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Glycine 3g vs Vitamin B12 — Which Should You Take?

Glycine 3g

amino acids

Typically £8–£25/month

Vitamin B12

vitamins

Typically £8–£25/month
Feature
Glycine 3g
Vitamin B12
Typical Dosage
3g per day
500-1,000mcg daily
Best Form
Powder
Methylcobalamin
Key Benefits
5 listed
5 listed
Evidence Rating
★★★★
★★★★
Best Time
Evening for sleep support; anytime for general benefits
Morning — may be energising
Upper Limit
10g per day
No established upper limit (water-soluble)
Side Effects
3 noted
2 noted

Glycine 3g Benefits

Improved sleep quality and sleep onset
Reduced daytime fatigue and hypersomnolence
Cognitive function and mental clarity
Joint and connective tissue support
Nervous system regulation

Vitamin B12 Benefits

Energy production
Nerve function and protection
Red blood cell formation
DNA synthesis
May reduce homocysteine levels

Glycine 3g Side Effects

Mild gastrointestinal upset at high doses
Sedation or fatigue with evening dosing
Bitter taste in powder form

Vitamin B12 Side Effects

Very safe — excess excreted in urine
Rare: acne at very high doses in some individuals

Can You Take Glycine 3g and Vitamin B12 Together?

In most cases, Glycine 3g and Vitamin B12 can be taken together safely. However, always check the interactions section of each supplement and consult a healthcare professional if you take medication or have existing health conditions.

Glycine 3g: Minimal interactions; may potentiate sedative medications

Glycine 3g: Generally safe with other supplements and pharmaceuticals

Vitamin B12: Metformin reduces B12 absorption — supplement if on metformin

Vitamin B12: Proton pump inhibitors (PPIs) reduce absorption

Which Should You Choose?

Choose Glycine 3g if your primary goal is: improved sleep quality and sleep onset. Choose Vitamin B12 if your primary goal is: energy production.

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Frequently Asked Questions

Is Glycine 3g better than Vitamin B12?

It depends on your goals. Glycine 3g and Vitamin B12 serve different purposes and are often taken together.

Can I take Glycine 3g and Vitamin B12 together?

In most cases, yes. Glycine 3g and Vitamin B12 can be taken together safely. However, always check for specific interactions and consult a healthcare professional if you take medication.

What is the best time to take Glycine 3g?

Evening for sleep support; anytime for general benefits

What is the best time to take Vitamin B12?

Morning — may be energising

What are the side effects of Glycine 3g?

Mild gastrointestinal upset at high doses. Sedation or fatigue with evening dosing. Bitter taste in powder form.

What are the side effects of Vitamin B12?

Very safe — excess excreted in urine. Rare: acne at very high doses in some individuals.

How We Compare Supplements

This comparison is based on published clinical research, peer-reviewed studies from PubMed, and established nutritional science. We evaluate dosages based on clinically-effective amounts, not manufacturer recommendations. Benefits listed have at least moderate evidence from human studies. When evidence is limited or conflicting, we note this.

Disclaimer: This comparison is for educational purposes only and is not medical advice. Always consult a qualified healthcare professional before starting any supplement, especially if you take medication or have existing health conditions.

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