A Closer Look at the Safety of Lysine

is Lysine safe at 1000 mg Dosing?

L-lysine (or “lysine”) is a supplement that is sometimes used in the clinic for helping patients with hair shedding disorders. It’s also used sometimes for patients with low iron or zinc levels that just won’t budge with typical supplements. At doses typically used in our clinic (ie 1000-1500 mg daily), L-lysine can be considered quite safe.

I was interested to recently read a review of 12 relatively high quality studies on lysine. The observed adverse events were mainly subjective symptoms related to the gastrointestinal tract such as nausea, stomachache, and diarrhea. These were observed typically only for individuals using very high doses (above 6000 mg daily) and not for the typical 1000-1500 mg doses used in the hair clinic.

Lysine safety

In general, L-lysine has a good safety profile for most people.


Hayamizu K et al. Safety assessment of L-lysine oral intake: a systematic review. Amino Acids. 2019

Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887

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