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01Fasting insulin · the upstream signal

Storedin sixes

In the pancreas, insulin is stored as a six-part cluster held together by zinc. After release into the blood the cluster comes apart, and single insulin molecules act on your cells.

Measured in
Blood (serum)
Units
µIU/mL, pmol/L
Also called
serum insulin
T6 human insulin hexamer (PDB 1MSO), rendered from its atomic coordinates.
T6 human insulin hexamer · PDB 1MSO

AWhat moves Fasting insulin

20 of 27 studied

In human studies, 15 of the 27 supplements and practices researched so far lowered fasting insulin and 1 raised it. 3 showed no change and 1 had mixed results. 7 were never studied for it.
  • Supported 16
  • No effect 3
  • Conflicting 1
  • Not studied 7
See Fasting insulin on the evidence map →Check claims about Fasting insulin →

Moves it16

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

HIITLowersGrade A

HIIT lowers fasting insulin.

Meta-analysis or review · 3 studies linked

Studied in: Overweight obese, T2DM, Metabolic syndrome, Children adolescents

Open the HIIT page →Check a claim about this →
MagnesiumLowersGrade A

Magnesium lowers fasting insulin.

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

Studied in: T2DM, Insulin resistant, Prediabetes

Reduction in basal hyperinsulinemia consistent with insulin sensitization mechanism; not a hypoglycemic effect in euinsulinemic individuals

  • Zhang X, Li Y, Del Gobbo LC, Rosanoff A, Wang J, Zhang W, Song Y (2016)
  • Simental-Mendía LE, Rodríguez-Morán M, Guerrero-Romero F (2014)
Open the Magnesium page →Check a claim about this →
Zone 2 cardioLowersGrade A

Zone 2 cardio lowers fasting insulin.

Meta-analysis or review · 2 studies linked

Studied in: Adults overweight obese, Adults T2DM

Open the Zone 2 cardio page →Check a claim about this →
NACLowersGrade A

NAC lowers fasting insulin.

Human trials · Small to moderate effect · 1 study linked

Studied in: PCOS, Female, Adult

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ZincLowersGrade B

Zinc lowers fasting insulin.

Human trials · 3 studies linked

Studied in: T2D, Prediabetes, Overweight, Adults

More consistent in insulin-resistant populations. Effect size variable; driven primarily by insulin-sensitizing mechanism rather than direct insulin secretion suppression.

Open the Zinc page →Check a claim about this →
BerberineLowersGrade B

Berberine lowers fasting insulin.

Meta-analysis or review · 2 studies linked

Studied in: T2DM, PCOS, Insulin resistant, NOT healthy euglycemic

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MelatoninLowersGrade B

Melatonin lowers fasting insulin.

Small effect · 2 studies linked

Studied in: Adults, T2DM, PCOS, Metabolic syndrome

CONTESTED — shares genotype-dependent mechanism with HOMA-IR; 10 studies in MA vs single genotyped RCT for opposing signal

  • Mohammadi-Sartang M et al. (2021)
  • study mel shabani2019 · not matched to a paper yet
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Vitamin D3LowersGrade B

Vitamin D3 lowers fasting insulin.

Meta-analysis or review · 2 studies linked

Studied in: Gestational diabetes, Prediabetes, Deficient baseline

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L-carnitineLowersGrade B

L-carnitine lowers fasting insulin.

Moderate effect · 1 study linked

Studied in: PCOS, Female, Hyperinsulinemic

Large proportional reduction from high baseline; PCOS hyperinsulinemia context; before-after

  • Salehpour S, Nazari L, Hoseini S, Hosseini MS, Azizi E, Ghasemnejad-Berenji H (2019)
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NAD+RaisesGrade B

NAD+ raises fasting insulin.

Human trials · 1 study linked

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

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Vitamin K2LowersGrade B

Vitamin K2 lowers fasting insulin.

Small effect · 1 study linked

Studied in: Type2 diabetes, Insulin resistant, Asian

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Milk thistleLowersGrade B

Milk thistle lowers fasting insulin.

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, Insulin resistance, NAFLD, Metabolic syndrome

Fasting insulin reduction demonstrated in T2DM + NAFLD RCTs. AMPK activation and reduced hepatic lipotoxicity proposed as mechanism. Mohammadi 2020 zebrafish data (zare_mehrjerdi_2024 content) suggests silibinin + metformin synergy — preclinical only, Grade C ceiling applies to that specific finding.

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AshwagandhaLowersGrade C

Ashwagandha lowers fasting insulin.

Meta-analysis or review · 1 study linked

Studied in: Type2 diabetes, Not established normoglycemic

Open the Ashwagandha page →Check a claim about this →
CollagenLowersGrade C

Collagen lowers fasting insulin.

Meta-analysis or review · 1 study linked

Studied in: T2DM, Prediabetes, Adult mixed sex

Direction 'decrease' with grade C from jalili_2023 — described as 'reported in 2 RCTs within jalili_2023' with insufficient data for pooling. C grade is appropriate. source_studies reference is valid.

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Vitamin CLowersGrade C

Vitamin C lowers fasting insulin.

1 study linked

Studied in: Adults, Type 2 diabetes, Insulin resistance

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TaurineLowersGrade C

Taurine lowers fasting insulin.

Lab or animal studies · 0 studies linked

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

Studied in: Type 2 diabetes, Insulin resistance

3 corpus studies — thin. Grade C pending dedicated MA inclusion.

Open the Taurine page →Check a claim about this →

Studied, no change3

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

Omega-3No changeGrade B

Studies of Omega-3 found no change in fasting insulin.

Negligible effect · 1 study linked

Studied in: General adult, Insulin resistant, T2DM

CONTESTED — HOMA-IR subgroup showed SMD 0.30 improvement but overall IS measure did not

  • pmid 41156531 corpus
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Vitamin ENo changeGrade B

Studies of Vitamin E found no change in fasting insulin.

0 studies linked

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

Studied in: T2DM, NAFLD, Adult

Inconsistent results across trials; modest insulin reduction in some NAFLD subgroups not replicated in diabetic populations. Insufficient pooled data for grade A.

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CreatineNo changeGrade C

Studies of Creatine found no change in fasting insulin.

Human trials · Negligible effect · 1 study linked

Studied in: Healthy adults, Metabolic syndrome

Fasting insulin generally unchanged in healthy adults. Insulin sensitivity improvements in metabolic syndrome populations are plausible given GLUT4 mechanism but insulin level changes are not the primary reported endpoint in available studies.

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Mixed results1

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

ResveratrolMixed resultsGrade B

Studies of Resveratrol and fasting insulin disagree.

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

Studied in: Obese, T2DM, Insulin resistant, Adults

NULL finding. Insulin sensitization appears population-specific (insulin-resistant/T2DM subjects).

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Not studied7

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

Finnish saunaIronL-theanineLion's manePQQRed yeast riceUbiquinol (CoQ10)

Commission research on a gap →

BThe molecule

T6 human insulin hexamer

  1. T6 human insulin hexamer, whole structure.

    01Six insulin molecules, packed for storage.

  2. T6 human insulin hexamer, cut-away view.

    02Two zinc ions sit on the central axis and hold the cluster together.

  3. T6 human insulin hexamer, close-up.

    03One molecule breaks free: the form that works in the blood. Fasting insulin shows how hard the pancreas is working to keep glucose steady.

Structure: PDB 1MSO · X-ray 1.0 Å · Smith, Pangborn & Blessing, 2003. Rendered from atomic coordinates in Blender; 2,414 atoms, about 5.8 nm across.

Why trials measure it. Read with fasting glucose, it shows how hard the body is working to keep blood sugar steady, so insulin-sensitivity trials track it.

About this marker: Insulin in Blood (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.