Side effects are generally minor, including occasional injection site reactions and mild flu-like symptoms
Possible adverse effects may include: Injection site reactions : Redness, swelling, irritation, or discomfort Gastrointestinal symptoms : Nausea, vomiting, stomach cramps, or diarrhea Headaches or dizziness Allergic reactions : Rash, itching, shortness of breath, or facial swelling (rare) Increased heart rate or anxiety (typically temporary from B-vitamins) Fatigue or weakness if used improperly Elevated liver enzymes when taken in excess particularly with methionine or choline Insomnia if taken late in the day due to increased energy levels Who should avoid or use caution
FGF21 selectively uses Klotho as its co-receptor, whereas, FGF23 uses Klotho
Al-Aly suggests it might have to do with overlapping reward pathways in the brain
How to increase your vitamin B12 intake If you are deficient, it's more than likely that you'll end up having to get regular injections