Search results show common pack sizes of 30-count, a 90-count option, and a 180-count bottle.
Many products use single-use, airtight, pre-dosed capsules—these protect the retinoid from air and light and provide a measured dose for nightly use.
Suitability varies by product: some target mature skin, others say 'suitable for all skin types.' One product explicitly lists acne-prone, dry, extra sensitive, normal, combination, very dry, sensitive, oily, and mature skin.
Directions commonly say to twist open a single capsule and smooth the serum over cleansed face and neck at night—use one capsule per night or mix the serum into a night moisturizer. New users are advised to introduce retinol gradually (every other night).
Some listings state the capsules are vegetal-based and 100% biodegradable. Several items also claim to be cruelty-free or not tested on animals.
Common labels include paraben-free, fragrance-free or 'no fragrance added,' unscented, and in some cases sulfate-free.