Does caffeine affect HRV?

Probably not if you're a regular drinker. A systematic review of 13 studies found habitual coffee drinkers showed no significant HRV changes from caffeine. In non-habitual drinkers, caffeine slightly increased parasympathetic HRV — the opposite of what most people assume. Tolerance develops quickly. Your morning coffee almost certainly isn't affecting your readings.

Why is my HRV so different from my partner's?

Possibly genetics — twin studies show 47-74% of resting HRV is heritable. But it could also be lifestyle differences: sleep, exercise levels, alcohol intake, medications like beta-blockers or antidepressants, or hormonal factors like menopause. Two people living in the same house can have very different HRV for entirely explainable reasons. Compare to your own trend, not to each other.

Can HRV predict how long I'll live?

There's a statistical relationship at the population level. A meta-analysis of over 38,000 people found those with the lowest HRV had 56% higher all-cause mortality. But this is statistics, not individual prediction. Your HRV reflects your current health — it doesn't determine your future. The things that improve it are the same things that reduce mortality risk independently: exercise, sleep, moderate alcohol.

Do I need to check my HRV every morning?

No. Let your wearable record it in the background and glance at the weekly average occasionally. Daily checking creates anxiety about normal fluctuations. If you're making a lifestyle change and want to see whether it's having an effect, look at weekly trends over a month or two.

What's the difference between RMSSD and SDNN?

Both measure heart rate variability, but in different ways. RMSSD looks at the variation between one heartbeat and the very next one — this specifically captures your recovery system (the parasympathetic nervous system). SDNN looks at the total variation across a longer measurement window, which includes your recovery system, your stress system, and slower background rhythms like breathing and blood pressure cycles. Most wearables (Oura, WHOOP, Garmin, Fitbit) report RMSSD. Apple Watch reports SDNN. The numbers aren't comparable.

Does Creatine Cause Hair Loss? What the Evidence Shows

Q: I'm a woman going through the menopause. Will creatine thin my hair?

Nobody has studied creatine and hair in women, so there's no direct answer. Hair often thins around the menopause anyway, as oestrogen falls. If yours is, raise it with your GP - there are treatments for female pattern hair loss, and they work best started early.

Q: I take finasteride. Does creatine still matter?

Probably not. Finasteride works by blocking the enzyme that turns testosterone into DHT, and it cuts DHT in the blood by around 70%. If creatine did nudge DHT up, it would have to go through the same enzyme your tablet is already blocking.

Q: If I stop taking creatine, will my hair grow back?

Stopping creatine is unlikely to change much, because creatine is unlikely to be the cause. If your shedding followed a diet, an illness or a stressful spell, it usually settles once the trigger has passed, though it can take a year or more for your hair to get back to full thickness. Pattern hair loss doesn't come back on its own. That's one for a dermatologist.

Q: I've also heard creatine is linked to cancer and kidney problems. Is it safe?

Neither is a reason for a healthy person to stop. The cancer study was in mice, and the kidney scare is a blood test being misread. I go through both, and the rest, in another blog I wrote on creatine side effects.

Man in his forties checking his hairline in the bathroom mirror

Key Takeaways

No study has shown that creatine causes hair loss. The one trial that measured hair found no change.
Shedding after starting creatine usually has another cause - your age, or a change in diet or training two to three months earlier.
3 to 5 grams of plain creatine monohydrate a day is all you need. Skip the loading phase.

Does creatine cause hair loss? It's a worry that puts a lot of people off taking it.

The short answer is no, not on the evidence we have. The idea comes from a single study in 2009 that never looked at anyone's hair. The only trial that has actually measured hair found no difference.

But plenty of people are sure it happened to them, and there are good reasons for that too.

I'm an emergency medicine doctor, and in this article I'll walk you through what the research shows, why people notice shedding when they start creatine, who might still want to be careful, and what to do if you're worried.

In this article

Does Creatine Cause Hair Loss? What the Research Shows

The worry started from one study in 2009.

Twenty college rugby players took creatine for three weeks, and a hormone linked to baldness, DHT, rose by 56%. DHT is made from testosterone, and it's the hormone behind male pattern baldness. So the worry was that it would lead to hair loss.

But nobody looked at their hair.

And no study since has found that same rise. For seventeen years, this worry persisted.

It took until 2025 for anyone to check hair directly. Researchers gave men aged 18 to 40 who lift weights either 5 grams of creatine or a placebo every day for 12 weeks. Dermatologists then measured their hair - how many hairs, how thick, and how many were still growing.

Thirty-eight men finished the study. There was no difference between the groups, in their hair or in their DHT. It's also a small study, but the largest and most detailed we have, and it's the only one that has measured hair.

Why Do So Many People Say Creatine Made Their Hair Fall Out?

There are three common explanations, and none of them needs the creatine.

Age. Pattern hair loss is common, and it gets more common every decade. In one US study, 16% of men aged 18 to 29 had moderate or more extensive hair loss. Among men aged 40 to 49, it was 53%.

That's about half of men over 40, with or without creatine.

In women it starts later: about a quarter show signs by 49, and around four in ten by 69.

Bar chart of pattern hair loss by age: 16% of men aged 18 to 29 and 53% of men aged 40 to 49 have moderate to extensive hair loss, while 12% of women by 29, 25% by 49 and 41% by 69 have detectable hair loss

If you start creatine over 40 and then take a close look in the mirror, there's a good chance you'll find thinning you hadn't noticed before. It was likely already happening.

Something else changed. When your body goes through a shock - a crash diet, losing weight quickly, an illness, a stressful few months - a large number of hairs stop growing and switch to resting at the same time. They don't fall out straight away. They stay put for two to three months, then shed together.

People rarely start creatine on its own. It usually comes with a new training plan, often a new diet, sometimes a push to lose weight. Two or three months later the hair starts coming out in the shower, and the creatine - the newest thing - gets the blame.

Timeline of hair shedding: a trigger such as a crash diet or illness, then two to three months with nothing visible while the hairs stay in place, then the shedding, then regrowth over the following months

Normal shedding. Losing 50 to 100 hairs a day is normal. On the days you wash your hair, a few days' worth can come out at once.

None of this proves creatine has never affected anyone's hair. But it explains why so many people are convinced it does.

Could Creatine Still Affect Some People?

So could it still affect some people? It hasn't been ruled out. The 2025 trial was small, and 12 weeks is short when pattern hair loss develops over years. It only included men under 40. And nobody checked whether the men were genetically prone to baldness. That last point matters most, because of how DHT thins hair.

Whether DHT thins your hair depends mostly on your hair follicles, not on how much DHT is in your blood. In people prone to pattern baldness, the follicles on the top and front of the head are unusually sensitive to it. DHT gradually shrinks them, so each new hair grows back finer and shorter than the last, until the scalp starts to show through. That sensitivity is largely inherited, which is why baldness runs in families.

If creatine affects anyone's hair, it would be people whose follicles are already sensitive, where a small rise in DHT might speed things up. But the 2025 trial found no rise in DHT at all. So far, there's nothing to suggest it happens.

A six-month trial was registered in 2020 to settle it, and never ran.

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So What Should You Do?

If you're healthy and strength training, nothing here is a reason to avoid creatine. Here's how to take it.

Take 3 to 5 grams of creatine monohydrate a day. That's the dose the research uses, and it's all you need.

Skip the loading phase. That's the advice to take 20 grams a day for the first week. At 3 grams a day your muscles reach the same level in about four weeks, and loading is where the 2009 DHT rise came from.

Stick to monohydrate. Don't pay extra for "hair-safe" versions like creatine HCl. There's no evidence any form is kinder to your hair, and monohydrate is the one all the research was done on.

Personally, I've taken creatine for two months and haven't noticed any change.

If baldness runs in your family, take a photo of your hairline and the crown of your head before you start, in the same light, and compare in six months. If you're worried, see a dermatologist. There are treatments that work, and they'll do far more for your hair than avoiding creatine.

If your hair is already shedding, look back two to three months. A new diet, weight loss, an illness or a stressful spell is a more likely cause than the creatine. It's also worth seeing your GP, because low iron and an underactive thyroid are both common, treatable causes of shedding, and a simple blood test checks for both.

If you're wondering whether creatine is worth taking at all, I've covered that in my post on creatine over 50.

I look at the recent concerns around Creatine and cancer spread in the following video:

The Bottom Line

The idea that creatine causes hair loss comes from one small study that measured a hormone, not hair. When someone finally measured hair, nothing had changed.

If your hair is thinning, look at your age, your family and the last few months before you look at the tub.

And if hair is the only thing that's stopped you taking creatine, take it. Just remember it only adds a little on top - the strength training is what builds the muscle.

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Frequently Asked Questions

I'm a woman going through the menopause. Will creatine thin my hair?

I take finasteride. Does creatine still matter?

If I stop taking creatine, will my hair grow back?

Can reading about a side effect make you notice it?

Yes. In one trial, men given finasteride for their prostate were split into two groups. One group was told about its possible sexual side effects and the other wasn't. On the same drug, 44% of those who'd been told reported side effects, compared with 15% of those who hadn't. Nobody has tested this for creatine and hair. But once you've read that creatine makes your hair fall out, you'll look harder, and you'll usually find something.

I've also heard creatine is linked to cancer and kidney problems. Is it safe?

Sources

van der Merwe J, Brooks NE, Myburgh KH (2009). Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clinical Journal of Sport Medicine. PubMed
Lak M, Forbes SC, Ashtary-Larky D, et al. (2025). Does creatine cause hair loss? A 12-week randomized controlled trial. Journal of the International Society of Sports Nutrition. Full text
Antonio J, Candow DG, Forbes SC, et al. (2021). Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? Journal of the International Society of Sports Nutrition. Full text
Rhodes T, Girman CJ, Savin RC, et al. (1998). Prevalence of male pattern hair loss in 18-49 year old men. Dermatologic Surgery. PubMed
Gan DC, Sinclair RD (2005). Prevalence of male and female pattern hair loss in Maryborough. Journal of Investigative Dermatology Symposium Proceedings. PubMed

Medical Disclaimer

This content is for informational purposes only and is not intended as medical advice. Always consult your healthcare provider before making changes to your health routine. What works for one person may not work for another — this is a roadmap, not a prescription.

About Dr. Eoghan Colgan

Emergency medicine physician researching what actually works for longevity. I interview world-class experts in health and longevity and test everything personally. Everything I teach is what I'm implementing myself. More about me →

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