How Long Does It Take for Tirzepatide to Work? Detailed Review

Tirzepatide is a dual GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist. Marketed under two famous and FDA-approved brands, i.e., Mounjaro and Zepbound. To answer ‘How Long Does It Take for Tirzepatide to Work?’, while the injections start working right after being injected, it reaches its peak level in about 8 to 72 hours, as confirmed by PubMed.

Moreover, it has a half-life of 5 days (approx.), as we tend to have different metabolism rates, some individuals may notice its effects within 1 – 3 days, while others may notice differences between 1 – 2 weeks. Here we have not only discussed the time taken for tirzepatide to work, but have covered its mechanism, dosage, increase in dosage, common and severe side effects, and more.

Mounjaro is for treating type 2 diabetes, and Zepbound for treating chronic weight management and obstructive sleep apnea – obstructive sleep apnea is a condition that causes interrupted breathing, leading to loud snoring, gasps. Administered via subcutaneous injection once weekly, tirzepatide has demonstrated significant efficacy in improving glycemic control and reducing body weight.

Chronic Snoring should not be left untreated as it disrupts breathing, which may result in a heart attack.

To answer ‘How long for tirzepatide to start working?’, the onset of action for tirzepatide varies depending on the condition being treated:

Type 2 Diabetes

Clinical trials have shown that tirzepatide can lead to significant reductions in HbA1c levels (a marker of long-term blood glucose control) within 2 weeks of starting treatment. These reductions continue over time, with sustained improvements observed throughout the treatment period.

Weight Loss with Tirzepatide in Individuals Without Diabetes

Tirzepatide has been studied for its effectiveness in helping people who are obese or overweight (but without diabetes) lose weight. The clinical trials assessed the percentage of weight loss at week 72, which is roughly 1.5 years after starting treatment. The results showed a significant reduction in body weight across different dosages of tirzepatide:

• 5 mg dose: Individuals who took the 5 mg weekly dose of tirzepatide lost an average of 15.0% of their body weight. The “95% Confidence Interval” (CI) means that there is a 95% chance that the true average weight loss falls between −15.9% and −14.2%. This means that the weight loss could vary a little, but on average, it is around 15%.
• 10 mg dose: Those on the 10 mg weekly dose of tirzepatide lost an average of 19.5% of their body weight, with a 95% CI of −20.4% to −18.5%. This suggests that people on this higher dose typically lost a bit more weight compared to the 5 mg dose.
• 15 mg dose: The individuals taking the 15 mg weekly dose of tirzepatide experienced the greatest weight loss, averaging 20.9% of their body weight. The 95% CI here was −21.8% to −19.9%, which again shows the weight loss could vary slightly, but the average loss was around 21%.

What Does the Confidence Interval Mean?

• The Confidence Interval (CI) provides a range of values that are likely to contain the true average weight loss. For example, for the 5 mg dose, the weight loss is expected to be between 15.9% and 14.2%, meaning it’s very likely that the true average falls somewhere within this range.
• The smaller the range, the more precise the measurement.

Did you know?

Pricking a finger is no longer required to check blood sugar. Instead, continuous glucose monitors (CGMs), such as Freestyle Libre 3 Plus sensors, monitor your glucose 24/7 without requiring fingerpricks.

Indications

Tirzepatide is approved for:

• Mounjaro (tirzepatide): Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes.
• Zepbound (tirzepatide): Alongside a reduced-calorie diet and increased physical activity, for chronic weight reduction in adults with obesity or overweight with at least one weight-related comorbidity.

Administration Forms and Doses

Tirzepatide is not administered orally and is only available in injection form. Administered as an intravenous injection, this drug is available in different doses, i.e., 5 mg, 10 mg, and 15 mg. The starting dose is usually 2.5mg per week and may only be increased upon a doctor’s recommendation. The increase is also 2.5 mg after at least 4 weeks on the current dose. On top of it all depends on the patient’s health conditions, response to the medication, and tolerability.

Factors Influencing Efficacy

The effectiveness of tirzepatide can vary based on several factors:

• Age: Elderly patients may experience different pharmacokinetics and pharmacodynamics, potentially affecting the drug’s efficacy and safety profile.
• Other Health Conditions: Comorbidities such as kidney or liver impairment, gastrointestinal disorders, or a history of diabetic retinopathy can influence the response to tirzepatide.
• Dosage and Administration: Higher doses may lead to greater efficacy but also increase the risk of side effects. Adherence to the weekly injection schedule is crucial for optimal results.

Side Effects of Tirzepatide

Common Side Effects:

• Nausea
• Diarrhea
• Decreased appetite
• Vomiting
• Constipation
• Upper abdominal discomfort
• Abdominal pain

Serious Side Effects:

• Thyroid C-cell tumours (in rats; human relevance unknown)
• Pancreatitis
• Hypoglycemia, especially when used with insulin or sulfonylureas
• Kidney problems
• Gallbladder issues
• Severe allergic reactions
• Diabetic retinopathy complications
• Suicidal behaviour and ideation

Patients are advised to monitor for these side effects and consult healthcare providers if they occur.

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Mechanism of Action

Answering ‘How does tirzepatide lower blood sugar?’, Tirzepatide functions as a dual agonist (a substance that initiates or increases receptor’s activity) for the GIP (a receptor involved in glucose metabolism, insulin secretion) and GLP-1 receptors (regulating glucose homeostasis and promoting insulin secretion). This dual action enhances insulin secretion in response to meals, inhibits glucagon release, slows gastric emptying, and reduces appetite, leading to improved glycemic control and weight loss.

Genetic Variability

Individual responses to tirzepatide can vary due to genetic differences affecting drug metabolism, receptor sensitivity, and other factors. Personalized treatment approaches may be necessary to achieve optimal outcomes.

Popular FDA-Approved Brands

• Mounjaro: Approved for type 2 diabetes.
• Zepbound: Approved for chronic weight management and treatment of moderate-to-severe obstructive sleep apnea.

Time Span for Weight Reduction

Significant weight loss is typically observed within the first few weeks of treatment. Continued weight reduction occurs over several months, with the most substantial changes seen between 12 to 72 weeks. Long-term maintenance of weight loss is achievable with ongoing treatment and lifestyle modifications.

For more detailed information, including prescribing information and clinical study results, refer to the FDA labels for Mounjaro and Zepbound:

• Mounjaro: FDA Access Data
• Zepbound: FDA Access Data

Conclusion

As Mounjaro is recommended for treating type 2 diabetes, and Zepbound for treating obesity or obstructive sleep apnea. The tirzepatide onset of action varies depending on the condition being treated. Mounjaro suppresses your appetite, and it does that by triggering receptors in your mind that you are full. This feeling helps you eat less; thus, it’s recommended to consume a nutritious diet to avoid malnutrition.