By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv
Starting weight loss medication: the first steps
How do you go about starting weight loss medication safely and correctly? It is one of the most common questions I hear in my clinic. The short answer: we don’t start with the drug, we start with the person. A good medical workup, a well-informed choice of medication and a gradual increase in dose are the three foundations of success.
In this guide, I will walk you step by step through what happens before the first injection or pill, and in the months that follow.
Step 1: Is starting weight loss medication right for you?
Obesity medications are generally intended for adults with a BMI of 30 or higher. In addition, they are also suitable for people with a BMI of 27 or higher who have a weight-related condition, such as type 2 diabetes, high blood pressure or sleep apnea. These are the conditions under which the drugs were tested in the large clinical trials.
That said, BMI is only a starting point. If you are not sure the time has come, read my article on when to seek medical treatment for obesity.
Step 2: A medical workup before you begin
At the first visit, I ask about your weight history, previous diets, appetite and sleep. Next come blood tests: blood sugar, lipids, liver and kidney function and, when needed, thyroid function.
There are also situations in which the medication must not be used. For example, according to the Wegovy prescribing information, it should not be given to anyone with a personal or family history of medullary thyroid carcinoma (MTC) or MEN 2 syndrome. In addition, women who are planning a pregnancy should stop Wegovy at least two months beforehand.
Step 3: Choosing the right medication
Today there are several main options. As a weekly injection, there is Wegovy (semaglutide) and Mounjaro (tirzepatide). As a daily pill, there is the 25 mg Wegovy pill, which the FDA approved in December 2025, and Foundayo (orforglipron), which was approved in April 2026.
The choice depends on your other medical conditions, your weight loss goal, whether you prefer an injection or a pill, and cost. So there is no single “best drug” for everyone. For a full overview of the options, see my guide to obesity medication and my page on medications for obesity and metabolic disease.
Step 4: Starting weight loss medication at a low dose
All of these medications start at a low dose and go up gradually. The goal is to give your digestive system time to adjust. With Wegovy, according to the prescribing information, you start at 0.25 mg a week. After that, the dose goes up every four weeks to 0.5, 1 and 1.7 mg, and from week 17 you move to the maintenance dose of 2.4 mg. For people who need further weight loss, the dose can go up to 7.2 mg.
With Mounjaro, according to the FDA prescribing information for tirzepatide (sold in the US for weight loss as Zepbound), you start at 2.5 mg a week for four weeks. Then you go up to 5 mg, and after that in steps of 2.5 mg, staying at least four weeks on each dose. The maintenance doses are 5, 10 or 15 mg. Here is something important to know: women who take birth control pills should add a barrier method, or switch to a non-oral method, for four weeks after starting treatment and after every dose increase.
When the injection itself feels scary
Many people dread the first injection, but the needle is very thin. I have gathered my tips in an article on how to cope with a fear of injections. Besides, for those who prefer them, pills are now an option too.
Step 5: Getting ready for side effects
In the first months, nausea, feeling full quickly, constipation or diarrhea are common. In most cases, they are mild and pass. A few simple habits help: small meals, eating slowly, stopping at the first sign of fullness and drinking plenty of fluids. On the other hand, severe, persistent abdominal pain or repeated vomiting means you should contact your doctor.
Step 6: Nutrition, protein and exercise
The medication turns down the food noise, so this is the best time to build new habits. First, eat protein at every meal to protect your muscle mass. Second, do strength training two to three times a week, along with walking. I wrote about this in my guide to changing habits during medication treatment.
What’s more, the medication is only part of the picture. A healthy lifestyle adds extra protection for your heart and blood vessels.
Step 7: Follow-up and realistic expectations
How much can you lose? In the STEP 1 trial, semaglutide 2.4 mg led to an average loss of 14.9% of body weight after 68 weeks. In the SURMOUNT-1 trial, tirzepatide 15 mg led to 20.9% after 72 weeks. This means weight loss is gradual, and the full result only comes after a year or more.
It is also important to know from the outset that this is long-term treatment. After semaglutide was stopped in the STEP 1 follow-up, participants regained about two-thirds of the weight they had lost within a year. That is why we plan the maintenance phase right from the start.
Starting weight loss medication with the right doctor
Finding a doctor online is easy today. Even so, make sure your doctor specializes in obesity treatment and stays with you for the long haul, not just until the prescription. As for cost, all four of Israel’s health funds (HMOs), Clalit, Maccabi, Leumit and Meuhedet, offer Wegovy and Mounjaro through their supplementary insurance plans at about half the market price or less, depending on the fund and the dose. The prices are posted on the health funds’ websites. If you would like to get to know my approach, you are welcome to read about Dr. Asnat Raziel.
The bottom line
So how do you go about starting weight loss medication? With a medical workup, a tailored choice of medication and a gradual increase in dose. Alongside that, protein, strength training and regular follow-up protect both your health and your results. Most important of all, see the treatment as a long-term process, not a two-month fix.
The information in this article is general and does not replace personal medical advice.
Questions and answers
Can I start straight away at a high dose?
No. Increasing the dose gradually reduces nausea and other side effects. Skipping steps makes it more likely that you will stop treatment.
When will I see weight loss?
Many people notice a drop in appetite within the first few weeks. Significant weight loss usually comes after you reach the maintenance dose.
Injection or pill?
Both options work. You inject the shot once a week, and you swallow the pill every day. The choice depends on your preference, your other medical conditions and the result you want.
Starting weight loss medication when you have diabetes
These medications also lower blood sugar. For this reason, your doctor needs to adjust your existing diabetes medications in advance, especially insulin or sulfonylureas, to prevent a sharp drop in blood sugar.
Starting weight loss medication after many failed diets
Past attempts are not a personal failure. They teach us what was hard for you, so they help us build a precise plan, this time with the support of medication.
Sources
WEGOVY (semaglutide) prescribing information
ZEPBOUND (tirzepatide) prescribing information
Once-Weekly Semaglutide in Adults with Overweight or Obesity
Tirzepatide Once Weekly for the Treatment of Obesity
Wegovy pill approved in the US as first oral GLP-1 for weight management
FDA approves orforglipron, an oral GLP-1, for adults with obesity
