Shoulder Pain and Weakness – Could It Be Vitamin or Thyroid Related?

Reviewed by Dr Lauren Holland • Marylebone Diagnostic Centre
Results within 24 – 42 hours. Westminster residents receive 20% off.

Shoulder pain and muscle weakness are common in London and can affect daily activities such as lifting, reaching, or carrying bags. While many cases are linked to posture or strain, shoulder discomfort can also be caused by vitamin deficiency, thyroid imbalance, inflammation, iron deficiency, blood sugar issues or reduced muscle recovery. Many London patients describe heaviness, tension, burning, reduced strength or pain that worsens after work, exercise or long hours at a desk.

Clinically, we see many cases where shoulder symptoms are not purely muscular. Blood testing is often the key to identifying internal contributors that delay recovery. This guide explains why shoulder pain happens, the red flags to watch for, and which tests at Marylebone Diagnostic Centre help pinpoint the cause.

Why Does Shoulder Pain and Weakness Happen?

Shoulder discomfort may originate from:

• muscle tension
• tendons
• nerves
• joints
• nutritional imbalance
• hormonal changes

Common causes include:

Blood tests help separate muscular strain from internal imbalance.

Common Symptoms That Come with Shoulder Pain

Patients often experience:

• weak grip
• neck stiffness
• tension in traps
• muscle fatigue
• heaviness in the arm
• burning pain
• pins and needles
• shoulder aches at night
• poor mobility
• slow recovery after exercise
• headaches

These symptoms often match vitamin, iron or thyroid imbalance.

When Shoulder Pain Is Concerning

Seek testing if you experience:

• persistent weakness
• swelling
• pain with fever
• long-term stiffness
• pain at rest
• numbness
• inability to lift the arm
• worsening symptoms
• fatigue and weakness together
• symptoms in both shoulders

These patterns may indicate metabolic or hormonal issues.

Risk Factors for Shoulder Pain in London

You are more likely to develop shoulder discomfort if you:

• work long hours at a desk
• carry heavy bags
• cycle or gym frequently
• have low vitamin D
• have a thyroid condition
• sleep poorly
• have high stress
• consume low nutrients
• recently recovered from illness
• experience muscle fatigue

These patterns are very common in urban environments.

What Blood Tests Reveal About Shoulder Pain

At Marylebone Diagnostic Centre, the following tests help identify internal contributors.

Vitamin D

Low levels weaken muscle fibres and increase pain.

Common signs:

• shoulder heaviness
• muscle fatigue
• bone pain
• slow recovery

Vitamin B12

Essential for nerve function.

Low B12 causes:

• burning pain
• tingling
• weakness
• nerve irritation in the shoulder or arm

Thyroid Panel

Imbalance leads to:

• stiffness
• muscle aches
• reduced strength
• low energy

Ferritin (Iron Stores)

Low ferritin reduces oxygen supply to shoulder muscles.

Symptoms include:

• fatigue
• weakness
• poor endurance

Magnesium & Mineral Profile

Low magnesium increases:

• spasms
• tension
• tightness
• prolonged muscle soreness

Included in MDC’s Vitamin & Mineral Profile.

HbA1c (Blood Sugar Stability)

Glucose swings cause:

• muscle fatigue
• slow recovery
• weakness

CRP (Inflammation Marker)

Useful when inflammation or tendon irritation is suspected.

Wellness Profile

Ideal for persistent shoulder pain combined with fatigue or weakness.

Includes:

• vitamins
• minerals
• thyroid
• HbA1c
• FBC
• inflammation markers

Which MDC Profiles Are Best?

Symptom-Test Matching Table

Clinical Insight

“Many people assume shoulder pain is muscular, yet low vitamin D, low B12 or thyroid imbalance are common underlying causes. Testing provides clarity and prevents long periods of discomfort.”
– Dr Lauren Holland

FAQs (People Also Ask)

Book Your Shoulder Pain Tests at Marylebone Diagnostic Centre

Marylebone Diagnostic Centre
73 Baker Street, London W1U 6RD
Tel: +44 7495 970109
Open Monday–Saturday, 08:00–16:00

Fast, private and confidential testing with results in 24–42 hours.
Westminster residents receive 20% off.

Quick Links

• Cardiac Profile
• HbA1c Test
• Full Lipid Panel
• Fatigue and Energy Profile
• Kidney Function Test
• Electrolytes Test
• Liver Function Test
• Thyroid Function Test
• Magnesium Test
• Full Blood Count
• Urinalysis & Culture
• Book an Appointment
• ECG Testing
• Wellness Profile
• Pancreatic Profile
• Advanced Sexual Health Panel
• STI Testing London

Read More

• NHS: Shoulder Pain
• NHS: Vitamin D Deficiency
• NHS: Thyroid Issues
• NHS: Iron Deficiency