Chemically Affecting Libido
What hormones most affect libido? And other drugs?
Day 27/30 of writing daily.
It’s worth noting that most things here have a lot of variance between people. I give my general impression, but this is more speculative than many other posts I have done. I err towards painting a concrete image that is mostly true, rather than a muddy picture that is more technically accurate.
Types of Libido
It’s worth understanding that libido can be felt differently depending on the person, but roughly there are two main axes for what libido can feel like.
Both feel like an urge/desire to have sex, but can feel qualitatively different
One axis, is a more “spontaneous” libido. This can feel like:
Libido is never quite off, more like low enough to be not noticeable behind the background of everything else. If this were a gas stove, one can dial it down the the lowest setting, but one need only turn up the dial, not reignite it again.
Heightened sensitivity is felt localized in the genitalia.
The means are nice but the end is what you most strive for.
Once achieving a final orgasm, the drop in libido is quite sharp and sudden.
Refractory period before next orgasm is typically moderately long.
The second, is a more “Responsive” libido style. This can feel like:
Libido is often completely off, and takes more effort to ignite, though can sometimes ignite more spontaneously. And more sensitive to relatively sudden turn-offs.
Heightened sensitivity is felt all over the body
The means are perhaps a larger part of the experience than the end be default.
Refractory period is typically quite short
Achieving orgasm leads a drop in libido over a slower period of time
People differ significantly, and can have a combination of factors between the two. A lot of this can be altered by various medical aids.
Sex Hormones
There are a few main hormones that can alter profile of sexual experience for people:
Testosterone
This has the strongest effect on libido. Transfeminine people often experience a huge drop in libido after lowering testosterone levels, and transmasculine people often experience a huge surge upon raising testosterone levels.
There are many other effects from testosterone though. It’s worth noting that some women do supplement testosterone to be in upper female range to have some higher libido without masculinizing effects
It is possible to lower
Estrogen
This has a relatively weaker effect on libido. Some transfeminine people report regaining a more feminine-style libido after having their hormone levels in the feminine range for a long time. Others do not.
Progesterone
Though anecdotes, people do report higher libido on Progesterone if their libido was low on Estrogen. True for some, not for all.
Synthetic Progestins
There exist synthetic variants of progesterone, called progestins, which typically lower libido. These can lower libido. Part of this is by lowering testosterone, but they can also separately block libido even if testosterone is replaced.
There are many forms, Medroxyprogesterone acetate, cyproterone acetate, levonorgestrel, drospirenone, etonogestrel, levonorgestrel IUD. These can be looked at seprately.
Blood Flow Enhancers
PDE5 inhibitors
Sildenafil, aka Viagra, is perhaps the most well known drug used for sexual purposes. It generally is just a blood-flow enhancer, and can lead to making it easier to getting errections. It does not generally affect libido directly (mental state), rather only affecting physiology (physical state).
Tadalafil, aka Cialis, is basically a longer-lasting version of Sildenafil. The elimination half-life of Tadalafil is 17.5 hours, compared to 4 hours for Sildenafil.
It is contraindicated with some few medical conditions and other medications. Though it generally has few side effects, and there is moderate evidence it might be correlated with reduced all-cause mortality for older people.
Direct Libido Enhancers
Flibanserin was the first drug approved for improving libido. It had many side effects and was not very effective.
Bremelanotide/PT-141 is another libido enhancing drug, used to treat low sexual desire in women. It is typically administered by injection. The elimination half-life is reported to be 2-4 hours, though may be different depending on route of administration.
It depends on the person, but effects can be useful or can be modest. It has more potential side-effects than the previous drugs. Hyper-pigmentation is one rare side effect(~1 in 100, higher if abused), for interesting reasons.
Melanotan II, is a peptide that is used for increasing melanin production in skin. This was found to raise libido in people, and so was used as inspiration when discovering PT-141. If you want to use either, you should use PT-141
kisspeptin is currently under study, and might be approved as a replacement for PT-141.
Dopamine can also affect libido significantly. Drigs that affect dopamine (eg: bupropion) though this is usually a secondary concern for most of these drugs.
Direct Libido Dampeners
The main libido drop comes from dropping testosterone/blocking androgen signalling. See feminizing HRT.
Synthetic progestins help, as mentioned before
There are various other levers too, often incidental. Affecting dopamine, or prolactin-raising drugs can reduce libido.
Refractory Period
There is little research on how to affect this directly.1 My vague current understanding:
There are separable neural circuits for orgasm and ejaculation
Things like ejaculation and refractory period seem to be affected by testosterone-driven maturation.
It might be possible to affect the circuits separately to alter refractory period.
Cabergoline
This drug that has some interesting effects. It affects prolactin and dopamine D2, and also maybe helped reduce refractory period:
Administration of cabergoline decreased prolactin levels and significantly enhanced all parameters of sexual drive (P<0.05), function (P<0.01) and positive perception of the refractory period (P<0.01).
It has a half-life of ~65 hours, and at long-term high doses can lead to heart valve failue, so it’s mostly only used treat prolactinomas and Parkinson’s disease.
Closing Thoughts
There are many drugs that chemically affect libido. Some drugs can affect how easy physical sex is.
These will not, necessarily make you enjoy sex if you didn’t enjoy it before, or vice versa. These can be different axes.
If you enjoy sex, you may benefit from raising libido, if you don’t enjoy sex, you may benefit from lowering libido.
Many of these things that affect libido, however, will be incidental compared to other parts of your life.
Most of my info comes from one good reddit post and some conversations with claude