Enlarged prostate sufferer here. I am currently using the Selle SMP TRK Medium saddle on my old Schwinn steel road bike: https://www.sellesmp.com/en/trk-medium.html. Although I don't feel any excess pressure or discomfort while riding, it seems that my urine flow slows down in the days after a ride. The SMP TRK is a touch soft and, despite the deep center groove, I'm wondering if I'm sinking too deep into it as I ride (I'm 174 pounds). Do I need a stiffer saddle in order to keep the perineum more elevated as I ride?

Does anyone here have a suggestion on a road bike saddle that completely relieves perineal pressure, possibly with an adjustable width?

I have enlarged prostate, prostate cancer fixed couple years back. I ride an SMP saddle (and many others). Consider Selle Anatomica with a cut-out. Longer cut-out and thinner/softer leather than Brooks, Ideale, etc.
Leather Bike Saddles | Anatomica Saddles for Cyclists – Selle Anatomica

Your urine flow slows down days after a ride. The number of times you have to pee. The quantity you have to pee. Or if it really haw strong the flow of urine is coming from you?

For the first two, it's probably just that you drink more on the day you ride. Days later you probably are just not drinking as much.

As for the latter, it probably has more to do with you and nothing to do with the saddle. Perhaps you should talk with your doctor about it.

Doctors have said I had a enlarged prostate for many of the annual medical checks I did during my middle ages. Never did I equate any of it to cycling or the saddle.

Seconded

My doctor recently told me that I have a slightly enlarged prostrate. I'm riding the Fizik 3d printed saddles on my bikes, and they are extremely comfortable to me. No prostate pressure felt although that may or may not be the saddle. Pricey, but worth it to me as they are very comfortable.

I took Tom Hanks advice and started taking specially formulated supplements. Issue fixed in less than 2 weeks.

I never found a saddle, and I have Selle Italia cutouts, that helped with the issue. What did help was getting on two prescription meds which took care of the stream and urgency issues. Sitting on non-cutouts back in my 40s exacerbated the situation. Nothing like the urgency thing happening with no bathrooms insight with no recourse.

since when did a cyclist need a bathroom?

I am taking Tamsulosin twice daily. After riding I do feel a little residual pressure in the perineum, which isn't painful or anything, but starting the next day I can feel that there is more resistance to my urine stream. May I ask what medications you are taking?

Does the Selle Italia saddle in the photo work well for you? I've come to the conclusion that saddles with firm padding are best for keeping the perineum pressure low.

Same, Tamsulosin and dutasteride 0.5 mg capsule. The combo is fantastic - other than occasionally feeling light headed when I get up too fast.

I see. Is the Sella Italia saddle working well for you?

I find it reasonably comfortable for rides up to 50-60 miles. I don’t know if there is a saddle out there that is supremely comfortable for hours on end, but this is the best I have found for my backside and prostate.

Consult a real doctor. There are dozens of quack remedies on the web. Check the ingredients, they are ALL the same thing. Pharmaceuticals actually work and they are not like the web collection. AND your health insurance will probably pay for the prescription from a doc.
But if saw palmetto and horney goat weed do it for you, go for it.

JMO of course

Saying you have a prostate issue then asking for saddles to fix it is like saying, "I have foot pain. Tell me what shoes to buy." While most of us have had our own issues and can give guidance with regard to our own issues we simply won't be able to fix your specific problem. For those that say "go to a doctor" you must be in the medical profession because almost all of us not in the profession understand that doctors don't have a clue when it comes to real life stuff like this. They will throw generalized medication at the issue as required by insurance and walk away.

I was diagnosed with benign prostatitis like 15-20 years ago. Urologist's recommendation: "change saddles". I went on a journey of a pile of saddles. When you find the one that works you buy them all. I am currently running a Cobb Fity-Five which is a tri style short nosed saddle. They don't make it anymore and almost all of mine are worn out. I will probably move to Selle Italia after this. I have been on most of the ones out there.

What has worked the most is prostate specific supplements over the years. Even then I have found I have to combine them. Huge doses of the most common still didn't fix things. Just made it slightly better. Certain combinations did GREAT. Currently on Saw Palmetto, Zinc, a TINY amount of Taurine, and Soy Lecithin. None of it works though until I add the TINY amount of Taurine. Too much and it doesn't work again. Too little and I am back to square one. Taurine won't do it on it's own either.

Everyone is different. I wish you luck in your search for relief.

I am a recently retired urologist, practiced for 37 years, cyclist since about 1988. averaged 6-8000 miles per year, . I can tell you it is much more likely urinary issues after cycling are coming from your urethra(the tube the urine flows through)rather than your prostate, unless you have a very large prostate ( which btw most doctors have no clue about prostate size) urethral pressure and cause voiding symptoms. Anatomically when you are sitting on the saddle and leaning forward on your bars, your prostate is away from the saddle unless you have an extremely upright position. Coffee or energy drinks with caffeine will increase your urine output and increase bladder sensitivity and make you go more often.
Tamsulosin is a great medicine, dutasteride not so much, and saw palmetto and all OTC meds absolutely no proof they work. Now saying there is no proof that they work is not the same as saying there is proof they do not. They won't hurt you so take em if you think they work. You might get some help from a urologist but unless your urologist cycles good luck. If you are taking saw palmetto or dutasteride(aka Avodart) or finasteride(aka Proscar) be sure and tell the urologist as all can give a false low reading if they measure your PSA-prostatie specific antigen, cancer screening test.