Can Hormone Pellets Cause Hair Loss?

Hormone pellets can contribute to hair loss in some people, but the relationship is more nuanced than a simple yes or no. The key factor is not the pellet itself but what happens after the testosterone it delivers gets converted into dihydrotestosterone, or DHT, a hormone that can shrink hair follicles in people who are genetically susceptible. Interestingly, a large questionnaire study of women on testosterone pellet therapy found that not a single patient reported scalp hair loss, and many who had been losing hair before treatment actually saw regrowth. That finding complicates the popular narrative that testosterone pellets reliably cause thinning, and the real picture depends heavily on dose, genetics, and sex.

What Testosterone Pellets Do Once They Are Implanted

Hormone pellets are small, rice-grain-sized implants placed under the skin, usually in the hip or buttock area. They release testosterone (or sometimes estradiol) steadily over several months. After implantation, blood levels of testosterone rise, peak within the first couple of weeks, and then gradually decline. In one pharmacokinetic study, testosterone pellets delivering 900 mg kept total testosterone at or above 300 ng/dL for about 113 days, with free testosterone, DHT, and estradiol all following a similar curve.¹ The number of pellets implanted also matters: men receiving fewer pellets saw lower peak testosterone levels than those receiving more, though the rate at which levels declined was roughly the same across groups.²

The slow, sustained release is part of what makes pellets attractive compared to injections, which can cause sharper spikes and troughs. But steady release does not mean hair-safe release. Because the body converts a portion of circulating testosterone into DHT through an enzyme called 5-alpha reductase, any method that raises testosterone levels, whether pellets, injections, gels, or patches, can increase DHT at the scalp.

The DHT Connection to Hair Follicles

DHT is the main hormonal driver of androgenetic alopecia, the pattern hair loss that affects both men and women. It binds to androgen receptors in genetically susceptible hair follicles and triggers a process called miniaturization, where follicles progressively shrink and produce thinner, shorter hairs until they eventually stop producing visible hair altogether. Animal research has shown this effect clearly: when DHT was applied to hair follicles in mice, it caused early hair regression, reduced hair density, and altered hair shape. Blocking the androgen receptor with an antagonist partly reversed these changes.³

The critical phrase here is “genetically susceptible.” Not every hair follicle responds to DHT the same way. Follicles on the sides and back of the scalp tend to be resistant, which is why those areas are spared in typical pattern baldness. Follicles at the temples, crown, and frontal scalp carry more androgen receptors and are more vulnerable. If your follicles do not have a strong genetic predisposition to shrink in response to DHT, raising your testosterone and DHT levels may not affect your hair at all. If they do carry that predisposition, the additional DHT from pellet therapy could accelerate a process that was going to happen anyway, or kick-start one that had not yet become visible.

What Clinical Studies Show in Women

Some of the most reassuring data on hormone pellets and hair come from women receiving testosterone pellet therapy for androgen deficiency. In a study of 285 women, about a quarter reported hair thinning before starting testosterone. Of those, roughly two-thirds reported their hair actually grew back during treatment. Strikingly, not a single woman in the entire cohort reported scalp hair loss as a side effect, even though their testosterone levels during therapy averaged about four times higher than the upper limit of what the body normally produces.⁴

That result surprises many people, but it aligns with a broader understanding of how androgens interact with hair. In androgen-deficient women, low testosterone can itself cause diffuse thinning. Restoring testosterone to a therapeutic range may actually support the hair growth cycle. Estrogens, which also rise alongside testosterone during pellet therapy, play a protective role as well. Research has identified that estrogen synthesis within the hair follicle itself appears to help regulate the hair growth cycle, with a drop in local estradiol production coinciding with the end of the active growth phase.⁵ Because testosterone pellets can raise estradiol as well as testosterone, the net hormonal environment at the follicle may not be as aggressively androgenic as you would expect from the testosterone number alone.

A separate long-term study of women receiving testosterone pellets found that adverse events were limited to the higher-dose group. In women receiving 75 mg pellets, about 5% reported mild facial hair growth, but again, scalp hair loss was not among the reported side effects.⁶ Facial hair growth and scalp hair loss are driven by the same hormone but in opposite directions: androgens stimulate facial and body hair follicles while potentially shrinking scalp follicles. The fact that some women experienced one without the other reinforces how follicle-specific the response to androgens is.

The Picture Looks Different in Men

While the women’s data is encouraging, the situation for men is less clear-cut. Men receiving testosterone pellets generally reach higher absolute testosterone and DHT levels than women do, simply because the doses used are larger. A narrative review of testosterone use in athletic populations documented a case of a man in his thirties who developed androgenetic alopecia about a year after beginning hormone supplementation that included testosterone pellet implantation.⁷ A single case report does not prove pellets caused the hair loss; the man may have been on the verge of developing pattern baldness regardless. But it illustrates the concern, especially for men with a family history of hair loss.

Men are statistically far more likely than women to carry the genetic profile for androgenetic alopecia in the first place. When you layer higher-dose testosterone replacement on top of a strong genetic predisposition, the odds of noticeable thinning go up. The delivery method, whether pellets, injections, or topical gel, is less important than the resulting DHT levels at the scalp. Pellets do not uniquely cause hair loss compared to other testosterone formulations. They simply sustain elevated testosterone for months at a time, which means DHT exposure at the follicle is also sustained rather than fluctuating the way it might with shorter-acting formulations.

Dose and Monitoring Are the Practical Levers

If you are already on pellet therapy or considering it, the most actionable variable is dose. Because pellets cannot be easily removed once implanted, getting the dose right upfront matters more than with a gel or patch you can stop applying. The pharmacokinetics of pellets also mean that peak testosterone levels in the first two weeks can be substantially higher than the steady-state level you reach a month or two later.¹ That early spike produces a corresponding spike in DHT, which is the window where follicles most susceptible to androgenic damage may be affected.

Checking blood levels of testosterone, free testosterone, and ideally DHT a few weeks after insertion gives you and your clinician a picture of where you actually land. Supraphysiologic levels, meaning levels above the normal range, carry more risk for hair and for other side effects. If levels come back higher than needed for symptom relief, the next round of pellets can use a lower dose. This is one area where pellets are less flexible than daily or weekly formulations: you cannot simply dial down the dose tomorrow if levels are too high. You wait until the pellets are depleted and then adjust.

Other Reasons You Might Lose Hair During Pellet Therapy

Not every instance of hair shedding that coincides with pellet therapy is caused by the hormones. Correlation in timing does not always mean causation, and several other conditions can trigger hair loss in the same demographic that tends to seek hormone pellet therapy.

Thyroid disorders: Both hypothyroidism and hyperthyroidism cause diffuse hair thinning. Women in perimenopause and menopause, one of the largest groups using hormone pellets, are also at elevated risk for thyroid dysfunction. A thyroid panel is a reasonable step before attributing hair changes to the pellets.
Iron deficiency: Low ferritin is a well-recognized contributor to hair shedding, particularly in premenopausal women. It can mimic or worsen androgenetic alopecia.
Telogen effluvium: This is the widespread shedding that happens a few months after a physical or emotional stressor, including surgery, illness, rapid weight change, or even the hormonal shift of starting a new therapy. It is temporary and resolves on its own, but it is easy to blame on whatever medication you started around the same time.
Age-related thinning: Hair density naturally decreases with age in both sexes. Starting hormone therapy in your forties or fifties means any age-related thinning happening in the background will overlap chronologically with the treatment.

Research examining the relationship between thyroid-stimulating hormone levels and androgenetic alopecia in men found no statistically significant association between the two, suggesting that thyroid abnormalities are a separate issue rather than a contributor to the pattern hair loss driven by androgens.⁸ That distinction matters because the treatment is completely different. Thyroid-related hair loss resolves when thyroid function is corrected. Androgen-driven hair loss requires addressing DHT directly or protecting the follicles.

What You Can Do If You Notice Thinning

If your hair starts thinning after pellet insertion, the first step is figuring out whether the pellets are actually the cause. A blood draw checking testosterone, DHT, thyroid function, ferritin, and a complete blood count gives you a solid foundation. If DHT is elevated well above the normal range, the pellet dose is a likely contributor, and lowering it at the next insertion is the most direct fix.

For people who want to stay on pellet therapy at their current dose, topical minoxidil is one of the most widely used options to support hair growth independently of hormonal changes. It works by extending the growth phase of the hair cycle and improving blood flow to follicles. Some clinicians also prescribe medications that block 5-alpha reductase, the enzyme that converts testosterone to DHT. In men, oral finasteride is well established for this purpose. In women, the situation is more complicated because these drugs can cause birth defects, so they are generally reserved for postmenopausal women or those using reliable contraception. Spironolactone, which has anti-androgen properties, is sometimes used in women as well.⁹

Low-level laser therapy, platelet-rich plasma injections, and nutritional optimization (particularly iron and vitamin D) round out the toolkit that many dermatologists and trichologists draw from. None of these specifically counteract the DHT produced by hormone pellets, but they support hair follicle health through parallel pathways.

Facial and Body Hair Growth Versus Scalp Hair Loss

One pattern that confuses many pellet therapy patients is experiencing thicker facial or body hair at the same time as scalp thinning, or getting one without the other. Androgens have opposite effects on different follicle populations. Vellus hairs on the face and chest are stimulated by testosterone and DHT to become thicker terminal hairs, which is why testosterone therapy can produce new facial hair growth. Scalp follicles in susceptible areas respond to the same hormones by shrinking. The fact that the long-term women’s study found mild facial hair growth in a small percentage of the higher-dose group, without corresponding scalp hair loss, is a good example of this divergence in action.⁶

For women in particular, mild facial hair growth is often manageable and may be preferred over the symptoms of androgen deficiency that prompted treatment. But it does signal that androgens are reaching follicles at biologically active concentrations, which means scalp follicles are seeing those androgens too. Whether scalp hair responds negatively depends almost entirely on the genetic sensitivity of your specific follicles. There is no reliable way to test for this in advance other than family history, which is imperfect: some people with strong family histories of pattern baldness tolerate testosterone replacement without visible scalp changes, while others with no obvious family pattern notice thinning.

How Pellets Compare to Other Testosterone Delivery Methods

Patients sometimes ask whether switching from pellets to gels or injections would spare their hair. The short answer is that the delivery vehicle is not the primary issue. What matters is how much testosterone enters your bloodstream, how much of it converts to DHT, and how sensitive your follicles are. Pellets, injections, topical gels, and transdermal patches all raise testosterone and consequently DHT. Some evidence suggests that topical testosterone produces less systemic DHT elevation than injectable forms because more of the conversion to DHT happens locally in the skin rather than in the liver, but the clinical significance of that difference for hair outcomes is not well established.

Pellets do have a unique profile in one respect: because they deliver testosterone continuously for months, you cannot “take a break” if you notice early signs of thinning. With a gel or patch, you can stop immediately and see levels drop within days. With pellets, you ride out the remaining duration. This irreversibility within a cycle is worth factoring into your decision, especially if you already know you carry risk factors for androgenetic alopecia. Starting at a conservative dose and monitoring your response before committing to higher doses is a reasonable strategy that many hormone therapy clinicians recommend.

Pellet therapy also raises estradiol alongside testosterone, as pharmacokinetic studies have confirmed.¹ Given the protective role estrogen appears to play in the hair growth cycle, this parallel rise may partly offset the androgenic pressure on scalp follicles, which could help explain why hair loss rates in clinical studies of pellet therapy have been lower than many patients expect going in.