Are Gonal-f and Follistim the same medication?
No. Gonal-f and Follistim are not the same product, even though they are used for similar purposes in fertility treatment and they both come as injections.
What are they made of?
Gonal-f contains follitropin alfa (recombinant follicle-stimulating hormone, FSH).
Follistim contains follitropin beta (recombinant FSH).
Both are forms of recombinant FSH, but they are different molecules (alfa vs beta) and are manufactured differently.
Are they interchangeable?
They are often used for the same kinds of stimulation protocols (for example, to stimulate ovarian follicle growth), but they are not considered directly interchangeable product-for-product. Dose conversions, unit differences, and how each product is prescribed can vary, so the treating clinician uses a specific protocol for the chosen brand.
What’s the practical difference patients notice?
The main differences in day-to-day care usually come down to:
- the exact product/brand prescribed,
- the dose and administration schedule set by the fertility clinic,
- how the prescription is written and dispensed (including injection pens/vials depending on the formulation).
Why do they sound similar?
Because both are recombinant FSH drugs used to stimulate the ovaries (or, in some protocols, the testes). People often assume “same class = same drug,” but in this case the active ingredients differ as alfa vs beta versions of FSH.
If you tell me what your prescription says (the strength and units, and whether it’s Gonal-f or Follistim), I can help you compare what it contains and what questions to ask your clinic about switching.