Top 7 ED supplements, tested and ranked.
I spent around $430 across six months. Here's what actually got me hard again.
I've been a urologist for 18 years. I've sat across from hundreds of men and told them the same thing my own doctor told me when I started losing my erections: here's a prescription, take it 30 minutes before, call if you have side effects.
Not one of us had ever stopped to ask the obvious question: why does the blood flow slow down in the first place, and can you actually fix it without a pill every time?
Short on time? Out of the seven I tested, only one actually brought my erections back to where they were ten years ago.
See the winner →So I stopped assuming and started testing. Over six months I bought seven ED supplements: gas-station enhancement pills, herbal extracts, amino acid precursors, a testosterone booster gummy, and one I almost didn't try. I used each for four weeks, tracked what I noticed in the bedroom, ran a blood flow test before and after each one, and took two weeks off in between. Total cost including lab work: around $430.
Below are all seven, ranked worst to best. The last one is the one I'm still taking.
"Instant Male Enhancement" Blend
Gas Station / Amazon No-Name
The supplement equivalent of a slot machine. I felt nothing. No difference in the morning, no difference with my wife, nothing. And that's before you get to the real problem: the FDA has issued over 300 warning letters to products like this for containing hidden pharmaceutical ingredients. No published dosing, no named compounds, just a "proprietary blend" label hiding everything.
What works
What doesn't
It's the first thing most men try because it's right there at the gas station counter or the first page of Amazon. The packaging looks pharmaceutical, the name sounds clinical, and the bottle says "maximum performance" in bold letters. What it doesn't say: several products in this category have tested positive for hidden drug compounds that interact with blood pressure medications. After four weeks I couldn't point to a single night where anything was different. My blood flow test confirmed it: nothing moved.
Horny Goat Weed (Epimedium Extract)
The most Googled "natural Viagra alternative" on the internet. It actually contains a compound that works the same way as the prescription. The problem: in pill form, it's about 80 times weaker. You'd need to eat the plant by the bushel to get enough into your bloodstream to make a difference. Four weeks in, nothing changed for me.
What works
What doesn't
The best story in the category. An ancient Chinese herb with a name that sells itself, and technically, it does contain a compound that works the same way as the prescription. What every blog post skips: the dosing math. A 2008 Journal of Sexual Medicine study showed the active compound only works at concentrations way higher than what a capsule delivers. A standard 1,500mg capsule contains maybe 15-30mg of the active ingredient, and most of it gets broken down before it reaches your blood vessels. After four weeks, my erections were exactly the same. My blood flow test barely moved: 5.1 to 5.2. Within the margin of error. The science is real. The dose is fiction.
Testosterone Booster Gummies
The TikTok favorite. Ashwagandha, fenugreek, zinc, and vitamin D packed into a fruit-flavored gummy and marketed with influencer deals. The pitch: boost your testosterone, reclaim your edge. The problem: for most men over 40, testosterone isn't why you can't get hard. Your body's ability to send blood where it needs to go drops roughly 50% between age 25 and 45. That's a plumbing problem, not a hormone problem. Taking a testosterone gummy when the real issue is blood flow is like upgrading the engine in a car with clogged fuel lines.
What works
What doesn't
These are everywhere: Instagram, TikTok, podcast ads. A fruit-flavored gummy and a promise that your testosterone is the thing holding you back. For about 15% of men over 40, that might be true. But here's what the influencer ad skips: testosterone doesn't open blood vessels. Even if a gummy nudges your free T up 10-15%, the system that actually controls whether blood flows into an erection doesn't respond to testosterone. It responds to a completely different signal. After four weeks, I had slightly more energy during the day. In the bedroom, nothing changed. My blood flow test confirmed it: 5.1 to 5.1.
"I've spent probably $300 on supplements from Amazon over the last two years. Tongkat ali, maca, zinc, ashwagandha. My wife is patient but I can tell she notices. I don't want a prescription. I just want something that actually works on the plumbing, not the desire."
L-Arginine
The right idea, wrong execution. L-arginine is the raw material your body uses to make nitric oxide, the molecule that relaxes blood vessels and lets blood flow in. In theory, more arginine means more blood flow. In reality, your gut destroys most of it before it ever reaches your bloodstream. A 2003 BJU International study found L-arginine only worked when combined with another compound. Alone, it's like pouring water into a bucket with a hole in the bottom.
What works
What doesn't
The supplement every cardiologist has heard of and most won't recommend. The logic sounds right: arginine is what your body converts into nitric oxide, the molecule that opens blood vessels. More raw material should mean more blood flow. But your gut contains an enzyme that breaks most of it down before it ever gets where it needs to go. A 2003 BJU International study only got results when L-arginine was paired with another compound. Alone, it was no better than a sugar pill. After four weeks at 3,000mg daily, my blood flow test barely moved: 5.1 to 5.4. And in bed, I couldn't tell the difference from the month before.
Tongkat Ali (Eurycoma longifolia)
Tongkat ali has legitimate testosterone data. A 2022 meta-analysis confirmed it does raise free testosterone modestly. But here's the question most men don't ask: is testosterone actually the reason you can't get hard? If you're under 35, maybe. If you're over 40, the problem is almost always blood flow, not hormones. Boosting testosterone when the blood can't get where it needs to go is like upgrading the engine in a car with clogged fuel lines.
What works
What doesn't
I expected more from tongkat ali. The 2022 meta-analysis is solid: fourteen studies, modest but real free testosterone increases. I felt a difference in energy and mood during the four weeks. But my erections were about the same, and when I looked at the mechanism it made sense. Testosterone drives desire and arousal. It doesn't open blood vessels. For a man in his 30s with low T and healthy blood flow, this is a reasonable first move. For a man in his 50s whose real problem is that the blood isn't getting there, testosterone is a supporting actor, not the lead. This product does what it says. It just doesn't do what most men buying it actually need.
L-Citrulline
The smart upgrade from L-arginine. L-citrulline takes a different route through your body and actually survives long enough to do its job. It skips the gut enzyme that destroys L-arginine and converts to the raw material for blood flow in the kidneys instead. A 2011 Urology study found that 50% of men with mild ED reported firmer erections at 1.5g daily. This one is legitimate. Real mechanism, real data, real improvement. It's #2 for a reason.
What works
What doesn't
The first product in six months of testing where I actually noticed a difference. I woke up harder more mornings than not. L-citrulline survives digestion, reaches the kidneys, converts to the raw material for nitric oxide there, and actually raises blood flow. The 2011 Urology study is one of the few in this category that used a real functional endpoint and found a real result. I took 3,000mg daily for four weeks. My blood flow test went from 5.1 to 6.2. The reason it's #2 and not #1: citrulline gives your body more raw material to work with, but it doesn't fix the part of the system that's actually slowing down. After 40, the enzyme that tells your blood vessels to open starts underperforming. More raw material helps, but it doesn't fix the root problem. You're filling the tank without tuning the engine.
Clovi High Flavanol Cocoa
One ingredient. Clinical dose. And it goes after the actual problem. This is the product that changed everything for me. Every other supplement on this list either gives your body more raw material or weakly blocks an enzyme. Clovi's cocoa flavanols, specifically 600mg of epicatechin per serving, go straight to the source: they activate the enzyme that tells your blood vessels to relax and open. Not more raw material. Not a weak blocker. The on-switch itself.
What works
What doesn't
I almost didn't test this one. A cocoa powder for erections. In a category full of capsules with Latin names, it seemed too simple. Then I looked at the research. Epicatechin, the main compound in unprocessed cocoa, goes straight to the lining of your blood vessels and turns on the enzyme that makes them open. Not more raw material. Not a weak version of a prescription drug. It flips the actual switch. Blood flow increases within hours of your first serving.
The COSMOS trial at Brigham and Women's Hospital followed 21,442 people taking cocoa flavanols. Studies in the British Journal of Nutrition, the American Journal of Clinical Nutrition, and the European Heart Journal all found the same thing: real, measurable improvement in blood flow. I started with one serving daily. By week four, I was waking up harder than I had in years. My blood flow test went from 5.1 to 7.8. I kept going to eight weeks. Final score: 8.7.
The processing matters: standard Dutch-processing destroys 60-90% of the compounds that actually work. Most cocoa powder at the grocery store has been stripped of everything useful. Clovi is non-alkalized, cold-extracted, single-origin Peruvian Criollo. I mix it into my morning coffee. It tastes like dark chocolate. After six months and seven products, this is the only one that's still on my counter.
All seven, side by side
Every product, every price, every blood flow result, lined up.
Based on six months of testing: only one product on this list goes after the actual reason blood flow declines, at the dose the research used, in a form your body can actually absorb.
What the industry doesn't tell you
What I wish I'd known
If you're tired of guessing and want to see for yourself
I'm not your doctor. I'm one urologist who got tired of giving advice I wouldn't take myself. Clovi has a 60-day money-back guarantee, which means you can try it and ask for your money back if you don't notice a difference. Your body will tell you whether it's working. That's the only test that matters.
CHECK AVAILABILITY →EDITORIAL NOTE & DISCLOSURE
This article contains affiliate links to one product (Clovi); if you buy through them, Men's Vitality Report may earn a small commission at no extra cost to you. This does not influence the ranking, and Men's Vitality Report does not accept paid placement. The other six products were purchased at retail with personal funds and are not affiliated.
Dr. Ellison's experience is his own and is not typical. Individual response to any supplement varies based on age, health status, medications, and underlying conditions. Blood flow and vascular function should always be evaluated by a licensed physician for your specific case. This article should not be construed as medical advice for any individual reader; it is one clinician's documented self-test. Always talk to your doctor before starting or stopping any supplement.
All competitor brand names are the trademarks of their respective owners and are referenced for editorial comparison only; no affiliation is implied.