Blog · GLP-1 basics
GLP-1 Side Effects: Basics to Know Before You Start Anything
GLP-1 side effects of the prescription medicines are mostly digestive: nausea, vomiting, diarrhea and less appetite. Rare serious problems include pancreatitis. Low blood sugar is a bigger risk with insulin or sulfonylureas. Supplements sold with GLP-1 wording have no such studied profile, so their risks are unknown.
Written by the GLPro label deskUpdated · 4 min read
01Common ones
What are the common GLP-1 side effects?
The common GLP-1 side effects are nausea, vomiting, diarrhea and a drop in appetite. They come from how the medicines work: they slow stomach emptying and raise the feeling of fullness (Cleveland Clinic, GLP-1 agonists).
These effects are listed for the prescription drugs, such as semaglutide, liraglutide and tirzepatide. Most are mild at first. Clinicians often start with a low dose and raise it slowly, so the gut can adjust.
Appetite loss is both an effect and a reason people take the drugs. It is one reason a prescriber also checks that you are still eating enough protein and drinking enough fluid.
Small habits help many people, such as smaller meals, slower eating and fewer greasy foods. These are comfort tips, not treatment. If a side effect stops you from eating or drinking, call the prescriber rather than waiting it out.
02Less common
Which GLP-1 side effects are serious?
Serious GLP-1 side effects are rare, but they matter. They include inflammation of the pancreas (pancreatitis) and a warning about a type of thyroid cancer called medullary thyroid cancer (Cleveland Clinic, GLP-1 agonists).
For that reason, GLP-1 and tirzepatide medicines are not for people with a personal or family history of medullary thyroid cancer or MEN 2. They are not for use in pregnancy and are not recommended while breastfeeding (NIDDK, Rx obesity medicines).
Call a clinician quickly for strong, lasting stomach pain, repeated vomiting you cannot stop, or signs of dehydration such as dark urine, dizziness on standing and a very dry mouth. These are reasons to be seen, not to wait.
Tell the care team about every supplement and medicine you use, since a full list helps them judge a new symptom.
03Low sugar
Can GLP-1 medicines cause low blood sugar?
On their own, GLP-1 medicines seldom cause low blood sugar, but the risk rises when they are combined with insulin or a sulfonylurea such as glipizide, glimepiride or glyburide (Cleveland Clinic, GLP-1 agonists).
A low is usually a reading below 70 mg/dL, though a personal target may differ. Early signs are shakiness, sweating, hunger, dizziness and a racing heartbeat. A severe low can cause confusion or loss of consciousness and needs emergency care (NIDDK, Low Blood Glucose).
LOW BLOOD SUGAR
Signs of a low (hypoglycemia)
- Shaking, sweating, hungerOften the first signs
- Racing heartbeat, dizzinessSit down; check if you can
- Irritability, trouble concentratingCan come on fast
- Confusion, trouble seeing or speakingTreat at once
THE NUMBERS DOCTORS USE
What the test results mean
- A1CBelow 5.7% normal · 5.7-6.4% prediabetes · 6.5% or above diabetes
- Fasting glucose99 mg/dL or below normal · 100-125 prediabetes · 126 or above diabetes
- 2-hour glucose test139 mg/dL or below normal · 140-199 prediabetes · 200 or above diabetes
- A low, for many people with diabetesBelow 70 mg/dL
Emergency?A severe low (passing out or a seizure) needs glucagon and a 911 call. For a mild low, take 15 to 20 grams of fast-acting carbohydrate and recheck after 15 minutes.
Signs and steps from NIDDK and Mayo Clinic (NIDDK, Low Blood Glucose) (Mayo Clinic, diabetic hypoglycemia); test cutoffs for non-pregnant adults from NIDDK and CDC (NIDDK, Diabetes Tests & Diagnosis) (CDC, Diabetes Testing). Lows are most likely with insulin, a sulfonylurea or more than one diabetes medicine; some supplements may add to the effect (NIH ODS, Chromium) (NCCIH, Diabetes and Dietary Supplements). Keep taking prescribed medicine.
Treat a low as the care plan says, often with 15 to 20 grams of fast carbohydrate, then recheck in 15 minutes.
GLPro: from $49 a bottle30 capsules · 2, 3 or 6 bottles · free US shipping on 6 · 60-day money-back guarantee
See packs04Supplements
Do GLP-1 supplements have the same side effects?
Nobody knows, because supplements with GLP-1 wording have not been studied the way the drugs have. Their risks depend on what is in the capsule, and many labels do not say.
FDA has found drug ingredients that were not listed in weight-loss products sold as supplements (FDA, FATZorb hidden drugs). Supplements can also interact with medicines or raise bleeding risk, so providers should hear about every one before surgery (NCCIH, Using Supplements Wisely).
| Item | GLP-1 medicine | GLP-1 supplement |
|---|---|---|
| Side effects listed | Yes, from trials | Often not |
| Warnings for thyroid and pancreas | Yes | Not stated |
| Clinician monitoring | Part of care | Not built in |
| Where to report | MedWatch | MedWatch or the safety portal (FDA, Report a Supplement Problem) |
05GLPro
What do we know about GLPro side effects?
Nothing is published about GLPro side effects. The sales page names no warnings, and no ingredient list is shown, so the label cannot be matched against your medicines.
That means you should read the printed warnings on the bottle when it arrives and follow them. If no warnings are printed, call the order desk at +1 (302) 200-3480 before using it, and ask a clinician or pharmacist about interactions.
Keep taking any prescribed medicine, and do not start a supplement without telling your prescriber. Our GLPro side effects page lists what to watch for.
U.S. stocking partner for GLPro
Ready to try GLPro?
Check your medicines first, then pick a pack. Six bottles ship free and cost the least per bottle, and every pack carries the 60-day money-back guarantee.
- Secure checkout
- 60-day money-back guarantee
- Ships from the U.S.
06FAQ
GLP-1 side effect questions, answered
Q01Do GLP-1 side effects mean the medicine is working?
Not necessarily. Nausea is a side effect, not a measure of benefit. Progress is judged by your clinician using weight, blood sugar and other checks over time.
Q02How long do GLP-1 side effects last?
Digestive effects are often strongest after a start or a dose rise and ease over days to weeks. If they persist or worsen, contact the prescriber, who may adjust the dose.
Q03Is hair loss a GLP-1 side effect?
Rapid weight loss of any kind can be followed by temporary shedding. Talk to a clinician about hair changes, diet and nutrient intake rather than assuming the cause.
Q04Can you take a GLP-1 supplement and a GLP-1 medicine together?
Ask the prescriber first. A supplement adds unknown ingredients to a drug with known effects, and the combination has not been studied. Never stop a medicine for a capsule.
07Who wrote this
Written and reviewed by
Pages built from the bottle images, the sales page and linked NIH, FDA, CDC, FTC and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a U.S. stocking partner for GLPro, not by the manufacturer. We earn money when you buy through our order links.
→Keep reading
More about GLPro
U.S. stocking partner for GLPro
Ready to try GLPro?
Check your medicines first, then pick a pack. Six bottles ship free and cost the least per bottle, and every pack carries the 60-day money-back guarantee.
- Secure checkout
- 60-day money-back guarantee
- Ships from the U.S.