What you can take to lower blood sugar depends on whether you need a prescription medication, an over-the-counter supplement, or a dietary change, and the answer is different for someone with type 2 diabetes than for someone trying to prevent it. Metformin remains the most widely prescribed first-line drug, but a surge of newer medications and a handful of evidence-backed natural compounds have expanded the options considerably. The catch is that not everything marketed for blood sugar actually works, and some combinations can push glucose dangerously low.
Metformin, the Default Starting Point
For most people diagnosed with type 2 diabetes, metformin is the first medication a doctor will prescribe. It works mainly by reducing the amount of glucose your liver releases into your bloodstream. Research has shown that metformin achieves this by inhibiting a key enzyme in the liver’s glucose-manufacturing pathway, essentially putting the brakes on sugar production at the source.1Europe PMC. Metformin reduces liver glucose production by inhibition of fructose-1-6-bisphosphatase Because it does not force the pancreas to pump out more insulin, metformin carries a low risk of causing blood sugar to drop too far. It is inexpensive, available as a generic, and has decades of safety data behind it. Side effects are mostly gastrointestinal, like nausea and diarrhea, and they often ease after a few weeks.
SGLT2 Inhibitors
A newer class of drugs takes a completely different approach: instead of changing how your body makes or uses insulin, SGLT2 inhibitors cause your kidneys to dump excess glucose into your urine. Drugs in this class, including empagliflozin, dapagliflozin, and canagliflozin, block a transporter in the kidney’s early filtering tubes so that glucose that would normally be reabsorbed back into the blood is instead excreted.2American Journal of Hypertension. State-of-the-Art-Review: Mechanisms of Action of SGLT2 Inhibitors and Clinical Implications The result is lower blood sugar without directly affecting insulin levels. These drugs have also shown benefits for heart failure and kidney disease, which is why they are increasingly prescribed even in people whose blood sugar is already reasonably controlled. The trade-off is a higher risk of urinary tract and genital yeast infections, since bacteria and yeast thrive on the extra sugar passing through.
GLP-1 Receptor Agonists and Dual-Receptor Drugs
GLP-1 receptor agonists like semaglutide (Ozempic, Wegovy) and liraglutide (Victoza) mimic a gut hormone that your body normally releases after eating. That hormone boosts insulin secretion when blood sugar is high, suppresses glucagon (a hormone that raises blood sugar), and slows the rate at which food leaves your stomach.3PubMed Central. GLP-1 receptor agonists and delayed gastric emptying: implications for invasive cardiac interventions and surgery By slowing gastric emptying, these drugs moderate the rush of glucose into the bloodstream after a meal, which flattens the post-meal spike that many people with diabetes struggle to control. They also reduce appetite, which is why several have been approved for weight management as well.
Tirzepatide (Mounjaro) goes a step further by activating two receptors at once: GLP-1 and GIP. Clinical data show that tirzepatide at higher doses improved markers of pancreatic beta-cell function and insulin processing beyond what a GLP-1-only drug achieved, including greater reductions in proinsulin-to-insulin ratios, which suggests the pancreas is working more efficiently.4The Journal of Clinical Endocrinology & Metabolism. Dual GIP and GLP-1 Receptor Agonist Tirzepatide Improves Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes For people who need aggressive blood-sugar control along with weight loss, the dual-receptor drugs represent one of the most potent non-insulin options available right now.
Sulfonylureas and Thiazolidinediones
Older drug classes still see plenty of use, especially where cost matters. Sulfonylureas like glipizide and glyburide work by blocking potassium channels in the insulin-producing cells of the pancreas, which triggers those cells to release more insulin.5PubMed Central. The impact of sulfonylureas on diverse ion channels: an alternative explanation for the antidiabetic actions They are effective and cheap, but because they push insulin out regardless of how much sugar is in the blood, they carry a real risk of hypoglycemia and tend to cause weight gain.
Thiazolidinediones (TZDs) like pioglitazone take a different path. They activate a receptor in fat tissue that improves the body’s sensitivity to insulin, partly by redirecting fatty acids into fat cells and reducing inflammatory signaling molecules.6PubMed Central. Thiazolidinediones: effects on insulin resistance and the cardiovascular system TZDs don’t cause hypoglycemia on their own, but they can cause fluid retention and weight gain, and one member of the class (rosiglitazone) was restricted over cardiovascular concerns. Pioglitazone is still widely available and sometimes used in people with fatty liver disease or strong insulin resistance.
Alpha-Glucosidase Inhibitors
If your main problem is post-meal blood sugar spikes rather than fasting glucose, alpha-glucosidase inhibitors like acarbose and miglitol slow the digestion of carbohydrates in the small intestine. They work by altering the rate at which the body breaks down and absorbs carbohydrates, which means glucose trickles into the bloodstream more gradually after a meal.7American Diabetes Association (Diabetes Journals). 2025-26 Guide to Medications for the Treatment of Diabetes Mellitus – Chapter 11: α-Glucosidase Inhibitors They are not commonly prescribed in the United States because the gastrointestinal side effects (bloating, gas, diarrhea) are hard for many people to tolerate, but they remain popular in parts of Asia and are sometimes useful as add-on therapy.
Insulin
For people with type 1 diabetes, insulin is non-negotiable: the body produces little or none. In type 2 diabetes, insulin injections or pump therapy become necessary when the pancreas can no longer keep up despite oral medications. Insulin comes in rapid-acting, short-acting, intermediate, and long-acting formulations. Rapid-acting insulin covers meal spikes; long-acting insulin provides a steady background level throughout the day. The main risk is hypoglycemia, and dosing has to be matched carefully to food intake and activity. Newer “smart” insulin analogs and automated pump systems have reduced that risk considerably, but insulin still demands more active management than most pills.
Berberine
Among non-prescription supplements, berberine is the one with the strongest clinical evidence for lowering blood sugar. It is a compound found in several plants, including goldenseal and barberry, and it has been used in traditional Chinese medicine for centuries. A multi-center, double-blind, randomized trial found that berberine taken alone reduced fasting blood glucose by about 0.50 mmol/L compared with placebo, and when combined with a probiotic (Bifidobacterium), the reduction was about 0.55 mmol/L. The combination group also had a meaningful decrease in HbA1c, a marker of long-term blood sugar control.8Genome Medicine. Effectiveness and safety of Bifidobacterium and berberine in human hyperglycemia and their regulatory effect on the gut microbiota: a multi-center, double-blind, randomized, parallel-controlled study Those numbers are modest compared with prescription drugs, but for someone with prediabetes or mildly elevated blood sugar who wants to avoid medication, berberine is one of the few supplements with rigorous trial data behind it.
A word of caution: berberine can cause gastrointestinal side effects similar to metformin, and it interacts with several prescription drugs because it affects the same liver enzymes that metabolize many common medications. If you are already on a diabetes drug, adding berberine without telling your doctor is a bad idea.
Cinnamon, Fenugreek, and Other Herbal Compounds
Ceylon cinnamon (Cinnamomum verum) is commonly promoted as a blood-sugar-lowering spice. It contains compounds that appear to increase insulin sensitivity, and observational evidence suggests it can reduce blood lipids as well.9ScienceDirect / Journal of Future Foods. Ceylon cinnamon: a versatile ingredient for futuristic diabetes management The evidence is more mixed than the marketing suggests, though. Trial sizes have generally been small, dosing has varied widely, and the species of cinnamon matters: cassia cinnamon contains higher levels of coumarin, a compound that can be harmful to the liver in large amounts. If you want to try cinnamon, look for Ceylon cinnamon and treat it as a modest addition, not a substitute for proven treatments.
Fenugreek is another herb with some evidence. Its active amino acid, 4-hydroxy isoleucine, has been shown to stimulate glucose-induced insulin secretion from pancreatic cells in laboratory studies.10PubMed Central. Treatment on Nature’s lap: Use of herbal products in the management of hyperglycemia Human trials exist but are generally small, and the herb has a strong, distinctive taste that some people find off-putting. Like cinnamon, fenugreek can complement other efforts but probably won’t move the needle on its own for someone with significantly elevated blood sugar.
Magnesium and Alpha-Lipoic Acid
Two micronutrient-based options deserve mention because they address a specific and common problem: insulin resistance driven by nutritional deficiency.
Magnesium is involved in the signaling cascade that allows insulin to work at the cellular level. When magnesium levels are low, the insulin receptor’s ability to relay signals into the cell is impaired, leading to reduced glucose uptake regardless of how much insulin is circulating.11PubMed Central. Effects of Magnesium Deficiency on Mechanisms of Insulin Resistance in Type 2 Diabetes: Focusing on the Processes of Insulin Secretion and Signaling Animal research has confirmed that magnesium-deficient rats show about a 50% reduction in insulin receptor activity in muscle tissue.12PubMed. Impaired tyrosine-kinase activity of muscle insulin receptors from hypomagnesaemic rats Many people with type 2 diabetes are low in magnesium, so correcting that deficiency with a supplement or through magnesium-rich foods (dark leafy greens, nuts, seeds) can improve how well insulin works. If your magnesium levels are already normal, extra supplementation is unlikely to help much.
Alpha-lipoic acid (ALA) is an antioxidant compound with effects on both insulin sensitivity and insulin secretion. It is most commonly prescribed for diabetic nerve pain, but its glucose-lowering effects have also been documented in people with metabolic syndrome and polycystic ovary syndrome.13PubMed Central. Alpha-Lipoic Acid and Glucose Metabolism: A Comprehensive Update on Biochemical and Therapeutic Features ALA is available over the counter and is generally well-tolerated, though it can occasionally lower blood sugar enough to cause symptoms in people already taking diabetes medications.
Soluble Fiber
You do not always need a pill. Soluble dietary fiber, the kind found in oats, barley, psyllium husks, and certain gums, forms a viscous gel in the gut that slows glucose absorption after a carbohydrate-heavy meal.14Journal of Functional Foods. Effect of soluble dietary fibre on postprandial blood glucose response and its potential as a functional food ingredient The gel physically delays the movement of sugar from the intestine into the bloodstream, which flattens the post-meal glucose curve. Some soluble fibers also get fermented by gut bacteria into short-chain fatty acids, which in turn stimulate the release of GLP-1, the same hormone targeted by semaglutide and tirzepatide.15PubMed Central. The Effects of Soluble Dietary Fibers on Glycemic Response: An Overview and Futures Perspectives
The practical takeaway: a tablespoon of psyllium husk in water before a meal, or a bowl of oatmeal with beta-glucan-rich oats, can blunt a glucose spike meaningfully. This is not exotic supplementation; it is grocery-store fiber. For someone with prediabetes or early diabetes, adding soluble fiber to meals is one of the simplest and safest things you can do.
Apple Cider Vinegar
Apple cider vinegar (ACV) has a dedicated following on social media, and here the evidence is mixed but not absent. A randomized controlled trial in diabetic patients found that consuming ACV over eight weeks led to a significant drop in fasting blood glucose compared with control, along with a significant reduction in HbA1c.16PubMed Central. The improvement effect of apple cider vinegar as a functional food on anthropometric indices, blood glucose and lipid profile in diabetic patients: a randomized controlled clinical trial The acetic acid in vinegar is thought to slow gastric emptying and may affect liver glucose metabolism, though the exact mechanism is still debated. The main downside is that vinegar is unpleasant to drink, it can erode tooth enamel, and the effect size is small enough that it should be considered a helpful add-on, not a treatment.
Meal Timing and Time-Restricted Eating
When you eat can matter nearly as much as what you eat. Time-restricted eating, where you confine all food intake to a window of roughly eight to ten hours per day, has shown benefits for blood sugar even without weight loss. One trial found that eating within an early window (finishing dinner in the mid-afternoon) improved insulin sensitivity, beta-cell function, and blood pressure without any change in body weight.17PubMed Central. Time-restricted eating for patients with diabetes and prediabetes: A systematic review The body processes glucose more efficiently earlier in the day, and late-night eating tends to produce higher glucose spikes for the same food. For someone looking to lower blood sugar without adding a supplement or drug, shifting more calories to earlier in the day is a free intervention with decent evidence behind it.
The Danger of Going Too Low
Lowering blood sugar is the goal, but there is such a thing as too much success. Hypoglycemia, defined as blood glucose below 70 mg/dL, triggers a cascade of counter-regulatory hormones including glucagon and adrenaline. Symptoms range from shakiness and sweating to confusion and seizures in severe cases.18PubMed Central. Hypoglycemia: The neglected complication The drugs most likely to cause hypoglycemia are insulin and sulfonylureas, because both push blood sugar down regardless of its current level. Metformin, SGLT2 inhibitors, and GLP-1 agonists carry much lower risk because their mechanisms are glucose-dependent, meaning they are less active when sugar is already low.
The risk climbs when people stack multiple glucose-lowering interventions. Combining a sulfonylurea with berberine, for example, or taking insulin alongside a large dose of cinnamon supplement, can push glucose lower than either would alone. Herb-drug interactions are a real concern: many herbal products used for blood sugar have pharmacokinetic interactions with mainstream diabetes drugs, meaning they can change how the drug is absorbed or metabolized and amplify its effects unpredictably.19PubMed Central. Interactions between antidiabetic drugs and herbs: an overview of mechanisms of action and clinical implications Repeated episodes of low blood sugar can also dull the body’s warning signals, a condition called hypoglycemia unawareness, making severe episodes more likely in the future.18PubMed Central. Hypoglycemia: The neglected complication If you are adding anything new to your blood-sugar-lowering routine, whether prescription, supplement, or dietary change, mention it to your prescriber.
Supplement Quality Is Not Guaranteed
One reason doctors are cautious about supplements for blood sugar is that the supplement industry operates under minimal regulation in the United States. An analysis of FDA warning data from 2007 through 2016 found 776 adulterated dietary supplements, many containing undeclared pharmaceutical ingredients.20JAMA Network Open. Unapproved Pharmaceutical Ingredients Included in Dietary Supplements Associated With US Food and Drug Administration Warnings While the worst offenders tend to be weight-loss and sexual-enhancement products, the broader issue is that what is on the label of a supplement may not match what is in the bottle. If you decide to take berberine, cinnamon extract, or ALA, choosing a product from a manufacturer that uses third-party testing (look for USP, NSF, or ConsumerLab seals) reduces the risk of getting a contaminated or underdosed product.
Why the Same Food Raises Your Blood Sugar More Than Someone Else’s
A frustrating reality of blood sugar management is that two people can eat the same meal and see very different glucose responses. Continuous glucose monitoring data from healthy, non-diabetic adults illustrate this variability: while the group average glucose was about 99 mg/dL, individual averages ranged widely, and adults over 60 averaged about 104 mg/dL, a statistically significant difference from younger groups.21The Journal of Clinical Endocrinology & Metabolism. Continuous Glucose Monitoring Profiles in Healthy Nondiabetic Participants: A Multicenter Prospective Study Even among healthy people, time spent above 140 mg/dL averaged about 30 minutes per day, though some individuals spent much more.
This individual variation means that a supplement or dietary strategy that dramatically helps one person may do very little for another. Factors like gut microbiome composition, genetics, sleep quality, stress hormones, and the degree of existing insulin resistance all shape how your body handles glucose. If you are experimenting with any of the options discussed here, a continuous glucose monitor (now available over the counter in some countries) can show you in real time whether a particular change is actually helping your numbers, rather than relying on a fasting blood draw every few months to tell you what happened on average.