Supplements to Lower Blood Sugar: A Dietitian's Guide
- Serena Benali, Registered Dietitian
- 5 days ago
- 8 min read
Written and medically reviewed by Serena Benali, Registered Dietitian. Published January 20, 2026.
Managing blood sugar isn’t just about cutting sugar or carbs. It’s about understanding how your body handles glucose, how insulin works, and where lifestyle changes and supplements may (or may not) play a role.
With so much supplement marketing aimed at people with diabetes or pre-diabetes, it can be hard to separate helpful supplements from hype. Our In Good Nutrition dietitian, Serena Benali, created this clear, evidence-informed breakdown of what supplements may support blood sugar regulation, who they’re for, and why food and lifestyle always come first.
Table of Contents
First Things First: Blood Sugar 101
When you eat carbohydrates, your body breaks them down into glucose, which enters your bloodstream. Insulin, a hormone made by the pancreas, helps move that glucose into your cells to be used for energy or stored for later.
Problems arise when:
The body doesn’t make enough insulin
Cells don’t respond well to insulin (insulin resistance)
Blood sugar stays elevated for long periods
Over time, chronically high blood sugar increases inflammation and oxidative stress, raising the risk of complications affecting the heart, kidneys, nerves, and eyes.
How Blood Sugar Is Measured
Blood sugar control can be assessed in several ways, including:
Fasting blood glucose, measures blood sugar after at least 8 hours without eating, showing how well your body manages glucose at baseline.
Hemoglobin A1c (HbA1c), reflects your average blood sugar levels over the past 3 months, providing a long-term view of blood sugar control.
Post-meal (postprandial) glucose, tracks how high blood sugar rises after eating, helping identify blood sugar spikes from meals.
Continuous glucose monitoring (CGM), uses a small sensor worn on the body to measure blood sugar throughout the day and night in real time, revealing patterns and trends.
Each test tells a slightly different story. Someone can have “normal” fasting glucose while still experiencing large spikes after meals, one reason personalized care is so important .
Diet and lifestyle First: The Non-Negotiables
Before considering supplements, we want to emphasize: lifestyle matters most.
Balanced diet
Regular physical activity
Consistent eating patterns
Supplements are not a substitute for these habits. At best, they may provide additional support when the fundamentals are already in place.
Buyer Beware: What’s Really in That Bottle?
Even high-quality-looking supplements can be hit or miss. Labels aren’t always accurate - yep, let that sink in for a minute... Some products may contain more or less of an ingredient than listed, or even extra ingredients that aren’t on the label. Supplements can also be contaminated (for example, with heavy metals or pesticides) and may include common allergens or non-medicinal fillers that don’t agree with everyone.
Bottom line: Supplements can be helpful for some people, but they aren’t risk-free and should always be used with intention.
A quick safety note: many supplements that affect blood sugar can increase the risk of low blood sugar when combined with diabetes medications. It’s important to inform your healthcare provider.
First-line Supplements for Blood Sugar Control
Fibre: Blood Sugar MVP
Fibre is the all-star when it comes to consistently supporting blood sugar control. If you take one thing from this conversation, make it this: fibre is often the highest-impact, lowest-risk place to start. Before adding more supplements, increasing fibre through diet first then supplement, if needed to bridge the gap, can improve blood sugar regulation on its own and can also make other strategies work better.
Why fibre matters for blood sugar regulation
Fibre is viscous and gel-forming which can help by slowing how quickly carbohydrates are digested and absorbed, which can blunt post-meal blood sugar rises.
Adequate fibre intake:
Slows glucose absorption
Reduces post-meal blood sugar spikes
Improves insulin sensitivity
A practical baseline target for fibre is 14 g of fibre per 1,000 calories consumed.
For many people, increasing fibre from food is enough - through vegetables, whole grain, fruits and sees.. If intake is low or it’s hard to meet needs consistently, a fibre supplement can be a useful add-on, especially when taken before meals. Fibre supplements should be increased gradually and paired with adequate fluid to reduce digestive discomfort.
Fibre is the most practical “first-line” supplement strategy for blood sugar regulation. Start by improving fibre from food, and consider supplement support if you’re not consistently meeting your needs.
Fenugreek
Fenugreek is a fibre-rich seed with compounds that may support glycemic control. In meta-analyses, it has been associated with improvements in fasting blood sugar and HbA1c, though individual response varies.
Research dosing overview:
Fenugreek has been tested in both extract and powder forms across a broad range of doses (including 500 to 2,000 mg/day for extracts and 5,000 to 20,000 mg/day for powders). Digestive side effects have been reported, particularly as amounts increase.
Key takeaway, Fenugreek: Fenugreek is a fibre-rich, food-adjacent supplement with evidence for improving fasting and post-meal blood sugar and HbA1c in type 2 diabetes, but it’s not appropriate for everyone and needs a safety check for pregnancy, allergies, and medication-related low blood sugar risk.
Probiotics
Probiotics are live microorganisms. When taken orally in adequate doses, they can influence the composition and function of the gut microbiota in ways that affect health.
How probiotics improve blood sugar markers
The main proposed pathways are gut-driven and metabolic:
More short-chain fatty acids (SCFAs): these are metabolic byproducts of bacterial fermentation that may influence glucose metabolism.
Better intestinal barrier function: supporting the gut barrier may reduce metabolic stress signals.
Lower inflammation: chronic inflammation is tied to insulin resistance, and shifting gut activity may reduce inflammatory signalling.
Improved incretin secretion: incretins help regulate insulin response after meals, so changes here can influence post-meal blood sugar handling.
What the evidence shows
Meta-analyses of randomized controlled trials report mixed results: some find improvements in fasting glucose, HbA1c, insulin sensitivity, and insulin concentrations, while others find limited or inconsistent effects. Overall, the evidence supports probiotics as a glucose management in people with moderately to severely impaired glucose metabolism, with moderate reductions in fasting glucose reported (about 5% to 9%).
Research dosing overview:
A common research-based approach is a multi-strain probiotic that includes Lactobacillus and Bifidobacterium, around 40 billion CFU daily, taken for 8 to 12 weeks.
Key takeaway: Probiotics can be worth a structured trial, but strain and dosing matter, and they are not a substitute for fibre and diet strategy.
Second-line Supplements for Blood Sugar Control
These supplements can still support blood sugar regulation, but they’re not the first place to start. Compared with the top-tier options, they tend to have a smaller average impact, more variability between studies, or less clarity on the most effective form and dose. In other words, there’s signal, but not as much certainty or “bang for your buck.”
Berberine
You may have heard berberine touted as “nature’s Ozempic.” That comparison is mostly internet hype. Where berberine actually has its strongest impact is blood sugar, and in some people (including those with type 2 diabetes), it can improve markers of fasting blood sugar and HbA1c, with effects influenced by dose and context.
Research dosing overview:
In studies, berberine is typically taken in divided doses with meals, and total daily amounts vary. Higher totals tend to show stronger effects up to around 1.5 g/day, but GI tolerance is often the limiting factor for what people can stick with.
Cautions:
If you take diabetes medications, risk of low blood sugar needs to be assessed. It has a higher interaction burden (drug metabolism pathways and additive glucose lowering with medications), and results vary depending on dose, age, and medication context.
Key takeaway: Berberine can be a helpful tool for blood sugar regulation, but it’s best used intentionally and monitored, especially if medications are in the mix.
Magnesium
You’ll often see magnesium come up in blood sugar conversations. This is becuase magnesium plays a role in blood sugar metabolism and may help regulate inflammation, which can support insulin sensitivity. It tends to be most relevant when magnesium status is low, which may be more common in those with type 2 diabetes.
Research dosing overview:
Research uses different forms and amounts, but the practical limiter is usually digestion. Higher supplemental magnesium increases the chance of diarrhea, and adults should not exceed 350 mg/day from supplements. Forms often used include magnesium citrate, gluconate, and glycinate. Magnesium oxide is a common one on shelves, but it has poor bioavailability and is more likely to cause GI side effects.
Cautions:
Because magnesium can impair absorption of certain medications (including some antibiotics), spacing doses can matter (example: separate by at least 6 hours for some classes).
Key takeaway: Magnesium is most worth considering when levels are low. It can modestly improve insulin sensitivity and fasting blood sugar in that context.
Cinnamon
Some of cinnamon’s compounds are linked with increased insulin production, while others may improve insulin sensitivity, meaning cells respond more readily to insulin. It may also modestly reduce post-meal blood sugar spikes when taken with carbohydrates in people with normal blood sugar, especially in studies using higher doses at a single meal.
Research dosing overview:
Cinnamon can be used as a powder mixed into food or taken in capsule form. Lower daily amounts (under 2 g/day) tend to show less reliable effects in studies.
Cinnamon teas and infusions are harder to dose, and there isn’t enough evidence to know how these preparations affect the compounds responsible for cinnamon’s blood sugar effects.
Cautions:
Cassia cinnamon is high in coumarin, which can be hard on the liver. The coumarin content varies widely between products, and some people are more sensitive than others. People with liver disease or liver damage, a liver transplant history, or those taking medications that stress the liver should avoid cassia cinnamon supplementation.
Key takeaway: Cinnamon may offer a small benefit for some people, but it’s not predictable and it’s not risk-free in supplement form, especially if you are using cassia cinnamon.
Zinc
Similar to magnesium, zinc is most likely to be helpful when zinc stores are actually low. People with type 2 diabetes or insulin resistance may be more likely to have low blood zinc levels, and low zinc can worsen insulin resistance through zinc’s role in insulin secretion and blood sugar metabolism.
Research dosing overview:
In people with type 2 diabetes or prediabetes, trials suggest zinc can improve insulin sensitivity and in turn lower fasting blood sugar and HbA1c, but results are mixed. One reason is that zinc supplementation is most likely to help if zinc status is low to begin with, and if it’s taken long enough to meaningfully improve zinc status.
Key takeaway: Zinc can be helpful, but mostly when zinc levels are low. If you are not zinc-deficient, it’s less likely to move the needle.
Inositol
Inositol is one of the more targeted options, and it’s a good example of why “right supplement, right situation” matters. In PCOS, myo-inositol can reduce insulin resistance and fasting insulin.
Insulin resistance can lower inositol levels, and lower inositol can reduce a cell-membrane component (PIP3) that supports insulin signalling. In simple terms, if the signalling system is underpowered, blood sugar regulation can suffer, and inositol may help improve that signalling in PCOS.
Research dosing overview:
Myo-inositol is the most extensively researched form for PCOS. Some research has also looked at combining myo-inositol with a smaller amount of D-chiro-inositol, with the possibility of faster short-term changes, though differences may level out over time.
Key takeaway: Inositol is one of the better “condition-specific” tools for PCOS when insulin resistance is part of the picture.
Key takeaways: Supplements for Blood Sugar Control
Supplements are just one piece of the puzzle. You cannot out supplement poor blood sugar control.
The fundamentals still matter most: a balanced diet, adequate fibre intake, regular physical activity, and weight management (when relevant). When those foundations are in place, supplements may play a supportive role for some people, depending on your labs, medications, health history, and how your body responds.
If you want a plan that is tailored to you, book a session with one of our dietitians today. We will help you build a realistic blood sugar strategy and, if appropriate, a personalized supplement protocol for high blood sugar.
Disclaimer: This article is for educational purposes only and does not replace individualized medical or dietetic advice. Always consult a healthcare provider before starting new supplements.