L-Arginine

L-Arginine is an amino acid with moisturizing, skin conditioning, and barrier boosting properties.

As it has a really high (basic) pH it can be used to raise the pH of formulations, but cosmetic chemist Amanda Foxon-Hill doesn’t recommend using it for pH adjusting unless you’re working with an ingredient that specifically calls for L-Arginine instead of the more common sodium hydroxide (NaOH). Read more here!

The formulations I’ve found that use it as an active ingredient use it at 0.5–2%. Your mileage may vary, though! Depending on the formulation you may be able to work in enough L-Arginine to get skin benefits and a perfect pH.

Arginine

White crystalline powder

If working with an ingredient that needs L-Arginine for pH adjusting; as needed to get the pH of your formulation where you want it (generally less than 1%).

Nothing noticeable in finished products.

A 10% L-Arginine solution has a pH between 10.5–12.

L-Arginine is water-soluble.

L-Arginine will raise the pH of our formulations.

No, unless you’re working with an ingredient that needs L-Arginine to raise the pH; I purchased L-Arginine to work with natural cationic emulsifier Emulsence HC (which—side note—I hated).

L-Arginine only exists as a refined ingredient.

An easy, gentle ingredient for raising the pH of our formulations.

It’s not terribly easy to find.

If you’re including it for skincare/haircare benefits, look at other amino acids. In general, think about the “job(s)” you want it to do, and look for other ingredients that also do that job.

If you’re using L-Arginine for pH adjusting because another ingredient in your formula specifically needs it, please refer to supplier/manufacturer documentation for alternatives.

Include in the water phase; L-Arginine can be hot or cold processed as needed.

As L-Arginine is very basic you’ll need to test & adjust the pH of formulations that use it to ensure they’re in a good-for-skin/hair place.

Stored somewhere cool, dark, and dry, it should last at least two years.

Check out this awesome, informative article from cosmetic chemist Amanda Foxon-Hill about some of the challenges formulating with L-Arginine and why it’s not always a great alternative to NaOH for pH adjusting: “Amino Acids for pH Adjustment?; I question the wisdom of normalising the use of amino acids for pH adjustment…”

30g (1.06oz)

I’ve only found L-Arginine sold as a cosmetic ingredient at Skin Chakra (Germany).

You can purchase L-Arginine as a supplement, but I’m unsure if L-Arginine purchased from the drug store would be a good workaround if you can’t purchase cosmetic grade L-Arginine. I’d start by looking at purity; ensure any supplements aren’t cut with fillers (it should be 99–100% pure).