Transdermal gel and patches
✅ Transdermal administration (gels and patches) is a safe route, and easily accessible. The main downside is that it can be difficult to reach higher levels of estrogens necessary for monotherapy, and that the levels can vary a lot between individuals.
Estradiol is a good candidate for transdermal administration, meaning that it is rather well absorbed through the skin.
This mode of administration comes in two forms, gel and patches. There is no fundamental difference between the two. The choice is merely a matter of convenience (a daily or twice-daily application of gel, applying the patches once or twice a week). Note, however, that patches are subject to frequent shortages in pharmacies in Europe, and you sometimes need to apply many of them at the same time to reach the levels of estradiol you want, especially if the pharmacy is unable to provide the stronger ones.
In comparison to oral administration, the transdermal way has the advantage of avoiding liver first-pass - that this the quasi-total conversion of estradiol into estrone by the liver after digestion. With transdermal route, estradiol reach the bloodstream directly, without overcharging the liver.
However, there are great inequalities between each individual in terms of skin absorption abilities. Transdermal administration might be very efficient with some, but not with others, who would struggle to reach target levels of estradiol.
Pros:
- Easy and accessible, uninvasive
- Usually gives stable hormone levels if taken with regularity.
- Quite safe in terms of side effects, especially blood-clots (thrombosis)
Cons:
- Doesn’t work great on everybody
- For the gel, you have to let it dry, and be mindful of transfers if you touch people with the skin on which you applied the gel recently
- For the patches: can leave glue marks, irritate the skin, and they tend to fall off in the warm days of summer, with physical activity and warm shower/bath/sauna.
Gel
| Products | Doses | Blood values to monitor |
|---|---|---|
| Divigel, Estrogel (and Lenzetto, not ideal) | 2mg to 8mg a day, spread in morning and evening | Estradiol, Testosterone, FSH/LH (SHBG if you feel no effect after a few months) |
With the gel “Estrogel”, delivered in a bottle with a measured pump, the dosage is usually given in number of pump pressions.
Each pump pression delivers 0,75mg of estradiol; 4 pressions yelds 3mg…
Patch
| Products | Doses | Blood values to monitor |
|---|---|---|
| Estradot | 100 to 400 µg per day | Estradiol, Testosterone, FSH/LH (SHBG if you feel no effect after a few months) |
Equivalence between doses of patch, gel and pills
Theoretically, of 50µg/day patch is equivalent to a 2mg pill, and to 1.5mg in gel. These values, however, can considerably vary. Once again, the best way to ensure good levels is to do blood work.
How to apply gel/patches
Try as much as you can to apply on clean skin to optimize absorption. Apply on a hairless area (shaved works) Do NOT apply on breast: it does not help with breast development, but might increase the risks of breast cancer. Avoid applying on the inner forearm, as it might interfere with bloodworks results. If you do, start applying somewhere else at least a week before testing blood.
Note that a variant of transdermal route is nasal spray (intranasal). Estrogens are absorbed by the mucous membrane of the nose. This route is found to be more convenient by some people. However, this medication is not available in Sweden; but it can be found in other countries.
What is the scrotal method?
Scrotal method consists in applying the gel on the scrotum (the skin containing the testes). This skin being thinner and heavily vascularized, it leads to better absorption, so higher levels of estradiol for a same dose of gel(up to 6 times higher). Research has been conducted, but we know little on the long term effects of this method.
Some trans women using it report increased fragility of the penile skin, with skin easily breaking at points of frictions. Topical application of the gel on this area might also lead to overly low levels of testosterone, which is not recommended. Testosterone is part of a healthy hormonal balance for all individuals, and participates in maintaining cognitive functions such as memory, among other important functions… If, as a transfeminine person, you will want to stay under 0.5 ng/ml (50 ng/dl), reaching absolute zero (or close to it - under 0,8 ng/ml) is not recommended. Some trans women reported that stopping the scrotal method after using it for more than 6 months both improved the skin fragility, and the overly low testosterone level.
It remains, however, a possible method to use in order to achieve higher levels of estradiol with limited gel supply.
Sources
Testosterone replacement in male hypogonadism
« Due to the superficial vascularity of the scrotal skin, there is a 5-40 fold increase in steroid absorption when compared to other skin sites. »
« the relative permeability at other application sites was greatest for the scrotum (42.0), increased for the back (1.7), reduced for the lateral ankle (0.42), and lowest for the sole of the foot (0.14). »