FDA's product-specific guidances, the study plans behind each generic

As of Nov. 3, 2026, FDA's product-specific guidance database¹ listed 2,447 guidances for generic drug developers. Fifty-two of them were final. The other 2,395, about 98 percent, were drafts, according to GxRadar's count of the database.

That draft label undersells how much these documents matter. A product-specific guidance, or PSG, is FDA's written answer to the first question every generic developer asks: what evidence will the agency want to see for this particular drug? For a plain tablet the answer fits on two pages. For an inhaler, an eye drop or a long-acting injection it can run to 10 pages and offer several alternative study plans.

PSGs are where FDA's science on complex generics turns into instructions. The agency's user-fee commitments set the pace at which they appear.

What a PSG tells a developer

Every generic must show it is bioequivalent to its reference listed drug. FDA's regulation at 21 CFR 320.24¹¹ allows several kinds of evidence, from blood-level studies to laboratory tests to clinical endpoint trials, and says applicants should use the most accurate, sensitive and reproducible approach available. A PSG names which of those FDA recommends for one specific product.

Before 2010, developers had to ask FDA for those recommendations product by product and wait for an answer. A June 2010 guidance⁴ moved them onto FDA's website and opened each one to public comment. FDA's PSG program snapshot³ dates the program to 2007. Comments still go to a single docket, FDA-2007-D-0369.

Two current guidances show the range. The atorvastatin tablet PSG⁵, last revised in October 2024, is the simple case. The albuterol metered-dose inhaler PSG⁶, revised in the May 2026 batch¹³, is not.

FDA finalized the atorvastatin guidance in 2008, but its 2024 revision was issued as a draft, so the database now lists it as one. Our atorvastatin page tracks what pharmacies pay for the generic 20 mg tablet.

How many there are, and for what

Totals have grown steadily. FDA's snapshot put the total at "nearly 2,070" as of November 2022. The fiscal 2024 GDUFA performance report⁷ counted 2,223 published PSGs on Sept. 30, 2024, and the fiscal 2025 report⁸ counted 2,288 a year later. The database showed 2,447 on Nov. 3, 2026.

Issuance counts include revisions, so they swing more than the totals do. FDA issued 206 PSGs in fiscal 2024, 109 of them for complex products, and 925 in fiscal 2025, 49 for complex products. Most of the fiscal 2025 jump came from one exercise. FDA revised more than 826 draft PSGs for immediate-release oral products to match an international bioequivalence standard, known as ICH M13A, finalized in October 2024. GxRadar's count found 760 guidances in the current database dated Oct. 30, 2024, more than any other single date.

Source for the table is GxRadar's tally of every entry in FDA's PSG database by the route FDA assigns. Two-thirds are for oral products, and 1,473 of the 1,655 oral guidances cover tablets or capsules of some kind.

Why PSGs matter most for complex generics

For an ordinary tablet, the standard study is well established. For a cream, an inhaler or a peptide injection, the method itself is the hard part, and FDA has funded research through GDUFA to work out methods for some of them. FDA's Aug. 21, 2026, batch⁹ of 55 PSGs shows the emphasis: 24 new and 31 revised, 18 for complex products, and more than 30 for products with no approved generic at all. One new guidance in that batch, for a benzoyl peroxide and tretinoin cream, offers laboratory bioequivalence studies as an alternative to a comparative clinical endpoint study in patients.

User-fee commitments set the pace for newly approved brands. Under the GDUFA III commitment letter¹⁰, FDA aims to publish PSGs for 50 percent of complex products approved in new drug applications from Oct. 1, 2022, within two years of approval, and 75 percent within three years. For non-complex new chemical entities, the goal is 90 percent within two years. FDA reported issuing PSGs on time for 19 of 19 such products in fiscal 2024, and its preliminary fiscal 2025 figures show 28 of 28. Until a PSG exists, a developer of a complex product generally has to get FDA's views case by case, through controlled correspondence or a pre-ANDA meeting.

PSGs also feed into FDA's other work on generics. The agency's Office of Generic Drugs writes them through its Office of Research and Standards, and its 2019 guidance on citizen petitions lists one warning sign of a petition filed mainly to delay a competitor: arguing about approval standards for a product with a published PSG without ever commenting on that guidance.

What "draft" does and does not mean

The atorvastatin and albuterol guidances open with a standard disclaimer that each "does not establish any rights for any person and is not binding on FDA or the public," and that an applicant can use another approach if it meets the law. Each tells developers who want a different approach to contact the Office of Generic Drugs first. A developer that goes its own way has to persuade reviewers that its method is at least as good.

Revisions carry a cost when a study is already under way. Under GDUFA III, a developer whose in vivo bioequivalence study has started when a new or revised PSG appears can ask for a PSG teleconference with FDA, according to FDA's PSG page². The option is rarely used. FDA's monthly activities dataset¹² shows two PSG teleconferences in the 11 months from October 2025 through August 2026.

FDA's snapshot says it issues new and revised PSGs in quarterly batches and previews them on an "Upcoming Product-Specific Guidances" page. As of Nov. 3, 2026, the newest entries in the database were dated Aug. 21, so the next batch would be the first since then.