How Long Will Steroids Affect Blood Sugar?
For most people with type 2 diabetes receiving a single steroid injection (such as triamcinolone 20–40 mg or methylprednisolone 40 mg), blood sugar typically rises within hours and peaks during the first 24 hours, then often improves substantially within 48–72 hours, though some individuals may experience elevated readings for several days. In some people, the peak can occur later (24–72 hours after injection), and elevations may persist longer. With short oral steroid courses like prednisolone 20–40 mg daily for 5–7 days, glucose levels stay elevated throughout treatment and for roughly a few days (commonly 1–3 days) after the last dose. Long-term steroid treatment lasting weeks to months can affect blood sugar for the entire duration—and in some high-risk individuals, may unmask or trigger permanent type 2 diabetes.
Your baseline glucose control matters significantly. People with HbA1c above 7–7.5% tend to experience larger spikes, and in some cases more prolonged elevations, compared to those with well-controlled diabetes.
After you stop taking steroids, blood sugar levels may return to normal, but the timeline can vary depending on the type and duration of steroid use.
Typical duration after a single injection:
Blood sugar begins rising within 4–8 hours
Peak elevation most commonly occurs on day 1
Returns toward baseline by day 2–3 in many cases, though individual responses vary and some people experience longer effects
In many cases, blood sugar levels improve after stopping steroids, especially with proper monitoring and management.
Typical duration after oral steroids:
Elevated throughout the course of treatment
Continues for several days (often 1–3 days) after the final dose
Longer courses, higher doses, or long-acting steroids may cause more persistent effects
Blood sugar levels often return toward baseline within a few days after stopping short-acting oral steroids, though in some cases elevations may persist longer, particularly after injections or prolonged therapy.
Frequent blood sugar monitoring may be recommended, especially for individuals with diabetes or higher risk, based on clinician guidance.
What are steroids and why do they affect blood sugar?
When doctors prescribe steroids for inflammation, they’re referring to corticosteroids—medications like prednisone, dexamethasone, triamcinolone, and methylprednisolone. These are entirely different from anabolic steroids used for bodybuilding. Glucocorticoids work by mimicking cortisol, a hormone your adrenal glands produce naturally during stress. Steroids are synthetic versions of natural hormones, designed to regulate the body’s inflammatory and immune responses for therapeutic purposes.
Corticosteroids are incredibly effective at reducing inflammation, which is why they’re commonly prescribed for asthma flares and COPD exacerbations, rheumatoid arthritis and other autoimmune conditions, frozen shoulder, joint pain, and tendinitis, spinal nerve pain and sciatica, inflammatory bowel disease (Crohn’s, ulcerative colitis), and skin conditions like eczema and psoriasis.
Common steroid names you might encounter include prednisone or prednisolone (oral tablets), dexamethasone (oral, IV, or injection), methylprednisolone (oral, IV, or injection), triamcinolone acetonide (joint injections), and hydrocortisone (IV or topical). These medications can influence blood sugar levels and require careful management, especially for people with diabetes or those at risk.
Here’s why these medications increase your blood sugar: steroids block insulin action in your muscle and fat tissue, making it harder for glucose to enter cells where it’s needed for energy. At the same time, they signal your liver to release more glucose into your bloodstream through a process called gluconeogenesis. This dual mechanism creates insulin resistance throughout your body. Hydrocortisone, a short-acting steroid, typically has effects lasting around 6 hours.
Any route of administration—whether oral tablets, injections into joints or spine, or high-dose IV in hospital—can have systemic effects on blood glucose levels, especially in diabetic patients or those with prediabetes.
Signs and symptoms of steroid-induced high blood sugar
If you're taking prescribed steroids, you might develop high blood sugar levels—a condition called steroid-induced hyperglycemia. This happens to many people, especially if you already have diabetes or are at higher risk for developing it. When your blood glucose rises because of steroid treatment, your body will often give you warning signs.
Recognizing these symptoms early can help you take control of your blood sugar and avoid serious complications.
You might notice several common signs when your blood sugar gets too high from steroids. These include feeling much thirstier than usual, needing to urinate more often, experiencing unusual hunger, having blurred vision, and feeling very tired. Sometimes you might also lose weight without trying.
You may also find that cuts and scrapes heal more slowly than normal, or you might get infections more easily. Here's something important to remember: not everyone experiences obvious symptoms, even when their blood glucose is dangerously high. This is why checking your blood sugar regularly becomes so crucial, especially if you have diabetes or risk factors like being overweight, having family members with diabetes, or dealing with chronic kidney disease.
If you don't address high blood sugar from steroids, you could face serious complications. The most dangerous is diabetic ketoacidosis—a life-threatening condition where your body produces too many blood acids called ketones.
This risk is highest if you have type 1 or type 2 diabetes, but it can also happen if you develop diabetes for the first time while taking steroids.
Several factors can increase your chances of developing steroid-related blood sugar problems. Higher steroid doses and longer treatment periods both raise your risk. If you already have insulin resistance or health conditions like high blood pressure or chronic kidney disease, you're more vulnerable.
The specific type of steroid you're taking (like dexamethasone or prednisone), how you receive it (by mouth, injection, or IV), and your unique health situation all influence how your body responds.
Managing your blood sugar while on steroids starts with regular monitoring—ideally with guidance from your doctor or diabetes educator. You might need to check your glucose several times each day, especially when you first start steroids or when your dose changes.
If you notice high blood sugar symptoms or your readings consistently stay above your target range, contact your healthcare provider right away. They may adjust your diabetes management plan, change your insulin doses, add rapid-acting insulin, or suggest other treatment options.
Making smart lifestyle choices can significantly help your situation. Eating balanced meals, staying physically active, and maintaining a healthy weight can improve how well your body uses insulin and reduce steroids' impact on your blood sugar.
If you're already using insulin therapy or other diabetes medications, your doctor may need to temporarily adjust your treatment plan while you're on steroids.
Remember, you can successfully manage steroid-induced high blood sugar with the right approach. By staying alert to symptoms, monitoring your blood glucose levels, and working closely with your healthcare team, you can reduce your risk of complications and ensure your steroid treatment remains both safe and effective.
If you're looking for convenient ways to track your health markers at home, at-home urine test kits like those from Ribbon Checkup can provide valuable insights into your kidney function, hydration, and more—helping you stay proactive about your health during and after steroid therapy.
How long do different types of steroid treatments affect blood sugar?
The duration of blood sugar elevation depends heavily on which steroid you’re taking, the dose, and how it’s administered.
Oral prednisolone and dexamethasone
When you take prednisolone in the morning (the most common timing), blood sugar tends to rise throughout the day, peaking around lunchtime to late afternoon. This pattern means your highest readings often occur in the afternoon and evening hours.
Dexamethasone has a longer half-life than prednisolone. A single oral dose can affect your blood glucose for at least 24 hours and sometimes longer, which is why some people notice elevated readings even the following morning.
For a typical 5-day “steroid burst” used to treat asthma flares or severe inflammation, expect blood sugar to remain elevated throughout the course. Most people see readings start improving within a few days after taking steroids for the last time.
Local joint and spine injections
Even though these injections target a specific area, the steroid does enter your bloodstream and affects your whole body.
Shoulder or knee injections with triamcinolone 20–40 mg or methylprednisolone 40 mg typically cause noticeable blood sugar rises beginning 4–8 hours after the procedure. Research shows blood glucose often increases most dramatically on day 1, then improves over the following 2–3 days in many patients, though some experience elevations lasting several days.
Epidural injections for back pain may use corticosteroids such as dexamethasone or triamcinolone. They follow a similar pattern—the strongest effect commonly occurs on day 1, with improvement over the following 48–72 hours, though individual responses vary.
IV (drip) steroids in hospital
When high doses of methylprednisolone or dexamethasone are administered intravenously for conditions like severe asthma, COVID-19, or inflammatory eye disease, blood sugar can remain high throughout the entire IV treatment period and for 24–48 hours afterwards.
Hospital staff typically monitor glucose before meals and at bedtime during this treatment. Many patients require temporary insulin therapy even if they don’t normally use insulin at home.
Inhaled and topical steroids
Typical inhaled doses for asthma control and standard skin creams rarely cause significant blood sugar problems. However, high doses or prolonged use can contribute to elevated glucose levels in very sensitive individuals or those already at higher risk for diabetes.
Important: Even “local” injections into your shoulder, knee, or spine can cause whole-body effects on blood sugar. Don’t assume that because the injection site is far from your pancreas, your glucose won’t be affected.
Evidence from studies: what happens to blood sugar after a steroid injection?
Several research studies have tracked fasting blood sugar before and after steroid injections in people with type 2 diabetes. While these studies are relatively small, they paint a consistent but variable picture.
Fasting blood sugar often rises significantly on day 1, with average increases commonly reported in the range of ~50–100 mg/dL, though individual peaks can be much higher.
By day 2, average values in many studies fall back toward baseline, with some analyses no longer showing a statistically significant difference—however, not all individuals return to baseline this quickly, particularly those with higher baseline HbA1c or insulin dependence.
In published studies (largely involving people with type 2 diabetes), severe complications like diabetic ketoacidosis were rare.
Blood sugar levels often return toward baseline faster than many patients expect, though responses vary.
What factors change how long steroids affect blood sugar?
Not everyone’s blood sugar responds identically to steroids.
Baseline HbA1c is one of the strongest predictors. People with HbA1c above 7% tend to see larger increases after steroid exposure. Some studies also suggest these individuals may experience more sustained elevations, particularly with longer or repeated steroid use. A minority of patients may also show a measurable rise in HbA1c after large-joint steroid injections.
Duration and type of diabetes, existing insulin use, other health conditions, steroid dose, potency, half-life, route, and timing all influence the magnitude and duration of blood sugar elevation.
Will steroid-induced diabetes go away once steroids stop?
Steroid-induced diabetes refers to new-onset diabetes first detected while taking corticosteroids in someone without previously known diabetes. In many cases, blood sugar returns to normal or near normal within days to weeks after steroids are reduced or discontinued.
As blood sugar levels normalize after stopping steroids, it is important to monitor for hypoglycemia, especially if insulin or sulfonylurea doses were increased during steroid treatment.
However, in people with underlying risk factors—such as obesity, family history of diabetes, prediabetes, or prior gestational diabetes—steroids may unmask diabetes that persists even after treatment ends.
Follow-up testing with fasting glucose or HbA1c after steroid therapy is important to confirm whether glucose regulation has fully recovered. Monitoring thresholds and treatment adjustments should follow your clinician’s specific guidance.
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