Sign Up FREE

Sign In

Remember Me

Submit a review

How-to Guides and Articles


This product has been reported as discontinued.


Only 2 Reviews - Waiting for more trustworthy reviews

See all 87 ranked products in:
Growth Enhancers > Natural Testosterone Boosters

550-XD Black is a Natural Testosterone Booster manufactured by FINAFLEX. It helps optimize your natural testosterone levels, which helps encourage muscle growth and fat loss.

This product has been reported as discontinued.


  October 5, 2013

Well after finishing this bottle of Finaflex 550-XD I thought i'd better write up a review while I have some time. I just finished it off this morning and felt what better time to write it up? Also there isnt a decent review for this yet and I understand it is being discontinued, but it's still probably worthwhile to get this done. So let's go.

- Vitamin C - 50mg
Finaflex 550-XD - 170mg:
- Decasterone (3b-enanthoxy-19-nor-androst-4-ene-17-one)
- Bergamottin
- Naringin
- Arimistaneâ„¢ (Androsta-3,5-diene-7,17-dione)
Liver Detox - 300mg:
- N-Acetyl L-Cysteine
- Milk Thistle Extract (4:1)(seed)

So Decasterone is a 19nor compound, which some people say works and some say doesnt. Redefine believe they have found a new synthesis pathway for it to make it more effective, or something, but I am skeptical to be honest. Please read the below link for a better explanation of the chemistry behind it:

Vit C, Bergamottin and Naringin appear to all be there to aid the absorption of the 'working' ingredient, but as it's a prop blend, apart from the Vit C you dont really know how much.

I've been told the Arimistane is only in there at trace levels, so dont count it in your arimistane dose if you are going to run another compound with it that does contain arimistane (like AD-3, Erase etc).

Finally, the liver detox is nice, but not sure it's really required in this. I mean, if you were smart and organising a proper stack with this, you'd include some sort of milk thistle/liver protection anyway.

For the ingredient profile, i'll give it a 5/10. Because it contains what you bought the product for in the first place (19nor) but not much else that is useful. Personally I would have preferred Redefine to ditch the arimistane completely instead of suggesting there was the possibility an effective dose was in there when there isnt.


They are pills, you slam them down. The inside of the bottle did stink a bit though, but you dont eat the bottle.


Dosing protocol was 2 tablets, one taken first thing in the morning, one taken after workout. I spread it out this way so that I could still take a HIT in the morning and also take my Dpol pre-workout and they wouldnt interfere.


Now, i've given this a 5 because it didnt do anything for me, but it didnt do anything bad for me, apart from 1 situation(which I will go into in side-effects). I ran this with Dpol and ANS HIT and i've run Dpol many times so I know what to expect with it. I was hoping that the 550-XD would give me a little more leaning, and possibly some strength gains, that beyond what I would normally get with just Dpol. Well that didnt really happen strength-wise, and the leaning I saw I attribute more to good diet and the HIT. So I cant really say that the 550-XD was any more than a placebo. I gave it a chance though, I didnt see anything in the first few weeks so I thought maybe it would take a while to kick in, but it never did. Some supplements you get to the last week of the bottle and wish you had a 2nd bottle to really see how it would go for 8 weeks, well not the 550-XD. I finished up the bottle and was pretty meh about it.

SIDE EFFECTS - 7.5/10:

Normally I give products a 10 here if they dont give me any sides, but in this instance I believe the 550-XD may have contributed to 1 episode. In my last week I had a pretty crazy anxiety attack that lasted well over 24 hours. I've never had one before, so past experience is negative. I've never had anything like it on Dpol, so count that out too. It was strange, and once I got over it I was fine, but not something I really want to repeat. Was it caused by the 550-XD? Who knows. But i've never had one before and never had one on Dpol so I can conclude it may have contributed. Apart from that everything was smooth sailing. No blood pressure issues, no excessive sweating or dizzyness or anything.

VALUE - 5/10:

I paid $50 for my bottle of 550-XD 12 months ago. I dont think it was too much for something that works, but you cant give someone good value in my book no matter how much (or how little) it costs if it doesnt work, and 550-XD did not work for me. Nutraplanet current has it for $75 which is way too much in my opinion. For ~$40 I would give it a go, maybe you'll respond.

OVERALL - 5/10:

I dont know if there's much else to day. I gave this a go, it didnt work, I gave it a 5/10 for a half-way sort of thing. I probably could have been a bit harsher on the marking but it must work for some people (or not, they are discontinuing it after all).

If you decide to run this i'd run it alongside something like Dpol or Isa-test or TX-3, just so you dont waste your time if it doesnt work.
    • Not Effective

      July 18, 2012

    I'm so sad to say that I am horribly disappointed in my lack of results :[

    I took 2 bottles for 40 days. 2 caps in the morning, 1 cap in the evening. I'm training 5 days a week. Taking in 3000 calories.

    I swear I am not trying to troll, or talk down this company because they were very helpful when I first contacted them.

    It's just, this product did nothing for me. The results are nothing more than I could've have gotten without 550xd.

    I started at about 160 lbs even @ 10%bf.
    Ended 40 days later about 162 @ 10%.

    A plus was there was so side effects at all. At least this product didn't eff me up the butt and gave me sides while not giving me the results I wanted.

    Strength stayed the same. Appetite stayed the same. I maintained my body fat %. No water retention. No stomach bloating.

    So definitely no negatives... but not positives as well.

    I hope it works better for anyone else willing to try it.
    • No Sides
    • Not Effective

    Copyright © 2017 All rights reserved. All trademarks are property of their respective owners.
    Some links may earn us advertising or sponsor fees; see our Affiliate Disclosure.