Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[sadbuttrue]

Hello. wandering if any science based people on here can explain... evorel 25 patch and one spray of lenzetto are supposed to be equivalent doses. evorel 25 releases 25 micrograms of estradiol per 24 hours, one spray of lenzetto is 1.53 mg, which is 1530 micrograms, so how are they equivalent? i get that in the total 25 patch there is 1.6mg estradiol and that is all but equivalent to one spray of lenzetto, but you use lenzetto every day and only change the patch every 3 to 4 days. Any scientific explanation would be welcome, respectfully i dont want anecdotal replies, i just want the disparity explained, it is to do with bioavailability or something? thanks

[CLKD]

Sorry a) that U haven't had a response and b) that I can't help 

[sadbuttrue]

Thats kind, thank you

[bombsh3ll]

I think the equivalencies cited between gel and patches are largely based on clinical consensus rather than on any scientific study.

It is very difficult to derive any meaningful information from plasma estradiol levels on gel as there is a rapid spike after absorption, then it falls off sharply, whereas plasma levels on patches and to some degree pills are more stable.

It is possible to look at indirect measures such as changes in SHBG on a given dose of each.

Any difference in absorption between patches and gels is likely to be due to the properties of the carrier, how well it facilitates transfer of the estradiol molecules across the skin. There will also be some loss to evaporation or transfer to other surfaces with gel.

[sadbuttrue]

Thank you, so basically, with the spray, it really impossible to know how much estradiol you are getting because of variables like body composition and metabolism would you say?

[bombsh3ll]

It's impossible to treat to a numerical target with gel, you would just have to go by how you felt.

Some individuals really are sensitive to even small changes in estrogen and can tell where they are by their body's response.

Others like me are relatively estrogen blind, particularly where MHT is being used for health reasons such as osteoporosis prevention in someone without symptoms.

If you had a previous effective treatment to compare it to, and held everything else constant, SHBG could be used as an indirect marker.

Longer term, serial DEXA scans can tell you if your treatment is adequate, however waiting that long before finding out is obviously problematic.

The presence of vaginal atrophy points to very low systemic estrogen levels - Sarrell et al studied this in the 1990's and found VA was prevalent below 50pg/ml (note US units) but rare above this.

This therefore can serve as a prompt to review systemic treatment, but its absence doesn't guarantee the kind of systemic level that I personally would be happy with.

[sadbuttrue]

Thanks but i dont really feel that is in relation to my question. Im not trying to treat a numerical target, i asked why the amount of estradiol was so hugely disparate, but we are told the doses are equivalent.

HRT is not licensed for osteoporosis in people that do not have menopausal symptoms.

Testing my shbg would still not answer my question either.

Im trying to find out if there is a bioavailability issue that would lead such different doses to in fact actually be equivalent.

I appreciate you replying but feel you have gone quite far away from the question i asked, respectfully.

[Emma]

Evorel 25 Patch

- Delivers: 25 micrograms of estradiol per 24 hours
- Total content: 1.6 mg of estradiol in the patch
- Usage: Typically changed twice a week, so over 3–4 days
- The 25 micrograms/day is the actual absorbed dose — not the total estradiol in the patch.

---

Lenzetto Spray

- Each spray contains: 1.53 mg (1530 micrograms) of estradiol
- BUT: Only a fraction of that is absorbed through the skin
  - Rough estimate: ~8%–10% bioavailability via the skin
  - That means actual absorbed dose is around 120–150 micrograms per spray
- So you're applying more, but absorbing much less of it.

---

So how are they equivalent?

- Evorel 25: Absorbed dose = 25 micrograms/day
- 1 Lenzetto spray: Absorbed dose ≈ 125 micrograms/day (depending on skin, application site, etc.)

Here’s the catch: They’re not quite equivalent. 
- 1 spray of Lenzetto generally delivers more estrogen than Evorel 25.
- However, some guidelines consider 1 spray to be “low dose” similar to Evorel 25 in the broader sense, especially if the patch is being changed every 3.5 days — leading to an average total exposure that's closer over time.
 
But pharmacokinetically, Lenzetto is more variable — it has a faster rise and fall in blood levels than the steady delivery of a patch.

---

Summary

- The numbers look mismatched because they include different things:
  - Lenzetto's applied dose
  - Evorel’s absorbed dose
- After accounting for bioavailability, the absorbed doses are closer, though 1 spray of Lenzetto usually delivers a bit more than Evorel 25.
- Clinical “equivalence” is often based on therapeutic effect rather than exact microgram-to-microgram absorption.

---

If you're switching between them or adjusting doses, it's always worth checking with a doctor or pharmacist since individual absorption can vary a lot, especially with sprays.

[sadbuttrue]

thank you so much, that is exactly the information i was after, really helpful, thanks again