How can a 23-year-old increase the width of their clavicle (collarbone) naturally through exercise and diet?

Increasing Clavicle Width at Age 23: Evidence-Based Reality Check

You cannot meaningfully increase the width of your clavicle bone at age 23 through exercise or diet, as the clavicle continues growing longitudinally (in length) until approximately age 23-25 years but does not respond to exercise by increasing in width. 1

Understanding Clavicular Growth Biology

The clavicle has unique growth characteristics that differ fundamentally from other bones:

• The medial clavicular physis (growth plate) remains open until 23-25 years of age, making it one of the last bones to complete growth 1
• Longitudinal growth continues through early adulthood: Males show clavicular growth of 1.7 mm/year (1.1%/year) at ages 20-25 years, while females show 0.2 mm/year (0.1%/year) at the same ages 1
• Width (diameter) is determined by bone structure, not muscle hypertrophy: The clavicle's dimensions are established during skeletal development and do not increase in width through mechanical loading 2

What Exercise Can Actually Accomplish

While you cannot widen the clavicle itself, resistance training can create the appearance of broader shoulders through muscle development:

Pectoralis Major Development

Target the clavicular (upper) portion of the pectoralis major with specific exercises:

• Pec deck exercises produce significant hypertrophy: 17-18% increase in clavicular pectoralis thickness after 12 weeks of training in untrained men 3
• Volume requirements are minimal: One set produces equivalent hypertrophy to three sets (17% vs 18% thickness increase), making this time-efficient 3
• Prescription: Perform pec deck or incline pressing movements 2-3 days per week, using linear periodization from 20 repetitions maximum down to 8 repetitions maximum to failure over 12 weeks 3

Deltoid and Upper Back Training

Develop the muscles surrounding the shoulder girdle:

• Resistance training frequency: 2-3 days per week on non-consecutive days to allow muscle recovery 4, 5
• Intensity progression: Start at 40% of one-repetition maximum (1-RM) with 10-15 repetitions, progressing to moderate intensity (41-60% 1-RM) with 8-10 repetitions, then high intensity (>60% 1-RM) with 6-8 repetitions 4
• Exercise selection: Include overhead pressing, lateral raises, and rowing movements targeting deltoids, trapezius, and rhomboids 4

Bone Density vs. Bone Width: A Critical Distinction

Exercise can improve bone mineral density but not bone width:

• High-impact and resistance exercise increase bone mineral density: Standardized effect size of 0.15-0.17 for lumbar spine BMD with 60+ minutes of training, 2-3 times per week for 7+ months 4
• Optimal bone-building exercises: Jumping, weight-lifting, and activities generating 3-4.5 times bodyweight ground reaction forces 4, 6
• This strengthens existing bone structure but does not alter bone width or shape 7

Common Pitfalls and Realistic Expectations

Avoid these misconceptions:

• Clavicle width is genetically determined: Sex differences show substantial variation in clavicle diameters, with males having larger dimensions than females, but these are established during development 2
• No dietary intervention will widen the clavicle: While adequate calcium and vitamin D support bone health, they do not alter bone geometry in adults 4
• Surgical intervention is the only method to alter clavicle dimensions: This is not recommended for aesthetic purposes given the risks and lack of functional benefit 1

Practical Training Algorithm

For maximizing shoulder width appearance through muscle development:

1. Weeks 1-4: Pec deck or incline press, 1-3 sets of 15-20 repetitions to failure, 2-3 days/week 3
2. Weeks 5-8: Progress to 10-15 repetitions at moderate intensity (50-60% 1-RM), add overhead pressing and lateral raises 4, 3
3. Weeks 9-12: Advance to 8-10 repetitions at higher intensity (60-70% 1-RM), maintain 2-3 sessions weekly 4, 3
4. Beyond 12 weeks: Continue progressive overload by increasing weight when 15 repetitions feel "somewhat difficult" (Borg RPE 12-14) 4

This approach builds the musculature around the shoulder girdle, creating the visual effect of broader shoulders, which is the only realistic outcome achievable through training at your age. 3