1. GLP-1 Medications
Below are the most commonly reported side effects for two frequently prescribed GLP-1 therapies: semaglutide (GLP-1 receptor agonist) and tirzepatide (GLP-1 + GIP receptor agonist)
Common side effects:
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Decreased appetite
- Abdominal discomfort
- Fatigue
- Headache
- Indigestion
- Injection site reactions
What to Know:
Gastrointestinal (GI) side effects—like nausea, vomiting, and bloating—are the most common and are typically dose-related. This means they often appear or worsen after a dose increase but tend to settle as your body adjusts over time.
Some patients also experience delayed gastric emptying, which can lead to a sensation of prolonged fullness or bloating. You might not immediately recognize it as a side effect, but if you’re feeling unusually full for hours after eating or noticing slower digestion, this could be why.
Serious but Rare Complications:
While uncommon, serious potential complications associated with GLP-1 medications include pancreatitis, gallbladder problems, and elevations in kidney function tests. Patients should promptly report severe abdominal pain, jaundice, or significant changes in urination or swelling to their healthcare provider.
2. Naltrexone (low or standard dose)
Common side effects:
- Nausea
- Headache
- Dizziness
- Fatigue
- Vivid dreams or sleep disturbances (especially during titration at lower doses)
- Anxiety or irritability
- Abdominal cramps
3. Bupropion
Common side effects:
- Insomnia
- Dry mouth
- Headache
- Nausea
- Increased sweating
- Anxiety or restlessness
- Weight loss
- Risk of seizures (dose-dependent)
Important Note:
Although uncommon, elevated blood pressure may occur, particularly at higher doses. This can be serious for some individuals. It’s important to monitor blood pressure regularly during treatment, especially if you have a history of hypertension or cardiovascular concerns.
4. Metformin
Common side effects:
- Diarrhea
- Nausea
- Abdominal discomfort
- Metallic taste
- Bloating
- Appetite reduction
Rare but serious:
Lactic acidosis is a very rare side effect of metformin and is mostly seen in patients with underlying kidney problems or conditions causing low oxygen levels. If you have concerns or experience unusual symptoms like severe muscle pain, difficulty breathing, or weakness, contact your healthcare provider immediately.
5. Methylene Blue
Common side effects:
- Blue or green discoloration of urine and stools
- Headache
- Dizziness
- Nausea
- Anxiety or restlessness
- Gastrointestinal upset
- Photosensitivity
Important Safety Note:
Methylene Blue can interact with SSRIs and other serotonergic medications, increasing the risk of serotonin syndrome — a rare but potentially serious condition. Symptoms can include confusion, rapid heart rate, high blood pressure, dilated pupils, muscle rigidity, or fever. If you are taking SSRIs or similar medications, it’s essential to inform your healthcare provider before using Methylene Blue.
6. NAD+ (Nicotinamide Adenine Dinucleotide)
Common side effects (mostly with IV or injection):
- Flushing
- Chest pressure or tightness (infusion-related, not cardiac in nature)
- Lightheadedness
- Headache
- Nausea
- Fatigue during/after infusion
7. Sermorelin (GHRH analog)
Common side effects:
- Injection site redness or irritation
- Headache
- Dizziness
- Flushing
- Nausea
- Restlessness
8. Finasteride (oral or topical)
Common side effects:
- Decreased libido
- Erectile dysfunction
- Breast tenderness
- Mood changes (rare)
- Scalp irritation (topical)
What to Know:
Sexual side effects such as reduced libido or erectile dysfunction are generally reversible, but in rare cases, they may persist even after stopping the medication. If you experience these or any concerning symptoms, discuss them with your provider to determine the best path forward.
9. Minoxidil (topical or oral)
Common side effects:
- Scalp irritation or itching (topical)
- Increased hair shedding (initially)
- Unwanted hair growth
- Dizziness or lightheadedness (oral)
- Fluid retention or swelling (oral)
- Rapid heartbeat
Important Safety Note:
Oral minoxidil can, in rare cases, affect the heart or cause fluid to build up in the lungs. These risks are higher in people with heart or kidney problems, which are more common in adults over 65. If you're in this age group, it's especially important to use oral minoxidil only under close supervision from your healthcare provider, with regular check-ins to monitor your blood pressure and heart health.
10. Tretinoin (topical retinoid)
Common side effects:
- Skin dryness
- Peeling or flaking
- Redness or irritation
- Burning or stinging sensation
- Increased sun sensitivity
- Temporary purging (initial use)
11. Fluocinolone (topical corticosteroid)
Common side effects:
- Skin thinning (with prolonged use)
- Burning or itching
- Dryness
- Acne or folliculitis
- Delayed healing
12. Spironolactone
Common side effects:
- Breast tenderness or enlargement
- Irregular menstrual cycles
- Increased urination
- Fatigue
- Headache
- Elevated potassium levels
- Dizziness or lightheadedness
13. GHK-Cu (copper peptide)
Common side effects:
- Skin irritation (topical)
- Redness or itching
- Mild burning at application site
- Rare: Allergic skin reaction
14. MIC+B12Common side effects:
- Redness, swelling, or discomfort at the injection site
- Mild upset stomach or nausea
- Headache
- Light diarrhea
- Mild fatigue or restlessness
- Temporary changes in urine color (often bright yellow)
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