Finasteride Storage: Separate the Bottle Label, Expiration and Compounded Formula

Which label applies to your bottle?

Finasteride tablets sit under two branded approvals. Propecia, the 1 mg tablet, is NDA 020788, approved 12/19/1997, and is indicated for male pattern hair loss in men only [1][3]. Proscar, the 5 mg tablet, is NDA 020180, approved 06/19/1992, and is indicated for symptomatic benign prostatic hyperplasia [2][4]. Generic 1 mg and 5 mg tablets are approved under their own ANDAs and have their own labeling.

The product name and manufacturer printed on the bottle identify which labeling applies; strength alone does not, because a generic 1 mg tablet is not Propecia. Each label gives that product's storage conditions in section 16, How Supplied/Storage and Handling [3][4].

What the Propecia label says about storage

Section 16 of the Propecia label says to store the tablets at room temperature, 15-30°C (59-86°F), to keep the container closed and to protect it from moisture [3]. The 1 mg tablets are supplied in bottles of 30 and 90 with desiccant [3]. The section gives no light-specific instruction and no storage period for a split tablet [3].

Broken or crushed tablets: what the labeling says

The labeling states that the tablets are coated and that the coating prevents contact with the active ingredient during normal handling, provided the tablets have not been broken or crushed [3][4]. It identifies crushed or broken tablets as a possible exposure risk to a male fetus during pregnancy and states that the contact area should be washed immediately with soap and water if contact occurs [3]. Finasteride is contraindicated in pregnancy because blocking the conversion of testosterone to DHT may cause abnormal development of the external genitalia in a male fetus [3].

That language addresses handling and exposure. It applies to tablets that are not broken or crushed, and it gives no storage period for a split tablet [3].

If the tablets were exposed to heat

The Propecia label gives a room-temperature range of 15-30°C (59-86°F) and no instruction for tablets that were exposed to higher temperatures [3]. Stability after such exposure cannot be inferred from it, or from a different finasteride product's label.

Compounded topical finasteride is a different preparation

No topical finasteride product is FDA-approved. The Drugs@FDA entries for Propecia and Proscar list 1 mg and 5 mg oral tablets [1][2]. A compounded topical is a different preparation from an approved oral tablet, and the tablet labeling gives no beyond-use date for it [3].

Published formulation work on topical finasteride is early-stage. A 2024 study fused hair follicle stem cell extracellular vesicles with liposomes and loaded the hybrid with finasteride and gold nanoparticles, reporting 45.33% encapsulation efficiency for finasteride; the authors said the hybrid vesicles improved storage stability, and a once-daily topical gel was tested in an androgenetic alopecia mouse model against once-daily 5% minoxidil [5]. That is an experimental formulation tested in mice, and it did not set a patient beyond-use date.