at, technical failure

Start at the lower end of the volume range and add sets only if you are recovering well and still progressing. More is not automatically better — quality, hard sets that you can recover from drive growth. For the bigger picture on how muscles grow, read how to build muscle.

A sample arm session

Here is a balanced session you could run twice a week, or bolt onto the end of upper-body days:

  • Close-grip bench press or dips — 3 sets of 6–10
  • Incline dumbbell curl — 3 sets of 8–12
  • Overhead triceps extension — 3 sets of 10–15
  • Hammer curl — 3 sets of 10–15
  • Triceps pushdown — 2 sets of 12–15

Rest 1–2 minutes between sets, take each working set close to failure, and log your loads so you can chase progression next week.

Arm-training mistakes to avoid

Only training biceps

The classic error. If your triceps lag, your arms will always look small from the side. Fix: give triceps equal billing.

Swinging and using momentum

Heaving curls up with your back trains your ego, not your arms. Fix: control every rep, especially the lowering phase, and lower the weight if you have to swing.

Never progressing

Doing the same weight for the same reps forever means no new stimulus. Fix: add a rep or a small amount of load when you can, exactly as our progressive overload guide describes.

Protect your elbows

Heavy skull crushers and overhead work can aggravate the elbows if you rush them. Warm up the joint, control the load, and ease off any exercise that causes sharp elbow pain rather than pushing through it.

Food, recovery and patience

Muscle is built when you recover, not while you train. To grow your arms you need a slight calorie surplus or at least adequate calories, enough protein to support repair, and decent sleep. The CDC recommends muscle-strengthening activity on two or more days a week as a baseline for health; building visibly bigger arms takes consistent overload on top of that for months, not weeks. Be patient: arms are small muscles and their growth is slow and steady. Track your lifts, eat to support training, and the size will come.

Fuel the growth

If the scale and your lifts aren't moving, you are probably under-eating. Use our calculators to set your targets, then make sure protein is high enough — most lifters do well around 1.6–2.2 g of protein per kg of bodyweight per day.

Sources & further reading

  1. National Strength and Conditioning Association (NSCA) — Kinetic Select hypertrophy and resistance-training resources.
  2. American Council on Exercise (ACE) — Exercise Library with arm-exercise breakdowns.
  3. American College of Sports Medicine (ACSM) — resistance-training position stands and volume guidance.
  4. CDC — Physical Activity Basics: muscle-strengthening on 2+ days per week for adults.

External links are provided for reference and do not imply endorsement. arsenal.fit is an independent publisher and is not affiliated with any cited organisation.

Not medical advice. arsenal.fit publishes general educational fitness information. It is not a substitute for professional medical guidance. Talk to a doctor before starting a new exercise programme, especially if you are pregnant, recovering from injury or illness, or managing a health condition. Sources are cited from public health and exercise-science organisations (CDC, ACE, NSCA, ACSM, PubMed).

Frequently asked questions

Do biceps or triceps make arms bigger?
The triceps make up roughly two-thirds of your upper arm, so they contribute more to overall arm size than the biceps. Most people over-train biceps and neglect triceps. For bigger arms, give the triceps at least as much attention as the biceps.
How often should I train arms to grow them?
Two arm sessions a week generally beats one, because spreading your weekly sets across two days lets you train each session fresh and accumulate more quality volume. You can train arms directly or rely on the indirect work they get from heavy pressing and pulling.
How many sets per week build bigger arms?
Most people grow well on roughly 10 to 20 hard sets per week for the biceps and a similar amount for the triceps, including the indirect work from rows, pull-ups and presses. Start at the lower end, progress over time, and only add volume if recovery allows it.
Can I build bigger arms with just dumbbells?
Yes. Dumbbell curls, hammer curls, overhead extensions and skull crushers cover both heads of the biceps and all three heads of the triceps. Add close-grip pressing and chin-ups and you have everything you need for full arm development without machines.
Why aren't my arms growing?
Usually one of three things: not enough progressive overload, not enough total weekly volume, or not enough calories and protein to support growth. Track your lifts, make sure they trend up over weeks, eat enough protein, and be patient — arm growth is slow and steady.