Ashwagandha can lower blood sugar, which means it’s not inherently dangerous for people with diabetes, but it does carry a real risk of pushing blood sugar too low if you’re already on diabetes medication. The core concern isn’t the supplement itself. It’s the additive effect when combined with drugs like metformin or insulin.
How Ashwagandha Affects Blood Sugar
Ashwagandha lowers blood glucose through several pathways at once. Its active compounds improve how muscle and fat cells absorb glucose from the bloodstream, enhance insulin signaling, and protect the insulin-producing cells in the pancreas from inflammatory damage. Some compounds in ashwagandha also slow down the enzymes that break down carbohydrates during digestion, which blunts the blood sugar spike after meals.
There’s also an indirect route. Ashwagandha is best known as a stress-relief supplement, and it works partly by dampening the body’s cortisol response. Cortisol raises blood sugar. When cortisol drops, blood sugar tends to follow. For someone with diabetes who also deals with chronic stress, this dual action could be genuinely helpful, or it could compound the glucose-lowering effect of their medication in ways that are hard to predict.
What the Clinical Evidence Shows
In one clinical trial of 55 people with type 2 diabetes, the group taking ashwagandha saw their fasting blood sugar drop from about 167 mg/dL to 130 mg/dL, and their HbA1c (a measure of average blood sugar over three months) fell from 7.85% to 6.8%. The control group also improved, but less dramatically: fasting sugar went from 165 to 136, and HbA1c from 7.73% to 7.01%. Those are meaningful differences, especially the HbA1c reduction, which moved the ashwagandha group closer to normal range.
That said, the NIH’s National Center for Complementary and Integrative Health states plainly that there isn’t enough evidence to confirm ashwagandha is helpful for diabetes. The existing studies are small, and results have been inconsistent. Some trials show clear blood sugar reductions, while others don’t. The effects also take time to appear, typically requiring several months of daily supplementation before any measurable change shows up in blood work.
The Drug Interaction Risk
This is the part that matters most if you’re on medication. Taking ashwagandha alongside metformin or insulin can have additive effects on blood sugar, meaning both are pushing your levels down at the same time. That increases the risk of hypoglycemia, which can cause headaches, dizziness, confusion, tremors, sweating, and rapid heartbeat. In more serious cases, it can lead to loss of consciousness.
The interaction isn’t theoretical. Drug interaction databases flag ashwagandha with both metformin and insulin, recommending more frequent blood sugar monitoring if they’re used together. The unpredictable part is that ashwagandha’s blood sugar effects vary from person to person and take weeks to build, so you might not notice the interaction immediately. It could creep up gradually as the supplement accumulates its effects.
If you take diabetes medication and want to try ashwagandha, more frequent glucose checks are essential, particularly in the first few months. Watch for the classic signs of low blood sugar: sudden hunger, shakiness, sweating, or feeling foggy. These symptoms can be easy to dismiss as stress or fatigue if you’re not looking for them.
Type 1 vs. Type 2 Diabetes
Nearly all of the research on ashwagandha and diabetes has been conducted in people with type 2 diabetes. There is essentially no clinical safety data specific to type 1 diabetes. Because type 1 diabetes involves complete dependence on external insulin, and because insulin dosing is already a careful balancing act, adding a supplement that independently lowers blood sugar introduces an extra variable that’s difficult to account for. The risk of unexpected hypoglycemia is higher in this population.
Thyroid Effects Worth Knowing About
Ashwagandha can stimulate thyroid hormone production, which is relevant because thyroid disorders and diabetes frequently overlap. If you have both conditions, or if you take thyroid medication, ashwagandha could shift your thyroid levels in ways that complicate your overall hormone balance. Changes in thyroid function can, in turn, affect blood sugar control and metabolism, creating a chain of adjustments that’s hard to manage without close monitoring.
Practical Considerations
Experts generally recommend limiting ashwagandha use to three months or less, partly because long-term safety data doesn’t exist yet. Prolonged use has been associated with suppression of the body’s stress hormone system, which can cause its own set of problems including fatigue and hormonal imbalance.
If you’re not on any diabetes medication, the blood sugar lowering effect of ashwagandha is modest enough that it’s unlikely to cause problems on its own. The real risk concentrates in people who are already managing their glucose with drugs. For those individuals, the supplement doesn’t replace medication, and it introduces unpredictability into a system that works best when it’s tightly controlled. More frequent blood sugar checks, especially in the first 8 to 12 weeks, are the minimum precaution worth taking.