Corn starch is often used as a soothing, mattifying agent in DIY face masks. It can temporarily smooth or mattify the skin but does not penetrate deeply enough to affect wrinkles in a lasting way.

3. Wrinkles
Wrinkles are caused by a combination of aging, sun exposure, genetics, and lifestyle factors. Effective wrinkle reduction usually involves:

Retinoids (vitamin A derivatives)

Peptides

Hyaluronic acid

Sunscreen (for prevention)

In-office treatments (e.g. microneedling, laser, Botox)

So, yeast and corn starch might temporarily improve skin texture, but they do not permanently remove wrinkles, regardless of age.