How Long Will a Steroid Injection Affect Blood Sugar?

A steroid injection typically raises blood sugar for one to three days, with the sharpest spike on the first day after the shot. In people with well-controlled diabetes, levels often drift back toward normal within about two days, while those with poorly controlled diabetes can see elevations lingering closer to a week. The range depends on the type of steroid used, where it was injected, and how well your blood sugar was managed before the procedure.

The Day-by-Day Timeline

The most consistent finding across studies is that day one after the injection is when blood sugar peaks. In a study of diabetic patients receiving musculoskeletal steroid injections, blood glucose was significantly elevated one day after the shot but had already returned to baseline by day two in many participants.¹ A separate study tracking fasting blood glucose after hand and wrist injections found a more drawn-out pattern: a large jump on day one (an average increase of about 43 mg/dL), a smaller but still meaningful rise on day two (around 17 mg/dL), a borderline bump on day three, and a return to baseline somewhere between days four and seven.²

So the honest answer is a range: most people see the worst of it in the first 24 to 48 hours, with a tail that fades over the next few days. If your diabetes is tightly managed, the disruption tends to be shorter and smaller. If your blood sugar runs high to begin with, expect a bigger spike that takes longer to settle, sometimes staying elevated through the first week after the injection.

Who Gets Hit Harder

Your baseline blood sugar control before the injection is the single best predictor of how much trouble the steroid will cause. People whose hemoglobin A1c was above 7% before the shot experienced significantly larger blood glucose spikes on the first day compared to those with an A1c at or below 7%.¹ The relationship was dose-dependent in a meaningful way: the higher your A1c going in, the steeper the glucose climb afterward.

A study of shoulder injections put specific numbers on this. Patients with A1c below 7% saw an average blood sugar rise of about 38 mg/dL, while those with poorly controlled diabetes saw their levels jump by roughly 98 mg/dL on average. Well-controlled patients returned to near-baseline levels around day eight, while the poorly controlled group’s levels remained elevated beyond that point.³ That is a substantial difference, more than double the spike and a notably longer recovery.

Whether you use insulin also matters. Insulin-dependent patients in that same study had an average increase of about 99 mg/dL compared to 50 mg/dL in those managing their diabetes without insulin.³ This probably reflects the fact that insulin-dependent patients tend to have more advanced or harder-to-control diabetes, not that insulin itself worsens the response. The takeaway is straightforward: the less stable your blood sugar is before the injection, the bigger and longer the disruption you should prepare for.

Joint Injections vs. Epidurals

Where the steroid goes changes the picture. A joint injection delivers the drug into a relatively contained space, where it is absorbed more slowly. Epidural injections, which place the steroid near the spinal cord to treat back or nerve pain, tend to cause larger and sometimes longer blood sugar swings because the steroid reaches the bloodstream more quickly and in larger effective doses.

A review of the evidence found that following intra-articular injections, the timing of peak blood sugar increase was highly variable, ranging from 48 hours to seven days, though the most common window was 24 to 72 hours. Epidural injections painted a more dramatic picture. In one tracked group of patients with diabetes who received lumbosacral or caudal epidural injections with betamethasone, blood sugar peaked the day after the injection at roughly 236 mg/dL on average and remained significantly elevated through the second day. Levels stayed above normal for three days in total.⁴ Another group of patients who received epidural triamcinolone showed significant fasting glucose increases on both day one and day two, regardless of whether they had diabetes going in.

This distinction matters practically. If you are weighing a cortisone shot in a knee or shoulder, the blood sugar disruption is real but usually moderate and brief. If you are considering an epidural steroid injection for back pain, plan for a potentially larger and slightly longer spike, and discuss monitoring with your doctor ahead of time.

Different Steroids Behave Differently

Not all corticosteroids are the same drug, and they do not all affect blood sugar on the same schedule. A study using continuous glucose monitors found that dexamethasone produced a predictable, reproducible spike, methylprednisolone caused a more delayed rise, and triamcinolone showed inconsistent and variable effects across patients.⁵ This makes sense pharmacologically: these steroids differ in how long they stay active in the body. Dexamethasone is relatively short-acting but potent, methylprednisolone is intermediate, and triamcinolone is a depot steroid designed to release slowly over days to weeks.

The frustrating reality is that while clinicians know these differences exist, there are no good-quality head-to-head studies comparing the blood sugar effects of different corticosteroids or different doses when injected into joints.⁶ Reports of hyperglycemia have appeared with methylprednisolone, triamcinolone, betamethasone, and celestone, so no particular formulation appears to be “safe” from a blood sugar perspective. Still, the pattern differences are real enough that your doctor may have a preference for one steroid over another depending on your diabetes status. If blood sugar management is a primary concern, it is worth asking which steroid they plan to use and why.

One practical wrinkle: the injection site did not significantly affect the degree of blood sugar increase in at least one study, and neither did the steroid dose within the ranges typically used for musculoskeletal injections.¹ That finding ran counter to what many clinicians would expect, and it deserves more study with larger groups. But at face value, it suggests that the choice of steroid and your own metabolic state matter more than the specific joint being injected or minor dose adjustments.

Monitoring After the Shot

If you have diabetes, checking your blood sugar more frequently for at least the first two to three days after a steroid injection is the most widely recommended precaution. Professional guidelines from groups like the European Alliance of Associations for Rheumatology and the American Academy of Family Physicians recommend that patients with diabetes be told about the risk of temporary hyperglycemia and be advised to monitor their glucose for the next 72 hours.⁴

Continuous glucose monitors have proven particularly useful in this context. Unlike finger-stick checks that only show you a snapshot, a CGM captures the full arc of a blood sugar excursion, including overnight highs you might otherwise sleep through. One study called the first 48 to 72 hours the “clinically reliable monitoring window” for steroid-induced blood sugar changes, meaning that is the period where the most actionable data shows up.⁵ Another study of patients receiving eye-area steroid injections for diabetic macular edema echoed this, finding that CGM captured detailed trends that intermittent finger sticks would miss entirely.⁷

If you do not use a CGM, checking your fasting blood sugar every morning for about five days after the injection, plus a couple of readings in the afternoon or evening on the first two days, gives you a reasonable picture. The afternoon and evening checks are especially important because steroid-driven blood sugar spikes tend to be worse later in the day, when the steroid’s metabolic effects layer on top of the natural afternoon rise in insulin resistance that many people with diabetes already experience.

Pre-Injection Guidelines and When to Postpone

There is no universally accepted blood sugar threshold above which a steroid injection is considered off-limits. No major professional society has drawn a hard line.⁴ What does exist is expert consensus around a few guardrails. The American Diabetes Association recommends a blood glucose goal of 100 to 180 mg/dL within four hours of surgery and an A1c goal below 8% for elective procedures. While a steroid injection is not surgery, those benchmarks offer a useful reference point.

In practice, many clinicians will check a blood glucose level before the injection in patients with poorly controlled diabetes, defined roughly as an A1c above 8% or a fasting glucose above 130 mg/dL. If your glucose is above 180 mg/dL at that pre-procedure check, postponing the injection is a reasonable option to discuss. This is not a mandate; it is shared decision-making. A patient in severe pain with a blood sugar of 200 mg/dL may reasonably decide, with their doctor, that the injection is still worth the temporary spike. A patient whose injection is more elective might choose to get their blood sugar under better control first.

If you are planning a steroid injection and you have diabetes, bring it up proactively. Ask whether your most recent A1c and fasting glucose make you a candidate for extra monitoring, and discuss what to do with your diabetes medications during the post-injection window. Some patients on insulin may need a temporary dose adjustment for a few days. This conversation is worth having before you are on the procedure table, not after.

Medication Adjustments During the Spike

For people on insulin, the post-injection blood sugar spike may require a short-term increase in insulin dosing. This is most relevant for patients on oral steroids or high-dose IV steroids in a hospital setting, where researchers have studied the relationship between insulin dose and steroid dose in detail. One hospital-based study found that the optimal total insulin-to-steroid ratio varied depending on the steroid dose, with lower-dose steroid regimens requiring proportionally more insulin per unit of steroid to achieve glucose control.⁸ That study also found that pushing insulin higher improved glucose control but increased the risk of low blood sugar, a tradeoff that underscores why self-adjusting insulin doses without medical guidance can be risky.

For a one-time joint injection, the insulin adjustment is usually modest and temporary, perhaps an extra few units of rapid-acting insulin with meals for a day or two. But the specifics depend on your personal insulin sensitivity, the steroid used, and your baseline control. There is no generic formula you can safely follow from an article on the internet. Talk to the doctor who manages your diabetes before the injection and have a concrete plan: how much extra insulin should you take, at what glucose reading should you take it, and when should you call the office if things are not settling.

For people managing type 2 diabetes with oral medications only, adjustments are less commonly needed after a single injection. The spike is usually smaller and resolves faster. But if your blood sugar runs above 250 to 300 mg/dL at any point, or if you feel unusually thirsty, are urinating much more than normal, or feel nauseous, contact your healthcare provider rather than waiting it out.

Rare but Serious Complications

Steroid-induced blood sugar spikes after a joint injection are common, temporary, and almost always manageable. Genuine emergencies are rare. But they do happen. A published case report describes a patient with type 1 diabetes who developed diabetic ketoacidosis after an intra-articular steroid injection, a dangerous metabolic crisis that required hospitalization.⁹ The authors noted that while this complication is rare, or possibly underreported, it stands to reason that any patient with diabetes is at some risk when a steroid pushes blood sugar high enough for long enough.

Type 1 diabetes carries a higher risk of ketoacidosis than type 2 because of the absence of endogenous insulin production. If you have type 1 diabetes and receive a steroid injection, monitoring is not optional, it is essential. Watch for warning signs: nausea, vomiting, abdominal pain, fruity-smelling breath, or blood sugars that remain stubbornly above 300 mg/dL despite correction doses. If any of those appear, seek emergency care rather than waiting for the spike to pass on its own.

What About People Without Diabetes

Steroid injections can raise blood sugar even in people who do not have diabetes, though the effect tends to be smaller and clears faster. In a study that included both diabetic and non-diabetic subjects receiving epidural triamcinolone, fasting glucose rose significantly in all participants on the first two days after injection.⁴ For most non-diabetic people, the pancreas ramps up insulin production to compensate, and the elevation is mild and self-correcting. You may not even notice it without testing.

The more interesting question is whether steroid injections can unmask previously undiagnosed diabetes or prediabetes. If you receive a steroid injection and subsequently notice extreme thirst, frequent urination, or unusual fatigue lasting more than a few days, it might be worth getting your fasting glucose or A1c checked. The steroid did not cause diabetes, but it may have briefly overwhelmed a glucose regulation system that was already running near capacity.

Steroid-Free Alternatives for People Concerned About Blood Sugar

If repeated steroid injections are part of your pain management routine and blood sugar disruption is a recurring problem, alternatives exist. Platelet-rich plasma injections, for example, have been explored for conditions like adhesive capsulitis (frozen shoulder) in patients with diabetes, partly because patients themselves express concern about the blood sugar side effects of corticosteroid shots.¹⁰ PRP does not contain corticosteroids and would not be expected to cause the same metabolic disruption, though its effectiveness varies by condition and the evidence base is still growing.

Hyaluronic acid injections for knee osteoarthritis, physical therapy, targeted exercise programs, and non-steroidal anti-inflammatory drugs are other options that avoid the blood sugar issue entirely. None of these is a perfect substitute for a steroid injection in every scenario. Corticosteroids are sometimes the best tool for the job, and a temporary blood sugar spike managed with monitoring and a short-term medication adjustment is a reasonable price to pay for significant pain relief. But if you are getting steroid injections several times a year and wrestling with glucose control each time, asking your doctor about alternatives is a conversation worth having.