Aminoethanesulfinic Acid
Hypotaurine – amino acid, taurine precursor. In sunscreens works as a secondary antioxidant: stabilizes photo-unstable avobenzone, extending UVA protection duration. Safe, no standalone cosmetic effects.
Supporting ingredient
It gives a product its texture, stability or shelf life. It has no claimed effect on the skin, so an efficacy tier does not apply. What is known about its safety is below
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
Aminoethanesulfinic Acid (hypotaurine) is a sulfur-containing amino acid, a precursor of taurine in metabolism. Formed by cysteine oxidation in the hypotaurine-taurine decarboxylation pathway. Mechanism. On skin it acts as a second-order antioxidant – does not neutralize free radicals directly, but stabilizes other antioxidants and photo-unstable UV filters. Key use in sunscreens: extends avobenzone (butyl methoxydibenzoylmethane) photostability in combinations with octocrylene, diethylhexyl-2,6-naphthoate (Corapan TQ), and trisiloxane. Where applied. SPF 30+ sunscreens with avobenzone (0.1–1%). Brands: La Roche-Posay Anthelios XL, Bioderma Photoderm MAX, Avène Sun, Heliocare Advanced. Evidence base. In vitro and in vivo, 1% hypotaurine extends avobenzone photostability 1.5–2× after 2 MED UV irradiation (Bonda 2008). No direct skin effects (hydration, anti-aging) – purely a formulation ingredient. Safety. CIR confirmed safety. Hypoallergenic, non-irritating, non-comedogenic. Topical systemic absorption is minimal. Pregnancy and lactation – safe. Acceptable at any stage, including sunscreens for pregnant women with melasma. Functional role. No standalone skin effect. An invisible workhorse in avobenzone sunscreens.
Frequently asked questions
Is Aminoethanesulfinic Acid safe during pregnancy?
Aminoethanesulfinic Acid is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Aminoethanesulfinic Acid for?
Aminoethanesulfinic Acid suits: normal, dry, combination, oily, sensitive.
What is Aminoethanesulfinic Acid and what does it do in cosmetics?
Hypotaurine – amino acid, taurine precursor.
What's the INCI name for Aminoethanesulfinic Acid?
The INCI name is Aminoethanesulfinic Acid. It may also appear as: Hypotaurine.
See Aminoethanesulfinic Acid in a product composition right on the store page
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Similar role in the formula
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