Our Verdict
Four Sigmatic is the OG mushroom coffee brand and offers one of the cleanest, most transparent formulas in the category — only 4 ingredients with all amounts disclosed. The low total mushroom dose (500mg) is a concern for efficacy, but individual amounts are clearly listed, which is rare. The persistent lead contamination issue (2018 Prop 65 complaint + 2024 independent testing finding lead) is the major quality concern. Strong retail presence and brand trust, but the lead problem needs resolution.
Evident Ratings
Four Sigmatic Think Organic Mushroom Coffee (Instant)
Sub-scores are category scores on a 1–5 scale, shown out of 10.
About Four Sigmatic
Founded in 2012 by Finnish mycologist Tero Isokauppila, Four Sigmatic is credited as one of the brands that brought mushroom coffee to the U.S. market. The company uses exclusively fruiting body extracts and maintains a minimalist ingredient philosophy.
Product specifications
- Coffee
- 1 packet (2.5g)
- 50mg
- 0
How we scored this
Every data point below is tagged as Verified (confirmed in our research file) or Claimed (brand-stated).
Material Safety
- Fruiting Body
- YesClaimed
- Individual Amounts Disclosed
- YesVerified
- Organic Mushrooms
- YesClaimed
Testing & Trust
- Third-Party Tested
- YesClaimed
- COA Available
- UnknownClaimed
- Heavy Metals Tested
- YesClaimed
- USDA Organic
- YesVerified
- Prop 65 Warning
- YesVerified
Value & Policy
- Price Per Serving
- $1.50Verified
- Package Price
- $15.00 (10 servings)Verified
- Return Policy
- 60-day money-back guarantee on first order, no questions asked. 30-day return policy for unopened products.Claimed
- Money-Back Guarantee
- YesClaimed
Product Features
- Mushroom Species
- Lion's Mane, ChagaVerified
- Total Mushroom mg
- 500mgClaimed
- Caffeine
- 50mgVerified
- Coffee Type
- InstantVerified
- Adaptogens
- Rhodiola Rosea (100mg)Claimed
- Amazon Rating
- 4.4 (20,350 reviews)Verified
- Red Flags
- 2018 Prop 65 lead complaint filed by Environmental Research Center; Independent lab testing (Aug 2024) found detectable lead in Think coffee; Heavy metals appear to be a persistent issue despite brand claims of testingVerified
- Lawsuits
- 2018 Prop 65 complaint for lead content (Environmental Research Center)Verified
See how Four Sigmatic stacks up against every mushroom coffee we tested
Our full mushroom coffee comparison ranks every brand across the same scoring dimensions you saw above — formulation, testing, trust, value, and sourcing.
See Best Mushroom Coffee →Other top mushroom coffee we tested
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