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01Markers · Blood sugar

Fasting glucose

Fasting blood glucose

The amount of glucose, the main sugar the body runs on, in the blood after at least eight hours without food.

Measured in
Blood (plasma or serum)
Units
mg/dL, mmol/L
Also called
fasting plasma glucose, FPG, fasting blood sugar
  1. Berberine
  2. Zinc
  3. HIIT
  4. Vitamin D3
  5. Zone 2 cardio
  6. L-carnitine
  7. Taurine
  8. Magnesium
  9. Ashwagandha
  10. Melatonin
  11. Omega-3
  12. Red yeast rice
  13. Vitamin C
  14. Creatine
  15. Iron
  16. NAC
  17. NAD+
  18. Vitamin K2
  19. Milk thistle
  20. Finnish sauna
  21. Collagen
  22. Vitamin E
  23. L-theanine
  24. Resveratrol
  25. Ubiquinol (CoQ10)
  26. Lion's mane
  27. PQQ
Fasting glucose across the 27 supplements and practices researched so far · best evidence first

AWhat moves Fasting glucose

25 of 27 studied

In human studies, 19 of the 27 supplements and practices researched so far lowered fasting glucose and 2 raised it. 2 showed no change and 2 had mixed results. 2 were never studied for it.
  • Supported 21
  • No effect 2
  • Conflicting 2
  • Not studied 2
See Fasting glucose on the evidence map →Check claims about Fasting glucose →

Moves it21

Human studies found a change. The grade reflects the studies behind it, from A (strongest) to D.

BerberineLowersGrade A

Berberine lowers fasting glucose.

8 studies linked

Studied in: T2DM, Prediabetes, Metabolic syndrome, Predominantly Chinese RCTS

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ZincLowersGrade A

Zinc lowers fasting glucose.

Meta-analysis or review · 7 studies linked

Studied in: T2D, Prediabetes, Overweight, Adults

Effect population-dependent: robust in T2D with poor baseline glycemic control, attenuated in prediabetes, absent or minimal in normoglycemic adults. Publication bias toward positive trials cannot be excluded. Geographic concentration in Middle East and Asia.

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HIITLowersGrade A

HIIT lowers fasting glucose.

Meta-analysis or review · 6 studies linked

Studied in: T2DM, Prediabetes, Overweight obese, Metabolic syndrome

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Vitamin D3LowersGrade A

Vitamin D3 lowers fasting glucose.

Meta-analysis or review · Moderate effect · 5 studies linked

Studied in: Prediabetes, Deficient baseline, Overweight obese, European

Grade corrected from B to A. Three independent grade A MAs: Pittas 2023 IPD-MA (n=4190, p=0.009), Mirhosseini 2018 (n=3848, p=0.02), Swart 2018 (n=2994, p=0.03). Effect concentrated in deficient and prediabetic populations.

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Zone 2 cardioLowersGrade A

Zone 2 cardio lowers fasting glucose.

Meta-analysis or review · 4 studies linked

Studied in: Adults T2DM, Adults prediabetes, Adults overweight obese, Children obese

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L-carnitineLowersGrade A

L-carnitine lowers fasting glucose.

Meta-analysis or review · Small effect · 2 studies linked

Studied in: T2DM, Metabolic syndrome, Prediabetes, PCOS

Modest absolute reduction from mildly elevated baseline; before-after

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TaurineLowersGrade A

Taurine lowers fasting glucose.

Meta-analysis or review · 0 studies linked

This result is graded, but no study is linked to it yet. Treat it as unconfirmed.

Studied in: Type 2 diabetes, Metabolic syndrome, Overweight obese, Adults

18 corpus studies. ≥3 MAs confirm direction. Grade A assigned based on MA existence; exact pooled WMD requires MA outcome extraction (see oq_meta_analysis_outcome_extraction). Geographic caveat: T2DM RCTs overrepresented from Iran/Turkey.

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MagnesiumLowersGrade B

Magnesium lowers fasting glucose.

Meta-analysis or review · Moderate effect · 7 studies linked

Studied in: T2DM, Insulin resistant, Prediabetes, Hypomagnesemia

Inverse Mg-glucose association confirmed in both OA population (Wang 2018, OR 0.22 Q5 vs Q1 for DM prevalence) and diabetic/non-diabetic UK population (Yajnik 1984, rs=-0.33). Mechanism: Mg modulates insulin receptor tyrosine kinase activity and GLUT4 translocation — mediated through insulin sensitivity, not secreti...

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AshwagandhaLowersGrade B

Ashwagandha lowers fasting glucose.

Meta-analysis or review · 2 studies linked

Studied in: Type2 diabetes, Predominantly Indian cohorts

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MelatoninLowersGrade B

Melatonin lowers fasting glucose.

Small effect · 2 studies linked

Studied in: Adults, T2DM, Metabolic syndrome

Pooled MA shows modest fasting glucose reduction; contested — see contested_note; do not present as established benefit without genotype qualification

  • Chen (2022) · not matched to a paper yet
  • Lauritzen ES et al. (2022)
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Omega-3LowersGrade B

Omega-3 lowers fasting glucose.

Small effect · 2 studies linked

Studied in: General adult, T2DM, Prediabetes, Healthy adults

Rundblad 2018: krill oil 4g/d × 8 weeks reduced fasting glucose vs control (5.6→5.3 vs 5.2→5.5 mmol/L; p=0.024 krill vs control). Fish arm not significantly different from control. Single RCT, small n, COI present. Effect may reflect phospholipid EPA/DHA insulin-sensitizing mechanism or be a Type I error in secondar...

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Red yeast riceLowersGrade B

Red yeast rice lowers fasting glucose.

Human trials · 2 studies linked

Studied in: T2DM, Metabolic syndrome, Hyperlipidemia, Chinese predominantly

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Vitamin CLowersGrade B

Vitamin C lowers fasting glucose.

2 studies linked

Studied in: Adults, Type 2 diabetes, Elevated fasting glucose

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CreatineLowersGrade B

Creatine lowers fasting glucose.

Meta-analysis or review · Small effect · 1 study linked

Studied in: Metabolic syndrome, Type2 diabetes, Older adults

Delpino 2022 MA: creatine supplementation reduces fasting glucose particularly in populations with elevated baseline (metabolic syndrome, T2DM). Effect in normoglycemic individuals is attenuated or absent. Mechanism likely via GLUT4 translocation augmentation (mech_cr_007). Studies enriched for Latin American and So...

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IronRaisesGrade B

Iron raises fasting glucose.

1 study linked

Studied in: Iron overload, High tsat, Hemochromatosis, General adult population

Do NOT extrapolate to iron supplementation at standard doses. This biomarker effect applies exclusively to iron overload populations.

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NACLowersGrade B

NAC lowers fasting glucose.

Human trials · Small effect · 1 study linked

Studied in: PCOS, Female, Adult, Middle east

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NAD+RaisesGrade B

NAD+ raises fasting glucose.

Human trials · 1 study linked

Studied in: Adults overweight obese, European finnish, Mean age 40, 5 month intervention

Adverse metabolic signal. Remained within normal range. May reflect niacin-like gluconeogenesis effect or weight gain confound (+2.6 kg). Contested by animal models showing glucose improvement.

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Vitamin K2LowersGrade B

Vitamin K2 lowers fasting glucose.

Small effect · 1 study linked

Studied in: Type2 diabetes, Insulin resistant, Asian

All RCTs in MA involved T2DM patients; effect magnitude modest; extrapolation to normoglycemic individuals is speculative

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Milk thistleLowersGrade B

Milk thistle lowers fasting glucose.

Small to moderate effect · 0 studies linked

This result is graded, but no study is linked to it yet. Treat it as unconfirmed.

Studied in: Type 2 diabetes, NAFLD with diabetes, Metabolic syndrome

Kazazis 2014 review: 10–15% FPG reduction in T2DM RCTs with silymarin 140–200 mg TID. Multiple MAs confirm. Effect primarily in T2DM+NAFLD overlap populations — generalizability to isolated T2DM uncertain.

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Finnish saunaLowersGrade C

Finnish sauna lowers fasting glucose.

Meta-analysis or review · 2 studies linked

Studied in: Type 2 diabetes

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CollagenLowersGrade C

Collagen lowers fasting glucose.

Meta-analysis or review · 1 study linked

Studied in: T2DM, Prediabetes, Adult mixed sex, East asian

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Studied, no change2

Studies looked and found no meaningful change. That is a result, not missing data.

Vitamin ENo changeGrade B

Studies of Vitamin E found no change in fasting glucose.

2 studies linked

Studied in: Adult, Mixed sex, T2DM, Non diabetic

GRADE CORRECTION: Source study VE-MA-003 is a meta-analysis of 14 RCTs (n=714). Per pipeline rules ≥2 RCTs = grade A. Null finding from well-powered MA is grade A evidence of no effect, not B.

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L-theanineNo changeGrade C

Studies of L-theanine found no change in fasting glucose.

Human trials · 1 study linked

Studied in: Elderly japanese, Green tea mixture not pure ltheanine

Currently graded C with evidence_type 'single_rct_confounded_mixture' while source study ide_2016_greentea outcome is graded B. This is an intentional downgrade for compound-attribution confounding. Defensible but creates a grade inconsistency between clinical_evidence and biomarker_effects. Recommend adding explici...

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Mixed results2

Studies disagree, or the direction depends on who was studied.

ResveratrolMixed resultsGrade B

Studies of Resveratrol and fasting glucose disagree.

Meta-analysis or review · Small to moderate effect · 2 studies linked

Studied in: Obese, T2DM, Metabolic syndrome, Adults

NULL finding. Mechanistically expected floor effect in normoglycemia. Confirms fasting glucose lowering is specific to dysglycemic/T2DM populations. Does not undermine existing grade A MA evidence in T2DM.

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Ubiquinol (CoQ10)Mixed resultsGrade B

Studies of Ubiquinol (CoQ10) and fasting glucose disagree.

Human trials · 2 studies linked

Studied in: Type 2 diabetes, Dyslipidemia

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Not studied2

No usable human study has measured Fasting glucose with these. A gap is not a negative result: nobody has looked.

Lion's manePQQ

Commission research on a gap →

Why trials measure it. It changes faster than HbA1c, so short trials of blood sugar control often report it.

About this marker: Blood Glucose Test (MedlinePlus, U.S. National Library of Medicine).

Evidence states come from published human studies found in PubMed and OpenAlex and read by a model pipeline. "Not studied" means no usable human study was found for this marker, which is a gap, not a negative result. Every result links its studies so you can check it.

Research summary for education. Not medical advice.