The #1 Reason Men Over 40 Avoid Creatine — And Why a 2025 Clinical Trial Just Proved It's Wrong

For 16 years, a single study involving 20 rugby players has quietly stopped millions of men over 40 from taking one of the most well-researched supplements in history. Now, a 2025 randomized controlled trial — the first ever to directly measure hair follicle health after creatine supplementation — has given a definitive answer, and the data is clear.

If you've been skipping creatine because you're worried about going bald, you've been avoiding a supplement that could be protecting your muscles, your brain, and your energy — based on evidence that was never as solid as the internet made it seem.

Where the Fear Came From: The 2009 Rugby Study Everyone Cites

In 2009, a small study published in the Clinical Journal of Sport Medicine examined 20 male college rugby players. Researchers gave half the group a loading dose of 25 grams of creatine per day for 7 days, then dropped to a maintenance dose of 5g/day for 14 more days. The other half received a placebo.

The finding: DHT (dihydrotestosterone) increased by 56% during the loading phase and remained 40% above baseline during maintenance. Since DHT is the hormone that causes androgenetic alopecia — male pattern baldness — health forums erupted. The logic was simple but faulty: creatine raises DHT → DHT causes hair loss → creatine causes hair loss.

What most articles miss is what actually happened in that study. First, all DHT values — before and after supplementation — remained within normal physiological ranges for healthy adult males (0.8–3.5 nmol/L). Second, the loading dose of 25g/day is far above what anyone recommends for daily use. Third, no one ever actually checked whether hair was falling out.

For 16 years, this single study — never replicated, using an unusual high loading dose, measuring hormone levels but not a single hair follicle — became the basis for widespread creatine avoidance among men concerned about their hair.

The 2025 Study That Actually Tested Hair Follicles

In April 2025, researchers published what the 2009 study never attempted: a 12-week double-blind randomized controlled trial that directly measured hair follicle health in men taking creatine. The study, published in the Journal of the International Society of Sports Nutrition (PMC12020143), enrolled 38 resistance-trained males aged 18–40 and randomly assigned them to either:

• 5g/day creatine monohydrate (a standard, commonly used dose)
• 5g/day maltodextrin placebo (identical in appearance and taste)

Both groups maintained their usual diet and at least three resistance training sessions per week. Blood was drawn at baseline and at 12 weeks to measure testosterone, free testosterone, and DHT. Here's the critical difference from the 2009 study: board-certified dermatologists at the Iran Skin Research Center also used high-resolution imaging technology (FotoFinder system) to directly assess hair follicle density, count, thickness, and growth phase percentages in the vertex scalp region — the area most prone to male pattern baldness.

What the Results Actually Showed

After 12 weeks, researchers found no significant differences between the creatine and placebo groups on any measure:

• DHT levels: No change. No group-by-time interaction (p > 0.05).
• DHT-to-testosterone ratio: No creatine effect.
• Hair count: No difference.
• Hair density: No difference.
• Hair follicle thickness: No difference.
• Anagen (growth) phase percentage: No difference.
• Total follicular units: No difference.

The study authors stated directly: "These results refute the common claim that creatine causes baldness." This is the strongest evidence to date — not because it's the only study, but because it's the first study in history to actually look at hair follicles rather than just hormone proxies. There were also no changes in creatinine or eGFR, confirming what dozens of prior studies have shown: 5g/day of creatine is safe for kidney function.

What Actually Causes Hair Loss in Men Over 40

Understanding why the 2009 results were misleading requires understanding how male pattern baldness actually works — and why men in their 40s and 50s are uniquely positioned to worry about it for the wrong reasons.

The Role of Genetics (Not Supplements)

Androgenetic alopecia (male pattern baldness) affects approximately 50% of men by age 50. The driving factor is not how much DHT is circulating in your blood — it's whether your hair follicles are genetically sensitive to DHT. Men with a family history of hair loss have follicles that are programmed to miniaturize when DHT binds to their androgen receptors. Men without that genetic programming can have high DHT and keep a full head of hair for life.

What most people don't realize: DHT levels naturally rise relative to testosterone as men age. The enzyme 5-alpha reductase (which converts testosterone to DHT) increases activity with age, and testosterone itself declines — creating a higher DHT-to-testosterone ratio in your 40s and 50s compared to your 20s. If DHT were the direct culprit, every man over 50 would be bald.

The Real Triggers of Accelerated Hair Loss After 40

Research points to several factors that genuinely accelerate hair loss in genetically predisposed men after 40:

• Chronic cortisol elevation: High stress pushes hair follicles into telogen (resting/shedding) phase. A 2024 study in Nature identified a direct pathway where cortisol suppresses a hair growth molecule called GAS6.
• Nutritional deficiencies: Low iron, vitamin D, and zinc are among the top non-genetic drivers of diffuse hair thinning in men over 40.
• Poor scalp blood flow: Reduced circulation to follicles is a significant factor, which is why exercise (which increases nitric oxide and circulation) is associated with slower hair loss progression.
• Genetic predisposition: Having a father with hair loss doubles your risk. This, not any supplement, is the primary determinant.

Creatine monohydrate at 5g/day does not appear on any evidence-based list of hair loss accelerators. The 2025 RCT — with direct follicle assessment by dermatologists — is the most direct evidence we now have.

What Men Over 40 Are Losing by Skipping Creatine

Here's the real cost of the hair loss myth: the men who avoid creatine tend to be exactly the men who need it most. After 40, several things happen simultaneously that creatine directly counters:

Accelerating Muscle Loss

Men lose an average of 3–8% of muscle mass per decade after 30, with loss accelerating sharply after 60. Creatine supplementation combined with resistance training has been shown in multiple meta-analyses to significantly increase lean body mass and strength gains in older adults — outperforming protein powder alone.

Declining Brain Energy

Your brain runs on ATP, and creatine is the primary buffer that keeps ATP levels stable during high-demand cognitive tasks. Research shows that brain creatine levels drop with age, contributing to mental fatigue, slower processing speed, and difficulty concentrating — the "brain fog" many men notice in their 40s. A 2022 meta-analysis in Nutrients found creatine supplementation significantly improved memory and processing speed, with stronger effects in older adults.

Falling Testosterone Support

Ironically, the concern about creatine raising DHT gets the direction of fear backwards for most men. While the 2009 study suggested a possible DHT increase (which the 2025 RCT did not replicate), some research suggests creatine may modestly support testosterone levels through its role in energy metabolism and muscle signaling — a potential benefit, not a harm, for men in their 40s experiencing natural testosterone decline.

One supplement that men over 40 are increasingly turning to for both muscle and brain support is ATO Health Creatine — a pure micronized creatine monohydrate with no fillers or additives. The micronized form absorbs more efficiently, which matters especially as digestive efficiency declines with age.

What This Means For You: Practical Action Steps

Here's what the 2025 research actually means in practice for men over 40 concerned about hair:

• If you're genetically predisposed to hair loss (father or grandfather with male pattern baldness): The science does not support creatine as a meaningful contributor to hair loss progression. Your DHT sensitivity is genetically determined. If hair retention is a priority, evidence-based interventions include finasteride, minoxidil, and maintaining healthy scalp circulation through exercise — not avoiding creatine.
• If you have no family history of hair loss: There is no evidence-based reason to avoid creatine for hair reasons. None.
• If you're already experiencing hair thinning: Consult a board-certified dermatologist about proven DHT-blocking treatments. Creatine is not on any evidence-based list of aggravating factors.
• Optimal dosing for men over 40: 5g/day of creatine monohydrate is the standard effective and safe dose. Recent 2026 research suggests adults over 40 may benefit from slightly higher doses (7–10g/day) for brain benefits, but 5g is well-established as effective and safe per the 2025 RCT.

Frequently Asked Questions

Q: Does creatine cause hair loss?

A: Based on current evidence, no. A 2025 randomized controlled trial published in the Journal of the International Society of Sports Nutrition (the first study to ever directly assess hair follicle health during creatine supplementation) found no significant changes in DHT levels, DHT-to-testosterone ratio, hair density, hair count, or follicle thickness after 12 weeks of 5g/day creatine compared to placebo. The older 2009 study that sparked the concern has never been replicated and used an unusually high 25g/day loading dose.

Q: Does creatine increase DHT?

A: The 2009 rugby study found a DHT increase during a 25g/day loading phase, but all values stayed within normal physiological ranges and the effect was never replicated in subsequent studies. The 2025 RCT using standard 5g/day dosing found no effect on DHT whatsoever. The majority of research on creatine supplementation does not show meaningful changes in testosterone or DHT.

Q: Should men with male pattern baldness avoid creatine?

A: There is currently no evidence-based reason for men with androgenetic alopecia to avoid creatine. Male pattern baldness is driven by genetic sensitivity to DHT at the follicle level, not by total circulating DHT levels. If hair retention is a concern, evidence-based treatments include finasteride (5-alpha reductase inhibitor) and minoxidil — not eliminating creatine, which has no direct evidence linking it to hair loss progression.

Q: What actually causes hair loss in men over 40?

A: The primary driver of male pattern baldness is genetics — specifically, whether your hair follicles are genetically sensitive to DHT. Secondary contributors include chronic cortisol elevation, nutritional deficiencies (vitamin D, iron, zinc), and reduced scalp circulation. DHT levels naturally rise relative to testosterone as men age due to increased 5-alpha reductase activity — this age-related change is far more relevant than creatine supplementation, which the 2025 RCT showed has no effect on hair follicle health.

Q: Is creatine safe for men over 40 to take daily?

A: Yes. Creatine monohydrate is one of the most extensively studied supplements in existence, with over 500 peer-reviewed studies. For men over 40, 5g/day has been shown to support muscle mass retention, brain energy, and physical performance with an excellent safety profile. The 2025 RCT also confirmed no changes in kidney function markers (creatinine and eGFR) after 12 weeks of supplementation.

Q: What is the best form of creatine for men over 40?

A: Creatine monohydrate is the gold standard — it's the form used in the overwhelming majority of research, including the 2025 hair loss RCT. Micronized creatine monohydrate dissolves more easily and may be absorbed slightly more efficiently, which is relevant as digestive function changes with age. More expensive forms like creatine HCl have no proven advantage over monohydrate and far less research behind them.

Sources & Further Reading

• Lak M, Forbes SC, et al. "Does creatine cause hair loss? A 12-week randomized controlled trial." Journal of the International Society of Sports Nutrition. April 2025. PMC12020143. Read study →
• van der Merwe J, Brooks NE, Myburgh KH. "Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players." Clinical Journal of Sport Medicine. 2009;19(5):399-404.
• Antonio J, Candow DG, Forbes SC, et al. "Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?" Journal of the International Society of Sports Nutrition. 2021;18(1):1-16.
• Lolli F, et al. "Androgenetic alopecia: a review." Endocrine. 2017;57(1):9-17.
• Forbes SC, Candow DG. "Creatine and strength training in older adults: an update." Translational Exercise Biomedicine. 2024;1(3-4):212-222.