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Al

Alpha Lipoic Acid

Thioctic Acid · Alpha Lipoic AcidAntioxidant

Sulfur-bearing antioxidant. Both water- and oil-soluble; supportive role in serum formulations.

What it does

Alpha lipoic acid is unusual among antioxidants in being soluble in both water and oils, which lets it operate in both environments at once. Topical effects on photoaging and texture have been reported in small studies but the overall topical evidence base is moderate. As with many antioxidants, the pairing matters — ALA is most useful as a supporting ingredient in a vitamin C / vitamin E / ferulic acid stack.

The evidence, graded

moderateAntioxidants neutralize free radicals generated by the UV that gets through sunscreen. Layering an antioxidant serum under SPF compounds photoprotection.Wu 2011 · Clinical and Experimental Dermatology ↗
emergingVitamin C, vitamin E, and ferulic acid show synergistic photoprotection. The combination is more stable and doubles photoprotection compared to vitamin C alone.Lin 2005 · Journal of Investigative Dermatology ↗

Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.

Also known as

ala, thioctic acid

Pairs worth knowing

Vitamin E (Tocopherol) · works together ↗Ferulic Acid · works together ↗L-Ascorbic Acid (Vitamin C) · works together ↗Coenzyme Q10 · works together ↗

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