Inhaled Insulin Improves A1C, Reduces Body Weight

Inhaled insulin[1] is effective at lowering blood glucose[2] over time and may help people avoid the weight gain associated with injected forms of insulin, according to a new study published in the journal Endocrine Practice[3].

Researchers at the Cleveland Clinic, Stanford University and the insulin manufacturer MannKind — which makes Technosphere inhaled insulin[4] — enrolled 309 people with diabetes who used mealtime insulin in a 24-week clinical trial. Participants ranged in age from 18 to 80, and had an A1C level[5] (a measure of long-term blood glucose control) between 7.0% and 11.5%. Their average duration of diabetes was 12.2 years, and their average body-mass index[6] (BMI, a measure of body weight that takes height into account) was 30.8, which falls in the category of obese.


During a “lead-in” period lasting four weeks, all participants received insulin glargine (Lantus), a long-acting injected insulin, as their basal form of insulin, which continued throughout the study. In addition to receiving Lantus after the lead-in period, participants were randomly assigned to take one of two types of mealtime insulin: insulin aspart (Novolog), an injected short-acting insulin (154 participants), or Technosphere, an inhaled short-acting insulin (150 participants).

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Effectiveness of inhaled insulin

The researchers were most interested in whether inhaled insulin was as effective as injected insulin for long-term blood glucose control, but they also measured a number of other outcomes to compare side effects between the two insulin types. Before they started taking their assigned mealtime insulin, the average A1C level in the injected insulin group was 9.0%, and it was 8.9% in the inhaled insulin group. After 24 weeks, A1C dropped in both groups, to 7.7% in the injected insulin group and 7.9% in the inhaled insulin group, demonstrating a roughly similar level of effectiveness for blood glucose control.

But there were also certain benefits and risks that were unique to inhaled insulin. Compared with their body weight at the start of the study, members of the injected insulin group gained an average of 0.23 kilograms (0.5 pounds), while members of the inhaled insulin group lost an average of 0.78 kilograms (1.7 pounds). While these are relatively small amounts of body weight to gain or lose — especially compared with participants’ body weight to begin with — these changes also happened during a relatively short study period, and could be much more clinically significant if they continued at the same rate over a longer period of time.

The incidence of hypoglycemia (low blood glucose)[8] was also slightly lower in the inhaled insulin group, but this small difference wasn’t enough to be considered statistically significant. Members of the inhaled insulin group experienced a higher rate of coughing episodes, with 29 members reporting at least one such episode compared with six members of the injected insulin group, as noted in a Healio[9] article on the study. Throughout the study, participants in both groups received a similar overall amount of insulin, and there was no difference in their blood chemistry or lipid (cholesterol and triglyceride) levels at the end of the study period.

This study demonstrates that inhaled insulin may be an effective option for some people who can’t use, or prefer not to use, injected mealtime insulin. In addition, it may offer slight weight-loss benefits, but it also carries a greater risk of coughing — considerations that doctors and patients should weigh when deciding which option is best for an individual.

Want to learn more about insulin? Read “What Does Insulin Do?”[10] and “Insulin Types: Which Is Better for You?”[11]

  1. insulin:
  2. blood glucose:
  3. Endocrine Practice:
  4. Technosphere inhaled insulin:
  5. A1C level:
  6. body-mass index:
  7. sign up for our free newsletter:
  8. hypoglycemia (low blood glucose):
  9. Healio:
  10. “What Does Insulin Do?”:
  11. “Insulin Types: Which Is Better for You?”:

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