Independent comparison · Updated July 2026

Stop guessing which supplement to buy.

Vitfacts compares the supplements Chemist Warehouse, Amazon and iHerb stock side by side — on active dose, bioavailability and price per gram of useful nutrient. Cited sources, no sponsored order.

Start with Vitamin C Browse all comparisons

💰 Prices updated weekly · Affiliate links help fund this site · No extra cost to you

How we cut through the noise

Cite every claim

Every product, dose, and price links to a verifiable source. We name the date and URL.

Bioavailability first

A 500 mg dose that absorbs 80% beats a 1000 mg dose that absorbs 10%. We rank absorption, not label size.

Per-effective-dose pricing

Same dollar amount in your hand gives very different useful nutrient depending on the form. We normalize by active dose.

Browse all supplements

All 8 categories · 78 products reviewed

Every comparison is built from the same data set: peer-reviewed sources, retailer-verified prices (snapshot July 2025), and per-effective-dose math. Pick a category to see the full ranked table.

Vitamin C

5 forms · 12 products

Ascorbic acid vs Liposomal vs Ester-C vs Sodium Ascorbate vs Calcium Ascorbate. Ranked on bioavailability, dose, and price per effective mg.

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Magnesium

7 forms · 15 products

Glycinate vs Citrate vs Oxide vs L-Threonate vs Malate vs Taurate vs Chloride. Which form actually absorbs, and which is a waste of money.

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Whey Protein

4 forms · 12 products

Concentrate vs Isolate vs Hydrolyzed vs Plant blends. Protein per dollar, leucine threshold, taste and mixability.

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Omega-3

Triglyceride vs ethyl ester

EPA/DHA content, oxidation (TOTOX), and the top brands compared on freshness, dose, and price per gram of usable omega-3.

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Creatine HMB vs Monohydrate

8 products · HMB stacks vs plain creatine

Does adding HMB (a leucine metabolite) to creatine actually build more muscle than plain creatine monohydrate? The evidence is clear: most combo products are a waste of money.

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Probiotic

8 products · 4 forms

Multi-strain blends, Saccharomyces boulardii, and spore-based Bacillus — scored on strain identity, CFU per serving, and what the evidence actually says.

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Vitamin D

4 forms · 11 products

Cholecalciferol (D3) vs calcifediol (25(OH)D) vs lichen-D3 for vegans. Ranked on bioavailability, dose per capsule, and price per 1000 IU.

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Retinol

6 forms · 12 products

Retinol vs retinal vs HPR vs bakuchiol. Ranked on irritation, clinical evidence, and price per ml. The only AU/TH comparison covering all 6 retinoid forms.

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Coming next

Published weekly — driven by what readers ask, what trends on social media, and which products people are buying.

✓ Vitamin C types and forms (live)
✓ Magnesium forms deep-dive (live)
✓ Whey protein concentrate vs isolate (live)
✓ Omega-3 triglyceride vs ethyl ester
✓ Vitamin D3 + K2 pairing (live)
✓ Probiotic strains and CFU comparison (live)
✓ Retinol / retinoid buyer's guide (live)
📘 Retinol full guide — 6 forms, 8-week protocol, FAQ
○ Zinc picolinate vs gluconate (in progress)
○ Iron bisglycinate vs sulfate (in progress)