Deca with Finasteride effect on hair loss acceleration

Will Taking Deca With Finasteride Cause Hair Loss?

Whether or not combining NPP or Deca with Finasteride will accelerate hair loss is something often asked about in our community.

Typically Nandrolone Decanoate (Deca-Durabolin) and Nandrolone Phenylpropionate (NPP) are very hair safe compounds (they are the same hormone with different esters).

For those wanting to minimize hair loss on steroids, incorporating Nandrolone as the foundation of each cycle is a popular strategy.

Why Nandrolone Is Less Likely To Cause Hair Loss Than Other Steroids

The reason why Nandrolone is fairly hair safe is its relative lack of androgenicity in the body.

Relative to the base hormones we use as a reference point for hair loss (Testosterone and DHT), Nandrolone is a superior option.

However, this is not because Nandrolone is less androgenic than DHT and Testosterone.

In fact, Nandrolone is more androgenic than Testosterone, albeit less androgenic than DHT.

The low androgenic activity is solely due to the interaction of Nandrolone with 5α-reductase.

5α-Reductase is the enzyme mainly responsible for the production of dihydrotestosterone (DHT) in the body.

Testosterone is partially converted via 5α-reductase to the more androgenic metabolite DHT.

This same enzymatic process also partially converts Nandrolone into a metabolite known as dihydronandrolone (DHN).

Androgenicity Of Testosterone & DHT Vs. Nandrolone & DHN

DHN is the least androgenic of the four hormones.

If we were to list these four hormones in order of most to least androgenic, it would look like this:

  1. Dihydrotestosterone (DHT) – Most androgenic
  2. Nandrolone
  3. Testosterone
  4. Dihydronandrolone (DHN) – Least androgenic

Combining Nandrolone With Finasteride Or Dutasteride Will Accelerate Hair Loss

Because 5α-reductase is so dense in the scalp, we actually end up making Nandrolone more hair safe via our own natural endogenous enzymatic processes.

However, this is also why inhibiting this enzymatic process with 5α-reductase inhibitors can become problematic for steroid users.

Those utilizing NPP or Deca with Finasteride or Dutasteride are actually inhibiting this enzymatic process at 5α-reductase whereby Nandrolone would normally be converted into the far more hair safe metabolite DHN.

Thus, when combining Nandrolone with Finasteride or Dutasteride, the opposite effect occurs than with Testosterone [R].

Effect of a 5α-Reductase inhibitor on the androgenic activity of Testosterone, Nandrolone and MENT (Trestolone) in castrated rats.

As you can see in the graph above, using a 5α-reductase inhibitor partially inhibited the conversion of Testosterone to DHT.

This is why ventral prostate stimulation (a proxy for androgenic activity and hair loss) decreased so significantly in the 5α-reductase inhibitor treated group.

In the Nandrolone treated groups, using a 5α-reductase inhibitor partially inhibited the conversion of Nandrolone to DHN.

Because Nandrolone is much more androgenic than DHN, inhibiting this enzymatic process maintained higher serum concentrations of Nandrolone in 5α-reductase dense tissues and ventral prostate stimulation (a proxy for androgenic activity and hair loss) spiked significantly.

What Steroids Will Finasteride Protect You From?

Most of the steroids used for bodybuilding and powerlifting are not potent substrates for 5α-reductase, or are not substrates for 5α-reductase at all.

That means that Finasteride and Dutasteride will absolutely not help prevent hair loss on steroids like Dianabol, Trenbolone, Anadrol, Winstrol, Masteron, Equipoise, MENT (Trestolone), Proviron, Primobolan, DHB, and the list goes on.

It will also not help prevent hair loss on androgenic SARMs like S23.

At the end of the day, the only steroid worth mentioning that Finasteride or Dutasteride really help attenuate the progression of androgenic alopecia on is Testosterone.

And even with DHT substantially inhibited with Finasteride, or nearly wiped out entirely with Dutasteride, Testosterone still has its own inherent androgenicity and will miniaturize hair follicles too, just to a far lesser and slower extent.

This is why some individuals on Dutasteride with aggressive androgenic alopecia still lose hair even with zero DHT in their body.

How To Protect Yourself From Hair Loss On Deca Or NPP

The easiest way to do this is with a potent topical anti-androgen like RU58841.

Back in 2016 I was trying to find a log of someone who had used RU58841 concurrently with Deca or NPP to see if the same catastrophic Finasteride reaction would occur if I were to combine RU58841 with Nandrolone.

I scoured the Internet and could not find 1 single log of someone having tried them both at the same time.

I took it upon myself to guinea pig it, as NPP was my favourite bulking compound at the time.

If you have read my RU58841 article, you will know that I was in a state of severe diffuse thinning prior to starting RU58841.

At this state of diffuse thinning, I was also already about 1/3 of my way into a cycle of Testosterone and NPP.

I started with 50mg of RU58841 applied once per day, and within a week I already noticed that my shedding had dramatically decreased.

I went from losing 50-100+ hairs in the shower drain each shower to literally 1-5 hairs per shower.

Over the next couple months, I noticed significant density/thickness returning to my hair as I was now losing hair at a rate far slower than the rate at which I was growing it.

Within a couple months while still on my NPP cycle, I had regained a significant amount of ground I had lost from my previous cycles, and my hair looked as good as it did a couple years prior.

Obviously this experiment was super risky, as I could’ve ended up screwing myself far worse if RU58841 just so happened to have the same reaction with Nandrolone that Finasteride/Dutasteride has, but I lucked out, and uncovered a fantastic hair loss preventative measure for bodybuilders.

Reflecting on it now, I laugh to myself because I was so oblivious to the mechanism of action of these hormones that I failed to realize that topical anti-androgens facilitate their effects by binding to Androgen Receptors, and they have zero impact on 5α-reductase.

That means that there was no possible way Nandrolone converting into DHN would be inhibited, regardless of how much RU58841 I was applying.

All it does in layman's terms is compete with DHN in the scalp for androgen receptor binding.

Fortunately, RU58841 has a binding affinity equivalent to or greater than that of Testosterone, therefore it is actually quite effective at staving off androgenic activity that could be facilitated by DHN and residual amounts of Nandrolone in the scalp

In Conclusion

Never combine NPP or Deca with Finasteride or Dutasteride if you care about your hair.

If you want to use a more efficacious treatment to stave off androgenic alopecia on a Nandrolone cycle, a topical anti-androgen of formidable binding affinity like RU58841 would be worth considering.

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53 thoughts on “Will Taking Deca With Finasteride Cause Hair Loss?”

    1. Finasteride is Finasteride. It doesn’t matter if it’s a liquid or a pill, if you have Finasteride in your system then the same reaction would occur.

      1. Would the presence of deca potentially reduce the 5 alpha reduction of testosterone? I.E. If there is less 5 alpha reductase available as it’s binding to the deca, could that potentially decrease the hair thinning effects of the testosterone, without using finasteride?

  1. Im located in Australia who’s customs laws are some of the most strict in the world. Will this product reach me without being seized. Is there a high risk of the RU58841 being confiscated?

    1. I’m not sure, that’s up to whichever customs officer is looking at your package I would assume. It’s legal to possess, so it all depends on if they think it’s suspicious or not.

    2. I’m from Sydney. I received my package even though it was opened and inspected. It had a “Released from biosecurity control” sticker on where they opened it, and inside an “Opened for inspection” information pamphlet. the packets of RU58841 said RU58841 on them. the RU58841 packets were not opened.

  2. hi, I,m using deca 400mg per week with oxanderlon 40mg/day and I,ve started it for 2weeks but I thought I must pair finastride with deca as long as I use deca. now I find out that pair of them are harmful. so what should I do? can I stop using finastride and continue using of deca?

  3. Bro! I am planning to get off finisteride and use RU58841 *only* during Deca/NPP cycles. I would stop the fin a week before/start the RU at that time and vice verse afterward. Do you think that is a viable plan? Financially it is not worth it to be on RU year round.

      1. Say you were going to though. Would it be that bad to stop Finn for a month or so while using RU in the meantime and maintain RU while adding back the Finn after 4-6 weeks?

  4. I think I’m going to just try using deca & fin because there seems to be no conclusions drawn as to whether that combination is a myth or not.

  5. Derek – has previously run Deca & fin with no issues. Did it after having an HT, and hair looked best it had months after cessation of cycle.

    Fast forward to 3 weeks ago. Started moderate cycle of 500mg test, 300mg Deca, 4iu saizen GH. Using 1.25mg fin, 50mg RU, minox, and 2% keto – basically the exact blueprint from last cycle – and my hair is totally wrecked after 3 weeks. Transplanted hairline is fine, but totally thinner out behind it.

    Haven’t noticed much shedding. Have rubbed my hand through my hair for like 5 minutes over the sink and can get about 50 to drop on a given day, but nothing like the 2-300 you ready from other people.

    Nonetheless, thinning is apparent. Have dropped Deca and going back to my TRT dose to try and stabilize.

    Everyone will have different reactions, and no way to project, but it seems like you were able to get some nice density back in thinning areas. Is there hope for me, brah? I’m hoping it was a massive shed brought on by abrupt change in hormones & can repair due to short duration and low dosages.

    1. Trying to gauge what is causing what when you just added in 7 different things is pretty impossible, however, I will tell you what I believe is the most likely culprit based on the info given.

      You just started Minoxidil 3 weeks ago? As well as RU and 2% Keto? Even if you’re not noticing shedding, it’s definitely happening and you must not be noticing it. You can’t lose density without losing the hair off your head. 50 hairs is quite a bit for just rubbing your hair over the sink too. 100 hairs per day is typical for most guys, but honestly if you’re trying to gauge loss the best way in my experience is to check your hair catcher in the shower.

      When I’m stable, I literally will lose 5-10 hairs per shower max, sometimes less.

      Anytime I start to get into the 50-100+ hair range per shower, I know my rate of growth is starting to waver relative to my rate of loss.

      And that isn’t accounting for the other hair lost throughout the day that I don’t count because I don’t notice it.

      The shower hair catcher is the best benchmark in regards to gauging loss.

      So you’ve been on TRT for a while with no protection and have had no issues at all? I need more info.

      Based on what you’ve presented, it sounds like you ran Deca on TRT with minimal shedding, then you bumped the Test up, as well as added in Minoxidil and RU and 2% keto along with 4 iu’s GH and are starting to lose ground?

      My best guess is you are experiencing a shed from the introduction of Minoxidil and/or 500 mg of Test is too high of a dosage for your Fin and RU dosage to handle.

      But that’s based on the info provided, you’d have to clarify the timeline of the introduction of each of these products as it’s not clear if you’re sporadically starting and stopping these hair loss drugs or not.

      Any intermittent use of Minoxidil for example is a terrible idea and will always result in acute telogen effluvium

      1. Poor job of communicating on my part.

        Been on TRT for years. Been on fin/minox for years. Started using RU on my cycle prior to this one for added protection and continued use of it afterword. Started using 2% keto last week.

        The recent changes that brought on the shedding was moving Test dose from 200mg/wk TRT to 500mg/week, 2iu growth bumped to 4iu, and added 300 mg Deca.

        In other words, net change that brought on shedding was +300mg test, 300mg Deca, 2iu growth above baseline.

        As I said, it happened quick – only 3 weeks in, changes in my pictures look similar to your picture of being on/off RU.

        Hoping the drop back to TRT & 2iu with the full hair protocol can bring my shit back to where it was a month ago.

        1. Test is ruthless for some guys. Even one’s running full blown prevention protocols.

          I have a friend who uses 2.5 mg of Dutasteride per day (the highest dosage in clinical studies that inhibits 99% of systemic DHT conversion) and he still sheds even on TRT doses of Test.

          It’s a shame because it’s the bioidentical hormone we naturally produce and is thoroughly researched, but there are all of these other synthetic androgens out there that are far more hair safe but there’s just such a minimal amount of clinical data on them for us to judge their efficacy and safety profiles.

          I’m almost positive it’s your bump in Test that caused this. Especially if you’ve ran Deca in the past with no issues on Finasteride.

          Just goes to show that your hair follicles have a higher affinity to miniaturize from DHT and Testosterone than from DHN- dihydronandrolone.

          I know some guys who can run Tren and not shed but they’ll shed off of 500+ Test. It’s individually dependent, but I’m starting to learn in recent years more so how shit of a hormone Testosterone is when it comes to hair retention.

          You should recover within a few months if you drop the Test back down. I’m not sure if your TRT dose is actual TRT, or if you’re in the supraphysiological range, but I would advise you don’t push yourself past 900-1000 ng/dL and use the minimal amount necessary to achieve high-normal function. Most guys on TRT aren’t using true TRT, I’m sure you know what I mean.

          1. Thanks, Derek. 200mg puts me at ~1200 when I have labs done but doc is good with it because my H&H is still towards the low end.

            I’ve used as high as 600 test in the past with no issues. I guess lesson learned is just because hair survived in the past, doesn’t mean it will as you age.

            Rapid onset shedding led me to believe it was the fin/Deca reaction, but again, did the same thing 12 months ago with no reaction. Went as far as to tell friends the fin/Deca reaction was a myth.

            Anyway – appreciate the content. Great site, bro. Really good anecdotes on here.

          2. Ya that’s how I used to think as well, but what I didn’t realize is I just had more hair to work with and I wasn’t conscious of my slow progressive rate of loss relative to my rate of growth. You’ve finally just hit the threshold where minor increases of shedding result in very noticeable losses in density.

            Trust me man, when I was younger I thought I was immune to hair loss lol. In reality, I just hadn’t burned through enough hair yet to see the loss I was creating with my stupid dosages.

            That’s what inspired this article actually: You Won’t Notice Hair Loss Until You’ve Already Lost 50% Of It

  6. Great point. Your reclaimed density gives hope. I’ll throw an update on my implementation of the Derek hairstack in 3-4 months & see where we’re at.

  7. Question my dumb ass was running 5 mg of finastride will 200 mg Deca, 50 mg np, 200 of eq, with 400 mg of test e. 100 mg of anvar. I ran this cycle for 8 weeks lost a big Peice of hair on my hair line.. if I jump off all of it. Will it grow back I do not have male pattern baldness. I have got a very minimal reseeding hair line that I got fixed with an fue hair transplant. Will my hair start to grow back ?

    1. That’s literally what male pattern baldness is. You wouldn’t need a hair transplant otherwise, and wouldn’t be shedding severely with excessive androgens.

      Ya it could come back, however, you won’t recover if you continue to expose yourself to supraphysiological amounts of androgens.

  8. Interesting to read your hairline got wrecked. In my case, also had HT. All those hairs are fine and hairline good as ever. The mid scalp behind (original hairs) shed massively. Shedding has slowed but still 20-30ish in catcher after a good shampoo. Been off 3 weeks. Fingers crossed some comes back, even if thinner & shittier.

  9. Hi Derek, first of all thank you for all the information you show on your website, many of your articles are experiences that you have lived, and first-person accounts.
    I made a mistake that has me very worried, I explain.
    Since a year ago I am taking FINASTERIDA 1mg for a hair transplant that I did, and I have made the big mistake of using DECA, the amount has been small, it has only been 200mg a week for 3 weeks, I also used during that time SUSTANON 250mg, and I have noticed that my hair has been very weak and damaged, I even lost part of the transplanted hair
    I have used steroids only last year, before taking FINASTERIDA, and I had no problem.
    Of course I have stopped taking any anabolic or steroid, and I hope that having been so small, I can recover the good condition my hair had.
    Derek, my question is if under your experience what should I do? Do you think my levels will naturally be regulated? Should I take any other RU58841 type hair drug?
    I await your response with great enthusiasm.

      1. Thank you for the information, reading your messages I stay a little calmer. And I know that I must continue with my treatment of FINASTERIDE, MINOX and vitamins for hair. When I started reading comments online, and I saw that there were people who had had hair loss up to 16 months after using Deca and Finas together, I found it a bit strange since the Deca’s half-life in the body is not superior to one month, and it is assumed that from that period, more or less, the fall must be stopped. Knowing that you have recovered your hair gives me much joy and hope. I have not yet started with the UK, for now I will wait until I see how much it recovers, since with fine and minox I was doing very well, and I do not intend to consume more anabolic, I will try SARMS in a few months, since it seems That the side effects are much less. That said, I am very grateful, I am writing from Spain, here there is little information about it, and thanks to this page and your experiences I have clarified many doubts.

    1. Hey i also used deca/susta and fin. In middle of a Steroids cycle i start use finasteride and after 3 week i notice that shedding my hair then i read that fin and deca combine is shit. I stop everything only using now minoxidil after 1 month when deca out from system i start finasteride its possible that my hair regrow?

  10. What’s up guys – this is same AB that posted above. My hair thinned the fuck out with the deca/test/fin combo…

    I had done it before with no noticeable change. Perhaps age, introducing multiple hormones at once, increasing dosages on AI/Fin proactively player a roll.

    Anyway, dropped the cycle. I’m on prescribed TRT, which hasn’t changed. I kept shedding for another 4-6 weeks after stopping cycle, but good news is hair came back with fin/minox/RU/Keto regiment.

    It’s been a long time since I posted. Hair has maintained. Can no longer notice any different between pre/post cycle.

    I’m sure some was lost when thinking about it rationally, but can’t tell when inspecting and can’t tell in before/after pics.

    Good luck. Hope you end up in similar spot.

    1. AB, thanks for your response, knowing that much of the hair is recovering has reassured me a lot. It has been a month since the end of the use of DECA, and it seems that the hair is being a little thicker, and that tiny hairs appear on the first line, which has been quite deteriorated. I have continued with FINAS in this period of time, although I thought to leave it until the DECA disappeared from my body. What I have left completely have been the steroids, after this experience, surely later I used SARMS, I know they are not so effective, but their side effects are almost nil. Thank you very much for your interest.

    2. Hi AB, I wanted to ask you a question, I suppose that the UR58841 you started taking it in the wake of the sharp fall due to the use of DECA / FINAS? You didn’t use it before, since it wouldn’t have had problems in your hair. I wanted to know in what month after the fall you started with the UR, and if you continue with it today, or once the fall is stable, you left it and it was enough with the usual treatment of FINE and MINOX. If you want, and to not fill out this chat, my email fezansa1@hotmail.com
      Thank you for your help, who could be better for me that someone who has had a problem similar to mine to clarify that doubt. A greeting.

    3. There’s a lot of talk about this specific study and I’d like to point out that the comparison of test / Deca / Trest was in terms of relative androgenic potency. Trest is WAY MORE ANDROGENIC than test and Deca. Having them all on the same “0” baseline is therefore misleading.

      From the graph you’ve highlighted above:

      – Test “0” group represents DHT relative androgenic potency (at baseline)
      – Test “+” group represents Testosterone potency (as expected, weaker than DHT)
      – Nand “0” group represents DHN relative potency (baseline)
      – Nand “+” group represents Nandrolone itself (stronger than DHN)

      Those bars shouldn’t be used to compares different drugs, they’re only useful as a before/after 5ar use.

      Still, absolute androgenic rating of nandrolone (and Trest of course) is superior to that of testosterone but far inferior to DHT. Associating 5ar drugs with Deca solo sounds counter productive and will cause more hair loss than test+5ar, but less than test+DHT (sans 5ar). And associating 5ar drugs with test+Deca sounds positive since we avoid DHT. Still worse than test+5ar, or Deca solo.



      Interesting that testosterone isn’t that much more androgenic than DHN actually. So much for DHN being a piss weak, erectile dysfunction inducing compound. All in the head!

  11. Hi Derek, some food for thought because I think that your interpretation of the result is wrong, alongside Ergo-log’s here http://ergo-log.com/nandrolonefinasteride.html

    you guys forget that baseline androgenic stimulus is 5 times less for Nandrolone than Testosterone. It’s detailed in the first table in their article.

    So if you use Nandrolone+Finasteride, thus leading to 60% more androgenic effect… you’re still way below Test and DHT.

    1. basically what I’m getting at is that graph you shared should not compare % increases between groups. They don’t seem to be absolutes, but rather relatives and should be separated from one another. If we were to speak in absolutes, test being 100%, test+fin would be 60%, deca would be 20%, deca+fin would be 30%, Ment would be 400% and Ment+fina would be a touch under Ment only. We all know that similar doses of Trest and Test feel damn different, the former being far more androgenic at the same dose even with all the AI in the world to counter methylE2. That and other studies in other animals where small doses of Trest (in mg/kg, much smaller than Test) maintained prostate weight in mammals.

      So again, I think this chart above is misleading and you should discuss that maybe 😉

    2. Baseline androgenicity is accounting for 5-alpha reduction. Yes, “Testosterone” is probably 5 times less tissue selective than Nandrolone when you aren’t inhibiting 5-ar at all. The point of this article though is not whether or not Nandrolone + Fin/Dut leads to more or less androgenic activity than T, the point of this article is that it becomes more androgenic than baseline (Nandrolone monotherapy) with a 5-ar inhibitor present, hence it would not be wise to use a 5-ar inhibitor with Nandrolone if minimizing androgenicity is the goal. I see what you’re saying though, I may do another post on that specifically in the future.

  12. Hi Derek,

    After 6 years of using propecia, how long do you have to be off it to start an npp cycle so that they do not interact with each other? I know the half life of fin is only 6 hours but what would you suggest should be the time frame off finisteride before you start an NPP cycle?


      1. Hey Derek,

        On the flip side, how long after my last Deca shot before I can start back up on finasteride? From my understanding it stays in the system for up to 18 months but I assume that’s from a detection standpoint. What about it’s active life and interaction with finasteride? I don’t want to start finasteride until I know its out of my system from an interaction standpoint. What are your thoughts?

  13. What is your opinion on using Ketoconazole shampoo whilst running deca/npp.

    Just wondering if this combination will accelerate hair loss due to inhibiting 5ar like when using finasteride.

  14. I’m on 200mg/week of Test Cyp. and 300mg/week of NPP. I’m taking just enough arimedex to put my estrogen between 20-30 but my DHt is through the roof. I have bad acne that won’t go away, even had acne running the test only at same amount, but now I can’t take finasteride. What can I do to lower my DHT?

  15. How long after taking deca can I start finasteride and rogaine? In other words, how long does it take for deca to not be active and interfere with fina? I know it stays in your system up to 18 months but what about active and cause problems if I start the 2 drugs (fina and minoxidil)? Thank you!

  16. Sebastian Kunysz

    Would it be wise to run a 50mg Test and 60mg Deca as my TRT is 110mg per/week without the finasteride just RU? The Test dose would be for the much-needed estradiol. I really like Deca so If I can find a way to use it I’d love that.
    Right now I use:
    – 110mg Test C – split into 3 injections Monday, Wed, Friday
    -HCG from Innovation – 750 IU a week split into 3 injections. Monday, Wed, Friday
    – 1mg Finasteride day
    – Nizoral twice a week.

  17. Would topical finasteride create the same amount of issues as well? Prescribed deca recently and unclear whether topical fin should be discontinued.

  18. How long should I stop taking Finasteride if I want to do a NPP cycle? How long will I need to clear the Finasteride out of my system?

  19. Hi Derek, I ran a cycle of 250mg Test E combined with Deca 150mg/weekly for 8 weeks, I noticed quite a bit of shedding in my shower catcher in week 9 and have come off both completely.

    Ive been taking 0.5mg Finasteride daily for many years, my question is should I quit taking Finasteride for the next few weeks, then get back on it once more of the Deca has cleared my system. Thanks

  20. Hello,
    I think it might be good to use DHT Blocker Shampoos for Hair Loss instead ( as a compromise)?

  21. Hey Derek,
    Since topical fin has less chance of going systemic do you think you would still experience the same result as taking oral?

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