Several problems first:
1. Your body is the most significant variable. Your own metabolism, diet, and most importantly the expectations in your mind all matter.
2. Not only do ingredients matter, the amount of each ingredient matters.
3. Dosage and timing matter in relation to the other two.

First unlike a lot men I'm satisfied with my penis.  Trust me, strokin' or pokin' it has served me magnificently well over the years. The size of the my penis is average, the proportions are better than average.  More than once I have seen the appreciative stare in a woman's eyes and the words, "It's perfect!" Now mind you I didn't express my all thoughts to her at the time, realistically a man does wonder, 'just how many dicks have you seen?'
If she's seen a lot then you go wonder what you're sticking into. For once in my horny life I held my tongue.  I liked her enough my final thought of the moment was I'm going to make this so good you're not going to be seein' any other penises any time soon. Would I object if my penis were a couple inches longer?  Of course not! There are some devices that will help do that, do I want to bother with that? Frankly no.  When I see a penis pill advertising it will add inches and girth to your penis my bullshit detector sounds the alarm, not just a little dinging typewriter bell, more like a fire siren. (Yeah, I'm old, i.e. I remember typewriters.) More than once on the Supplement Critique website you will find the statements telling you pill by itself will not increase the size of the your penis, no pill will do that.  I don't know how many times that has to be repeated, nonetheless it's true. No pill in and of itself will increase the size of your penis.  Men just don't want to believe that so they keep looking for something that adds those extra couple of inches. Me?  As I said, I'm satisfied. Why did I take Xomax?  Several reasons, and a long thought process concluding that if I could find a supplement that made my erection harder, it would be well worth it. Getting it hard and keeping it hard are important, but an erection capable of penetration is necessary.  Somewhere between 35 and 50 the firmness of a man's erection fades. What was once capable of jackhammering concrete is wet spaghetti.  Pills make the penis size claim to get attention. Men, particularly aging men are thinking, "Hell will size, I need a harder dick.".  I know I was, over the years I've found a combo that works for me most of the time; it was a search of years, not weeks or months. During my transition from yocon and it's generics to other prescription meds and sex drive supplements I encountered Xomax.  I totally ignored the manufacture's claims about penis size and you should too. I very much hoped it would make my hard dick harder. Xomax only provided marginal help there.  Have realistic expectations, don't expect a state fair carnival.

Second, be thankful for SupplementCritique; the list of ingredients for each so easier found on SupplementCritique than elsewhere, even the manufacturer's website; in many cases there may not be a manufacturer's website at all and if there is, the ingredients may or may not be complete or even listed. The total amount of ingredients may not be listed, nor will the amount of each ingredient.  Most penis performance enhancing supplements contain epimidium, horny goat weed, in some form or another. Most do not say how much, except to list it as a component of a proprietary blend.  The older you are, the more boost you need. At 35 five hundred milligrams of horny goat weed may well be plenty.  The supplement you take may not even be close to that. I am well past 35, horny goat weed by itself will work for me, but I need five or six grams of the goat's kick; that's 5000 to 6000 milligrams.  I can't really really on that alone, there's too much better out there.

In the case of Xomax, the most accurate list of ingredients are shown on the SupplementCritique website, don't bother looking elsewhere, unless you have a month or more's time so to do. From my own use of Xomax, which is still available for sale a few scant places on the web, the beneficial ingredients in Xomax are not present I sufficient quantities to be of any major benefit.  If sexual stimulation, particularly tactile stimulation can raise you to at least half mast, Xomax might, might now mind you, help you get to full mast, with penetration capability for five to ten minutes. Don't expect a rock hard ramrod lasting fifteen minutes or longer.  Ain't happenin.'

Thirdly and finally, the dosage and timing for Xomax are not clear. Some sources say take two pills a day for weeks before any effect will be noticed.  Of course if you do that and notice nothing and contact the manufacturer he, or she, and likely the latter, these companies know you will be less likely to argue with a woman, will tell you that you are one of the those men who may be a slow respondent. You need to take it longer to get results.  This is just so they can sell you another bottle or two of the stuff while you sweat vain hope to make the man dong show more long.
I was hoping for harder, not longer.

Other instructions for Xomax said take two or three pills within forty five minutes of sexual activity. Having already taken one a day, then two, I knew I tolerated the stuff.  I took two pills before bed with the li'l woman and waited. There was a slight tingling and stirring.  A headache the next day, and sore balls, similar to blue balls, plus muscular aches in my nether regions. She was tired and was on her work schedule; she wasn't expecting sex, she wouldn't have refused me, but she wasn't begging for it either.  With prescription help for me and time to relax for her we had a love-making marathon over the weekend. No thanks to Xomax.

I would only recommend this to men who are younger and don't need much of a boost.  However, there's better out there, check out what's available from more reputable sellers on the web. These are generally third party sellers who have been in business for ten years or more.  These are also sellers who sell more than one line of products, not just penis products. Pharmacies such as your local store on CVS/Walgreen's style places have at least a moderate selection. Forget websites, there isn't one for Xomax, but there are others that only want to sell you their penis pill products and don't carry much if anything else.  Avoid them like the plague. In general I would not recommend this to a friend. Penis response to Xomax is modest at best.  I timed myself to full erection using nothing, and I measured the same time during stimulation while taking Xomax. No difference.  My erect penis was not any harder, nor truly fully erect for any sustainable time while I was taking Xomax; even though feminine company was readily at hand and in hand.
I took more time and was more verbose in this review than usual for two reasons. Xomax is still available and likely not worth your time nor trouble.  Two: When a man takes a prescription or OTC supplement for his penis, he needs to ponder carefully over time his methods, techniques, and expectations.

As usual, I'm tired of writing. Did not proof this so please ignore the typos.

Penis to penis, very truly yours,
Jasper