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Bulk Glycine Powder vs Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free

Side-by-side comparison of scores, ingredients, prices and real customer feedback for Bulk Glycine Powder and Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free.

Last verified: 07 Apr 2026 · Based on 43 reviews

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77.0
Quick Answer

Bulk Glycine Powder scores 77.0/100 vs Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free at 76.0/100. Bulk Glycine Powder wins on ingredient quality, value for money, certifications. Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free is stronger on effectiveness and side effects.

How Do the Scores Compare?

Bulk Glycine Powder
Nutricost L-Theanine 200mg,...
Bulk Glycine Powder
Bulk Glycine Powder
Bulk
 Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free
Nutricost L-Theanine 200mg,...
Nutricost
Overall Score 77.0 76.0
Effectiveness 72.0/100 82.0/100
Best
Ingredient Quality 87.0/100
Best
 75.0/100
Value for Money 86.0/100
Best
 62.0/100
Side Effects 74.0/100 90.0/100
Best
Certifications 68.0/100
Best
 58.0/100
Best Price £4.99 Amazon UK →
Cheapest
 £7.84 Amazon UK →
Price per Serving £0.03 166 servings
Best value
 £7.84 1 servings
Form Powder Capsule
Dose 3000mg glycine per serving 2.2 Ounces
Third-Party Tested ✓ Yes ✗ No
Reviews Analysed 27 16

Bulk Glycine Powder

Pros

  • ✓Clinical 3g serving matches research-backed dose for sleep quality improvement
  • ✓100% pure glycine — zero fillers, flavourings, or additives
  • ✓Excellent cost-per-serving: 166 servings at a competitive UK price
  • ✓GMP certified and third-party tested; made in the UK with strong brand transparency

Cons

  • ✗Individual response varies significantly — some users report glycine as stimulating rather than sedating
  • ✗At least one Reddit user reported anhedonia and worsened sleep at 3g daily; personal titration advised
  • ✗No NSF or Informed Sport certification — relevant for competitive athletes
  • ✗Prop 65 heavy-metal concerns raised by one user; COA should be requested for long-term high-dose use

Best For

People optimising sleep quality or struggling with insomnia DIY supplement stackers building a pre-sleep protocol Athletes and gym-goers seeking overnight recovery support Vegans wanting a clean, plant-friendly amino acid Budget-conscious buyers wanting maximum servings per pound spent
Amazon UK £4.99
View full review →

Nutricost L-Theanine 200mg, 120 ...

Pros

  • ✓Strong anxiety and stress reduction reported across the majority of reviews
  • ✓Highly effective for smoothing caffeine jitters and improving focus quality
  • ✓Notable sleep improvement, especially when combined with magnesium glycinate
  • ✓Well-tolerated with no side effects reported across all 12 reviews

Cons

  • ✗Price flagged as expensive relative to equivalent products on the market
  • ✗Sleep benefits may take 4–6 weeks to fully manifest for some users
  • ✗Third-party testing claimed in marketing copy but contradicted by product specs
  • ✗Not vegan — capsule shell may contain gelatin

Best For

Coffee and pre-workout users seeking to eliminate jitters Light sleepers or those with difficulty switching off at night People managing mild to moderate daily anxiety or stress Nootropic stackers looking for a clean calming base Anyone sensitive to sedating sleep aids who wants a gentler alternative
Amazon UK £7.84
View full review →

What does the data say about Bulk Glycine Powder vs Nutricost L-Theanine 2...?

Bulk Glycine Powder Winner 77.0/100

Bulk Glycine Powder delivers a clinical 3g dose of pure, additive-free glycine per serving across 166 servings, making it one of the better-value single-ingredient glycine options in the UK market.

Effectiveness
Bulk Glycine Powder
72.0/100
Nutricost L-Thea..
82.0/100
Ingredient Quality
Bulk Glycine Powder
87.0/100
Nutricost L-Thea..
75.0/100
Value for Money
Bulk Glycine Powder
86.0/100
Nutricost L-Thea..
62.0/100
Side Effects
Bulk Glycine Powder
74.0/100
Nutricost L-Thea..
90.0/100
Certifications
Bulk Glycine Powder
68.0/100
Nutricost L-Thea..
58.0/100

What are the key differences?

Bulk Glycine Powder is best for: People optimising sleep quality or struggling with insomnia, DIY supplement stackers building a pre-sleep protocol
Nutricost L-Theanine 20.. is best for: Coffee and pre-workout users seeking to eliminate jitters, Light sleepers or those with difficulty switching off at night

Frequently Asked Questions

Which is better, Bulk Glycine Powder or Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free? ▼
Bulk Glycine Powder scores 77.0/100 overall while Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free scores 76.0/100. Bulk Glycine Powder comes out ahead, scoring higher on effectiveness (72.0 vs 82.0). Bulk Glycine Powder is best suited for People optimising sleep quality or struggling with insomnia and DIY supplement stackers building a pre-sleep protocol. Nutricost L-Theanine 200mg, 12 is better for Coffee and pre-workout users seeking to eliminate jitters and Light sleepers or those with difficulty switching off at night.
Is Bulk Glycine Powder worth the price compared to Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free? ▼
Bulk Glycine Powder costs £4.99 while Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free is £7.84. For value, Bulk Glycine Powder scores 86.0/100 vs Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free's 62.0/100. Bulk Glycine Powder delivers better value relative to its quality. Note that Bulk Glycine Powder comes as powder while Nutricost L-Theanine is capsule, which may affect your preference.
Which has fewer side effects? ▼
Bulk Glycine Powder scores 74.0/100 for side effects (higher means fewer reported issues) while Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free scores 90.0/100. Reviewers report fewer side effects with Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free. For certification and testing, Bulk Glycine Powder scores 68.0/100 vs Nutricost L-Theanine's 58.0/100. Always consult a healthcare professional before starting any supplement.

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Disclaimer: AIScored provides data-driven comparisons based on publicly available reviews. This is not medical advice. Affiliate links may earn us a commission at no extra cost to you.

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