What is Letrozole 1 (Astera Labs)?
Astera Labs letrozole in 1mg tablets, 50 to a sachet. The strongest aromatase inhibitor there is, at the strength that makes it dosable.
Also sold as Femara, Letrozol or letrozole.
Letrozole is the most powerful aromatase inhibitor available, capable of suppressing estrogen almost completely. That is occasionally what you want, when reversing gyno, and almost never what you want for routine control on cycle. It is non-steroidal and binds reversibly, like anastrozole.
Letrozole 1 benefits
- The strongest aromatase inhibitor here, suppressing estrogen further than the alternatives
- The usual choice for reversing gynecomastia that is actively developing
- Clears water retention faster than anything else in this category
- Long half-life, so every other day dosing is enough
- 1mg tablets, which halve cleanly into the 0.5mg routine control dose
Letrozole 1 dosage
- Routine on-cycle control
- 0.5mg every other day, half a tablet
- Higher end
- 1.25mg every other day
- Gynecomastia reversal
- 2.5mg daily, short term, then taper
- Adjust from
- An estradiol blood test, not from symptoms
- Half-life
- About 2 to 4 days
- Post-cycle therapy
- Do not use, switch to a SERM
Half a tablet every other day is where routine control sits. That is the practical argument for this strength over the 2.5mg: you are halving rather than quartering, and small errors matter on a compound this strong.
Adjust from a blood test. Letrozole can take estrogen close to zero and the symptoms of that look just like high estrogen, so dosing by feel goes wrong quickly here.
Package content
- Tablets
- 50 per sachet
- Strength
- 1mg letrozole per tablet
- Letrozole per sachet
- 50mg
- Half-life
- About 2 to 4 days
- Brand
- Astera Labs
At 0.5mg every other day one sachet covers around 200 days.
Store below 30°C. Protect from light. Do not freeze. Keep out of reach of children.
Who is Letrozole 1 for?
People who specifically want letrozole rather than a milder aromatase inhibitor, and who are dosing it for routine control rather than a gyno protocol.
If instead you are reversing gyno that is actively developing, that protocol runs at 2.5mg daily and FEMAMED 2.5 is the strength built for it. Anastrozole and exemestane are the milder alternatives if letrozole is more than the job needs.
Before you run it. Crashed estrogen is worse than high estrogen and it is far easier to do. Low estrogen gives you aching joints, no libido, erectile problems, flat mood and worse cholesterol than the steroids alone would. The trap is that those symptoms look almost identical to high estrogen, so people feel bad, assume they need more anti-estrogen, and dig deeper.
Do not dose an aromatase inhibitor by feel. Measure estradiol and adjust from the number. The
estrogen management guide covers how. And keep this on cycle:
an aromatase inhibitor has no place in post-cycle therapy, where you need estrogen present for recovery to happen at all.
Letrozole is the compound most likely to crash you, because it works further and faster than the alternatives. It is the right tool for reversing active gyno at a high dose for a short period, and the wrong tool for routine estrogen control, where anastrozole or exemestane are far easier to steer. It also worsens cholesterol more than the others. Not for anyone under 18, and not for women who are pregnant or breastfeeding.
How to use Letrozole 1
Swallow with water, with or without food. Half a tablet every other day for routine control. If you use it for gyno at a high dose, taper down rather than stopping outright.
Frequently asked questions
How do I know if my estrogen is too low?
You largely cannot tell from symptoms, which is the whole problem. Low estrogen and high estrogen both produce low libido, erectile difficulty, poor mood and general flatness.
Aching or clicking joints and completely dry skin lean toward low, and puffiness and sensitive nipples lean toward high, but neither is reliable. This is the one thing in a cycle you genuinely should not guess at. Test estradiol.
Should I use it during PCT?
No. Post-cycle recovery depends on estrogen being present, because the feedback loop that restarts your own production runs through it. Suppressing estrogen at that point works directly against the goal.
Use a SERM such as tamoxifen or clomiphene for post-cycle therapy and stop the aromatase inhibitor when the cycle ends.
Why is letrozole harder to dose than anastrozole?
Because it is considerably stronger and the useful range is narrower. Letrozole can take estrogen close to zero, and the gap between controlling estrogen and eliminating it is small.
For routine control on cycle, anastrozole or exemestane are much easier to steer. Letrozole earns its place when you specifically need estrogen driven down hard and fast.
How do I use it for gyno?
The usual approach is a high dose for a short period to drive estrogen down and shrink active tissue, then a taper rather than a sudden stop, because stopping abruptly can rebound estrogen upward.
It works on gyno that is actively developing. Established fibrous tissue does not respond to any drug, and a SERM such as raloxifene is the better tool for lumps that have been there a while.
1mg or 2.5mg tablets?
Choose by what you are doing. Routine estrogen control on cycle sits around 0.5 to 1.25mg every other day, which is this tablet halved or taken whole.
Reversing gyno that is actively developing runs at 2.5mg daily, which is one whole tablet of the stronger strength.
