SP
StackPedia
All Comparisons

Keratin vs L-Theanine — Which Should You Take?

Keratin

★★★★★

amino acids

Typically £8–£25/month

L-Theanine

★★★★★

nootropics

Typically £8–£25/month
Feature
Keratin
L-Theanine
Typical Dosage
500–1000 mg daily
100-200mg daily
Best Form
Hydrolysed Keratin (Keratin Peptides)
L-Theanine (Suntheanine)
Key Benefits
5 listed
5 listed
Evidence Rating
★★★★★
★★★★★
Best Time
With meals to enhance absorption
With caffeine for focus, or evening for relaxation
Upper Limit
2000 mg daily
400mg daily
Side Effects
2 noted
3 noted

Keratin Benefits

✓May improve hair strength and reduce breakage
✓Supports nail growth and resilience
✓Could enhance skin hydration and elasticity
✓May reduce hair loss and promote thicker hair growth
✓Supports the structural integrity of keratin-rich tissues

L-Theanine Benefits

✓Calm focus without sedation
✓Reduces caffeine jitters when combined
✓Promotes alpha brain waves (relaxed alertness)
✓May improve sleep quality
✓Anxiety reduction

Keratin Side Effects

⚠Generally well-tolerated; mild digestive upset in sensitive individuals
⚠May cause temporary nausea or loss of appetite at high doses

L-Theanine Side Effects

⚠Very few — one of the safest supplements
⚠Mild drowsiness at high doses
⚠May lower blood pressure slightly

Can You Take Keratin and L-Theanine Together?

In most cases, Keratin and L-Theanine 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.

Keratin: No significant interactions with medications reported

Keratin: May have additive effects with biotin and collagen supplements

L-Theanine: Caffeine — synergistic (the classic nootropic stack)

L-Theanine: Blood pressure medications — additive hypotensive effect

Which Should You Choose?

Choose Keratin if your primary goal is: may improve hair strength and reduce breakage. Choose L-Theanine if your primary goal is: calm focus without sedation.

Affiliate links — we may earn a small commission at no extra cost to you.

Frequently Asked Questions

Is Keratin better than L-Theanine?

It depends on your goals. Keratin and L-Theanine serve different purposes and are often taken together.

Can I take Keratin and L-Theanine together?

In most cases, yes. Keratin and L-Theanine 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 Keratin?

With meals to enhance absorption

What is the best time to take L-Theanine?

With caffeine for focus, or evening for relaxation

What are the side effects of Keratin?

Generally well-tolerated; mild digestive upset in sensitive individuals. May cause temporary nausea or loss of appetite at high doses.

What are the side effects of L-Theanine?

Very few — one of the safest supplements. Mild drowsiness at high doses. May lower blood pressure slightly.

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.

Related Comparisons

Popular Supplements on Amazon

As an Amazon Associate we may earn from qualifying purchases.