Condition

Prediabetes

Prediabetes is when blood sugar runs higher than normal but not yet in the diabetes range, often because cells respond less well to insulin. Berberine, L-carnitine and saffron have the most support, and studies found blood glucose improved with each, with moderate evidence. Many of the studies were small, and some reviews also included people with type 2 diabetes, so results may not fit prediabetes alone.

Sources: PMID 32932644; PMID 39818282

Supplements studied: 21
Graded outcomes: 18
Trials: 16
People studied: 59,118

Evidence by supplement

Strong
Moderate
Limited
Very limited

21 supplements

Saffron

Saffron: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	6 studies	840 people
Studies that measured blood glucose Effects of Crocus sativus on glycemic control and cardiometabolic parameters among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials.Nutr Metab · PMID 38796446 The effect of hydroalcoholic Saffron (Crocus sativus L.) extract on fasting plasma glucose, HbA1c, lipid profile, liver, and renal function tests in patients with type 2 diabetes mellitus: A randomized double-blind clinical trialPhytother Res · PMID 30942510 Effects of Cinnamon, Cardamom, Saffron, and Ginger Consumption on Markers of Glycemic Control, Lipid Profile, Oxidative Stress, and Inflammation in Type 2 Diabetes PatientsRev Diabet Stud · PMID 26177486 and 3 more on the Saffron page
	Blood Pressure	Improves (the measure goes down)		3 studies	840 people
Studies that measured blood pressure Protective properties of the aqueous extract of saffron (Crocus sativus L.) in ischemic stroke, randomized clinical trialJ Ethnopharmacol · PMID 30914350 The effects of saffron supplementation on cardiovascular risk factors in adults: A systematic review and dose-response meta-analysisFront Nutr · PMID 36570145 An evaluation of the effects of saffron supplementation on the asthma clinical symptoms and asthma severity in patients with mild and moderate persistent allergic asthma: a double-blind, randomized placebo-controlled trialRespir Res · PMID 30795753
	Creatinine	Improves (the measure goes up)		2 studies	75 people
Studies that measured creatinine Immunomodulatory effects of saffron: a randomized double-blind placebo-controlled clinical trialPhytother Res · PMID 21480412 The effect of saffron ( Crocus sativus L.) supplementation on blood pressure, and renal and liver function in patients with type 2 diabetes mellitus: A double-blinded, randomized clinical trialAvicenna J Phytomed · PMID 31309071
	Triglycerides	Improves (the measure goes down)		2 studies	75 people
Studies that measured triglycerides Saffron and crocin improved appetite, dietary intakes and body composition in patients with coronary artery diseaseJ Cardiovasc Thorac Res · PMID 29391933 The effect of saffron (Crocus sativus L.) hydroalcoholic extract on metabolic control in type 2 diabetes mellitus: A triple-blinded randomized clinical trialJ Res Med Sci · PMID 29531568
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	75 people
Studies that measured high-density lipoprotein (hdl) The effect of saffron on weight and lipid profile: A systematic review, meta-analysis, and dose-response of randomized clinical trialsPhytother Res · PMID 31264281
	Liver Enzymes	Changes; see studies		1 study	840 people
	Sperm Count	Improves (the measure goes up)		1 study	60 people
	Blood Urea Nitrogen (BUN)	Improves (the measure goes up)			840 people
	HbA1c	Improves (the measure goes down)			75 people
	Kidney Function	Improves (the measure goes up)			840 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			75 people
	Sperm Quality	Improves (the measure goes up)			60 people
	Total cholesterol	Improves (the measure goes down)			75 people
	Urea	Improves (the measure goes up)			75 people

L-Carnitine

L-Carnitine: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	5 studies	2,900 people
Studies that measured blood glucose L-Carnitine's Effect on the Biomarkers of Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsNutrients · PMID 32932644 Ameliorating hypertension and insulin resistance in subjects at increased cardiovascular risk: effects of acetyl-L-carnitine therapyHypertension · PMID 19620516 Effects of exercise intensity and altered substrate availability on cardiovascular and metabolic responses to exercise after oral carnitine supplementation in athletesInt J Sport Nutr Exerc Metab · PMID 21813919 and 2 more on the L-Carnitine page
	High-density lipoprotein (HDL)	Improves (the measure goes up)		12 studies	33 people
Studies that measured high-density lipoprotein (hdl) Comparative study to evaluate the effect of l-carnitine plus glimepiride versus glimepiride alone on insulin resistance in type 2 diabetic patientsDiabetes Metab Syndr · PMID 30641691 Effects of simvastatin and carnitine versus simvastatin on lipoprotein(a) and apoprotein(a) in type 2 diabetes mellitusExpert Opin Pharmacother · PMID 19618992 Comparison between orlistat plus l-carnitine and orlistat alone on inflammation parameters in obese diabetic patientsFundam Clin Pharmacol · PMID 21077943 and 9 more on the L-Carnitine page
	Total cholesterol	Improves (the measure goes down)		6 studies	2,933 people
Studies that measured total cholesterol Effect of oral L-carnitine administration on insulin sensitivity and lipid profile in type 2 diabetes mellitus patientsAnn Nutr Metab · PMID 18714152 Effects of carnitine on glucose and lipid metabolic profiles and fertility outcomes in women with polycystic ovary syndrome: A systematic review and meta-analysis.Clin Endocrinol · PMID 36746677 Oral carnitine supplementation reduces body weight and insulin resistance in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trialClin Endocrinol · PMID 26666519 and 3 more on the L-Carnitine page
	Triglycerides	Improves (the measure goes down)		4 studies	2,900 people
Studies that measured triglycerides The effects of L-carnitine supplementation on cardiovascular risk factors in participants with impaired glucose tolerance and diabetes: a systematic review and dose-response meta-analysis.Diabetol Metab Syndr · PMID 39085907 Effects of combined treatment with simvastatin and L-carnitine on triglyceride levels in diabetic patients with hyperlipidaemiaClin Drug Investig · PMID 23315432 Effects of L-carnitine supplementation on lipid profiles in patients with coronary artery diseaseLipids Health Dis · PMID 27317162 and 1 more on the L-Carnitine page
	Insulin	Changes; see studies		3 studies	2,933 people
Studies that measured insulin Caloric restriction and L-carnitine administration improves insulin sensitivity in patients with impaired glucose metabolismJPEN J Parenter Enteral Nutr · PMID 20467011 The effects of L-carnitine supplementation on glycemic control: a systematic review and meta-analysis of randomized controlled trialsEXCLI J · PMID 31611746 Carnitine supplementation improves metabolic flexibility and skeletal muscle acetylcarnitine formation in volunteers with impaired glucose tolerance: A randomised controlled trialEBioMedicine · PMID 31676389
	Liver Enzymes	Changes; see studies		2 studies	33 people
	TNF-Alpha	Improves (the measure goes down)		2 studies	2,900 people
	Body Fat	Improves (the measure goes down)		1 study	2,900 people
	Body Mass Index (BMI)	Improves (the measure goes down)		1 study	2,900 people
	C-Reactive Protein (CRP)	Improves (the measure goes down)		1 study	2,900 people
	HbA1c	Improves (the measure goes down)		1 study	2,900 people
	Insulin Resistance	Improves (the measure goes down)			2,900 people
	Leptin	Improves (the measure goes up)			2,900 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			2,900 people

Panax Ginseng (Korean Ginseng)

Blood glucose: improves
Insulin: changes; see studies
HbA1c: improves

Panax Ginseng (Korean Ginseng): outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	3 studies	124 people
Studies that measured blood glucose Korean red ginseng (Panax ginseng C.A. Meyer) root fractions: differential effects on postprandial glycemia in healthy individualsJ Ethnopharmacol · PMID 21619921 Effect of Korean red ginseng on arterial stiffness in subjects with hypertensionJ Altern Complement Med · PMID 21235416 Effects of acute supplementation of Panax ginseng on endurance running in a hot & humid environmentIndian J Med Res · PMID 21321426
	Insulin	Changes; see studies		3 studies	182 people
Studies that measured insulin Effects of Korean Red Ginseng on Cardiovascular Risks in Subjects with Metabolic Syndrome: a Double-blind Randomized Controlled StudyKorean J Fam Med · PMID 22916320 Effects of Panax ginseng on hyperglycemia, hypertension, and hyperlipidemia: A systematic review and meta-analysis.J Ginseng Res · PMID 35509826 Panax ginseng has no effect on indices of glucose regulation following acute or chronic ingestion in healthy volunteersBr J Nutr · PMID 19017419
	HbA1c	Improves (the measure goes down)		2 studies	476 people
Studies that measured hba1c Ginseng therapy in non-insulin-dependent diabetic patientsDiabetes Care · PMID 8721940 Red ginseng for type 2 diabetes mellitus: a systematic review of randomized controlled trials.Chin J Integr Med · PMID 22139546
	Blood Pressure	Improves (the measure goes down)			702 people
	Body Fat	Improves (the measure goes down)			106 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)			753 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			657 people
	Total cholesterol	Improves (the measure goes down)			803 people
	Triglycerides	Improves (the measure goes down)			741 people

Inulin

Blood glucose: improves
HbA1c: improves
Insulin: changes; see studies

Inulin: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	2 studies	504 people
Studies that measured blood glucose Inulin-type fructans supplementation improves glycemic control for the prediabetes and type 2 diabetes populations: results from a GRADE-assessed systematic review and dose-response meta-analysis of 33 randomized controlled trials.J Transl Med · PMID 31805963 Effect of Inulin-Type Carbohydrates on Insulin Resistance in Patients with Type 2 Diabetes and Obesity: A Systematic Review and Meta-Analysis.J Diabetes Res · PMID 31534973
	HbA1c	Improves (the measure goes down)			504 people
	Insulin	Changes; see studies			504 people
	Insulin Resistance	Improves (the measure goes down)			504 people

Aloe Vera

Blood glucose: improves
HbA1c: changes; see studies
High-density lipoprotein (HDL): improves

Aloe Vera: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small improvement in fasting blood glucose	Improves (the measure goes down)	Small effect	2 studies	328 people
Studies that measured blood glucose Efficacy of Aloe Vera Supplementation on Prediabetes and Early Non-Treated Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsNutrients · PMID 27347994 Effect of Aloe vera on glycaemic control in prediabetes and type 2 diabetes: a systematic review and meta-analysisJ Clin Pharm Ther · PMID 27009750
	HbA1c	Changes; see studies			310 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)			115 people
	Insulin	Changes; see studies			151 people
	Low-density lipoprotein (LDL)	Changes; see studies			136 people
	Total cholesterol	Changes; see studies			206 people
	Triglycerides	Changes; see studies			206 people

Resistant Starch

Blood glucose: improves
HbA1c: improves
Insulin: changes; see studies

Resistant Starch: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	1 study	503 people
Studies that measured blood glucose Effects of resistant starch on glycaemic control: a systematic review and meta-analysis.Br J Nutr · PMID 32959735
	HbA1c	Improves (the measure goes down)			503 people
	Insulin	Changes; see studies			503 people
	Insulin Resistance	Improves (the measure goes down)			503 people

Carnosine

Beta-cell function: improves
Blood glucose: improves
Body Fat: improves

Carnosine: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Beta-cell function Small Increase	Improves (the measure goes up)	Small effect		377 people
	Blood glucose	Improves (the measure goes down)		1 study	377 people
Studies that measured blood glucose Effect of carnosine or beta-alanine supplementation therapy for prediabetes or type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials.BMC Endocr Disord · PMID 40999397
	Body Fat	Improves (the measure goes down)		1 study	43 people
Studies that measured body fat The Effect of Carnosine Supplementation on Musculoskeletal Health in Adults with Prediabetes and Type 2 Diabetes: A Secondary Analysis of a Randomized Controlled Trial.Nutrients · PMID 39770949
	Bone Mineral Density	Improves (the measure goes up)			43 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)			377 people
	Insulin	Changes; see studies			377 people
	Insulin Resistance	Improves (the measure goes down)			377 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			377 people
	Muscle Strength	Improves (the measure goes up)			43 people
	Total cholesterol	Improves (the measure goes down)			377 people

Berberine

Blood glucose: improves
HbA1c: improves
Total cholesterol: improves

Berberine: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Large Improvement	Improves (the measure goes down)	Large effect		912 people
	HbA1c	Improves (the measure goes down)		5 studies	786 people
Studies that measured hba1c The Effect of Berberine on Metabolic Profiles in Type 2 Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsOxid Med Cell Longev · PMID 34956436 Berberine in the treatment of type 2 diabetes mellitus: a systemic review and meta-analysisEvid Based Complement Alternat Med · PMID 23118793 Treatment of type 2 diabetes and dyslipidemia with the natural plant alkaloid berberineJ Clin Endocrinol Metab · PMID 18397984 and 2 more on the Berberine page
	Total cholesterol	Improves (the measure goes down)		3 studies	2,227 people
Studies that measured total cholesterol Overall and Sex-Specific Effect of Berberine for the Treatment of Dyslipidemia in Adults: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials.Drugs · PMID 36941490 Efficacy and safety of berberine for several cardiovascular diseases: A systematic review and meta-analysis of randomized controlled trials.Phytomedicine · PMID 36805484 The Effect of Berberine on Reproduction and Metabolism in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Randomized Control Trials.Evid Based Complement Alternat Med · PMID 31915452
	High-density lipoprotein (HDL)	Improves (the measure goes up)		2 studies	1,729 people
Studies that measured high-density lipoprotein (hdl) Effects of berberine on lipid profile in subjects with low cardiovascular riskExpert Opin Biol Ther · 2013 · PMID 23441841 The effects of berberine supplementation on cardiovascular risk factors in adults: A systematic review and dose-response meta-analysis.Front Nutr · PMID 36313096
	Triglycerides	Improves (the measure goes down)		1 study	2,291 people
Studies that measured triglycerides Efficacy and Safety of Berberine Alone for Several Metabolic Disorders: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.Front Pharmacol · 2021 · PMID 33981233
	C-Reactive Protein (CRP)	Improves (the measure goes down)			870 people
	Insulin Resistance	Improves (the measure goes down)			1,347 people
	Interleukin 6	Improves (the measure goes down)			536 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			1,860 people
	TNF-Alpha	Improves (the measure goes down)			466 people

Curcumin

Blood glucose: improves
Total cholesterol: improves
Fructosamine: changes; see studies

Curcumin: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	18 studies	81 people
Studies that measured blood glucose The Effect of Antioxidant Polyphenol Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis.Nutrients · 2024 · PMID 39683599 Curcumin alleviates postprandial glycaemic response in healthy subjects: A cross-over, randomized controlled studySci Rep · 2018 · PMID 30209353 Effects of Curcuma longa (turmeric) on postprandial plasma glucose and insulin in healthy subjectsNutr J · 2010 · PMID 20937162 and 15 more on the Curcumin page
	Total cholesterol	Improves (the measure goes down)		4 studies	81 people
Studies that measured total cholesterol Effects of curcumin/turmeric supplementation on lipid profile: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials.Complement Ther Med · PMID 37230418 Bread enriched with phytosterols with or without curcumin modulates lipoprotein profiles in hypercholesterolaemic individuals. A randomised controlled trialFood Funct · PMID 30990213 The Effect of Curcumin on some of Traditional and Non-traditional Cardiovascular Risk Factors: A Pilot Randomized, Double-blind, Placebo-controlled TrialIran J Pharm Res · PMID 25901155 and 1 more on the Curcumin page
	Fructosamine	Changes; see studies		1 study	81 people
Studies that measured fructosamine Curcumin and/or omega-3 polyunsaturated fatty acids supplementation reduces insulin resistance and blood lipids in individuals with high risk of type 2 diabetes: a randomised controlled trialLipids Health Dis · PMID 30684965
	C-Reactive Protein (CRP)	Improves (the measure goes down)			81 people
	HbA1c	Improves (the measure goes down)			81 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)			81 people
	Lymphocyte Count	Improves (the measure goes up)			81 people
	Monocyte Count	Improves (the measure goes up)			81 people
	Neutrophil Count	Improves (the measure goes up)			81 people
	White Blood Cell Count	Improves (the measure goes up)			81 people

Magnesium

Blood glucose: improves
Blood Pressure: improves
C-Reactive Protein (CRP): improves

Magnesium: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect	17 studies	86 people
Studies that measured blood glucose Efficacy of Magnesium Supplementation on Glycemic Control in Type 2 Diabetes Patients: A Meta-analysis.J ASEAN Fed Endocr Soc · PMID 33442083 Oral magnesium supplementation in insulin-requiring Type 2 diabetic patientsDiabet Med · PMID 9632126 The effect of lowering blood pressure by magnesium supplementation in diabetic hypertensive adults with low serum magnesium levels: a randomized, double-blind, placebo-controlled clinical trialJ Hum Hypertens · PMID 19020533 and 14 more on the Magnesium page
	Blood Pressure	Improves (the measure goes down)		10 studies	86 people
Studies that measured blood pressure Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.Hypertension · PMID 41000008 Effect on blood pressure of potassium, calcium, and magnesium in women with low habitual intakeHypertension · PMID 9449404 Effects of Magnesium Citrate, Magnesium Oxide, and Magnesium Sulfate Supplementation on Arterial Stiffness: A Randomized, Double-Blind, Placebo-Controlled Intervention TrialJ Am Heart Assoc · PMID 35253448 and 7 more on the Magnesium page
	C-Reactive Protein (CRP)	Improves (the measure goes down)		3 studies	86 people
Studies that measured c-reactive protein (crp) Effect of Magnesium Supplementation on Inflammatory Parameters: A Meta-Analysis of Randomized Controlled TrialsNutrients · PMID 35277037 Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleepMagnes Res · PMID 21199787 The effect of long-term magnesium intake on inflammatory markers in patients with metabolic syndrome: a systematic review and meta-analysis of randomized controlled trials.Front Nutr · PMID 41245414
	Triglycerides	Improves (the measure goes down)		2 studies	86 people
Studies that measured triglycerides The effect of magnesium supplementation on serum concentration of lipid profile: an updated systematic review and dose-response meta-analysis on randomized controlled trials.Nutr J · PMID 39905454 Effects of magnesium on postprandial serum lipid responses in healthy human subjectsBr J Nutr · PMID 19941679
	Insulin Resistance	Improves (the measure goes down)		1 study	86 people
Studies that measured insulin resistance Metabolic and hormonal effects of melatonin and/or magnesium supplementation in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trialNutr Metab · PMID 34092248
	HbA1c	Improves (the measure goes down)			86 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)			86 people
	Insulin	Changes; see studies			86 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			86 people
	Total cholesterol	Improves (the measure goes down)			86 people
	Uric Acid	Improves (the measure goes down)			86 people

Zinc

Blood glucose: improves
HbA1c: improves
Insulin: changes; see studies

Zinc: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood glucose Small Improvement	Improves (the measure goes down)	Small effect		10 people
	HbA1c	Improves (the measure goes down)		1 study	10 people
Studies that measured hba1c Effect of zinc supplementation on glycemic biomarkers: an umbrella of interventional meta-analyses.Diabetol Metab Syndr · PMID 38849958
	Insulin	Changes; see studies		1 study	10 people
Studies that measured insulin Effect of zinc supplementation on insulin resistance and components of the metabolic syndrome in prepubertal obese childrenHormones · PMID 20045801
	Insulin Resistance	Improves (the measure goes down)			10 people

Thiamine (Vitamin B1)

Blood Pressure: improves
High-density lipoprotein (HDL): improves
C-Reactive Protein (CRP): improves

Thiamine (Vitamin B1): outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People
	Blood Pressure Small Improvement	Improves (the measure goes down)	Small effect		12 people
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	12 people
Studies that measured high-density lipoprotein (hdl) The impact of thiamine supplementation on blood pressure, serum lipids and C-reactive protein in individuals with hyperglycemia: a randomised, double-blind cross-over trialDiabetes Metab Syndr · PMID 25982678
	C-Reactive Protein (CRP)	Improves (the measure goes down)			12 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			12 people
	Total cholesterol	Improves (the measure goes down)			12 people
	Triglycerides	Improves (the measure goes down)			12 people

Banana Flower

Body Weight/BMI: improves

Banana Flower: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Body Weight/BMI Double-blind RCT (PMID: 30887937): Green banana biomass significantly reduced body weight and BMI in prediabetic adults	Improves (the measure goes down)	Moderate effect		50 people

Flaxseed

Adiponectin
Blood glucose: improves
Leptin: improves

Flaxseed: outcomes studied for Prediabetes
Outcome	Effect	Size	Studies	People
Adiponectin No effect		NoneNo effect		460 people
Blood glucose	Improves (the measure goes down)		3 studies	2,080 people
Leptin	Improves (the measure goes up)		2 studies	460 people
HbA1c	Improves (the measure goes down)			2,080 people
Insulin	Changes; see studies			2,080 people
Insulin Resistance	Improves (the measure goes down)			2,080 people

Probiotics

Beta-cell function
HbA1c: improves
Blood glucose: improves

Probiotics: outcomes studied for Prediabetes
Outcome	Effect	Size	Studies	People
Beta-cell function No effect		NoneNo effect		153 people
HbA1c	Improves (the measure goes down)		2 studies	567 people
Blood glucose	Improves (the measure goes down)		1 study	576 people
Insulin Resistance	Improves (the measure goes down)		1 study	515 people
Total cholesterol	Improves (the measure goes down)		1 study	253 people
Blood Pressure	Improves (the measure goes down)			432 people
High-density lipoprotein (HDL)	Improves (the measure goes up)			323 people
Insulin	Changes; see studies			550 people
Low-density lipoprotein (LDL)	Improves (the measure goes down)			323 people
Triglycerides	Improves (the measure goes down)			323 people

Green Tea Extract

Blood glucose
Insulin: changes; see studies
Glycemic Control: improves

Green Tea Extract: outcomes studied for Prediabetes
Outcome	Effect	Size	Studies	People
Blood glucose No effect		NoneNo effect		1,251 people
Insulin	Changes; see studies		7 studies	870 people
Glycemic Control	Improves (the measure goes up)			189 people
HbA1c	Improves (the measure goes down)			460 people
Insulin Resistance	Improves (the measure goes down)			336 people

Chromium

Blood Flow
Weight: improves
Glycemic Control: improves

Chromium: outcomes studied for Prediabetes
Outcome	Effect	Size	Studies	People
Blood Flow No effect		NoneNo effect		50 people
Weight	Improves (the measure goes down)		12 studies	50 people
Glycemic Control	Improves (the measure goes up)		9 studies	50 people
Blood glucose	Improves (the measure goes down)		6 studies	50 people
Blood Pressure	Improves (the measure goes down)		1 study	50 people
High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	50 people
Kidney Function	Improves (the measure goes up)		1 study	50 people
Low-density lipoprotein (LDL)	Improves (the measure goes down)		1 study	50 people
Total cholesterol	Improves (the measure goes down)		1 study	50 people
Proteinuria	Improves (the measure goes up)			50 people
Triglycerides	Improves (the measure goes down)			50 people

Vitamin D

Beta-cell function
Glycemic Control: improves
Insulin: changes; see studies

Vitamin D: outcomes studied for Prediabetes
Outcome	Effect	Size	Studies	People
Beta-cell function No effect		NoneNo effect		66 people
Glycemic Control	Improves (the measure goes up)		4 studies	97 people
Insulin	Changes; see studies		3 studies	89 people
Insulin Resistance	Improves (the measure goes down)		1 study	66 people
Type 2 Diabetes Incidence	Changes; see studies		1 study	27,425 people

Nicotinamide Mononucleotide

Insulin Resistance: improves

Nicotinamide Mononucleotide: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Insulin Resistance	Improves (the measure goes down)		2 studies	25 people

Prebiotics

Glycemic Control: improves

Prebiotics: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Glycemic Control	Improves (the measure goes up)		1 study	546 people

Resveratrol

Glycemic Control: improves

Resveratrol: outcomes studied for Prediabetes
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Glycemic Control	Improves (the measure goes up)		1 study	10 people

Key findings

Blood glucoseSaffronImproves (the measure goes down)
Beta-cell functionCarnosineImproves (the measure goes up)
Blood PressureThiamine (Vitamin B1)Improves (the measure goes down)

The Prediabetes & Insulin Resistance protocol

2 primary supplements · 4 supporting supplements

Berberine500 mg three times daily with meals
Chromium500–1,000 mcg daily (chromium picolinate)

See the full protocol

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Studies cited

3 studies from PubMed

The cardiometabolic benefits of okra-based treatment in prediabetes and diabetes: a systematic review and meta-analysis of randomized controlled trials.Front Nutr · PMID 39726865
Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with PrediabetesCell Metab · PMID 29754952
Vinegar improves insulin sensitivity to a high-carbohydrate meal in subjects with insulin resistance or type 2 diabetesDiabetes Care · PMID 14694010

Evidence by supplement

Key findings

The Prediabetes & Insulin Resistance protocol

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Studies cited

Related conditions

Supplement stack for Prediabetes