Does Tresiba (Degludec) or Lantus (glargine) Cause More Weight Gain?

Woman Questioning

The easiest way to find out whether Tresiba or Lantus will cause weight gain is to look at the insert or label of each drug and see what it says for the common side effects.

Unfortunately, both Tresiba and Lantus have weight gain listed in the common side effects that result from taking this type of insulin. So now the question then becomes, which insulin – Tresiba or Lantus – will cause more weight gain?


Diabetes Starter Kit


It may seem like you’re stuck in between a rock and a hard place, unable to decide things when you have diabetes and have to take insulin therapy. You know that your weight has much to do with the progression of diabetes. If it increases, then there’s more stress and strain on your heart, and diabetes is known to be associated with higher than normal incidences of heart disease. You don’t want to do anything that will cause weight gain.

Blood Sugar Levels Impact Your Weight

Your blood sugar control is vital to the control of your weight and also the control of your life when you have diabetes. If it’s too high, you can go into a coma and die. If it’s too low, the same thing can happen, and you could die.

The main goals of insulin are to try to stimulate the physiology of beta cells that secrete insulin as closely as possible and to choose and use the right type of insulin that will contribute to the best blood sugar control during the day, avoiding hypoglycemia or low blood sugar. (1)

Changes in Insulin in the Past Decade

In the past decade, modern medicine has made some changes in their insulins used. Now they are ultra-long-acting insulins (such as glargine U300 and degludec (IDeg 100 and IDeg 200), which means you don’t have to take as many doses of them.

Tresiba vs. Lantus – Weight Gain Results in the Studies

Here’s what the medical literature says about the weight gain of these different types of insulins.

  • Lantus Wins This Study39 trials of 26,195 patients Glar 300 was associated with less weight gain than glargine 100 U/ml (Glar-100). However, the researchers rated the studies as low and very low-quality evidence. (2)
  1. Stalemate Between Tresiba and Lantus
  • 2019, a meta-analysis done by Chinese doctors evaluated 15 studies that included 9619 patients taking degludec and 7075 patients in the glargine. Degludec gave a better reduction in fasting plasma glucose of 5.2 and a lower ratio of participants experiencing >1 severe hypoglycemic event and nighttime hypoglycemia. 
  • And glargine provide similar glycemic control, but degludec also lowers the risk of hypoglycemia. Degludec may be an alternative treatment for the management of patients with type 2 diabetes who are prone to hypoglycemia with glargine. There was no difference in weight gain. (3)
  1. Tresiba No Better Than What Patients Were on Before
  • 2018, Italian doctors reported in Diabetes Therapeutics on the safety and effectiveness of degludec in an observational longitudinal study, analyzing results from 247 type 2 diabetics treated with degludec (Tresiba). (4)
  • Average diabetic was 67 years old and diabetic for 16 years. The patients were followed for about 10 months. Bodyweight increase was not statistically significant vs. baseline in both groups. Benefits on overall, nighttime, and severe hypoglycemia were found in the switch group. 
  • degludec or switching to degludec from other basal insulins in Type 2 diabetes did improve metabolic control without significant weight gain, and there was a decrease in the risk of hypoglycemia when switching to IDeg from another basal insulin. 

In studies, one thing to remember is that everyone’s body doesn’t act the same. The studies merely reflect the average of what was happening. Thus, some patients in the studies lost weight while others gained weight, no matter if it was Tresiba or Lantus. 

The question of which is better – Tresiba or Lantus – to prevent weight gain is one that really can’t be answered 100% accurate by anyone unless you try both types of insulin at different times and see what happens.

Consider What You Can Do to Keep Your Weight Stable

How your individual body reacts to a drug becomes your history and your knowledge of how your body acts under a given situation. What your weight maintenance may depend on is your personal habits more than the drug effects. 

In order to keep your weight stable, remember the following guidelines:

  1. Choose lower-calorie foods like vegetables and fruits rather than processed foods when you are snacking and when you are planning your meals.
  2. A plate of food should consist of ½ non-starchy vegetable, ¼ protein, and the remaining ¼ as a starchy vegetable. You really need a lot less food than you may think!
  3. Forget about skipping meals. Skipping meals can cause low blood sugar, and then you’ll end up running to comfort foods or poor food choices. Slow and steady always wins the race, and that means regular meals at regular times. 
  4. Exercise, especially after your meal. By exercising after you eat, you can help the insulin get into the muscle cells. 


Are there any other significant differences between Tresiba and Lantus besides weight gain? Yes, besides weight gain, there are differences in factors like blood sugar control, risk of hypoglycemia, and dosing frequency. Tresiba (degludec) is an ultra-long-acting insulin that offers a more consistent release and longer duration of action compared to Lantus (glargine). This may result in more stable blood sugar levels throughout the day and a lower risk of hypoglycemia, especially nighttime hypoglycemia.

Can switching from one insulin to another impact weight gain? Switching from one insulin to another, such as from Lantus to Tresiba or vice versa, may have varying effects on weight gain. Studies have shown mixed results, with some patients experiencing no significant change in weight while others may observe weight changes. Factors influencing weight gain after switching insulins include individual response to the new insulin type, dosage adjustments, and lifestyle factors.

What should I discuss with my healthcare provider before choosing between Tresiba and Lantus? Before choosing between Tresiba and Lantus, it's important to discuss your medical history, current diabetes management plan, lifestyle habits, and treatment goals with your healthcare provider. Factors to consider include your blood sugar control, risk of hypoglycemia, dosing convenience, and potential impact on weight. Your healthcare provider can help tailor a treatment plan that best suits your individual needs and preferences.



  1. Misra, S., Mathieu, C. Are newer insulin analogues better for people with Type 1 diabetes? Diabet Med 2018 Dec 26. Doi:10.1111/dme.13891.
  2. Brown, M.A., et al. The roule of Toujeo®, insulin glargine U-300, in the treatment of diabetes. J Am Assoc Nurse Pract 2016 Sep;28(9):503-9.
  3. Drummond, R., et al. Physicians’ real-world experience with IDegLira: results of a European survey. BMJ Open Diabetes Res Care 2018 Jun 14;6(1):e000531.
  4. Ponzani, P., et al. Impact of insulin Degludec in type 2 diabetes: real-world data on efficacy and safety. Diabetes Ther 2018 Dec;9(6):2209-2218.

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