Side boob fat (aka armpit fat, bra bulge, or axillary fat) is that roll/pouch of fat that overhangs your bra straps/tight clothing … usually a combination of subcutaneous fat around the upper back, chest, and underarm PLUS a loss of muscle tone in the back (lats), rear shoulders (rear delts), upper arms (triceps), and upper back.
That’s why this 10-minute side boob workout is targeted at sculpting and strengthening the muscles you need to tighten up under your clothes: your chest, shoulders, upper back, and serratus anterior (the “wing” muscles along your ribs that help tighten and smooth out the side boob area).
The 5 Best Exercises to Get Rid of Side Boob Fat Quickly – Tighten Underarm & Armpit Area, Sculpt Your Upper Body
1. Up-and-Down Plank
Muscles worked: Serratus anterior (side ribs/underarm tightener), pectorals, deltoids, triceps, entire core (transverse abdominis, obliques), shoulders.
How to do it:
- Begin in a high plank position with your hands directly under your shoulders and your arms fully extended.
- Keep your legs straight and aligned from your head to your heels.
- Engage your core, squeezing your glutes and quads. Do not let your hips sag or your butt stick out.
- Lower your right forearm to the floor, keeping your elbow under your shoulder. Then, lower your left forearm.
- You should now be in a forearm plank position. Keep your hips square and level, and avoid twisting or dipping from side to side.
- Press back up to a high plank, leading with your right hand first, then your left. Alternate which hand leads each cycle.
- Alternating shoulder tap variation: From high plank, tap opposite shoulder with one hand and switch sides. Keep hips square and brace core.
- Don’t rush your breathing. Stay controlled, and don’t swing.
- Perform 12–20 repetitions (or 20–30 shoulder taps total) for three sets.
Why it helps side boob fat:
This exercise works your deltoids, triceps, and serratus anterior (aka the muscles that run along your ribs and essentially help “suck in” your side boob area). Since you’re in a constant plank position as well, it hits your deep core muscles which will help improve your posture. The stronger these muscles are, the more they’ll pull everything back and tighten up that sloppy underarm flab we’re trying to say goodbye to.
2. Dumbbell Shoulder Press
Targets: Deltoids (front, side, rear), triceps, upper traps, serratus anterior (stabilization).
How to do it:
- Sit or stand tall: core braced, dumbbells (or water bottles) at shoulder height, palms facing forward (or neutral grip).
- Slight bend in elbows, shoulders down/back (no shrugging).
- Exhale: Press weights straight overhead until arms are nearly extended (don’t lock elbows completely).
- Hold 1 second at top (squeeze shoulders/deltoids hard).
- Inhale: Lower slowly with control (3–4 seconds descent — resist gravity, don’t drop).
- Keep core tight — no arching lower back or leaning backward.
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Reps/Sets: 10–15 reps × 3 sets.
Why it helps side boob fat:
It’ll give you those capped, rounded shoulders that pull everything back. The chest is opened by strong deltoids, a major cause of visible side boob fat is corrected by a rounded posture, and a lifted, defined upper body is created. It also activates the serratus muscles to smooth the armpits and boosts metabolism to promote fat loss.
3. One-Arm Dumbbell Row
Targets: Latissimus dorsi, rhomboids, rear deltoids, traps, biceps, core (stabilization).
How to do it:
- Place left knee and left hand on bench/chair (or sturdy surface) for support — right foot flat on floor, torso roughly parallel to ground.
- Hold dumbbell in right hand, back flat/neutral, core braced, slight bend in right knee.
- Exhale: Pull dumbbell up toward hip — elbow close to body, squeeze shoulder blade back (think “pull with back, not arm”).
- Hold 1 second at top (feel upper back/rhomboids contract).
- Inhale: Lower slowly with control (full stretch at bottom — don’t swing).
- Complete reps, then switch sides.
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Reps/Sets: 12–15 reps per side × 3 sets.
Why it helps side boob fat:
The upper back and rear shoulders are strengthens, the shoulders are pulled into proper alignment, slouching that accentuates side boob is fixed, a thicker back is built to create the illusion of a V-taper (making the upper body look leaner), and the bra line and underarm area are tightened.
4. Jump Squat to Shoulder Press
Targets: Glutes, quads, hamstrings, deltoids, triceps, core, cardio system.
How to do it:
- Stand tall: feet shoulder-width, hold light dumbbells at shoulders (or bodyweight only), core braced.
- Inhale: Lower into squat (hips back, thighs parallel or close, chest up, knees over toes).
- Exhale: Explode upward into jump — fully extend hips/knees, press dumbbells straight overhead at peak (arms nearly extended).
- Land softly on balls of feet (knees bent to absorb impact), reset immediately into squat position.
- Low-impact modification: Regular squat + shoulder press (no jump).
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Reps/Sets: 12–15 reps × 3 sets.
Why it helps side boob fat:
It combines lower-body power with upper-body pressing to burn calories and create an afterburn effect. The targeted pressure on the shoulders activates a boost in metabolism, which aids in shedding excess fat from the upper body, even in areas that tend to be more challenging to slim down. When the whole body is engaged, you’ll see faster visible toning.
5. Kettlebell Sumo High Pull
Targets: Rear deltoids, upper traps, rhomboids, lats, core, glutes.
How to do it:
- Stand wide (sumo stance): feet wider than shoulders, toes out 30–45°, hold kettlebell/dumbbell between legs (both hands or single if dumbbell).
- Slight knee bend, core braced, back flat/neutral.
- Inhale: Hinge hips slightly, then explosively drive hips forward.
- Exhale: Pull weight up to chin height — elbows high/wide, shoulders back, squeeze upper back/rhomboids.
- Lower with control — repeat.
- No kettlebell? Use one dumbbell with both hands or alternate single-arm high pulls.
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Reps/Sets: 12–15 reps × 3 sets.
Why it helps side boob fat:
Perform this series of exercises to develop your posterior deltoid muscles, upper back, and the muscles along the sides of your torso. These exercises ensure optimal core engagement and strengthen your oblique muscles, enhancing stability. The explosive pull builds lean muscle and burns fat quickly, tightening the area around the bra line and underarms. A strong upper back and shoulders lead to better posture and less visibility of “side boob.”
Minimize side boob fat and define your chest, back, and arms with this 5-exercise circuit. Do this routine four to five days a week. In a few weeks, you’ll feel stronger, stand taller, and notice that your upper body looks tighter and more toned. Your clothes will fit better, and your confidence will soar! You’ve got this! Grab your weights and start today!
