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:
- Dihydrotestosterone (DHT) – Most androgenic
- 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].
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.
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
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.