A compounded blend of estriol and estradiol, conventionally in an 80:20 ratio. The ratio describes how the total estrogen is split between the two, not two independent strengths. Commonly supplied at 1–10 mg/mL in a click dispenser.
Also known as Biest, BiEst, Estriol/Estradiol
Educational research referenceTRT / HRT & Ancillary
Quick reference. Everything you need to run Bi-est —
dosing, frequency, reconstitution math for the vial sizes people actually buy,
and what it stacks with. For anything specific to your situation,
ask the Guru.
Often cycle-day anchored — days 1–25 is a common pattern.
These are the numbers people actually run, drawn from the published record and from
what the community has settled on over time. Educational reference, not medical
advice — a starting point to work from, and one you can adjust as you learn how you
respond.
How to run it
How often
Once or twice daily
Cycle length
Often cycle-day anchored — days 1–25 is a common pattern.
Consistency matters more than perfect timing. Pick a slot in your day you will
actually keep, and let DoseIQ handle the rest.
For women
Dosing is by clicks, and the click volume depends on the dispenser the pharmacy filled — 0.05 mL on a Micro, 0.25 mL on the standard TC-35, 0.5 mL on a TC-140. The same two clicks can therefore be a tenfold difference in delivered dose, so the device matters as much as the strength. A common starting point is 0.5 mL of a 1 mg/mL cream daily, adjusted every four to six weeks.
What to expect
Most people tolerate Bi-est well. Here is what is worth knowing going in,
so nothing catches you by surprise.
Compounded, so there is no approved label and potency is not verified batch by batch. ACOG’s 2023 consensus notes a lack of high-quality safety and efficacy data for compounded bioidentical hormone therapy, and that salivary and serum monitoring are not recommended for dose titration. Anyone with a uterus taking a systemic estrogen needs adequate progestogen alongside it — and guidance is that transdermal progesterone does not provide that.
Known interactions
Interactions involving Bi-est's drug class that DoseIQ screens for.
Each one cites where it comes from — an FDA label section or the published
record — because an interaction warning you can't trace is just noise.
Worth knowingAromatase inhibitor + estrogen — working against each other
One suppresses estrogen while the other supplies it — pharmacologically contradictory unless very deliberately prescribed.
What to do: Worth confirming both are supposed to be running at once.
Source: Mechanism; anastrozole label
DoseIQ screens your whole protocol against these rules automatically — every
compound, prescription and supplement you track, cross-checked as you add them.
Serious flags are always free.
Preparing it
Bi-est does not need reconstituting — it comes ready to use.
Nothing to reconstitute. One click of a 2 mg/mL cream on a standard TC-35 dispenser is about 0.5 mg.
This page is an educational research reference and is not medical advice.
Dose figures reflect the published record and what the community has converged on —
starting points to weigh, not instructions. Consult a qualified healthcare provider
before starting any protocol.