Dr Neil Paulvin has a polite way of talking about the elephant in the room. One minute he’s breaking down growth hormone peptides like CJC-1295 – what they’re used for, how they stack up against Tesamorelin, and why they don’t always move the needle on your lab work. The next, he’s explaining how podcast superstar Andrew Huberman accidentally triggered a mild biohacking panic by overstating cancer risks in a podcast episode.
Paulvin is careful but not cagey. He’s prescribed CJC-1295 to many patients, from young professionals chasing better sleep to older adults looking for a recovery edge, and he’s the first to admit the data isn’t perfect. Some patients feel great. Others don’t feel much at all. It’s part biology, part belief and part what he calls “how empty your tank is.”
He’s frank about the theoretical risks and clear about who should avoid it. He won’t prescribe it to anyone with a history of cancer. He won’t prescribe it indefinitely. And he won’t pretend it’s a miracle cure. “We don’t have clear evidence either way,” he says, “so we proceed with caution.”
The result is a revealing, insider’s view of how a compound like CJC-1295 actually fits into the world of functional medicine; one expert, explaining what he’s seen work, what still needs proof and what it takes to do this properly.
Can you give us an overview of CJC-1295?
CJC-1295 is a growth hormone receptor agonist. It helps make growth hormone more effective. It may raise growth hormone levels, though I’ve had patients say their growth hormone didn’t increase, but it was still making it work better.
We use CJC-1295 specifically for sleep, skin, recovery, and muscle-building, since it works through the growth hormone pathway.
How would you monitor the effectiveness of CJC-1295?
With CJC-1295, it’s really a mix. Some people say their workouts are better. Some say their sleep improves. Some notice better skin. So the feedback is often anecdotal.
We don’t automatically monitor growth hormone levels. I will test it in some patients, but it varies. I’ve had patients where their IGF or other growth hormone markers don’t move — and others where they increase.
It goes back to this; how empty is the person’s tank? If their tank is full, you might not see a change in the labs, but you might still get a noticeable response in terms of how they feel.
I hear “increased growth hormone” and I think about IGF and cancer risk. Is that a myth or is that legitimate?
That’s the big elephant in the room. There is a theoretical risk. So we don’t use it continuously – only for a couple of months at a time. And if anyone has a history of active cancer, we don’t use it at all.
Andrew Huberman, in one of his early peptide podcasts, misstated some things that scared the dickens out of everyone, and I get it.
But in terms of data: we’ve had hundreds of thousands of patients on it, and we don’t have any clear evidence that it increases the risk of any specific cancer. That said, yes – growth hormone can affect tumour growth, so no one wants to push it too hard. It’s a kind of Catch-22 – we don’t have definitive evidence either way, so we proceed with caution.
Are there things you do to help mitigate risk or make it safer?
Yes. We typically have patients take it at night to match their natural growth hormone spike. We also make sure they take it on an empty stomach, usually 90 minutes after eating, so insulin doesn’t interfere.
In some patients, we monitor levels; in others, we don’t. If you ask 10 doctors whether they monitor growth hormone levels for peptides like this, most will say no, especially in relation to this class of peptide.
And again, we take a full medical history. If someone has a history of cancer, we won’t prescribe it – simple as that.
Is there a clear difference between CJC-1295 and other peptides that claim to boost growth hormone?
Yes and no — it depends.
Tesamorelin, for example; I sort of think of it as the stronger version. It’s excellent for muscle-building and recovery – better than CJC-1295, actually. But it doesn’t do as much for skin or sleep as CJC-1295 does.
Tesamorelin is also great for things like blood pressure, cholesterol and vascular health. That’s not really what CJC-1295 targets.
There’s some overlap, but also some differences — it’s kind of a Venn diagram. Then you’ve got the pills that people talk about – things like MK-677 or Ibutamoren – which are growth hormone secretagogues. They have different side effect profiles and work differently. They can also cause bloating, and they’re mostly used for muscle building.
So if someone’s doing a competition where they’re not being tested, or it’s summertime and they want to look good on the beach — that’s the niche. It’s a much smaller use case.
It’s the same with AOD. That’s another one we mostly use for joints. There’s some weight loss benefit too, but again, different side effect profile. So there’s overlap among these compounds, but quite a lot of differentiation as well.
You tend to think of low growth hormone as something that happens as you get older. But are there still benefits for people in their thirties and forties to be taking these sorts of things?
As I said, it really depends on the patient. We have patients in their twenties who are using it more for muscle building or sleep optimisation. So yes — people of all ages may be using it, but again, everything depends on the individual and what their goals are.
Some patients say, “I want the peptide with the fewest side effects,” so it becomes a bit like filling out a recipe card. You’re ticking boxes: “This helps with sleep, this helps with skin, this is a lower side effect option.” It’s not always about lab values. It’s more about understanding what each peptide does best. Some patients want pills, others want injections. So you work with what’s right for each person.
We’ve talked about growth hormone peptides. Are there peptides that target entirely different mechanisms as well?
Oh, definitely. There are between 90 and 150 peptides, depending on how detailed you want to get, especially if you include all the GLP-1s. You can use them to either lead or assist in almost any medical or preventative context.
Sometimes they’re the superstar, like with gut health, where they’re incredibly effective. For more complex neurological conditions, they’re often just an add-on to support healing or extend function – not the primary treatment.
But honestly, we use peptides head to toe. When I get asked that question, I usually break them down into six “buckets”:
- Inflammation
- Gut health
- Brain (for optimisation or healing)
- Mitochondrial and anti-ageing – where you’d include things like Epitalon and mitochondrial-targeted peptides
- Vanity – hair, skin, muscle building
- Miscellaneous – the ones that don’t fit neatly into a category
That framework helps patients get a sense of where everything fits.
For more on Dr Pauvlin, visit doctorpaulvin.com. Photography Luke Witter
