Estradiol valerate is a synthetic form of the natural estrogen your body produces, designed to be slowly absorbed and converted into active estradiol once injected. It is one of the most commonly prescribed injectable estrogens, used in menopausal hormone therapy, treatment of low estrogen conditions, and gender-affirming feminizing hormone therapy. The medication works as a prodrug: estradiol is chemically bonded to valeric acid (a short fatty acid), and once in your body, enzymes break that bond apart, releasing the same estradiol your ovaries would naturally make.
How It Works in Your Body
Estradiol valerate is dissolved in an oil solution and injected into muscle tissue (or sometimes under the skin). From there, it slowly releases into your bloodstream. Your body’s enzymes split the molecule into two parts: 17-beta estradiol, which is biologically identical to the estrogen produced by the ovaries, and valeric acid, which is harmlessly metabolized. The ester bond that holds these two components together is what controls the slow release, giving you days of steady estrogen levels from a single injection rather than requiring daily dosing.
After a typical injection of 4 to 5 mg, estradiol levels in the blood peak around day 2, reaching concentrations between 400 and 667 pg/mL. Those levels then gradually taper over the following days, with elevated estrogen lasting roughly 14 days before dropping back toward baseline. This pharmacokinetic profile is why most people inject estradiol valerate every one to two weeks, depending on their prescribed dose and how their body responds.
FDA-Approved Uses
The branded injectable version, Delestrogen, is FDA-approved for four indications. The most common are treating moderate to severe hot flashes (vasomotor symptoms) during menopause and relieving vaginal dryness and irritation caused by declining estrogen levels. It is also approved for treating low estrogen caused by conditions like hypogonadism, surgical removal of the ovaries, or primary ovarian failure. A less common indication is palliative treatment of advanced prostate cancer that depends on androgens to grow.
Beyond these formal approvals, estradiol valerate is widely used in feminizing hormone therapy for transgender women and nonbinary individuals. UCSF’s transgender care guidelines list it as a standard option, with typical starting doses around 2 mg per week, moderate doses around 4 mg per week, and maximum doses up to 20 mg per week. Dose increases are guided by blood hormone levels and how the individual responds, not by chasing a specific maximum number.
How It Compares to Other Injectable Estrogens
The two most common injectable estrogens are estradiol valerate and estradiol cypionate. They differ mainly in how long each injection lasts and how high estrogen levels spike. Estradiol valerate reaches its peak faster, around 2 days after injection, compared to about 4 days for cypionate. However, cypionate keeps estrogen elevated for longer, roughly 11 days versus 7 to 8 days for valerate. A third option, estradiol benzoate, peaks at a similar speed to valerate but wears off much faster, in only 4 to 5 days.
Research comparing all three esters found that estradiol valerate provides the most predictable pharmacokinetic behavior, meaning blood levels follow a more consistent, repeatable pattern from injection to injection. Cypionate produces lower peak levels but sustains them longer, which some people prefer because it smooths out hormonal fluctuations between injections. In practice, the choice often comes down to availability, insurance coverage, and individual preference for injection frequency.
Blood Clot Risk and Safety
One of the biggest concerns with any estrogen therapy is the risk of blood clots (venous thromboembolism). The risk varies significantly depending on the type of estrogen and how it enters your body. Oral estrogens pass through the liver first, which increases clotting factor production. Injectable and transdermal estrogens largely bypass this “first pass” liver effect, which is one reason many clinicians prefer them for patients with elevated clot risk.
A study comparing estradiol valerate-based oral contraceptives to those containing the older synthetic estrogen ethinyl estradiol found a significantly lower clot risk with the estradiol valerate formulation, with roughly a 54% reduction in risk. This finding reflects the broader pattern that bioidentical estradiol (whether oral, injectable, or patch) carries a more favorable safety profile than older synthetic estrogens. That said, any estrogen therapy increases clot risk to some degree, and your baseline risk factors, such as smoking, obesity, age, and personal or family history of clots, all factor into safety decisions.
Available Formulations
Estradiol valerate injections are available as both brand-name Delestrogen and generic versions. The generic is typically much less expensive and sits on the lowest cost tier of most insurance formularies, while brand-name Delestrogen is usually placed on a higher specialty tier. The medication comes in multi-dose vials containing the estradiol valerate dissolved in castor oil or sesame oil, with concentrations typically available at 10 mg/mL, 20 mg/mL, and 40 mg/mL. The different concentrations allow for smaller injection volumes at higher doses.
Estradiol valerate also exists in oral tablet form combined with dienogest, marketed as a combined oral contraceptive. This is a different use case from the injectable, and the two should not be confused. The injectable is used for hormone replacement and feminizing therapy, while the oral combination product is a birth control pill.
Storage and Handling
Because estradiol valerate is dissolved in oil, temperature matters. Vials should be stored at room temperature, between 68°F and 77°F (20° to 25°C). If the vial gets too cold, you may notice small crystals forming in the oil. This is normal and does not mean the medication has gone bad. The crystals redissolve easily when the vial is warmed back to room temperature. Rolling the vial gently between your palms or letting it sit in warm water for a few minutes before injecting is enough to restore a clear solution.
Cold medication is also more viscous, making it harder to draw into a syringe and more uncomfortable to inject. Warming the vial to body temperature before use makes the oil flow more smoothly and can reduce injection-site discomfort. Avoid heating it above body temperature or microwaving it, as extreme heat can degrade the medication.
What to Expect on Estradiol Valerate
If you are starting estradiol valerate for menopause symptoms, the primary effects you will notice are a reduction in hot flashes, improved vaginal moisture, and often better sleep and mood stability. These changes typically begin within the first few weeks but may take one to three months to reach full effect.
For those using it as part of feminizing hormone therapy, changes unfold over months and years. Breast development, fat redistribution, softer skin, and reduced body hair growth are among the expected effects. Clinicians generally start with a lower dose and increase gradually based on blood work, checking estradiol levels to ensure they fall within the target range without overshooting. The goal is to mimic the hormonal environment of premenopausal women, not to push levels as high as possible.
Common side effects across all uses include breast tenderness, mild nausea (more common with oral forms), headaches, and mood changes during the adjustment period. Injection-site soreness or small lumps at the injection site can occur, particularly with larger volume injections or if technique needs refinement. Most side effects diminish as your body adjusts to stable estrogen levels over the first few months.