Signs and symptoms of diabetes (type 1 and 2)

Over the past 35 years the number of people with diabetes worldwide has increased four-fold and currently stands at more than 400 million, according to the World Health Organization (WHO). What’s more, millions are unaware that they have diabetes or its precursor, prediabetes.1

Could you have diabetes? It’s a disease with many early symptoms; although some are subtle, others are hard to ignore. Read on to learn about the most common symptoms of diabetes and what you can do if you have them.

1. What is diabetes?

Diabetes is a chronic disease characterized by high levels of sugar (glucose) in the bloodstream. Although it can take several forms, type 1 and type 2 are by far the most common.

  • In type 1 diabetes, pancreatic cells that produce the hormone insulin are destroyed as the result of an autoimmune process. Therefore, people with type 1 diabetes can no longer produce insulin on their own and must inject insulin in order to survive.
  • In type 2 diabetes, the pancreas still produces insulin, initially often even more than normal, but the body doesn’t use it effectively. Over time, the pancreas may lose its ability to make enough insulin to maintain normal blood sugar. Type 2 diabetes is also called non-insulin-dependent diabetes because people with this form of the disease continue to produce insulin.

A related and very important condition is prediabetes, in which blood sugar is higher than normal but not high enough to be classified as diabetes. Additionally, both fasting and post-meal insulin levels are usually elevated.

Over time, prediabetes may progress to type 2 diabetes; however, it carries some of the same health risks of diabetes, even if blood sugar remains in the prediabetes range.2 Additionally, it usually does not have the same constellation of symptoms from elevated blood sugars, but some of the more subtle symptoms may present even in prediabetes.

2. Symptoms of diabetes

These are some of the most common symptoms of diabetes. You may have one, two, or several of them — or you may have none. Please remember, an absence of symptoms does not mean an absence of diabetes. However, being alert to potential symptoms may help make the diagnosis much earlier and thus prevent potential long term complications

Increased thirst and urination

Starch structureHave you been feeling very thirsty or running to the bathroom more often lately? Frequent urination coupled with a near-constant sensation of thirst are well-known signs of diabetes.

When blood sugar is too high, water is pulled from your bloodstream and organs to help your kidneys flush out the excess glucose. The sugary urine smells sweet – and even tastes sweet. In fact, although it’s rather unsettling to think about, tasting patients’ urine helped doctors identify diabetes before blood tests and glucose meters were available. Because so much water is leaving your body, the brain triggers your thirst mechanism in order to ensure that you drink enough to replace what is being lost.

Excessive thirst and urination is more common in type 1 diabetes when blood sugar levels are very high but may also occur late in type 2 diabetes.3 In a study of over 1,100 people recently diagnosed with type 2 diabetes, more than half reported increased urination, and nearly two-thirds reported being abnormally thirsty.4

Severe fatigue

Although there are hundreds of conditions that can cause fatigue, it’s a symptom that often accompanies diabetes. In undiagnosed diabetes, fatigue can be quite pronounced; you may feel so tired that you can barely keep going during the day, despite getting plenty of sleep.

Why does diabetes make you feel tired? One theory is because glucose — one of your body’s major fuel sources — is accumulating in your bloodstream rather than getting into your cells.

The pancreas produces the hormone insulin, which allows glucose to enter your cells. When your body doesn’t produce insulin or your cells are resistant to its effects, glucose remains in the blood. As a result, you may feel tired and weak because your cells are deprived of the fuel they need.5

Studies confirm that many people with newly diagnosed diabetes report fatigue as one of their main symptoms.6

Feeling hungrier than usual

It’s normal for your appetite to vary somewhat based on activity, sleep, mood, and dozens of other factors. However, if you’ve recently been much hungrier than usual, diabetes could be the reason. Along with frequent urination (polyuria) and thirst (polydipsia), severe hunger (polyphagia) is one of the “Three P’s” considered to be classic symptoms of diabetes.

Increased hunger is related to another diabetes symptom, fatigue. Your body breaks down carbohydrates into sugar (glucose) to be used as energy. But if glucose can’t get into your cells due to a lack of insulin or insulin resistance, your body may perceive this as starvation. Therefore, you become hungrier and more tired than ever — even if you’re eating as much or more than usual.

Unfortunately, eating more food usually doesn’t satisfy this hunger. What’s more, reaching for carbohydrate-rich foods (including fruit, legumes, and whole grains) will cause blood sugar to increase even further.7 This is because starchy carbohydrates like cereals, potatoes or bread are made up of lots of glucose molecules joined together. The process of digestion breaks these starches back down into glucose which when absorbed puts our blood glucose up by surprisingly large amounts.8

Although it can occur in type 2 diabetes, a significant increase in hunger is especially common in type 1 diabetes.9

Unexplained weight loss

Starch structureLosing weight as a result of making diet and other lifestyle changes is a welcome and expected outcome. However, if it happens when you haven’t changed what or how much you eat, something is amiss. Everyone experiences small weight fluctuations from day to day, but if you’ve lost 10 pounds (5 kg) or more without trying, diabetes may be the cause.

In addition to allowing glucose to enter your cells, insulin helps prevent muscle and fat breakdown. If you have diabetes, your pancreas isn’t making sufficient insulin or your cells aren’t using the insulin properly. Therefore, your body begins to break down fat and muscle, leading to weight loss. This typically happens in type 1 diabetes. Although weight loss is usually considered a rare and very late sign in type 2 diabetes, there are indications that some populations may exhibit weight loss in conjunction with type 2 diabetes more often than others.10

Unexplained weight loss is more common in people with type 1 diabetes — including children and lean adults who can’t afford to lose weight — but may also occur in people with type 2 diabetes. In one study, slightly more than one-third of people newly diagnosed with type 2 diabetes reported that they had recently lost weight unintentionally.11

Delayed healing of injuries

Have you noticed that cuts, scrapes, or other injuries have been taking longer to heal than usual? This may be a warning sign of diabetes.

Research suggests that elevated blood sugar drives inflammation and impairs the immune system’s ability to repair wounds effectively.12 In a setting of high blood sugar, minor injuries might take weeks or months to heal rather than days.

Blurred vision

Starch structureSometimes blurry vision isn’t a sign that you need a new prescription for eyeglasses. It could actually be a symptom of diabetes.

When blood sugar is elevated, it causes the lens of the eye to swell, which changes its shape. When this occurs, the lens can no longer focus light properly, causing vision to become cloudy. When blood sugar levels return to a healthy level, the lens goes back to its usual shape, and vision becomes normal again. In one study, about one quarter of people with newly diagnosed diabetes reported that their vision had become blurry.13

Numbness and tingling in feet or toes

The “pins and needles” feeling we’re all familiar with usually occurs after sitting in one position for a while or putting too much pressure on one part of the body. However, if it occurs in your feet or toes for no apparent reason, diabetes or prediabetes could be responsible.

Elevated blood sugar can damage the nerves leading to your feet, resulting in numbness and tingling The medical term for this condition is diabetic peripheral neuropathy. Importantly, blood sugar does not need to be very high for this damage to occur; in one study, 49% of people with prediabetes and 50% of those with newly diagnosed diabetes were found to have peripheral neuropathy.14

Dark patches of skin

Starch structureHave dark, velvety patches of skin developed over certain parts of your body, especially the creases of your armpits, groin or neck? Do they appear grayish, brown or black?

The medical term for these patches is acanthosis nigricans, which may be caused by several conditions but often reflects elevated insulin levels and insulin resistance.15 It has also been linked to type 2 diabetes, especially in those who are overweight or obese. In one study of people newly diagnosed with type 2 diabetes, 54% of those who were obese had acanthosis nigricans.16

Skin lesions or rashes

Rashes, lesions, and other skin problems may be an early warning sign of diabetes.

Several skin conditions — including eruptive xanthomatosis, necrobiosis lipodica, and diabetic dermopathy — are characterized by itchy rashes or painful blisters that appear when blood sugar is too high. Although the precise mechanism for these and other diabetic skin disorders isn’t clear, elevated blood sugar may lead to inflammation and interfere with the ability to grow healthy new skin cells to replace old ones.17 One large review of existing studies found that between 51-97% of people with diabetes worldwide had some type of diabetes-related skin disorder.18

Yeast and urinary tract infections (women)

Have you been experiencing yeast infections or urinary tract infections (UTIs) more often lately? Frequent infections may be an early warning sign of diabetes, and this includes yeast infections and (UTIs) in women. High blood sugar fuels the growth of both Candida (the fungus responsible for vaginal yeast infections) and several types of bacteria that can cause UTIs. In addition, elevated blood sugar levels may depress immune function, making your body more susceptible to these infections.19

Erectile dysfunction (men)

In men, one of the first signs of diabetes may be difficulty with sexual function. High blood sugar can affect the nerves and blood vessels that lead to reproductive organs, resulting in erectile dysfunction. Studies have found that men with diabetes are more than three to five times as likely to have erectile dysfunction compared to non-diabetic men.20

3. How to find out if you have diabetes

If you have one or more of the symptoms above and suspect you may have diabetes, it’s important to make an appointment with your primary care provider. He or she will perform an examination and order lab tests to confirm whether you have type 1 diabetes, type 2 diabetes or prediabetes, and to rule out other causes of your symptoms.

You can also test your blood sugar at home to see if it is elevated. Regardless of the results, be sure to follow up with your healthcare provider if you have any symptoms of diabetes.

Importantly, in many cases, you may have no obvious symptoms of prediabetes or early-stage type 2 diabetes.

4. What can you do if you have diabetes or prediabetes?

If you have been diagnosed with diabetes or prediabetes, you’re likely to be upset and concerned. Although this is completely understandable, take heart. In addition to following up with your doctor on a regular basis, there are steps you can take right now to get your blood sugar under control and make sure it stays there.

In fact, in many cases, type 2 diabetes and prediabetes can be reversed or put into remission with a low-carbohydrate diet alone.21 Check out our guide below.

And although type 1 diabetes cannot be reversed, following a low-carbohydrate diet can help control blood sugar.22 See our guide below.

Finally, please don’t ignore the symptoms of diabetes, no matter how subtle they seem. It’s never too early to see your doctor and get checked out — or to start following a low-carb diet to achieve healthy blood sugar levels.

Furthermore, even if your blood sugar is normal now, limiting sugary and starchy foods may help to keep it that way. This doesn’t mean going on a diet, just eating better. Take a look at our guide below on six steps you can take to eat better.

Videos about diabetes


  1. In the US alone, nearly one quarter of all people with diabetes and more than 80% of those with prediabetes don’t know they have the disease:

    Centers for Disease Control and Prevention: National Diabetes Statistics Report 2017 [report; ungraded]

  2. Minerva Medica 2019: Treating prediabetes: why and how should we do it? [overview article; ungraded]

    Among people with prediabetes, high blood sugar levels after eating have been linked to greater risk of heart disease:

    Diabetes Care 1999: Impaired glucose tolerance is a risk factor for cardiovascular disease, but not impaired fasting glucose: the Funagata diabetes study [observational cohort study with RR > 2.0; weak evidence]

  3. Diabetes Care 2007: Symptoms of diabetes and their association with the risk and presence of diabetes [observational study; very weak evidence]

  4. Diabetologia 2005: Symptoms, signs and complications in newly diagnosed type 2 diabetic patients, and their relationship to glycaemia, blood pressure and weight [observational study; very weak evidence]

  5. Advances in Biochemical Research 2017: Biochemico-physiological mechanisms underlying signs and symptoms associated with diabetes mellitus [overview article; ungraded]

  6. Diabetes Care 2007: Symptoms of diabetes and their association with the risk and presence of diabetes [observational study; very weak evidence]

    Diabetologia 2005: Symptoms, signs and complications in newly diagnosed type 2 diabetic patients, and their relationship to glycaemia, blood pressure and weight [observational study; very weak evidence]

  7. Research has confirmed that high-carbohydrate foods raise blood sugar levels in people with diabetes as well as those without diabetes:

    Diabetes Care 2004: Dietary carbohydrate (amount and type) in the prevention and management of diabetes [overview article; ungraded]

    The Journal of Nutrition 1996: Source and amount of carbohydrate affect postprandial glucose and insulin in normal subjects [non-randomized study; weak evidence]

  8. Journal of Insulin Resistance 2016: It is the glycaemic response to, not the carbohydrate content of food that maters in diabetes and obesity: The glycaemic index revisited [overview article; ungraded]

  9. Point of Care 2017: Type 1 diabetes – a clinical perspective [overview article; ungraded]

  10. Social Science and Medicine 2019: “Wasting away”: diabetes, food insecurity, and medical insecurity in the Somali region of Ethiopia [observational study; very weak evidence]

  11. Diabetologia 2005: Symptoms, signs and complications in newly diagnosed type 2 diabetic patients, and their relationship to glycaemia, blood pressure and weight [observational study; very weak evidence]

  12. Journal of Surgical Research 2016: The effect of local hyperglycemia on skin cells in vitro and on wound healing in euglycemic rats [animal study; very weak evidence]

    Diabetes 2013: High-glucose environment enhanced oxidative stress and increased interleukin-8 secretion from keratinocytes: new insights into impaired diabetic wound healing [animal study; very weak evidence]

  13. Diabetologia 2005: Symptoms, signs and complications in newly diagnosed type 2 diabetic patients, and their relationship to glycaemia, blood pressure and weight [observational study; very weak evidence]

  14. Diabetes Care 2015: Peripheral neuropathy and nerve dysfunction in individuals at high risk for type 2 diabetes: the PROMISE cohort [observational study; very weak evidence]

  15. Journal of Family Medicine and Primary Care 2017: Acanthosis nigricans: a screening test for insulin resistance – an important risk factor for diabetes mellitus type-2 [observational study; very weak evidence]

  16. Endocrine Practice 2004: Prevalence of acanthosis nigricans in newly-diagnosed type 2 diabetes [observational study; very weak evidence]

  17. Diabetology & Metabolic Syndrome 2017: Skin disorders in diabetes mellitus: an epidemiology and pathophysiology review [overview article; ungraded]

  18. Diabetology & Metabolic Syndrome 2017: Skin disorders in diabetes mellitus: an epidemiology and pathophysiology review [overview article; ungraded]

  19. Diabetes, Metabolic Syndrome and Obesity 2015: Urinary tract infections in patients with type 2 diabetes mellitus: review of prevalence, diagnosis, and management [overview article; ungraded]

    Journal of Clinical Medicine 2019: Candida sp. Infections in patients with diabetes mellitus [overview article; ungraded]

    Clinical Focus: Diabetes and Concomitant Disorders 2013: Genital mycotic infections in patients with diabetes [overview article; ungraded]

  20. Diabetic Medicine 2017: High prevalence of erectile dysfunction in diabetes: a systematic review and meta-analysis of 145 studies [observational study with hazard ratio > 2; weak evidence]

    International Journal of Impotence Research 2017: Erectile dysfunction in young men with type 1 diabetes [observational study with hazard ratio > 2; weak evidence]

  21. The European Journal of Clinical Nutrition 2017: The interpretation and effect of a low-carbohydrate diet in the management of type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials [strong evidence]

    Frontiers in Endocrinology 2019: Long-term effects of a novel continuous remote care intervention including nutritional ketosis for the management of type 2 diabetes: a 2-year non-randomized clinical trial [weak evidence]

    The American Journal of Clinical Nutrition 2018: Effects of low-carbohydrate- compared with low-fat-diet interventions on metabolic control in people with type 2 diabetes: a systematic review including GRADE assessments [strong evidence for some benefits of a low-carb diet]

    Diabetes Care 2019: Nutrition therapy for adults with diabetes or prediabetes: a consensus report by the American Diabetes Association [overview article, the ADA now endorses low-carb diets for type 2 diabetes treatment]

  22. Diabetes, Obesity & Metabolism 2019: Low versus high carbohydrate diet in type 1 diabetes: A 12-week randomized open-label crossover study [moderate evidence]

    Asia Pacific Journal of Clinical Nutrition 2016: A randomised trial of the feasibility of a low carbohydrate diet vs standard carbohydrate counting in adults with type 1 diabetes taking body weight into account [moderate evidence]