Why these picks

How each pick was chosen, and what its brand claims

Brian grades the ingredient first and the label second, and only then picks a product. These are the receipts: what each brand claims, what the evidence actually supports, and the alternatives each pick beat.

Why these brands

  • Every pick has a single named ingredient at a fixed dose, so the label matches what the research actually studied instead of a proprietary blend.
  • Where a pick carries an independent testing mark, such as NSF Certified for Sport (a mark issued by NSF International, not the brand), we name it. Where we found none, we say that instead.
  • Every pick is sold on Amazon in your country, so there is one listing to check. This site shows no price, because Amazon's own page has the current one.
  • The same brand is not sold everywhere. The picks you see follow your country, and you can switch it in the footer.

None of that is a substitute for the ingredient-level evidence review each product page carries. If a better-evidenced or better-priced option appears in a re-check, the pick changes; this page gets updated when it does.

Claim by claim: brand copy vs. the evidence grade

Magnesium

Pure Encapsulations Magnesium Glycinate

Also considered: Thorne Magnesium Glycinate (sold direct, not on Amazon in the UK); Micro Ingredients Magnesium Glycinate (higher dose, bulkier pack); Nature Made Magnesium Glycinate (familiar pharmacy brand, lower elemental dose).

What the brand claims

  • “120mg Bioavailable Magnesium Glycinate Chelate”— Title of the Amazon UK listing
  • “A highly bioavailable magnesium chelate that is well tolerated and suitable for sensitive individuals”— Description on the Amazon UK listing

Brian's read

The 120 mg figure is the label dose, and it sits well under the 350 mg a day supplemental upper limit, so it suits building up in steps. “Bioavailable” and “well tolerated” are the brand's own descriptions; glycinate is generally one of the gentler forms, but Brian has not seen a head-to-head trial that ranks the forms. We found no independent certification mark for this product, so we do not claim one.

Creatine

Pure Encapsulations Creatine Monohydrate

Also considered: Nutricost Performance Creatine Monohydrate (lower cost per gram); Optimum Nutrition Micronized Creatine Powder (familiar sports-nutrition brand).

What the brand claims

  • “Supports muscle strength, performance and recovery”— Title of the retailer listings for the 315 g tub

Brian's read

The strength claim fits the research: meta-analyses in older adults found creatine alongside resistance training added strength. The 5 g serving is the studied dose. We found no independent testing mark for this one (such as NSF Certified for Sport), so it should not be pitched to athletes who need banned-substance testing.

L-theanine

Pure Encapsulations L-Theanine

Also considered: Thorne Theanine (sold direct, not on Amazon in the UK); NOW Foods L-Theanine (cheapest per capsule, includes added inositol); Lamberts L-Theanine (UK practitioner brand).

What the brand claims

  • “200mg Clinically-Studied Suntheanine L-Theanine”— Title of the Amazon UK listing
  • “Amino Acid Supplement to Support Relaxation, Stress and Nervous System”— Title of the Amazon US listing

Brian's read

The independent research is a systematic review of 9 human randomized controlled trials on stress and anxiety, and a separate crossover trial measuring brain activity directly: real, but small and narrow. “Clinically studied” is true of the Suntheanine ingredient in general, not of this product. Both bottles name Suntheanine: the UK listing says so in its title, and the US bottle's own label reads “With Suntheanine®”. The US listing's relaxation and stress wording is not allowed in UK advertising.

How to read the grades

Every claim above still carries one of three grades, explained in full in how we choose:

  • Robust evidence — Consistent results across several randomized trials or meta-analyses.
  • Promising evidence — Supportive trials exist, but results vary or populations are narrow.
  • Early evidence — Small, short or mixed studies. Worth watching, not worth relying on.

A brand's own marketing claim never raises a grade on its own. It has to be backed by the kind of independent citation shown on each product page.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. This page is general information, not medical advice. Talk to your doctor before starting a supplement, especially if you are pregnant, have a medical condition or take medication.