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L-lysine explained: what it is and where it's found

The NIH says lysine is an essential amino acid and that breast milk naturally contains it. Two products we reviewed list L-lysine, but neither label prints its individual amount: NeuroQuiet is an oral spray and Boostaro comes in capsules.

By HowNook's Health desk · Updated

OHONH₂NH₂OHONH₂NH₂
What it is
Amino acid
In the products we reviewed
2, none prints the amount

What L-lysine is

  • Lysine is an essential amino acid.1
  • Breast milk naturally contains lysine.1

How much L-lysine each product gives

Per serving, as each label prints it

Amount not printed: the dashed line shows the most it can be, the whole blend

NeuroQuietNot printed · at most 1,000 mg
BoostaroNot printed · at most 645 mg

Before you take it

Ask a doctor first

  • Use caution with lysine amounts significantly above those normally found in food, including during breastfeeding.1
  • Ask your healthcare provider for breastfeeding advice specific to your situation.1

These statements have not been evaluated by the FDA. A supplement is not a medicine.

The 2 products we reviewed that list L-lysine

ProductForm and servingL-lysine per servingOur scorePrice a bottleBuy
NeuroQuiet#3 in hearing supportOral spray6 spraysNot printedIn the 1000 ng HGA Blend9.7$49Check price
BoostaroMen's health supportCapsules2 capsulesNot printedIn a 645 mg proprietary blendNot ranked$49Check price
Prices checked Oct 9, 2026

Questions people ask

What is L-lysine?

Lysine is an essential amino acid, according to the NIH. The NIH also says breast milk naturally contains lysine.

Is lysine a vitamin?

Lysine is an essential amino acid, according to the NIH. Breast milk naturally contains lysine.

What should I check before taking a lysine supplement?

Use caution with lysine amounts significantly above those normally found in food, including during breastfeeding. Ask a clinician before starting, and ask your healthcare provider for breastfeeding advice specific to your situation.

Which of your reviewed products contain L-lysine?

NeuroQuiet and Boostaro list L-lysine, but neither prints its individual amount. NeuroQuiet lists it inside the 1000 ng HGA Blend per serving of 6 sprays. Boostaro lists it inside a 645 mg proprietary blend per serving of 2 capsules.

Sources

The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.

  1. 1NIH LactMed, Lysinencbi.nlm.nih.gov/bookschecked