A Primer on the Weight Loss, Health & Longevity Benefits of GLP-1 Receptor Agonists

By Dr. J.E. Williams | 21st May 2025 | Reading Time: 7 minutes

GLP-1 (Glucagon-like peptide-1) receptor agonists (RAs) therapies are in demand for weight loss because of the obesity epidemic, and because they work. These include the prescription peptides Ozempic (semaglutide), Victorza (liraglutide), and Mounjaro (tirzepatide). The number of GLP-1 prescription users is expected to exceed 30 million by 2030. And that doesn’t include generic, non-prescriptive peptides. 

What is GLP-1? What are GLP-1 receptor agonists? 

Glucagon-like peptide-1 belongs to a class of incretin hormones produced in the gastrointestinal tract that help regulate glucose metabolism. GLP-1 stimulates insulin release by β cells and inhibits glucagon release by pancreatic α cells, resulting in less glucose production in the liver. Too much glucagon raises blood sugar levels; less glucagon reduces it. 

Glucagon chemically communicates with your liver to make just the amount of glucose your body needs. However, things can go wrong with this process, which is where GLP-1 RAs help regulate it. 

GLP-1 can also slow the rate at which the stomach empties, which helps control appetite and lowers food intake. You feel fuller longer. 

It also has another appetite-suppressing effect by acting on the hypothalamus, the gland in your brain that promotes balance between the hormonal and nervous systems by increasing satiety. 

An added benefit is that GLP-1 is essential in maintaining whole-body health.

These hormone-mimicking prescription drugs are approved for the treatment of type 2 diabetes and obesity. However, generic versions are available from compounding pharmacies and online services, typically without a doctor’s prescription. 

Does biohacking your metabolism work? And is it safe? 

Using these medications is a way to biohack your metabolism to control high glucose levels by promoting better insulin management. These medications are very effective and considered safe for weight loss. However, they are not entirely free of side effects. Some individuals experience nausea, vomiting, diarrhea, dizziness, and headaches. 

Do not use GLP-1 medications during pregnancy or when nursing. Don’t use them on your own if you have advanced liver or kidney disease. 

Don’t share your prescription with your children. The FDA approved GLP-1 RAs for use in overweight children aged 12 years or older under the care of a physician. 

What Is the Most Effective Dose? 

Prescription medications, such as Ozempic and Mounjaro, come in pre-loaded injectable pens. A typical regimen begins with a low dose and gradually increases to the maximum therapeutic, or effective, dose. 

For generic tirzepatide, the maximum dose is 15 mg/mL injected once a week.

But everyone is different. Microdoses of 0.25 or 0.5 mg per week are effective for some and have low side effects. Others need more. I recommend patients start at the recommended effective dose and gradually lower their weekly amount to be cautious about potential adverse effects or save on the cost. 

Beyond Weight Loss 

Though these medications are best known for their weight loss and glucose-lowering benefits, they can also help patients with degenerative neurological diseases, cardiovascular disease, and fatty liver disease. 

Alzheimer’s and Parkinson’s Disease: These complex progressive neurological syndromes have no effective medical treatment and have only minimally useful disease-modification drugs. However, ongoing research using GLP-1 drugs, such as liraglutide and semaglutide, has produced favorable, albeit minimal, symptom improvement.

Cardiovascular Benefits: Weight reduction and a low-fat diet, with or without GLP-1 RAs, help lower blood pressure and reduce LDL cholesterol. However, this family of peptides can not only lower total glucose and hemoglobin A1c but can also significantly lower C-reactive protein. 

Fatty Liver Disease: GLP-1 can also reduce fat buildup in the liver, reverse fatty liver disease, and lower glucose. It may also have a positive effect on liver fibrosis, a condition characterized by the scarring of tissue that occurs in advanced liver disease. 

GLP-1 RA Options and Doses

There are three main peptides in this class of drugs. Doctors prescribe different dosages depending on whether they’re intended for treating type 2 diabetes or for weight loss. These are the commonly prescribed amounts for weight loss. 

1. Tirzepatide 15 mg is the most effective peptide for weight loss in overweight individuals without type 2 diabetes, according to a study published in The New England Journal of Medicine on May 11, 2025. The recommended starting dose is 2.5 mg for 4 weeks; thereafter, the dose is increased by 2.5 mg weekly to a maximum of 15 mg weekly. 
2. Semaglutide starts at 0.25 mg weekly for one month, with a maximum of 2.4 mg once a week. 
3. Liraglutide 0.6 mg is the starting dose, with a maximum daily dose of 3 mg.

Are there advantages to microdosing versus full-strength prescription dosing? 

Microdosing GLP-1 offers benefits beyond weight loss, including improved overall health and reduced inflammation. Users report fewer aches and pains and often experience increased energy. 

It may also reduce the risk of Alzheimer’s disease and modify the progression of Parkinson’s disease.

For some, small doses between 0.25 and 0.5 mg per week are just as effective as higher dosages and have few side effects. 

Many of my patients report an overall feeling of well-being with microdoses of GLP-1. I consider microdoses of GLP-1 a lifestyle medicine that improves health and supports longevity.  

A compounding pharmacy can customize a GLP-1 RA microdose for you with your doctor’s prescription. Some report benefits from amounts as low as 2.0 mg weekly.

Are oral forms available, and are they effective? 

GLP-1 RAs are given by subcutaneous injection. However, some other peptides, such as BPC-157, are available in capsule form, though not used for weight loss. 

For now, GLP-1 peptides require self-injection. However, the US drug maker Lilly is about to release the first oral GLP-1 agonist, Orforglipron. 

How to Take GLP-1 RA Peptides 

1. Prescriptions: Zepbound is the brand name for Tirzepatide. Semaglutide is available as a prescription medication under the brand names Wegovy and Ozempic. 
2. Generic: These include tirzepatide, semaglutide, liraglutide, and retraglutide. Tirzepatide is the recommended generic peptide for weight loss and glucose management. It is available without a prescription and from compounding pharmacies.

The recommended dose is 15 mg of Tirzepatide administered subcutaneously once weekly. However, the effective dosage range is from 10 mg to 16.5 mg/mL. 

What’s the Difference Between Bioidentical GLP-1 Peptide and GLP-1 RAs, the pharmaceutical version?

GLP-1 (glucagon-like peptide) is a peptide hormone naturally produced in the body that helps regulate glucose (blood sugar) and manage appetite. GLP-1 RAs are a class of medications that are pharmaceutically produced. Since enzymes quickly break down natural GLP-1, GLP-1 RA drugs extend the effects of the natural hormone. 

What To Expect 

Several studies, like the SURMOUNT-2 trial using weekly injection of 10 mg or 15 mg of tirzepatide, found that obese patients with type 2 diabetes had an average weight loss of 15%. Side effects were mild and included nausea, diarrhea, and vomiting. If you improve your diet and exercise regularly, you can expect to drop 20% or more of your weight, assisted with GLP-1. 

Natural Ways to Increase GLP-1

Soluble fiber in fruits, vegetables, whole grains, legumes, and flax and chia seeds can increase GLP-1 levels. Some herbal supplements, such as berberine, curcumin, and ginseng, help boost GLP-1 levels. 

Self-Monitoring and Side Effects 

The kidneys eliminate GLP-1 from the body. They also support the pancreas-liver axis. Don’t take GLP-1 RA peptides if you have impaired kidney or liver function. I recommend checking your kidney and liver functions with a blood test before you start and then every three months.

Since GLP-1 influences glucose, self-monitor your glucose level from a blood or finger-prick home test. If you have type 2 diabetes, check your glucose level daily. 

Toxic reactions or serious complications are rare. The safety profile for low-dose self-administered peptides is acceptable for self-use. However, consult your doctor if you experience any side effects. 

Other Benefits 

Because GLP-1 agonists help reduce body weight and lower glucose levels, they can also lower blood pressure and alleviate chronic inflammation, conditions that contribute to the development of chronic cardiovascular disease. Doctors term the combination of these two conditions cardiometabolic disorders. 

GLP-1 agonists can lower blood lipids, including LDL, VLDL, total cholesterol, and triglycerides. However,  they have little effect on HDL, the “good” lipid. 

Besides glucose, liver, and kidney function tests, get a lipid profile before you begin a self-administered GLP-1 peptide program. Since it also helps lower hemoglobin A1c and reduces inflammation, as indicated by decreased C-reactive protein (CRP), get baseline CRP and A1c tests.

What Happens When You Stop? 

A 2025 JAMA article found that when you stop semaglutide or tirzepatide, even after use of up to one year, there is rapid regain of weight and reversal of cardiovascular benefits. Otherwise, there are no rebound effects associated with discontinuing GLP-1 RAs. 

Therefore, it’s important to implement dietary and lifestyle changes that promote health and manage weight lifelong. 

Does biohacking metabolism work? And is it safe? 

Biohacking your metabolism with GPL-1 RAs is a practical and generally considered safe approach to treating obesity and managing glucose levels. 

Conclusion

The era of GLP-1 prescriptions for weight loss is just beginning. However, the solution is not in more prescriptions. The answer lies in eating a healthier diet, managing portions, and getting enough exercise. GLP-1 RAs can support reversing unhealthy metabolism and maintaining a normal weight. 

As the buzz of the end of obesity dies down, GLP-1 RA drug use will plateau. The new normal is that now there’s a drug for being overweight that works. However, the cause is overeating of calorie-dense foods. The long-term solution is better dietary choices, calorie reduction, regular exercise, and eating normal amounts of food. 

I’ve prescribed peptide injections for over two decades and found them beneficial and safe. In addition to weight control, many patients report an overall improvement in wellness with GLP-1 therapy. Those with chronic fatigue, chronic inflammation, and achy muscles or painful joints can benefit as well. 

Selected Citations 

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Drucker, D. J. (2025). GLP-1-based therapies for diabetes, obesity, and beyond. Nature Reviews Drug Discovery, 1-20. https://doi.org/10.1038/s41573-025-01183-8

Hammoud, R., & Drucker, D. J. (2023). Beyond the pancreas: Contrasting cardiometabolic actions of GIP and GLP1. Nature Reviews Endocrinology, 19(4), 201-216. https://doi.org/10.1038/s41574-022-00783-3

Hölscher, C. (2024). Glucagon-like peptide-1 class drugs show clear protective effects in Parkinson’s and Alzheimer’s disease clinical trials: A revolution in the making? Neuropharmacology, 253, 109952. https://doi.org/10.1016/j.neuropharm.2024.109952 

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